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Project Specific Discussions => Filters/Equalizers => Topic started by: onlymeeee on June 02, 2015, 08:53:20 PM

Title: 500 series Sontec / GML type eq
Post by: onlymeeee on June 02, 2015, 08:53:20 PM
Hi!
In my never ending hunt for the 'best' recording/mixing chain..  a great mixbus EQ had always escaped me..  I'm a GML 8200 lover and the amount of times that it's saved a mix of mine is countless!  It really should get the mix fee...!
 
So I made it my goal to attempt to recreate the magic in 500 series format..   This lead me of course to the original Sontec circuit..  (the orginal as opposed to the Igor modified one)

Some pictures!

(http://s22.postimg.org/ghip4iki9/250eq_front.jpg)
(http://s17.postimg.org/e9c3ogr2n/insides_250_EQ.jpg)
I've seen inside a couple of Sontecs over the years and knew there were polystyrene caps in there so I used them where appropriate for the value.. 
I ended up socketing every cap in the unit (apart from power decoupling) in case my ears weren't impressed!

(http://s18.postimg.org/bpdnyt2m1/prototype_250_EQ.jpg)
prototype with socketed caps ^ 

Now, everyone says the sound of the Sontec is the opamps..  so I put the two DOA footprints in case I needed to come up with a DOA to satisfy my ears! 
For my initial tests, I experimented with ICs..   I knew I wanted FET input, fast, low input current..  so I chose 5 that satisfied this and had "good reviews" online for my initial tests.. 
The OPA134, OPA827, OPA1641, ADA4627 & AD8512.

As it turns out..  I couldn't be happier with the sound!  I've been amazed at how much I can push the top end without it sounding harsh..  It's forced me to check the EQ curves several times as my brain refuses to believe it..   
To my ears it's smoother than a GML and cleaner than a Sontec..  It's now been permanently on my mix bus for a month & it's never leaving! 

Title: Re: 500 series Sontec / GML type eq
Post by: bruno2000 on June 02, 2015, 09:15:20 PM
That is absolutely stunning!  Where did you get the pots?
Best,
Bruno2000
Title: Re: 500 series Sontec / GML type eq
Post by: weiss on June 02, 2015, 10:34:09 PM
Wow, these frequency selection pots look interesting!
Title: Re: 500 series Sontec / GML type eq
Post by: Winetree on June 02, 2015, 10:49:33 PM
Are you teasing us? Or is this going to be your newest Kit?
Title: Re: 500 series Sontec / GML type eq
Post by: frazzman on June 02, 2015, 11:27:30 PM
Wow... that is seriously impressive. You've succeeded in teasing us... well done.
Title: Re: 500 series Sontec / GML type eq
Post by: leadbreath on June 02, 2015, 11:56:01 PM
i...want...
Title: Re: 500 series Sontec / GML type eq
Post by: Rocinante on June 03, 2015, 03:19:47 AM
Well done. Really. Please tell us this is going to be available soon.
Title: Re: 500 series Sontec / GML type eq
Post by: KDE on June 03, 2015, 03:55:49 AM
MUST HAVE NOW!
Title: Re: 500 series Sontec / GML type eq
Post by: pvision on June 03, 2015, 06:11:38 AM
Wow

Great panel layout - it looks like it will work really well

Nick Froome
Title: Re: 500 series Sontec / GML type eq
Post by: Electrobumps on June 03, 2015, 06:59:59 AM
I've heard this baby and it can only be described as the most musical EQ you will ever hear.   Its like a GML but better.  I've never dialled in top end that sounds like this!

Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on June 03, 2015, 09:22:24 AM
Thanks everyone!  And especially Electrobumps who let me use his vastly experienced 'producer ears' as a test subject!

I don't currently have any spare boards..  although as there seems to be interest, there's no problems ordering a batch of kits..  and I will do so asap..   

The pots are by UK company Omeg who make fantastic handmade pots..  A thing that I like about them is the strong feel.. it means that they can't be moved just by a little flick which sometimes happens with concentric pots..  Often I'm moving the frequency on a GML and the Q gets turned by accident..  This doesn't happen with the Omegs..  They're very firm when turning..  also means that at the extremities of the frequency ranges, you can really dial it in accurately..

The centretapped pots are Alps..   As the centre of rotation is tapped and grounded in this circuit, it this lends itself nicely to a centre detent pot which these are.. meaning essentially a bypass for each frequency at the centre detent.

One thing I changed from the initial prototype is the shelf switch..  As you know, the shelf switch on a GML is on the Q pot..  and more specifically the widest Q..   So it's seamless operation...  however on the prototype, I had a separate switch which meant I had freedom to change the Q of the shelf too..  This was great, however, it felt a little wrong when on the sharpest Q setting..   As it wasn't really a shelf as such at the highest Q on shelf setting..
Of course I could have just always made sure to widen the Q but it just 'felt' wrong.
So what I did was:  when the shelf switch is pressed..  it also switches in a resistor to limit the sharpness of the Q possible on the shelf setting only..   this meant that it was always a shelf no matter what the Q..  and you still have the flexibility of the Q on the shelf. 
This wasn't a problem on the bottom shelf.

Any other questions just ask! 

Oh.. the other thing that I wanted to do was eliminate all wiring..  so the only thing that's needed is that one 10way ribbon cable!
Title: Re: 500 series Sontec / GML type eq
Post by: Rocinante on June 03, 2015, 10:25:28 AM
Definitely interested,  down for two. Are the Omegs available from AML? How about the Alps?
The ribbon cable is a beautiful thing.
I have been waiting for this.
Title: Re: 500 series Sontec / GML type eq
Post by: Axelerator on June 03, 2015, 01:46:21 PM
amazing !
i still have to build the full blown igor version, bought the pcb´s right before everything went way down..
but sure i would be interrested in two kits if this comes true as i have unfilled slots in my 511 rack!
i hate unfilled slots  8)
axel
Title: Re: 500 series Sontec / GML type eq
Post by: adastra on June 03, 2015, 02:47:32 PM
I'm in for a pair, great work!
Title: Re: 500 series Sontec / GML type eq
Post by: weiss on June 03, 2015, 02:57:34 PM
interested in a pair!
Title: Re: 500 series Sontec / GML type eq
Post by: KDE on June 03, 2015, 03:23:44 PM
Pair please  ;D
Title: Re: 500 series Sontec / GML type eq
Post by: petermontg on June 03, 2015, 03:58:52 PM
In for two pair 8)
Title: Re: 500 series Sontec / GML type eq
Post by: Ericbazaar on June 03, 2015, 04:22:24 PM
 :o i'm in for two ;)
Title: Re: 500 series Sontec / GML type eq
Post by: shot on June 03, 2015, 05:57:11 PM
Wow! Impressive!

Needles to say - I'm interested in a pair too!

Since I'm not into 500 format, I'd rack it in a regular 19" case and have some space left inside maybe to fit Wayne Kirkwood's MS board! Hehe!

Except for pots maybe, are there any hard to get components?
Title: Re: 500 series Sontec / GML type eq
Post by: Studio Mollan on June 03, 2015, 06:42:12 PM
I'm in for at least a pair. Are they mono or stereo units?
/
Emil
Title: Re: 500 series Sontec / GML type eq
Post by: Winetree on June 03, 2015, 07:16:08 PM
Seeing this turned into a feeler thread.
I'm in for a pair.
Title: Re: 500 series Sontec / GML type eq
Post by: fizmo on June 03, 2015, 08:20:10 PM
I'm in for pair.
Title: Re: 500 series Sontec / GML type eq
Post by: fragletrollet on June 03, 2015, 09:25:12 PM
Also in for a pair  8)
Title: Re: 500 series Sontec / GML type eq
Post by: Pip on June 03, 2015, 09:52:21 PM
I'll join the I want a pair army as well.
Title: Re: 500 series Sontec / GML type eq
Post by: Biasrocks on June 03, 2015, 10:35:19 PM
Put me down for a pair.

I have an Igor Sontec here that I've been using on the master bus for a number of years. I definitely worked on improving on his design by using premium opamps and increased p/s bypassing. Made a huge difference.

Curious what improvements you've realized.

Mark
Title: Re: 500 series Sontec / GML type eq
Post by: okgb on June 04, 2015, 12:31:41 AM
I'm in!
Title: Re: 500 series Sontec / GML type eq
Post by: Bassniac on June 04, 2015, 06:21:29 AM
I am in for a pair...

Cheers
Title: Re: 500 series Sontec / GML type eq
Post by: mrcase on June 04, 2015, 07:13:19 AM
Interested in a pair.
Title: Re: 500 series Sontec / GML type eq
Post by: pvision on June 04, 2015, 07:34:17 AM
The only thing I'd change is the eq in/out switch mid-panel. It breaks up the nice symmetry of the panel and (I would think) is an obstacle to using it quickly

Nick Froome
Title: Re: 500 series Sontec / GML type eq
Post by: tskguy on June 04, 2015, 08:35:23 AM
I am in for a pair as well!!!!! ;D ;D ;D ;D ;D
Title: Re: 500 series Sontec / GML type eq
Post by: bruno2000 on June 04, 2015, 09:26:33 AM
If you are going to make this available, I would like a pair as well.
Thanks!
Best,
Bruno2000
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on June 04, 2015, 11:05:39 AM
@Biasrocks That's interesting yes..  there's quite a few changes on that version compared with the original schematic..   It differs quite a bit..  I've stuck to the original schematic...  http://www.gyraf.dk/schematics/Sontec_MEP250a.GIF

In regards to bypassing, I've done ceramics (100nF) on every IC power pin to ground.  And also an extra 2 larger low impedance electrolytic/tantalum on +V & -V to ground on each filter / and the 2 main amp opamps.  (47uF) 
The layout can also have a big impact on bypassing needs too.  As this is very compact, I was able to keep power rail impedances very low throughout..
On the rails going to the filter section, there's also space for a bit of extra filtering (resistor/inductor/ferrite etc) if it needed some extra filtering/isolation, however I've not found it needs anything so jumpered them.. the footprints are still there though.. 

How does that compare with your findings?

Opamp wise, I've stuck with NE5534 & TL071 for the filters, as I know for certain these were in the original..    However I'm sure curiosity will get the better of me at some point and I'll try some more modern ICs here..

Regarding the two main amp opamps,  I tried to keep as close to the written specs as possible but with an IC, and I think I chose ones too similar, as they all nulled around the same level as a second pass with the same IC did..   They were OPA134, O1641, OP827. 
Which did you try?
 

@pvision  I think the flash hit the switch and made it seem more prominent than it is real life..  The bushing is recessed behind and doesn't reach the front of the panel.. and the metal shaft only extends around 5mm..  so it quite tight to the panel to not get in the way..  It being diy of course..  experimentation is the spice of life!  Nothing to stop you say using the hole as an LED and wiring the switch somewhere else...  ;)


Regarding kits!  Ok.. well it seems there's quite a lot of interest..  So I'll order a batch of PCBs & metal..   and I think what could be best is if I stocked the knobs too..  and the centretapped pots..  So that you would only have to purchase one order from Mouser, and one order from Omeg,  (they have a minimum order of 10 which is perfect for a pair)  Also I have a part number with them, so it's easy to order. 

I forgot to mention power.. !    Current draw is about 50mA..   and it can either use solely 16V rails..  or 16V rails for ICs and 24V rails for DOAs...  or if you use a zener to drop the voltage a little, it can use solely the 24V rails. 
Title: Re: 500 series Sontec / GML type eq
Post by: petermontg on June 04, 2015, 11:20:19 AM
Awesome would it be possible to get without the metal. I would like to rack mine in a 2U case.

That would put some of the front panel details on their side if I did.
Or maybe for those wanting to build a racked stereo pair you could order some metal with the details set for that option.

Just a throught.
Title: Re: 500 series Sontec / GML type eq
Post by: jasonallenh on June 04, 2015, 03:49:34 PM
Two please  ;D
Title: Re: 500 series Sontec / GML type eq
Post by: pvision on June 04, 2015, 04:20:39 PM
Awesome would it be possible to get without the metal. I would like to rack mine in a 2U case

I'd be in for a pair I could build into a 2U case

Nick Froome
Title: Re: 500 series Sontec / GML type eq
Post by: qmp audio on June 04, 2015, 04:28:52 PM
Very nice.  I'm in for a pair too if you're making them available!
Title: Re: 500 series Sontec / GML type eq
Post by: Biasrocks on June 04, 2015, 05:26:30 PM
Ok,  back in the memory banks...

I added extra large capacitance on the filter board, I think 100uf was specified I think I went with 470uf on the rails. I'm sure I added extra decoupling on the I/O boards as well.

I also upgraded all the filter opamps to LME49860 which I beleive Harpo recommended, instead of the OPA2604's which I found sluggish and smeared in comparison. Iirc there are ceramic p/s bypasses on each opamps in Igor's design.

I'm pretty sure I used Tantalum's for all audio paths as I see you have.

I used a Forsell 992 discreet (now discontinued) on the inputs and a John Hardy 990 on the outputs, huge difference there too.

With those changes, it went from screechy and shrill to a most pleasant piece of kit.

Mark

@Biasrocks That's interesting yes..  there's quite a few changes on that version compared with the original schematic..   It differs quite a bit..  I've stuck to the original schematic...  http://www.gyraf.dk/schematics/Sontec_MEP250a.GIF

In regards to bypassing, I've done ceramics (100nF) on every IC power pin to ground.  And also an extra 2 larger low impedance electrolytic/tantalum on +V & -V to ground on each filter / and the 2 main amp opamps.  (47uF) 
The layout can also have a big impact on bypassing needs too.  As this is very compact, I was able to keep power rail impedances very low throughout..
On the rails going to the filter section, there's also space for a bit of extra filtering (resistor/inductor/ferrite etc) if it needed some extra filtering/isolation, however I've not found it needs anything so jumpered them.. the footprints are still there though.. 

How does that compare with your findings?

Opamp wise, I've stuck with NE5534 & TL071 for the filters, as I know for certain these were in the original..    However I'm sure curiosity will get the better of me at some point and I'll try some more modern ICs here..

Regarding the two main amp opamps,  I tried to keep as close to the written specs as possible but with an IC, and I think I chose ones too similar, as they all nulled around the same level as a second pass with the same IC did..   They were OPA134, O1641, OP827. 
Which did you try?
Title: Re: 500 series Sontec / GML type eq
Post by: dmp on June 05, 2015, 10:33:16 AM
Interested in a pair.
Title: Re: 500 series Sontec / GML type eq
Post by: synchroman on June 05, 2015, 01:44:11 PM
I would be into 4
Title: Re: 500 series Sontec / GML type eq
Post by: buckethead on June 05, 2015, 04:06:03 PM
Amazing, interested in a pair  :)

Best regards,
Mathias
Title: Re: 500 series Sontec / GML type eq
Post by: duantro on June 05, 2015, 10:05:10 PM
Wow! I'm interested in a pair, depending on price.
Title: Re: 500 series Sontec / GML type eq
Post by: jordan s on June 06, 2015, 03:56:10 AM
Put me down for a pair.
Title: Re: 500 series Sontec / GML type eq
Post by: jasonallenh on June 06, 2015, 10:51:16 AM
onlymeeee is clearly too busy playing with his shiny new toys to respond to us  8)
Title: Re: 500 series Sontec / GML type eq
Post by: rmaier on June 06, 2015, 11:05:12 AM
Very cool! Interested in a pair, depending on price, no metal (they'll go into a 2u box).

At the risk of getting ahead of things, would it difficult to implement the mod  for switching the range of the cut/boost pots?

Ralph
Title: Re: 500 series Sontec / GML type eq
Post by: SKJGProject on June 06, 2015, 01:24:49 PM
in for 6!!!
Title: Re: 500 series Sontec / GML type eq
Post by: pvision on June 06, 2015, 04:36:33 PM
I think it's fair to say that onlymeeee has started something here!

It looks like a lovely piece of work

Nick Froome
Title: Re: 500 series Sontec / GML type eq
Post by: DonnieDarko on June 07, 2015, 08:11:37 AM
I definitely in for 2.
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on June 07, 2015, 08:58:38 AM
Hey everyone!   Ok so I've ordered everything including some extra PCB/L-brackets for those who wish to rack them in a 2u rack with their own front panels etc..    The L-bracket may still be useful in this configuration to hide the nuts etc.. 

So around 3 weeks I'd imagine, I'll have everything ready  :) 

In regards, to modding the gain..  very easily done..  I experimented myself too..  just a resistor change..   
Title: Re: 500 series Sontec / GML type eq
Post by: mitsos on June 07, 2015, 11:52:32 AM
Hi, maybe I missed it, but is there a price yet for the PCBs and/or kits?

thanks
Title: Re: 500 series Sontec / GML type eq
Post by: mutterd on June 07, 2015, 02:09:48 PM
Wow! good work David!

Im interested too!
T.

Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on June 07, 2015, 02:18:22 PM
Hi, maybe I missed it, but is there a price yet for the PCBs and/or kits?

thanks

Not 100% sure yet..  the metal/PCBs/hardware etc will be around the same price as my other kits.. but I still have to work out the pricing on top for knobs and pots..  This week I'll work it all out and make the manual/webpage and everything...
Title: Re: 500 series Sontec / GML type eq
Post by: Meyer on June 07, 2015, 03:00:53 PM
Cool! I'm in for 2!
Title: Re: 500 series Sontec / GML type eq
Post by: pvision on June 07, 2015, 07:07:02 PM
I like those GML-style knobs. If you use the Elma versions they add a lot to the appearance of the unit. They are quite expensive but I think the additional cost is worthwhile. If you can do a group buy on them it might be possible to get the prices a bit more sensible

Elma will do quantity discounts but the minimum order is relatively high and it is per-item. If you approach them with a decent-sized order they should be amenable to a decent-sized discount and maybe they'll be more flexible re minimum quantities

Happy to help with this if required

Nick Froome
Title: Re: 500 series Sontec / GML type eq
Post by: MHanson on June 08, 2015, 02:44:37 AM
Totally interested ... probably 2 ... maybe 4 ...

waiting on final price.

Michael
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on June 08, 2015, 10:03:00 AM
I like those GML-style knobs. If you use the Elma versions they add a lot to the appearance of the unit. They are quite expensive but I think the additional cost is worthwhile. If you can do a group buy on them it might be possible to get the prices a bit more sensible

Elma will do quantity discounts but the minimum order is relatively high and it is per-item. If you approach them with a decent-sized order they should be amenable to a decent-sized discount and maybe they'll be more flexible re minimum quantities

Happy to help with this if required

Nick Froome

The knobs I've used and ordered are OKW ones, which have a 4mm opening for the Omeg pot shafts to fit through.   They look very similar to the Elmas, but Elma don't have any that would work for the Omeg dual concentric pots..  Also they're cheaper too which is an added bonus!

 
Title: Re: 500 series Sontec / GML type eq
Post by: DonnieDarko on June 08, 2015, 01:01:45 PM
I think the Knobs you used look very good.
Title: Re: 500 series Sontec / GML type eq
Post by: maq3396 on June 08, 2015, 11:26:54 PM
Great work!

Likely in for 2

Cheers
Mac
Title: Re: 500 series Sontec / GML type eq
Post by: flaheu on June 09, 2015, 02:05:04 PM
I'm in for 2 as well !!!!
Title: Re: 500 series Sontec / GML type eq
Post by: Dr Gris on June 09, 2015, 04:44:47 PM
Darn...got's to have me two of these...
Title: Re: 500 series Sontec / GML type eq
Post by: wowi on June 10, 2015, 10:00:36 AM
Great work ! I am in for two.

Wolfgang
Title: Re: 500 series Sontec / GML type eq
Post by: jasonallenh on June 10, 2015, 03:10:44 PM
I like those GML-style knobs. If you use the Elma versions they add a lot to the appearance of the unit. They are quite expensive but I think the additional cost is worthwhile. If you can do a group buy on them it might be possible to get the prices a bit more sensible

Elma will do quantity discounts but the minimum order is relatively high and it is per-item. If you approach them with a decent-sized order they should be amenable to a decent-sized discount and maybe they'll be more flexible re minimum quantities

Happy to help with this if required

Nick Froome

I'm currently trying to work this out for some 4mm/ 1/8" collet knobs (see my black market thread post), and they are telling me there is also a $100 minimum order. I could certainly use/offer some help with this.
Title: Re: 500 series Sontec / GML type eq
Post by: goetzmd on June 13, 2015, 12:07:56 PM
Put me down for a pair please. It would be great if your kit comes with the pots an knobs!  :)
Title: Re: 500 series Sontec / GML type eq
Post by: john12ax7 on June 13, 2015, 10:11:49 PM
Very nice work
Title: Re: 500 series Sontec / GML type eq
Post by: j.frad on June 14, 2015, 06:38:20 PM
Well i might regret it forever if I don't do this so please add me to the list for a pair :)
Title: Re: 500 series Sontec / GML type eq
Post by: craig on June 14, 2015, 08:01:42 PM
Add me to the list for 4

Craig
Title: Re: 500 series Sontec / GML type eq
Post by: kosi on June 15, 2015, 07:34:53 AM
Also in for a pair !
Title: Re: 500 series Sontec / GML type eq
Post by: adrian on June 15, 2015, 07:17:54 PM
I'm in for 2!  ;)
Title: Re: 500 series Sontec / GML type eq
Post by: leadbreath on June 16, 2015, 04:37:45 PM
me two !! me two!! (pardon the pun)
Title: Re: 500 series Sontec / GML type eq
Post by: pidah on June 17, 2015, 05:08:03 PM
I would really like a pair too. It would be amazing, if you have the time and energy to make it happen. Thanx in advance.
Title: Re: 500 series Sontec / GML type eq
Post by: zenmastering on June 17, 2015, 05:13:15 PM
I'll buy a pair...no metal work needed as I'll be rack-mounting them.

Thanks for your efforts!

Graemme
Title: Re: 500 series Sontec / GML type eq
Post by: mylesgm on June 18, 2015, 12:32:05 AM
I'll take at least a pair and possibly 2x pairs for the 500 rack.  Top work!
Title: Re: 500 series Sontec / GML type eq
Post by: mitsos on June 26, 2015, 04:58:29 PM
Hi, I'm probably in for 2-4 if possible to do PCBs only, I want to rack mount them using separate pots instead of the dual concentrics.  thanks!
Title: Re: 500 series Sontec / GML type eq
Post by: pachi2007 on June 27, 2015, 02:53:35 AM
2 here. full kit 500
Awesome!!
Title: Re: 500 series Sontec / GML type eq
Post by: jpuhhuh on June 30, 2015, 09:23:46 PM
I wouldn't want to miss this.
2 please
jp
Title: Re: 500 series Sontec / GML type eq
Post by: monkeyxx on June 30, 2015, 10:25:18 PM
I'm certainly interested!
Title: Re: 500 series Sontec / GML type eq
Post by: kcstudiohk on July 01, 2015, 05:43:18 AM
count me a pair please !
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on July 02, 2015, 03:42:45 AM
Is there a price for just the boards??? I'd rack these, but I'm for sure in for a pair. Awesome work, and thank God someone took the GML/Sontech DIY by the reigns again.

Do you know when you might be able to start selling the PCB's?

Thanks David! Your designs are always so true to the originals, I'm giddy!
Title: Re: 500 series Sontec / GML type eq
Post by: Peterson Goodwyn on July 02, 2015, 09:41:09 AM
Gorgeous work! Love the symmetry of the PCB layout.
Title: Re: 500 series Sontec / GML type eq
Post by: CBR on July 02, 2015, 12:48:13 PM
I'm up for a pair. Full 500. Maybe also an extra pair for rack mounting.
Title: Re: 500 series Sontec / GML type eq
Post by: Trench Recordings on July 03, 2015, 12:22:23 PM
I'm in for a pair. Full kits would be great  :)
Title: Re: 500 series Sontec / GML type eq
Post by: jrasia on July 03, 2015, 10:39:32 PM
two here please! :D
Title: Re: 500 series Sontec / GML type eq
Post by: audiomsg on July 07, 2015, 07:00:03 AM
Add my name to the list for a pair!
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on July 07, 2015, 09:51:44 AM
Thanks for the kind words everyone! 
The PCBs should be with me next week.  I have already have all the other metalwork.. knobs etc..  So not long now! 

Finalising the manual as we speak..   
Title: Re: 500 series Sontec / GML type eq
Post by: petermontg on July 07, 2015, 04:43:04 PM
Thanks for the kind words everyone! 
The PCBs should be with me next week.  I have already have all the other metalwork.. knobs etc..  So not long now! 

Finalising the manual as we speak..

That is great news. Thanks for taking the time to do this project. I guess alot of us missed the last project.

Looking forward to getting stuck into this EQ.

Best
Peter
Title: Re: 500 series Sontec / GML type eq
Post by: sharpeleven on July 07, 2015, 05:48:17 PM
pls count me in for two! Tx!!  8)
Title: Re: 500 series Sontec / GML type eq
Post by: Marc Duchesne on July 08, 2015, 08:31:40 PM
In for a pair,
Thanks for this great work...
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on July 08, 2015, 11:52:43 PM
Hey Dave,

Any idea right now on what the PCB's will cost? I will need 2 sets as I'm building one for me, and another for a friend and we're just going to rack mount this. The knobs still would be nice to get as well. I'm not sure how you're going to offer this, if it's going to end up being a kit on your site, or if you might just break everything down and let folks do a-la-carte. I hope the latter! I can't wait to start this baby and get it on my buss.
Title: Re: 500 series Sontec / GML type eq
Post by: tonycamp on July 13, 2015, 03:45:43 PM
Holy cow! Can't wait to read this thread tonight!  I'm on my phone right now  from work,  whatever's going on I am 100% in !!!
Title: Re: 500 series Sontec / GML type eq
Post by: Unit7 on July 13, 2015, 04:08:35 PM
Holy cow! Can't wait to read this thread tonight!  I'm on my phone right now  from work,  whatever's going on I am 100% in !!!
Ha! M8, not much to read.. 2-3 posts with info and the rest just drooling, wanting and needing :D
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on July 13, 2015, 09:29:42 PM
Not 100% on costs yet, as I prefer to wait until I have everything in and know for sure that I haven't forgotten any extra costs or anything.. but as a rough estimate..  usual kit price for metal & PCBs..  about half that price for just PCBs.. 

Yes I can do a-la-carte for those that just want certain things..  as well as the standard kits with PCBs, metalwork, knobs & coloured caps,  hardware, centre-tapped pots, polystyrene caps..   

No sign of the DHL email yet to say the PCBs are in the van...  Will keep you informed when I get it!
Title: Re: 500 series Sontec / GML type eq
Post by: tonycamp on July 14, 2015, 12:33:24 AM
ok, read through it, i'm so excited i can hardly stand it! 2 for me, all the fixins PLEASE!
Title: Re: 500 series Sontec / GML type eq
Post by: Rocinante on July 14, 2015, 11:00:25 PM
Its awesome you're willing to do this a la carte.
Mad respect.
Title: Re: 500 series Sontec / GML type eq
Post by: nielsk on July 15, 2015, 08:18:46 AM
Up for a few, will this be a group buy or will you be offering this on the WM?
Title: Re: 500 series Sontec / GML type eq
Post by: Wiz on July 15, 2015, 08:35:14 PM
I am interested in two of these.. would be cool if they were rack mount.

cheers

Wiz
Title: Re: 500 series Sontec / GML type eq
Post by: desol on July 19, 2015, 01:00:08 PM
Interesting project. Although, had a listen to the samples and thought the dry sound was bigger and better sounding(as a sound on it's own). The affected signal was brighter.
Title: Re: 500 series Sontec / GML type eq
Post by: kml23956 on July 19, 2015, 07:24:36 PM
How much are they? I have looked through the thread and don't see a price.  8)
Title: Re: 500 series Sontec / GML type eq
Post by: Unit7 on July 19, 2015, 08:03:19 PM
How much are they? I have looked through the thread and don't see a price.  8)
No set price yet. Look 6 posts up for a rough estimate.
Title: Re: 500 series Sontec / GML type eq
Post by: j.frad on July 20, 2015, 08:23:42 AM
Interesting project. Although, had a listen to the samples and thought the dry sound was bigger and better sounding(as a sound on it's own). The affected signal was brighter.

I must have missed the link, which samples are you talking about?
Title: Re: 500 series Sontec / GML type eq
Post by: Category 5 on July 20, 2015, 09:00:24 PM
This looks like a stellar project.   Tack my name on for a pair of these when you get the deets ironed out.  My gut tells me you'll be needing to do multiple runs of this one.  ;)
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on July 21, 2015, 10:41:49 AM
Interesting project. Although, had a listen to the samples and thought the dry sound was bigger and better sounding(as a sound on it's own). The affected signal was brighter.

Definitely the right thread you're thinking of?   I haven't uploaded any samples   :-\
Title: Re: 500 series Sontec / GML type eq
Post by: kml23956 on July 21, 2015, 09:02:27 PM
Put me down for a pair. Which option will depend on the cost.
Title: Re: 500 series Sontec / GML type eq
Post by: jackinthebox on July 27, 2015, 05:43:45 AM
I would love a pair of these!

Put me down for two please.

Jack
Title: Re: 500 series Sontec / GML type eq
Post by: Indecline on July 27, 2015, 02:51:35 PM
Wow, that is amazing work!! Definitely interested in a pair
Title: Re: 500 series Sontec / GML type eq
Post by: mrscary on July 29, 2015, 03:13:42 PM
Wow...definitely interested in a pair
Title: Re: 500 series Sontec / GML type eq
Post by: jensenmann on July 29, 2015, 04:03:32 PM
Wow, great project. Congrats, onlymeeee

Since I´m servicing and keeping a bunch of Sontecs in mastering rooms in my area alive I have an opinion on these. While repairing  250s we did a bit of experimentation with caps an chips. There´s a lot of blahblah about swapping chips which in this case is not recommended. We found that sticking with TL071 and 5534 is the way to go. Having said that I had a 250 on the bench which was stuffed with a few LF356 instead of TL071 and  the owner did not notice a difference between channels.
He did complain, though, when I replaced the tantalum caps in the filter section with electrolytics. He said that it sounded cleaner than he wanted it to be. So stick with tants in the original spots if you want it to sound like a Sontec 250.
The original in/out circuit is DC coupled. I´d go for a precision chip in these spots. I found the OPA (2)132 series in my measurements to have at least double the DC precision of the OPA(2)134 series, which means less DC offset, but without any difference in sound. I tried hard to find a sonic difference in many circuits but I did not. Double the price, though. Anyway, just to throw another chip into the game.
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on July 30, 2015, 02:29:46 AM
I'll take a pair of PCBs.
Title: Re: 500 series Sontec / GML type eq
Post by: nielsk on August 01, 2015, 11:13:35 AM
Interesting about the TL0 chips, that has been my experience in many EQs. Seems in an EQ a nice slow chip sounds so much better than a fast chip.
Of course GML used their own op amp, but I have no idea how fast that is...
Is the schematic for the original that indicates component types posted here somewhere?
Title: Re: 500 series Sontec / GML type eq
Post by: petermontg on August 01, 2015, 11:17:43 AM
Have a search for Igors or fabios old boards should be schematic around somewhere.
Title: Re: 500 series Sontec / GML type eq
Post by: zenmastering on August 01, 2015, 02:51:38 PM
Here's the original schematic, courtesy of Gyraf:

http://gyraf.dk/schematics/Sontec_MEP250a.GIF

 
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 02, 2015, 06:01:34 PM
@jensenmann - Awesome. Thanks for the info.  So it seems like your findings echo my own..  which is always good! 
Yes, I believe the OPA132 is made identically and labelled either 134 or 132 depending on how they test in regard to DC offset..   Lots of options in regards to great sounding fast FET input opamps these days!


PS. The PCBs arrived! But the most innocuous of parts, the lowly screws, got themselves into trouble at customs having come from US.  However I've received a card saying they'll be with me on Tuesday!  So everything will be ready on Tuesday finally!

Title: Re: 500 series Sontec / GML type eq
Post by: tskguy on August 02, 2015, 06:18:06 PM
PayPal at the ready
Title: Re: 500 series Sontec / GML type eq
Post by: kosi on August 03, 2015, 04:16:48 AM
Do we have a price yet ?
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 04, 2015, 05:34:59 AM
The screws arrived, so all is here finally! 

Yes no worries, now everything's in my hand I can confirm price on everything...   

It's  £165 for a raw kit with all the hard to get parts...
ie. PCBs, front panel, L-bracket, hardware, centre tap pots, polystyrene caps, knobs & coloured caps.. 

Then for anyone that wants something else, just PCBs etc, just email..  as it's easier than doing different paypal buttons for each combination of items.. 

Pricewise for that.. it's : 
£30 off for knobs & coloured caps.. so, £139 without knobs. 
£60 off for metal.. so £79 without knobs or metal.
£5 off for polystyrene caps
£10 for hardware
£10 for centre tap pots

Full details at:  www.thedonclassics.com/250eq_diy.html


Any questions or broken links etc let me know..  you may have to refresh browsers etc to see the new website addition... 
Title: Re: 500 series Sontec / GML type eq
Post by: guilds100 on August 04, 2015, 09:10:15 AM
I noticed the first item in the mouser cart, 12v relay, is out of stock. Is there anything special about that relay, or will any relay that meets the specs work?
Title: Re: 500 series Sontec / GML type eq
Post by: kosi on August 04, 2015, 09:47:24 AM
Have a look in the General BOM, there's an alternative under column K
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 04, 2015, 10:31:10 AM
Yep, as things go on backorder I'll add alternatives to the general BOM.. 

The Omron alternative works great...
653-G6K-2P-DC12

Title: Re: 500 series Sontec / GML type eq
Post by: guilds100 on August 04, 2015, 11:20:09 AM
Can you tell me what the row to row spacing is on the dual concentric pots? Ive contacted the US distributor for these items and they say there are 2 choices, 7.5mm or 10mm.
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 04, 2015, 11:55:39 AM
Can you tell me what the row to row spacing is on the dual concentric pots? Ive contacted the US distributor for these items and they say there are 2 choices, 7.5mm or 10mm.

I've uploaded the footprint with a 2mm grid...   So between rows there's 10mm...

(http://www.thedonclassics.com/images/250eq/dual%20concentric%20footprint.png)

I've told Omeg to expect diyers to order these so they gave me a part number to always quote, so they should know the exact way to make it.. Perhaps the distributor is just being extra thorough
   
Title: Re: 500 series Sontec / GML type eq
Post by: bruno2000 on August 04, 2015, 02:22:42 PM
Can you tell me what the row to row spacing is on the dual concentric pots? Ive contacted the US distributor for these items and they say there are 2 choices, 7.5mm or 10mm.

Great!  Will you let us know the results of your work?
Thanks!
Best,
Bruno2000
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on August 04, 2015, 03:23:41 PM
I'm currently working on this as well with the US dist.  Simple part # prompted some questions back so they may not be familiar with these. If I find something out before the other fella I will post.

Cheers.
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on August 04, 2015, 03:29:57 PM
I'm currently working on this as well with the US dist.  Simple part # prompted some questions back so they may not be familiar with these. If I find something out before the other fella I will post.

Cheers.

This is the response I just got.... is this what we should expect to hear or is something not right?

"This should do it.  I will let you know if any confusion remains.
Please keep in mind that these are not a stock item.  They are built to order and we can expect about 8 weeks for the entire process."
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 04, 2015, 05:19:14 PM
I'm currently working on this as well with the US dist.  Simple part # prompted some questions back so they may not be familiar with these. If I find something out before the other fella I will post.

Cheers.

This is the response I just got.... is this what we should expect to hear or is something not right?

"This should do it.  I will let you know if any confusion remains.
Please keep in mind that these are not a stock item.  They are built to order and we can expect about 8 weeks for the entire process."

I was told 4 weeks lead time on two separate occasions and each time they arrived much faster.  Having a look at an older email..   
I ordered 10 pots on 4th Feb and they were in the post to me on the 11th Feb.   A second order to a friend was around the same time frame I believe.     

So at least in these two cases it was much faster..   as they're hand made custom pots, the lead time will probably vary depending on how many orders they have on at the one time.. 
Certainly worth it though..  handmade British pots just gives a diy project and its user that warm fuzzy feeling inside...  ;)   
Title: Re: 500 series Sontec / GML type eq
Post by: guilds100 on August 04, 2015, 05:50:33 PM
I'm currently working on this as well with the US dist.  Simple part # prompted some questions back so they may not be familiar with these. If I find something out before the other fella I will post.

Cheers.

This is the response I just got.... is this what we should expect to hear or is something not right?

"This should do it.  I will let you know if any confusion remains.
Please keep in mind that these are not a stock item.  They are built to order and we can expect about 8 weeks for the entire process."


I haven't heard back from them yet. They'll probably tell me the same thing. Did they quote a price?
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on August 04, 2015, 06:10:10 PM
Not a price, since they are custom anything under 100 pieces has to be quoted by Omeg. What if we pooled and did a group buy with the US distrib? Maybe get a break too? That would be 10 stereo units. Not sure how many in the US have bought, but I sent an email asking about it. Could bring the time down as well.
Title: Re: 500 series Sontec / GML type eq
Post by: qmp audio on August 04, 2015, 06:19:40 PM
What if we pooled and did a group buy with the US distrib? Maybe get a break too?

Id could be in on this.
Title: Re: 500 series Sontec / GML type eq
Post by: jpuhhuh on August 04, 2015, 06:23:53 PM
I would as well. Be into a U.S. Group buy if pricing is right.
Title: Re: 500 series Sontec / GML type eq
Post by: Winetree on August 04, 2015, 07:00:31 PM
Just ordered 2 kits, so I'd be in for 10 pots of a group buy.
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on August 04, 2015, 08:25:57 PM
Ok, well he's supposed to let me know tomorrow on what the pricing would be, told him to ask for a break on 100-250 units.
Title: Re: 500 series Sontec / GML type eq
Post by: IndietownRecording on August 04, 2015, 09:05:57 PM
Just bought a pair. I'm in on the group buy for the pots.
Title: Re: 500 series Sontec / GML type eq
Post by: nielsk on August 04, 2015, 11:30:51 PM
I am interested in the US group buy for the pots, can someone clarify if this is for pots not included in the kit ( and the kit should be ordered WITH the center-tap pots)?
I would much rather get a higher quality unit, Omeg is not top quality, but most likely nothing else would fit ...
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on August 05, 2015, 02:57:19 AM
I am interested in the US group buy for the pots, can someone clarify if this is for pots not included in the kit ( and the kit should be ordered WITH the center-tap pots)?
I would much rather get a higher quality unit, Omeg is not top quality, but most likely nothing else would fit ...

If I can make a group buy happen I am going to try to get them 1.) Cheaper and 2.) Faster.

David designed this EQ with those pots in mind I'm sure, and there's not a whole lot of folks I place absolute trust in regarding 100% faithful recreations in the 500 format, but David is one of them. If these are the pots he says get, then I know that's what I'm getting.

The specs for the pot are in the part number he listed, you should be able to contact another dealer that you feel is higher quality and I assume they can custom build the pots for you. I'm sure David can guide you much better than I can regarding that, but I'm only doing the group through Omeg. I hope to know something tomorrow morning.
Title: Re: 500 series Sontec / GML type eq
Post by: Rocinante on August 05, 2015, 03:14:37 AM
i'm in.
Title: Re: 500 series Sontec / GML type eq
Post by: nielsk on August 05, 2015, 08:51:49 AM
Please clarify, is the pot group order for the NON center tap pots, and the center tap pots should be obtained with the kit?
Title: Re: 500 series Sontec / GML type eq
Post by: nielsk on August 05, 2015, 08:55:14 AM
BTW, the LDR on the in/out switching is pretty interesting, I take it this version does not employ it?
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 05, 2015, 09:04:07 AM
I've always been impressed with Omeg pots and have seen them recommended for years on here..   have you had issues in the past?  Is it the metal versions you're not a fan of or the green plastic style pots?  I'm not sure how their green pastic ones stack up but the 16mm metal pots, I've always been impressed with.   The main thing I like in this case is the sturdiness of the turn..  The thing I hate about dual concentrics is when it's too easy to rotate the wrong shaft by accident.  This doesn't happen with the Omegs.   

Interested to hear your opinion on them..   

If you wanted to go a different route, with a different footprint pot, there's a lot of space so you can flip the pot over so the legs face up and then wire it to the board..   The best thing about DIY is doing things how you want, so it's certainly possible!    Or if it's a rack version..  you can always use separate pots rather than dual concentric of course for more choices.. 

  (PS. confirmation.. yes this group buy is for the dual concentrics..    not the centre tap pots)   
The centre tap pots are the main tricky thing to get in small quantities so I'd recommend getting them along with the PCBs..   
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 05, 2015, 09:13:01 AM
BTW, the LDR on the in/out switching is pretty interesting, I take it this version does not employ it?

Yes the circuit originally uses an LDR initially to bypass the EQ and then after a delay, the relay closes & shorts it over..  this would give a lower click.  Used mainly for mastering while changing EQs on the fly I believe. 

I've used the relay only and the click doesn't even meter on ProTools so is at least below -70dBFS
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 05, 2015, 10:50:02 AM
Hi everyone.. 
Don't kill me but I completely underestimated the initial first day surge and have run out of knobs..  I've got more arriving in 10 days and so they'll be back on sale then..   

If you're ordering without knobs, then that's ok..  but for everyone else..   Huge apologies..

Or if you prefer I can send orders in two packages..  so you can have it built by the time I send the knobs in a couple of weeks..     If you email me then I can do that..  (I've stopped the paypal button for the time being)    That way they'll probably arrive at the same time as the Omeg pots anyway.. 


 
Title: Re: 500 series Sontec / GML type eq
Post by: bruno2000 on August 05, 2015, 12:15:25 PM
I've always been impressed with Omeg pots and have seen them recommended for years on here..   have you had issues in the past?  Is it the metal versions you're not a fan of or the green plastic style pots?  I'm not sure how their green pastic ones stack up but the 16mm metal pots, I've always been impressed with.   The main thing I like in this case is the sturdiness of the turn..  The thing I hate about dual concentrics is when it's too easy to rotate the wrong shaft by accident.  This doesn't happen with the Omegs.   

Interested to hear your opinion on them..   

If you wanted to go a different route, with a different footprint pot, there's a lot of space so you can flip the pot over so the legs face up and then wire it to the board..   The best thing about DIY is doing things how you want, so it's certainly possible!    Or if it's a rack version..  you can always use separate pots rather than dual concentric of course for more choices.. 

  (PS. confirmation.. yes this group buy is for the dual concentrics..    not the centre tap pots)   
The centre tap pots are the main tricky thing to get in small quantities so I'd recommend getting them along with the PCBs..

Allow me to chime in here on the Omeg pots.  I have used them in my 4K5 and 9K5 builds, and the quality is OK, but not like JAN spec Allen Bradleys.  I have probably bought 50 or so of the single, dual, and triple versions from AudioMaintance with about a 10% failure rate after a month or so.  All of the failures were intermittent. Colin being the gem of a person that he is has replaced ALL of the defective pots for me, and that's one reason I keep buying stuff from him.  I wonder what the factory will do, or what hoops will have to be jumped through if any of these "special order" pots get weird.
My $0.02.  YMMV.
Best,
Bruno2000
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 05, 2015, 12:36:30 PM
That's strange to hear.  5 pots failing out of 50?  That's incredible.  Were Omeg spoken to?  What was their stance?   What kind of failures? 

A friend & I are up to 60 pots now being used for a couple months currently and not had a failure..   

There was one where they'd forgotten to close the clips around the legs properly and so it didn't make a connection but a quick bend with needle nosed pliers sorted it..   (human errors like this can certainly happen with handmade pots.. )
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on August 05, 2015, 12:46:19 PM
OK this is from the US dist. Yeah I'd say buying in group is an absolute!

"So we have everything worked out on our end.
Delivery times will be 5 to 6 weeks from firm purchase order
That is with us flying everything in via FedEx
Omeg is aware and familiar with this project, but these are always built to order.  There aren’t any in stock anywhere.
 
10-24 pieces =US$49.95 each
25-49 pieces =US$39.95 each
50-99 pieces =US$24.95 each
100-249 pieces =US$17.95 each
250-499 pieces =US$14.95 each
 
These prices are for FOB from our Arlington Heights IL warehouse.  Vimex absorbs FedEx/US Customs/Delivery charges
So additional cost to each buyer for approx. 10 pieces each is say $10.00 UPS charge
 
We will accept orders with a 20% deposit.  Balance would be due the day we ship from Illinois
We will be accepting payments via Visa or MasterCard
The parts are considered custom, so there is a no cancel no return policy (except for defective goods)
 
If you are going to try and get best pricing for everyone we would not place the order with Omeg until all orders were firm and deposits received.  So if there are multiple buyers some co-ordination would be helpful"
Title: Re: 500 series Sontec / GML type eq
Post by: bruno2000 on August 05, 2015, 12:58:39 PM
That's strange to hear.  5 pots failing out of 50?  That's incredible.  Were Omeg spoken to?  What was their stance?   What kind of failures? 

A friend & I are up to 60 pots now being used for a couple months currently and not had a failure..   

There was one where they'd forgotten to close the clips around the legs properly and so it didn't make a connection but a quick bend with needle nosed pliers sorted it..   (human errors like this can certainly happen with handmade pots.. )

I have no idea if Colin contacted Omeg or not.  He probably buys hundreds at a time, and just shipped replacements to me.  These failures were usually after they had been in service for a bit.  In some of the failures, the wiper seemed to lift off of the resistive trace at a certain point in rotation.  I say "lift off" because the specified resistance was still there between the outer pins.  Another failure I observed was an intermittent connection between the pin and the resistive element.  Now, I must say that most of this happened several years ago, but only last week I had to replace an Omeg pot in a new 9K5 build that a friend was having trouble with.
Again........YMMV
Best,
Bruno2000
Title: Re: 500 series Sontec / GML type eq
Post by: bruno2000 on August 05, 2015, 01:09:16 PM
OK this is from the US dist. Yeah I'd say buying in group is an absolute!

"So we have everything worked out on our end.
Delivery times will be 5 to 6 weeks from firm purchase order
That is with us flying everything in via FedEx
Omeg is aware and familiar with this project, but these are always built to order.  There aren’t any in stock anywhere.
 
10-24 pieces =US$49.95 each
25-49 pieces =US$39.95 each
50-99 pieces =US$24.95 each
100-249 pieces =US$17.95 each
250-499 pieces =US$14.95 each
 
These prices are for FOB from our Arlington Heights IL warehouse.  Vimex absorbs FedEx/US Customs/Delivery charges
So additional cost to each buyer for approx. 10 pieces each is say $10.00 UPS charge
 
We will accept orders with a 20% deposit.  Balance would be due the day we ship from Illinois
We will be accepting payments via Visa or MasterCard
The parts are considered custom, so there is a no cancel no return policy (except for defective goods)
 
If you are going to try and get best pricing for everyone we would not place the order with Omeg until all orders were firm and deposits received.  So if there are multiple buyers some co-ordination would be helpful"

Wow!~ On the DON website, he says

 "• Firstly you can buy the dual concentric pots from Omeg.  The part number is:
"PC3C16BU 100KCx2-FRONT-OUTER x 4K7A, Bush C, Spindle M16 L1=30mm L2=19.5mm"

They only have a minimum order of 10, so perfect for a stereo pair!
You can email the very friendly Margaret at:
[email protected]
They're around £14 each.. 

That's about $22 US a pop.  The quote you got was for almost $50 each?  I say forget the US distributor.
Best,
Bruno2000
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 05, 2015, 01:11:34 PM
If it's easier for you guys, I don't mind ordering direct from here and then shipping them to one person stateside or individually depending on what you'd prefer. 

I pay about £14 each for 10 pots.  exc shipping 

I'm assuming everyone in Europe is doing ok with Omeg?  You can deal direct too I believe?
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on August 05, 2015, 03:18:08 PM
If it's easier for you guys, I don't mind ordering direct from here and then shipping them to one person stateside or individually depending on what you'd prefer. 

I pay about £14 each for 10 pots.  exc shipping 

I'm assuming everyone in Europe is doing ok with Omeg?  You can deal direct too I believe?

I honestly believe that would be the best way... and you could even pool it on your side David.... if we could get you enough for 100 of them maybe it'd be cheaper from Omeg to you??
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 05, 2015, 10:15:22 PM
No worries.. in the morning I'll get quotes for 1 set, 5 sets and 10 sets from Omeg..   
That way you can order either individually or in a group of 5 or a group of 10.   

Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 06, 2015, 02:30:45 PM
Hey everyone, so I've come up with a plan..  I'm still waiting to work out exact costs..  but I believe I can offer individual shipping and 10 pots Stateside for the £14 each including the shipping..   And even less if you didn't mind slower shipping..
That way, I can ship to everyone individually and if there's any issues, I can deal with it myself rather than one of you nice people getting the complaint if a parcel has gone awry with a groupbuy or something of the like!

I've got to run out now.. but hope that's ok.. if I knew that Omeg weren't really set up for international shipping the way I thought, I'd have sorted something earlier.. 

PS.. I've already ordered 10 sets that they can be getting on with..

PPS.  Everyone's kits are now dispatched / on route.. 
Title: Re: 500 series Sontec / GML type eq
Post by: Winetree on August 06, 2015, 07:41:40 PM
Save 2 sets for me as I've got 2 kits in the mail.
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on August 07, 2015, 12:41:05 AM
^^^^^ Yes please, put me down or two sets for the pair I bought as well.
Title: Re: 500 series Sontec / GML type eq
Post by: pachi2007 on August 07, 2015, 05:50:52 AM
Hi everyone.
I was wondering if it´s too  complicated to make the gain 6db instead of 12?
I think it would be more precise and useful for mix/bus duties.
Maybe change a couple of resistors here and there, or it needs different pot values too?
Thx a lot
Title: Re: 500 series Sontec / GML type eq
Post by: Winetree on August 07, 2015, 02:24:29 PM
Just got my 2 kits.
That was fast.
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on August 07, 2015, 02:59:04 PM
For DOA's I wonder how these would do for the Sontech??

http://www.sonicimagerylabs.com/products/Model995FET-Ticha.html
Title: Re: 500 series Sontec / GML type eq
Post by: john12ax7 on August 07, 2015, 03:41:23 PM
Hi everyone.
I was wondering if it´s too  complicated to make the gain 6db instead of 12?
I think it would be more precise and useful for mix/bus duties.
Maybe change a couple of resistors here and there, or it needs different pot values too?
Thx a lot

If you look on the original schematic there is R42 and R48 each 100 ohm to each side of the pot that is the level control. Increasing these will decease the +/- gain per band, they work as a divider in conjunction with the level pot. You would need to either simulate or measure an actual unit to determine the correct values.

Note: This may also impact the DC servo.
Title: Re: 500 series Sontec / GML type eq
Post by: pachi2007 on August 07, 2015, 04:57:45 PM
Thanks a lot John.
I´m looking for DC servo info to find out what you mean.
Is it like... if you put a sine wave through it the waveform wouldn´t be centered anymore with respect to the horizontal axis?
Like a offset?
Slowly learning here  :)


Title: Re: 500 series Sontec / GML type eq
Post by: john12ax7 on August 07, 2015, 09:04:06 PM
The servo takes the place of an ac coupling capacitor to remove dc offset (no vertical offset in a sine wave).

Mostly likely it won't matter. I just bring it up because most dc servos are connected to the output of an opamp. Here it goes through the 100 ohm resistor, which will now be changed to 10k or 20k  or whatever it needs to be to get  the 6db desired gain range. So a solution could be to connect R49 to other side of R48, of its even am issue at all.

Also you would need to figure out which parts on the board correspond to the original schematic.
Title: Re: 500 series Sontec / GML type eq
Post by: pachi2007 on August 08, 2015, 05:04:21 AM
Tnank you John.
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 08, 2015, 11:43:38 AM
I see there being 3 ways of doing this.. 

You could as stated change R42 / R48 up to around 7k5 ish..

Or possibly tweak R61 / R62.. 

I'd be inclined to try and change the R69 resistors up to 47k..   

Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on August 09, 2015, 03:31:54 AM
For DOA's I wonder how these would do for the Sontech??

http://www.sonicimagerylabs.com/products/Model995FET-Ticha.html

David ^^^^^

What do you think?
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 09, 2015, 11:35:16 AM
For DOA's I wonder how these would do for the Sontech??

http://www.sonicimagerylabs.com/products/Model995FET-Ticha.html

David ^^^^^

What do you think?

Ah yes I saw those when I was looking up suitable DOAs and they seem like they'd work great but I wasn't able to find any reviews or anything from anyone I don't think..  but they certainly look promising..   
Title: Re: 500 series Sontec / GML type eq
Post by: Dr Gris on August 09, 2015, 12:20:09 PM
For DOA's I wonder how these would do for the Sontech??

http://www.sonicimagerylabs.com/products/Model995FET-Ticha.html

David ^^^^^

What do you think?

Ah yes I saw those when I was looking up suitable DOAs and they seem like they'd work great but I wasn't able to find any reviews or anything from anyone I don't think..  but they certainly look promising..   

They had a white market thread here once, but didn't get much attention. Looks nice!
I use some of PPA's 992 and they are really sweet!

C'mon get those knobs in so I can spend some money before my upcoming divorce kicks in
and I'll be broke for a long time to come ;)

Cheers
//Magnus
Title: Re: 500 series Sontec / GML type eq
Post by: kosi on August 10, 2015, 04:32:16 AM
Kits arrived !
Yummy
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 10, 2015, 09:11:31 AM
For DOA's I wonder how these would do for the Sontech??

http://www.sonicimagerylabs.com/products/Model995FET-Ticha.html

David ^^^^^

What do you think?

Ah yes I saw those when I was looking up suitable DOAs and they seem like they'd work great but I wasn't able to find any reviews or anything from anyone I don't think..  but they certainly look promising..   

They had a white market thread here once, but didn't get much attention. Looks nice!
I use some of PPA's 992 and they are really sweet!

C'mon get those knobs in so I can spend some money before my upcoming divorce kicks in
and I'll be broke for a long time to come ;)

Cheers
//Magnus

;)  No worries..  I put my order in just before the cut off deadline for their latest batch so shouldn't be too long to wait..  If I'd have not read their email before lunchtime that day I'd have had to wait til September apparently!
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on August 10, 2015, 05:06:12 PM
Got my kits! Look great!
Title: Re: 500 series Sontec / GML type eq
Post by: bruno2000 on August 10, 2015, 05:27:24 PM
A box came in today from UK, but I've been too busy to open it.  I'll check in tomorrow with the details.
Best,
Bruno1000
Title: Re: 500 series Sontec / GML type eq
Post by: tskguy on August 10, 2015, 08:20:01 PM
Received my kits yesterday, they look great! BOM is on the way... Some of the switches were back ordered but should be back in stock this week.  ;)
Title: Re: 500 series Sontec / GML type eq
Post by: duantro on August 12, 2015, 04:42:08 PM
Kits sold out quick! Will they be restocked?
Title: Re: 500 series Sontec / GML type eq
Post by: jasonallenh on August 12, 2015, 04:59:16 PM
HOW DID I MISS THIS :o
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 13, 2015, 05:03:18 PM
Good news...  The new batch of knobs arrived and so all is back on sale again!

(For those stateside, needing the Omeg pots from me.. no sign of the "they're dispatched" email yet, but will keep you informed.. 
Title: Re: 500 series Sontec / GML type eq
Post by: Rocinante on August 13, 2015, 10:27:29 PM
Good news...  The new batch of knobs arrived and so all is back on sale again!

(For those stateside, needing the Omeg pots from me.. no sign of the "they're dispatched" email yet, but will keep you informed..

Can't wait, as its all thats holding me back.
Title: Re: 500 series Sontec / GML type eq
Post by: kosi on August 15, 2015, 04:28:06 PM
Is there an ideal scenario with the voltage rails ?
I have an 51x Rack.
I don't understand the explanation of the choices, the manual says:

"Why the choice? Two main reasons... using discrete opamps at a higher voltage. And to use less loaded rails of a full lunchbox"

So, is it better to run DOAs on 24 V ? Better how ?
And what are less loaded rails in this scenario ? When I use both rails ? 

and another question ? Can I use my "regular" DOAs ? Like Gar 2520 etc ? The layout has 5 pins on one side, which confuses me a bit . Maybe the original 250 had DOAs with 5 pins ? But the regular DOAs fit in, I used one to solder the millmaxes.

thanks
Andreas
Title: Re: 500 series Sontec / GML type eq
Post by: Rocinante on August 15, 2015, 06:54:45 PM
I believe its because some DOAs prefer higher voltages (more headroom??) and are rated at 24v that might work really well in this application while others are rated at 16v and would be unusuable in a 51x rack but obviously fine in a 'regular' 500 series.
DOA's also can consume a good deal of power.
Furthermore DOA's can have a significant impact on circuits and they all do a little something different.  That said I believe he is just giving everyone lots of options to use.
I believe the 5th pin spot (but i am definitely not sure) is to give builders more DOA options. For example; iirc 'red dots' only have 3 pins on one side.
Title: Re: 500 series Sontec / GML type eq
Post by: Trench Recordings on August 16, 2015, 03:33:32 AM
Placed my order but now I'm wondering if I should have waited for omeg pots...
Title: Re: 500 series Sontec / GML type eq
Post by: Winetree on August 17, 2015, 05:26:41 PM
This is for 2 kits I ordered and received.
I just received a bill from UPS for duties to be paid for "Customs"
I've been ordering kits from all over the world for years and have never
received a bill or paid anything for CUSTOMS.
What's up is this legit?
Title: Re: 500 series Sontec / GML type eq
Post by: guilds100 on August 17, 2015, 07:24:46 PM
This is for 2 kits I ordered and received.
I just received a bill from UPS for duties to be paid for "Customs"
I've been ordering kits from all over the world for years and have never
received a bill or paid anything for CUSTOMS.
What's up is this legit?

I just received one too. I also had to give a check to ups on delivery for a package from pcbgrinder a couple of weeks ago. Something has changed as I too haven't received bills in the past.
Title: Re: 500 series Sontec / GML type eq
Post by: nielsk on August 17, 2015, 08:21:19 PM
That's UPS, in my experience there is always a customs charge receiving International shipments via them.
Never a charge when items are sent using the postal service... and the shipping cost is usually much less.
Title: Re: 500 series Sontec / GML type eq
Post by: Trench Recordings on August 17, 2015, 09:21:11 PM
I agree with the above statements. I will ship more expensive slower postal service any day if I can avoid UPS. Hate them with a passion. They will show up at your door with a package and sometimes demand 40% of the value in surprise brokerage fees and duty. Dont pay them ! Its extortion... Showing up at my door with an unknown fees that I didn't agree too upfront.   

FedEx and Purolator are alright. Postal service is best to avoid unexpected custom fees.


Title: Re: 500 series Sontec / GML type eq
Post by: DonnieDarko on August 18, 2015, 03:38:08 AM
Hey guys, hey David if you are listening in,

I´m almost finished with my build - besides waiting for the OMEG Pots off course.

Some small issues thogh:

The relay that I received when ordering the mouser cart wasn´t the right one. I does have a different footprint. A bummer, since now I have to order one single part and have to pay 20,- postage fees.

Does anybody have the correct part number of the relay?

Then for the different Voltage Options. Can´t we cut out the technical discussion and just get a recommendation for the best (best meaning: detailed and open sounding) DOA for this unit and then wire the thing accordingly to the needs of that DOA?

So, is there any DOA that we can agree that would be the best thing to put into this unit?

Besides those issues, fun build. Soldering a bit tricky sometimes.

Thanks guys!
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 18, 2015, 06:50:12 AM
Wow.. never had any issues with UPS before..  I used to use FedEx, a couple of years ago, but then I started to get these problems and then switched to UPS, which stopped problems like this.  Now it appears they've started to charge duty.  I don't mind shipping normal post, but would they not be the same?   
 
How much was charged?  According to this duty tax, it should be 0% charge if they class it as audio recording equipment..  or 2.6% if classed as an effects pedal.
http://www.dutycalculator.com/new-import-duty-and-tax-calculation/saved_calculations/view_details/194411981/
 However then they always put a fee on top for "handling".  It's a ridiculous practice.  Does anyone know if it's easy to set up so I pay the customs tax my end and so it's only the 2% or whatever, without the UPS fee.   Or if I can be more specific with the wording on the customs form to ensure it's 0% tax?  It seems quite hit and miss
Was everyone charged the same amount?
__

In regards to the relay, I used that relay the other day on a build and although it needed a little finesse, it slotted in fine as it's only a mm difference..   Just a small bend of the legs.
I've since updated the BOM with the 653-G6K-2P-Y-DC12 which will fit perfectly..   
DOA wise, and voltage rails wise, I'm not sure there is one that is universally accepted as being the best.. so it will be case of either trying some out and deciding..  or I recommend building it the way I have done with OPA134 ICs.. 
In regards to voltage rails..  again if you have no personal preference, I'd do it 500 series so you can use it in other 500 series lunchboxes.    It's as good a reason as a any!

___
Title: Re: 500 series Sontec / GML type eq
Post by: guilds100 on August 18, 2015, 06:59:36 AM

 
How much was charged? 
___


I was charged $12.54 customs and $7.00 brokerage fee.
Title: Re: 500 series Sontec / GML type eq
Post by: bruno2000 on August 18, 2015, 10:32:49 AM
I agree with the above statements. I will ship more expensive slower postal service any day if I can avoid UPS. Hate them with a passion. They will show up at your door with a package and sometimes demand 40% of the value in surprise brokerage fees and duty. Dont pay them ! Its extortion... Showing up at my door with an unknown fees that I didn't agree too upfront.   

FedEx and Purolator are alright. Postal service is best to avoid unexpected custom fees.

Two years ago I had a large order ($3k) of electronic parts delivered from UK.  8 MONTHS later, I got a bill from FedEx for $800 for customs & fees.  When I complained (loudly), they dropped the issue.
Hit up their FaceBook page.  You'll probably get results.
Best,
Bruno2000
Title: Re: 500 series Sontec / GML type eq
Post by: Winetree on August 18, 2015, 04:09:14 PM
UPS Custom Fees;
Duty Class:                           85.18.50.0000
Discription of goods:      Audio Amplifier Electronics DIY Kit
Entered value:                   $257.58
Tariff rate:                            4.90%
Amount:                                $12.64
Disbursement Fee:         $7.00
Total:                                       $19.64
Should I pay pay them?        If not what could happen?    I'm not on Facebook.
Title: Re: 500 series Sontec / GML type eq
Post by: Mulmany on August 18, 2015, 04:33:11 PM
UPS Custom Fees;
Duty Class:                           85.18.50.0000
Discription of goods:      Audio Amplifier Electronics DIY Kit
Entered value:                   $257.58
Tariff rate:                            4.90%
Amount:                                $12.64
Disbursement Fee:         $7.00
Total:                                       $19.64
Should I pay pay them?        If not what could happen?    I'm not on Facebook.

Well I did not pay my UPS fees on transformers from Audio Maintenance. Got 2 bills, then nothing. I still receive packages through UPS.

The kits I bought from David did not incur any fees.
Title: Re: 500 series Sontec / GML type eq
Post by: [silent:arts] on August 18, 2015, 05:39:05 PM
The harmonized code is fine (TARIC (http://www.tariffnumber.com/?year=2015&lang=en&q=8518500000))
The value is fine.
The tariff rate looks ok (in Germany between 3-5%).
The Disbursement Fee is low (I pay - value independent - EUR 12,00 at Fedex, and EUR 12,00 at DHL, don't know UPS).
They do the paper work for you, and have to pay the customs fee upfront.
In Germany there would be additional 19% VAT for everything together (import value + shipping costs + custom fee).

So - this is quite normal, for me for importing from outside the EU, on your site it will be from outside the US?
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 19, 2015, 06:31:19 AM
The only monster stories I've heard of personally have been FedEx actually..  With extortionate charges..  I've always been impressed with UPS.. But obviously it's going to vary country to country.   
Here in UK if we order anything from outside EU, we pay 20% on everything for VAT.. and then whatever "charges" the shipping company adds on top. Very rarely does something get through without charges..  however USA it seemed to be the other way.. very rarely were there charges.. perhaps this is now a nationwide change across the board?

Those charges don't look too bad..  It's the additional fee that normally bothers me but it seems it's only 7USD in this case which is less than royal mail charge going the other way here. (they charge £8) 

The other fees, I guess they may have started to cut down on letting smaller items go through uncharged perhaps now?   It's a tax though right?  So goes towards the country?  Far easier to stomach than a monstrous FedEx 'Additional Handling Surcharge' bill..   At lease that's what I tell myself when I pay the 20% every time I have to import something!
Title: Re: 500 series Sontec / GML type eq
Post by: kosi on August 19, 2015, 06:40:57 PM
Nearly finished with my build !
small things:
What happens with Ccomp4 TBC and complc5 TBC  12pF caps ? are they optional ?  they aren't installed in the pics.
You can read the bom in column G as: Compensation cap for audio amps if using DOA

there are holes for L1 and L2 ? not used ?

C18 has 2 plus signs on the pcb, which confused me a bit, but now I found out, that it's non/bi/polar

the values for shelf 1/2 are 357 and 4k7, the pcb says 420 and 5k

I went with configuration B, as I'm using it in my 51X Rack
It's a lot to solder but everything is very clear and straightforward.




Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on August 19, 2015, 08:46:20 PM
UPS Custom Fees;
Duty Class:                           85.18.50.0000
Discription of goods:      Audio Amplifier Electronics DIY Kit
Entered value:                   $257.58
Tariff rate:                            4.90%
Amount:                                $12.64
Disbursement Fee:         $7.00
Total:                                       $19.64
Should I pay pay them?        If not what could happen?    I'm not on Facebook.

I just got a bill for the exact same amount......
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 20, 2015, 03:46:56 PM
L1 & L2, will be used for different things depending on the voltage set up you use, so in your case of B, they'll be jumpered...    (Originally I called them L1/L2 in case any extra filtering was needed for the filter section but all good as is.. 

Yes the 357R drops the voltage rail for the relay coil..  The relay isn't too fussy about getting the exact voltage it needs, so a few values will work..    357 will give it 12.35V if fed from a 16V rail.  If 420 is used it'll be 11.87V.
The 5k is used to make the feel of switching the high shelf in, more natural.. (when going from sharp Q bell.. to shelf..      It can be tweaked to anything from 5k to 0ohms if you prefer ! 

The compensation caps are there depending on the opamps you use, if you need them if you're opamps oscillate etc etc..  12pF value was a rough 'go to' value.. 
Title: Re: 500 series Sontec / GML type eq
Post by: IndietownRecording on August 21, 2015, 12:13:54 PM
UPS Custom Fees;
Duty Class:                           85.18.50.0000
Discription of goods:      Audio Amplifier Electronics DIY Kit
Entered value:                   $257.58
Tariff rate:                            4.90%
Amount:                                $12.64
Disbursement Fee:         $7.00
Total:                                       $19.64
Should I pay pay them?        If not what could happen?    I'm not on Facebook.

I just got a bill for the exact same amount......

Just got a bill yesterday as well. What's the consensus? Are people paying these bills?
Title: Re: 500 series Sontec / GML type eq
Post by: tskguy on August 21, 2015, 02:20:40 PM
I received one as well... I say we all just hold off and not pay them... :o See what happens.
Title: Re: 500 series Sontec / GML type eq
Post by: Dr Gris on August 22, 2015, 07:35:41 PM
Hmmm.... I can't relate to your problems but " the other way around" it's always the same with both
UPS and Fedex. They take care of custom fees and VAT and I have to pay them for doing so.
My biggest problem is that UPS simply can't deliver to me. I don' t work at my home adress and the option
to change the delivery adress never works....so my package will probably be sent back or " if I'm lucky"
I can make them keep it at their local facility for me to pick it up.
And that's an one hour drive from here...
Either way I didn't know that it was shipped with UPS and don't have any shipping info...trackin number
and so forth so I can't even try to get my package, maybe it's already returned???
Now what do I do???

Cheers
//Magnus
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 24, 2015, 09:45:35 AM
Hmmm.... I can't relate to your problems but " the other way around" it's always the same with both
UPS and Fedex. They take care of custom fees and VAT and I have to pay them for doing so.
My biggest problem is that UPS simply can't deliver to me. I don' t work at my home adress and the option
to change the delivery adress never works....so my package will probably be sent back or " if I'm lucky"
I can make them keep it at their local facility for me to pick it up.
And that's an one hour drive from here...
Either way I didn't know that it was shipped with UPS and don't have any shipping info...trackin number
and so forth so I can't even try to get my package, maybe it's already returned???
Now what do I do???

Cheers
//Magnus

Just emailed you with all tracking details.. for some reason the tracking number wasn't sent to you like they normally automatically are.. 
Did they not leave a card through the door? 
I'm getting in touch with UPS now to see if we can change the delivery address... 
Title: Re: 500 series Sontec / GML type eq
Post by: Dr Gris on August 24, 2015, 11:44:43 AM
I was in contact with UPS today and for the first time things went smooth and they were friendly.
They're gonna try to deliver it to me at my work tomorrow.
Thanks for your support!!

Cheers
//Magnus
Title: Re: 500 series Sontec / GML type eq
Post by: Biasrocks on August 24, 2015, 01:56:50 PM
Yep. They even throw in an extra $30 here in Canada for 'brokerage' of your duty free item which nine times out of ten they'll get the wrong tariff code for.

Call UPS and complain, tell them you didn't authorize them to clear the package and they didn't give you the option to do it yourself and you're not going to pay the brokerage fee. They will refund it in most cases.

If you let it go, they will sick a collection agency on you, but will gladly deliver more packages.

NEVER Ship international packages by UPS,  always use the postal service.

This is for 2 kits I ordered and received.
I just received a bill from UPS for duties to be paid for "Customs"
What's up is this legit?
Title: Re: 500 series Sontec / GML type eq
Post by: Trench Recordings on August 24, 2015, 07:56:48 PM
Ok thanks for speaking up of us Canadians Biasrocks. I though I was the only crazy one here. UPS broker fees are definitely much high here in Canada compared to UPS USA rates/fees.

I have gone to the extent of importing my own packages with my business number. Also know as "self-clearing". Its a couple hours of my time and I have to drive to the nearest Customs CBSA Office and pay the taxes/duty directly. But usually I get away with 5% GST tax on the value and that's it. This process will slow down your delivery date but you will save money compared to UPS Brokerage.

Postal service is good because most times the packages clear without any taxes or duty simply because the customs offices doesn't have time to process every package. If the postal service/customs office does decide to process your package, the fees/taxes are less than UPS. But it is slower... sometimes things get stuck in customs.
Title: Re: 500 series Sontec / GML type eq
Post by: Winetree on August 25, 2015, 09:14:36 PM
Any word on the pots?
Title: Re: 500 series Sontec / GML type eq
Post by: kosi on August 26, 2015, 09:12:01 AM
Finished !
Got my 2 running and they sound brilliant  ! Everything went so cool with this build, really fantastic.

One thing to consider: I choose for the voltage rails variation B, 24V for the DOAs and 16 V for the rest.
But I have only one power supply at home , where I can have 24 OR 16V, so now I have to build a +-16V supply to do a proper calibration.
At home, I tried to run with only 16V connected, which worked with a lot of hum and a very low signal.
I could calibrate the filter section @ R70
I couldn't calibrate R83 TPS1 and2. Meter showed 0V and trimming R83 in either direction changed nothing.

Is there a way to calibrate the unit with only 16 or 24 V ?

thank you so much,  David, for making this possible ! I'm a true fan of your work
Title: Re: 500 series Sontec / GML type eq
Post by: Dr Gris on August 26, 2015, 12:36:15 PM
Ordered my pots 13:th of august, were told they would despatch week 38, but they despatched today  :D
Now if I could only find my package from UPS....

Cheers
//Magnus
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on August 27, 2015, 07:36:08 AM
Great work Kosi! Love to hear of units being completed!  And thanks for the kind words!

In regards to your R83 calibration... 

Did you have EQ in?  It needs to be on bypass for this adjustment.  Other adjustments can be in either setting..


No words on the pots for me yet, but perhaps they're a little busier than I expected with the European orders put in before mine..  Will let you know when I get my "dispatched" email..  sounds like pots are making their way out of Omeg now.. 
Title: Re: 500 series Sontec / GML type eq
Post by: kosi on August 27, 2015, 08:12:25 AM
Today I threw together a 16 V psu and with both voltages connected, it was no problem adjusting R83.

Both perform flawless !
Title: Re: 500 series Sontec / GML type eq
Post by: DonnieDarko on August 28, 2015, 05:54:02 AM
My pots shipped yesterday, I´m expecting them on monday. Can´t wait to finish this unit!

As I received the wrong relays, I guess other builders might have too, cause they used the same BOM.

Did anyone figure out how to mount those? They have two more pins than the footprint on the PSU, also they are larger than the needed part…

A photo of your builds would be very helpful! Thanks guys!
Title: Re: 500 series Sontec / GML type eq
Post by: kosi on August 28, 2015, 01:50:33 PM
I used the alternative relais from the BOM, which is
653-G6K-2P-Y-DC12
this has 8 legs.
They had a slightly different spacing, but with a little bending, it was no problem inserting them.


Title: Re: 500 series Sontec / GML type eq
Post by: DonnieDarko on August 29, 2015, 06:07:18 AM
Yeah, I know this will work.

But I wanted to know: Did anyone figure out how to use the Relay from the old BOM? Is there any possibiliy or do I have to place a new Mouser order, paying 20 Euro Shipment?
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on September 02, 2015, 06:11:56 AM
Yeah, I know this will work.

But I wanted to know: Did anyone figure out how to use the Relay from the old BOM? Is there any possibiliy or do I have to place a new Mouser order, paying 20 Euro Shipment?

Yes.. that´s the one being discussed..  just needs a little bend of the legs...

EDIT..  or did Mouser send you a completely wrong relay?  Can you post a pic?  If so, then they´ll rectify that mistake without charge...
Title: Re: 500 series Sontec / GML type eq
Post by: skal1 on September 02, 2015, 02:17:16 PM
Hi onlymeeee ,

were can i get 1 of these , you got a web site.

skal
Title: Re: 500 series Sontec / GML type eq
Post by: kambo on September 02, 2015, 03:30:26 PM
http://www.thedonclassics.com/products_diy.html#250eq_diy.html

Title: Re: 500 series Sontec / GML type eq
Post by: tskguy on September 02, 2015, 07:31:57 PM
Hey all, started my build and it seems I have the wrong relay as well... Not sure what the correct pin out is due to this one having five pins per side? I am sure I can make it work but wondering about which pins aren't used
Anyone???
Title: Re: 500 series Sontec / GML type eq
Post by: tskguy on September 03, 2015, 04:31:49 PM
Does anyone have a pic of the relay that was in the original BOM installed ??
Title: Re: 500 series Sontec / GML type eq
Post by: Krcwell on September 03, 2015, 10:06:38 PM
Regarding the UPS import fees, my guess would be that some mid-level exec found a new revenue source to exploit. We recieve and pay these invoices at work, but that's because we have a large account with UPS and it's less expensive to pay the fees than to bother fighting them and risk getting our account and twice daily pickups shut off.

Most people who recieve international packages via UPS probably buy into the fear of potential impact on their credit score and don't want to deal with a principled fight over $20-30. Seems like low hanging fruit.

Sorry to sidetrack... This project looks awesome and I'm currently saving up cash to get a pair of kits. I would be interested in hearing anyone's resolution of the UPS fees matter.
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on September 04, 2015, 12:57:03 AM
Still no word on the pots??
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on September 04, 2015, 06:05:21 AM
No email as of yet from Omeg..  It was a bank holiday on Monday so a slightly shorter week and I guess they´ve got quite a few to make before my order..  Will let you know when I hear something...

In regards to the initial relay.. yes I used the original BOM with that relay and it´s in the pics ín the manual.  Your relay has 5 pins on each side?  Can you post a pic as I think Mouser must have made a mistake..   Which part number is on the bag/invoice?
Title: Re: 500 series Sontec / GML type eq
Post by: tskguy on September 04, 2015, 08:07:35 AM
https://www.dropbox.com/s/0od26irzp3dgugs/2015-09-04%2008.01.52.jpg?dl=0

So it seems they made a mistake...I will call mouser and have them send me the correct one...is the correct part now on the BOM??
Title: Re: 500 series Sontec / GML type eq
Post by: Winetree on September 04, 2015, 02:44:01 PM
I don't think the ribbon connectors were on the BOM. Got the board mounted ones.
What's their part number?
Was mouser wrong on the relay?
My boards are completely built just waiting on the pots.
Thanks
Title: Re: 500 series Sontec / GML type eq
Post by: tskguy on September 16, 2015, 09:05:59 AM
Success!!!
 ;D ;D ;D ;D ;D ;D ;D
They sound great! Hard to tell if the curves are spot on but they sure work great!

(http://i280.photobucket.com/albums/kk187/tskguy/IMG_1473.jpg) (http://s280.photobucket.com/user/tskguy/media/IMG_1473.jpg.html)
(http://i280.photobucket.com/albums/kk187/tskguy/IMG_1474.jpg) (http://s280.photobucket.com/user/tskguy/media/IMG_1474.jpg.html)
(http://i280.photobucket.com/albums/kk187/tskguy/IMG_1472.jpg) (http://s280.photobucket.com/user/tskguy/media/IMG_1472.jpg.html)
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on September 17, 2015, 03:09:51 PM
Amazing work!!!  Happy mixing!!


The Omeg pots arrived and so I believe I've now emailed or messaged everyone who reserved a set..  let me know if not..   

Did people get in touch with Mouser about the wrong relay?

Ah yes.. ribbon connectors are now on the Mouser BOM and general BOM.. 
http://www.thedonclassics.com/250eq_diy_bom.html

(But if you're not planning on another Mouser order, then any local electronics shop or eBay will have 10 way IDC female connectors)
Title: Re: 500 series Sontec / GML type eq
Post by: Trench Recordings on September 19, 2015, 11:50:49 AM
Another pair up here. Kit went together easy....
Only hard part was waiting for the pots to show up  :)

Thanks
-Dave
Title: Re: 500 series Sontec / GML type eq
Post by: Monoklang on September 23, 2015, 01:10:16 AM
I ordered 2 kits yesterday. I'm very excited.
I've read the manual a couple of times but can't decide how I want to power them A, B, C or D...
I have 51x racks with both 16v and 24v running at the same time.
Maybe I just don't understand how the choices would affect me...
John
Title: Re: 500 series Sontec / GML type eq
Post by: Winetree on September 30, 2015, 07:30:24 PM
Onlymeeee
Received the pots today.
Thanks for doing this.
Title: Re: 500 series Sontec / GML type eq
Post by: Winetree on September 30, 2015, 07:48:03 PM
I ordered 2 kits yesterday. I'm very excited.
I've read the manual a couple of times but can't decide how I want to power them A, B, C or D...
I have 51x racks with both 16v and 24v running at the same time.
Maybe I just don't understand how the choices would affect me...
John
If you only have 51X racks and don't plan on using the modules in a 16 volt only rack, you could go for all 24 volt.
That means you'll have to run D.O.A.s or I.C's that will run on 24 volt.  Theory is with the higher operating voltage, more headroom.  Another reason is if the rack is at capacity  on 16 volt already. Too many high draw 16 volt modules.
I'm in the same situation. All 51X racks except for one in a different room.  If I go all 24 volt, I can't use the modules in that room or take them to another place without 51x racks. Just might go all 16 volt.

 
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on October 01, 2015, 09:23:48 PM
Got kind of an issue here, the throw on the band gain is pretty much a dead on -12db, but I'm only getting about 2.5 db on full +. All my voltages are dead on.... scratching my head on this. I'm using the OPA134's as the outputs, any ideas??
Title: Re: 500 series Sontec / GML type eq
Post by: Winetree on October 02, 2015, 01:44:51 AM
Seeing that I don't want to cut off the 17/18 tab, I thinking of going all 24 volt.
What I.C.s run on 24 volt?
Title: Re: 500 series Sontec / GML type eq
Post by: [silent:arts] on October 02, 2015, 05:19:24 AM
Got kind of an issue here, the throw on the band gain is pretty much a dead on -12db, but I'm only getting about 2.5 db on full.

At what level? Lover the input level. You might just clip either the EQ or the following equipment ;-)
Title: Re: 500 series Sontec / GML type eq
Post by: JeromeMason on October 02, 2015, 01:17:31 PM
Got kind of an issue here, the throw on the band gain is pretty much a dead on -12db, but I'm only getting about 2.5 db on full.

At what level? Lover the input level. You might just clip either the EQ or the following equipment ;-)

-18dbfs is what I'm running into it. It'll cut -12db but will only boost +2.5db.
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on October 02, 2015, 02:34:18 PM
2 kits ordered and paid some minutes ago.
This is an exiting project,thank you very much for it David!


Best regards,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on October 05, 2015, 03:44:32 PM
Quote from: onlymeeee link=topic=59638.msg763236#msg763236
I'm assuming everyone in Europe is doing ok with Omeg?  You can deal direct too I believe?

I can confirm it.Received a quotation from them,in GBP it is 12,76- each (set of 10),shipping to germany is 12,-,plus VAT (20%).
Estimated manufacturing time is 3-4 weeks.
Waiting for the order confirmation/invoice now.


Best,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: Monoklang on October 06, 2015, 04:10:52 PM
I ordered my 10 Omeg pots last week, estimated manufacturing time was 3-4 weeks  but I received them yesterday.

Happy times.
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on October 07, 2015, 11:29:00 AM
Kits received today,that was really fast,thank you very much indeed David!
Mouser order came in yesterday,good timing so far,no?


Best,


Udo.


Edit:Ridiculous questions removed,that was not my day.
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on October 22, 2015, 11:36:32 AM
Hi!
I'm planning to buy a pair of these and rack them. 2U is ok for those wide 500 serie, right?
As I'm going to make a PSU for those babies, what do you suggest for voltages?    +/-16 V?    +/-24 V?
What about OpAmps, what would you suggest?
Finally, as I'm going to make a custom front panel, is it possible to share your front panel file for freq and level scale, cut out etc...?
Thanks!
Best,

Ben
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on October 26, 2015, 10:02:04 AM
Ok so I've read more carefully the thread and found some response to my questions! Sorry for polluting the topic.
Thanks anyway ;)
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on October 26, 2015, 12:05:50 PM
All good! Sorry, I've not been receiving emails to let me know of new posts in this thread for some reason..

If you're racking them, then yes 2u will be fine..   

If you email me, I can offer just the PCBs..   (or with pots.. or whatever you need)

I'll upload a recall sheet when I get a chance later this evening, with some dimensions detail to assist with racking them... 
Title: Re: 500 series Sontec / GML type eq
Post by: john12ax7 on October 26, 2015, 07:26:08 PM
Having these in a rack would be pretty cool. You could also make it 3U and separate out the Q controls. At that point you could use any pots as well and just run leads to the PCBs.
Title: Re: 500 series Sontec / GML type eq
Post by: john12ax7 on October 26, 2015, 07:49:57 PM
For the people who have built/use these:

What do they shine on? It is basically mix bus?
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on October 27, 2015, 06:33:38 AM
All good! Sorry, I've not been receiving emails to let me know of new posts in this thread for some reason..

If you're racking them, then yes 2u will be fine..   

If you email me, I can offer just the PCBs..   (or with pots.. or whatever you need)

I'll upload a recall sheet when I get a chance later this evening, with some dimensions detail to assist with racking them...

That would be great, thanks a lot! I'll emailed you soon.


Having these in a rack would be pretty cool. You could also make it 3U and separate out the Q controls. At that point you could use any pots as well and just run leads to the PCBs.
I'll stay with David's layout, except maybe for the bypass switch. In a rack situation it would be more convenient if the 2 were side by side.
Title: Re: 500 series Sontec / GML type eq
Post by: Vintagear on October 30, 2015, 05:28:04 AM
Hi

Im measuring 40 volts on the 5 IC sockets facing the gold fingers.. The 5 ic's facing the front plate measure 17v ..

And 50 volts on the two doa's ic's
And the third one above 40 v again..

Anyone knows how to get correct value here?

(Hook up plan C )

Thx
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on October 31, 2015, 03:37:37 PM
Another pair up and running here.
Thank you David for this wonderful project!


Best regards,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on October 31, 2015, 03:38:46 PM
…and one pic while adjusting it.


Addendum:They sound awesome!
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on November 09, 2015, 05:28:44 PM
Top work!  Love seeing units built!

I've uploaded a recall sheet here (http://www.thedonclassics.com/images/250eq/500-250EQ_rev1_recall_dual_v1.pdf)

And also, I had another batch of omeg dual concentric pots delivered so now can offer them with the kits, to save the hassle of purchasing from Omeg..  I've added the option to the website (refresh if no option shows up)  http://www.thedonclassics.com/250eq_diy.html
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on November 19, 2015, 10:05:13 AM
Hi David,

Kits arrived today, thank you very much for your support, it's top notch!!!

One question: as I'm planning to put them in a 2U rack I'd like to move the "bell/shelf" switches off the L-bracket. Would it be a problem? Would there be a limitation as for the wires length? Thanks.

best

Ben
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on November 28, 2015, 10:37:11 AM
The compensation caps are there depending on the opamps you use, if you need them if you're opamps oscillate etc etc..  12pF value was a rough 'go to' value..

Hi there,

Just to clarify things: I should start without compensation caps, right? In this case, should I put a jumper or simply leave them?
Thanks guys for your input.

Ben
Title: Re: 500 series Sontec / GML type eq
Post by: Attamanu on December 05, 2015, 09:58:48 AM
Hi there,
i would like to build 2 of these for stereo use on my 2 buss.
The pot are stepped ?
Thanks
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on December 06, 2015, 12:58:44 PM
No, they're not. Gain pots are center detented, that's all.
Title: Re: 500 series Sontec / GML type eq
Post by: 3nity on December 07, 2015, 05:55:09 PM
How much a build like this costs?
Thanks
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on December 08, 2015, 08:22:23 AM
My case is not very representative but for a dual channel with PSU (JLM Audio), the 2U rack case and front and rear panel by Schaeffer it will cost about 1200€.
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on December 08, 2015, 10:17:29 AM
Hi guys,

Problem here!!! I’ve just finished soldering all the parts and made primary tests. While there’s no short between rails when the unit is off, when I turn it on there’s continuity between V+ and V- and I read +16V at 0V!
Any idea?
FYI I have not filled Ccomp4 and Ccomp5.
Thanks for your help

Ben
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on December 08, 2015, 12:15:49 PM
Hi guys,

Problem here!!! I’ve just finished soldering all the parts and made primary tests. While there’s no short between rails when the unit is off, when I turn it on there’s continuity between V+ and V- and I read +16V at 0V!
Any idea?
FYI I have not filled Ccomp4 and Ccomp5.
Thanks for your help

Ben
Hi Ben,


do you mean full continuity meaning zero ohms between the rails?If so then you will have a short somewhere,could be a solder blob,a residual ultra small piece of wire somewhere etc. Hard to tell.
Also why do you want to measure continuity while the unit is powered up?The resistance between the rails will of course change due to caps charging,stuff like that.
How did you read +16v at 0v when 0v should be the reference for measuring voltages?
I can only guess,but looks like you measured something wrong.Are ics in already,did something get very hot or even burning?
In any case you must have your black probe attached to a 0vdc point,dmm set to read dc.Then check the corresponding pins for propper positive and negative voltages on the ic sockets and the millmax points(for the doas).
Maybe some closeup pictures might help.
Also,how did you set up the rails for main and filters?Maybe something went wrong with your ptc and/or zener diode placement?
Just thinking,

Best,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on December 09, 2015, 10:54:13 AM
Hi Udo,

First, thanks for helping! I had tested continuity because I've measured 0V between V+ and 0V and +32V between V- and 0V. So I suspected a short.
I attache my black probe to the chassis, which is connected to my PSU 0V, which is connected to the ground gold finger of the PCB. One weird thing is that I don't have continuity between the gold finger and the 0V test point!
I have set up PCB for +/-16V operating.
Unfortunatly I will not have the time to work on it before monday for further tests. As soon as I'll do I keep you inform. First I will look for a short...
Anyway, thanks again.

Ben
Title: Re: 500 series Sontec / GML type eq
Post by: [silent:arts] on December 09, 2015, 11:17:42 AM
Ben, your chassis is somehow running on +16V ...
Title: Re: 500 series Sontec / GML type eq
Post by: qmp audio on December 09, 2015, 03:38:52 PM
Has anyone used jh990c in 24v?  Thoughts?
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on December 09, 2015, 08:00:00 PM
Hi Udo,

First, thanks for helping! I had tested continuity because I've measured 0V between V+ and 0V and +32V between V- and 0V. So I suspected a short.
I attache my black probe to the chassis, which is connected to my PSU 0V, which is connected to the ground gold finger of the PCB. One weird thing is that I don't have continuity between the gold finger and the 0V test point!
I have set up PCB for +/-16V operating.
Unfortunatly I will not have the time to work on it before monday for further tests. As soon as I'll do I keep you inform. First I will look for a short...
Anyway, thanks again.

Ben
Ben,


I've digged in your posts in this thread.
I wasn't aware that you are doing your own housing and psu,so not 51x or 500 series.Is that correct?
If so then I'd definetely start to look at the psu first!
I have a vague feeling that the culprit is not the eq modules but happening before them!
This would proof Volker's statement.
Looks like your psu makes an unwanted contact to your chassis.
To check this simply lift the connections to the eqs,if you used an edac style or card edge connector  unplug it.
Then,from what I remember from Joe's psus,measure the resistance from 0v directly on the psu board to the chassis.There should be something like 10 Ohms.Power to off during this procedure.If this resistance is zero then I think we found it,might be an easy fix.g
Where are the psu regulators seated,are they screwed to the chassis?
Also you can do the dc measurements again but with the eqs still lifted/unplugged.E.g. measure dc from the 0v on the psu to chassis etc. with power on.It might be you'll get the voltage readings a little higher because it is now unloaded.
This way you can sort out if it is eq or psu related.
I would bet it's the psu.......is it an ac/dc,a powerstation or kraftwerk?
Can you show us a picture of the psu and how it is mounted to the chassis?


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on December 09, 2015, 08:11:00 PM
Has anyone used jh990c in 24v?  Thoughts?
Hi,


no,I didn't,but I'm about to try APP992 when I find some time.


Best,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on December 10, 2015, 12:40:48 PM
Hi Udo,

Thanks a lot for you help, it's very kind of you. Yes the unit is in a rack with JLM PSU, regulators screwed to the chassis. I'll check what you suggest.
Unfortunatly I'll have very busy days today and toomorow so I'll won't be able to work on it before monday. As soon as I can I'll take pics and post them.
Thanks again for all your help.
Best,

Ben
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on December 10, 2015, 12:47:11 PM
Hi Udo,

Thanks a lot for you help, it's very kind of you. Yes the unit is in a rack with JLM PSU, regulators screwed to the chassis. I'll check what you suggest.
Unfortunatly I'll have very busy days today and toomorow so I'll won't be able to work on it before monday. As soon as I can I'll take pics and post them.
Thanks again for all your help.
Best,

Ben
Just take your time,patience is the key.


Good luck,have a not-too-busy weekend,


Udo.



Title: Re: 500 series Sontec / GML type eq
Post by: john12ax7 on December 10, 2015, 11:20:24 PM
Hi Udo,

Thanks a lot for you help, it's very kind of you. Yes the unit is in a rack with JLM PSU, regulators screwed to the chassis. I'll check what you suggest.
Unfortunatly I'll have very busy days today and toomorow so I'll won't be able to work on it before monday. As soon as I can I'll take pics and post them.
Thanks again for all your help.
Best,

Ben

Some regulators cannot use ground/chassis as a heat sink. You might need to electrically insulate them.
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on December 11, 2015, 01:52:19 AM
Some regulators cannot use ground/chassis as a heat sink. You might need to electrically insulate them.
Yes,that's why I asked Ben to measure dcr between ov and chassis connection.On JLM psus there is a 10 ohms resistor.If you measure 0 ohms it indicates a connection beetween one or more regulator backs to chassis.Normally caused by missing silicone insulators or overtightening the screws while mounting,the little plastic washers leading the screws isolated through the mounting hole are easy too break.


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on December 15, 2015, 11:09:20 AM
Hi Udo,

I still have lots of work, I only had 5 min to work on it!
Things I have checked and noticed:
- I have 12 ohms between PSU and chassis, and there's no shorts between regulators and case.
- voltages at the PCBs gold fingers are ok: +/-16V and 0V (ground) connected to chassis (connectors 12, 13 and 14 according to 500 series spec)
- I doesn't have continuity between gold finger 13 (GND) and the 0V tests points. Is it normal?
- I have DC voltages at the inputs and output of Op Amps (about 14,75 V)

As soon as I can I'll take some pics and look for shorts.

Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on December 15, 2015, 12:30:57 PM
Hi Udo,

I still have lots of work, I only had 5 min to work on it!
Things I have checked and noticed:
- I have 12 ohms between PSU and chassis, and there's no shorts between regulators and case.
- voltages at the PCBs gold fingers are ok: +/-16V and 0V (ground) connected to chassis (connectors 12, 13 and 14 according to 500 series spec)
- I doesn't have continuity between gold finger 13 (GND) and the 0V tests points. Is it normal?
- I have DC voltages at the inputs and output of Op Amps (about 14,75 V)

As soon as I can I'll take some pics and look for shorts.
Hi,
measure pin 5 on the card pcb goldfinger to the test point please.This is another ground point.Just ohm it out.
The 12 ohms between chassis and psu 0v are correct.
How did you measure the opamps' dc,to be more specific:Where was the black probe at that time?


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on December 16, 2015, 07:16:07 AM
@Ben,


I think I found the culprit,at least a major one.
Looks I´m right with thinking of a wiring mistake.
I have even pulled out one of my modules out of a rack to proof what I thought.

Please look at goldfinger number 13 on the pcb,hold it against a light if you want.
There´s absolutely no connection to anything!So you run the card without 0v reference!
Use goldfinger number 5 instead,this also connects to the test point.Simply rewire your 0v to pin 5 on the card edge connector.
Then-without ics inserted-carry out the initial voltage tests again and please use the test point for 0v reference.
Tell us what you´ve come up with then.


Fingers crossed,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on December 17, 2015, 10:36:27 AM
Wow, that would be awesome. I think I'll have some time to try this toomorow morning 1st hour!!! Damn Christmas, lots of work in commercial advertising I record in the studio. This is not a good time for hobby right now ;)
Again, thank you very, very much for all your support Udo, you deserve a medal, man!

Ben
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on December 17, 2015, 10:40:01 AM
Wow, that would be awesome. I think I'll have some time to try this toomorow morning 1st hour!!! Damn Christmas, lots of work in commercial advertising I record in the studio. This is not a good time for hobby right now ;)
Again, thank you very, very much for all your support Udo, you deserve a medal, man!

Ben
Not yet,make it work first  ;D


Best,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on December 17, 2015, 11:12:30 AM
I was too impatient and took a break to test your idea. Guess what? IT WORKS!!!
The test points are good, pins for ICs are good. Except for those on the filters sections with some mV (30-ish) on some pins, but I guess it's ok, isn't it?
Next step, put the ICs and proceed calibration... as soon as I'll have some break in my work!
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on December 17, 2015, 12:12:12 PM
I was too impatient and took a break to test your idea. Guess what? IT WORKS!!!
The test points are good, pins for ICs are good. Except for those on the filters sections with some mV (30-ish) on some pins, but I guess it's ok, isn't it?
Next step, put the ICs and proceed calibration... as soon as I'll have some break in my work!
Great stuff Ben!
The dc offset at some points should improve after calibration,that's the fun part.
Keep us posted when you're done,maybe some nice pics?


Have fun,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on December 21, 2015, 07:28:13 PM
Hi there!

Little report. Calibration went flawlessly now that my grounding is ok ;)

I have tested the unit with some audio... OMG!!! That eq is awesome.

IT IS THE DEFINITION OF SWEETNESS !

What a powerful eq. I hadn't heard an eq that sweet and that transparent! Maybe my Millenia STT1 but it's less flexible as the Hi and Lo band have stepped freq and it "only" have 4 bands...
Gorgeous hi-end unit. I only had a quick test with a rough mix but it was awesome.
I don't have any front panel yet so no pics for the moment, that will be for 2016 ;)

Thanks again to David for making this wonderful project and his help, and to Udo for his big support. You rock guys! If you're coming to Paris, let me know, I'd buy you a drink!!! ;D

Best

Ben
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on December 21, 2015, 10:05:09 PM
Excellent news Ben,congrats  ;)


Cheers,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: qmp audio on January 03, 2016, 02:52:59 AM
Anyone have issues with the little round head screws?  They seem to be to short to reach the plastic standoffs through thr pcb. 

Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on January 03, 2016, 04:29:32 AM
Anyone have issues with the little round head screws?  They seem to be to short to reach the plastic standoffs through thr pcb.
Yes,they're too short.
I swapped them out.


Best regards,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on January 08, 2016, 10:16:53 AM
That's strange..  Is it all of them?
It's the same screw/standoff combination I've used on all my stuff for years.. 
I normally loosely fit all screws in all holes as I line the PCB up..  then do a final tighten on all... 

What size did you move up to? 3/16" ?
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on January 08, 2016, 11:46:43 AM
That's strange..  Is it all of them?
It's the same screw/standoff combination I've used on all my stuff for years.. 
I normally loosely fit all screws in all holes as I line the PCB up..  then do a final tighten on all... 

What size did you move up to? 3/16" ?
Hello David,
swapping was meant I changed them with the others normally used at the bracket bottom.The others definetely do just reach the thread of the stand off so I was not able to make them securely  seated,even not a single rotation was possible.Due to the "angle" of the others and seaming to be a tad longer it worked.Not nice but o.k.
I might want to swap the hole construction to metric (M3) because I'm not familiar with those imperial screws.I do have all these screws in nearly any size/length in my workshop,but sadly metric only.
Maybe the stand offs have changed?As said they have an "entrance with a "guide" before the thread starts.
Hope to have helped,


best regards,


Udo.

Title: Re: 500 series Sontec / GML type eq
Post by: qmp audio on January 08, 2016, 11:52:46 AM
That's strange..  Is it all of them?

I was not able to get any of the screws catch the threads of the plastic standoffs.    I had no problem w/ the metal standoff. 
I have some long 4-40 screws.  I plan to dremel them down to length and use those.   Haven't had a chance yet due to recording schedules... but that and calibration is all I have left.   I'm really looking forward to hearing these.
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on January 10, 2016, 04:36:18 AM
Anyone have issues with the little round head screws?  They seem to be to short to reach the plastic standoffs through thr pcb.
Yes,they're too short.
I swapped them out.


Best regards,


Udo.

Yep, same issue here. I've swapped 2 of them with longer M3 screws.
Title: Re: 500 series Sontec / GML type eq
Post by: dribro on January 17, 2016, 12:27:17 PM
Hi David.

What's the availability of the kits?  I'm going after two!
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on January 17, 2016, 12:39:22 PM
Hi David.

What's the availability of the kits?  I'm going after two!
Hi,


have you looked at his homepage?Everything seems to be available:


http://www.thedonclassics.com/products_diy.html#250eq_diy.html


Best regards,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: dribro on January 17, 2016, 01:01:36 PM
Shure did, as i already knew his site. I'm only asking as the availability of kits take some time to pack, even if the site reports immediate availability. But i'd better get there, then, if all's good.
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on January 17, 2016, 01:04:27 PM
Shure did, as i already knew his site. I'm only asking as the availability of kits take some time to pack, even if the site reports immediate availability. But i'd better get there, then, if all's good.
I see.
My orders went pretty fast.


Cheers,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: dribro on January 17, 2016, 01:12:16 PM
Great! Done!
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on January 20, 2016, 07:55:35 AM
RE: screws...  Thanks for letting me know everyone..
I received a new batch of screws today slightly longer in size which now rectifies this..

It's a strange one.. I think the last batch I ordered were ever so slightly smaller than normal..  shame as I bought my usual large batch of them! 

Is everyone who bought a kit ok with screws or do you need me to send some?  Or if you can find some locally, they are #4-40 thread and 3/16" length that you will need..
Title: Re: 500 series Sontec / GML type eq
Post by: qmp audio on January 20, 2016, 01:12:55 PM
Is everyone who bought a kit ok with screws or do you need me to send some?

Thanks,  I was able to grab a handful of 3/16" 4-40 from my dad's shop.
I finished everything up,  calibrated,  did some quick listening tests.   sounds amazing. 

I would be interested in modifying for +-6db instead of 12.   There was some talk about it somewhere in this thread... is that just a resistor swap?
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on January 20, 2016, 02:01:58 PM
Is everyone who bought a kit ok with screws or do you need me to send some?  Or if you can find some locally, they are #4-40 thread and 3/16" length that you will need..
All good here,thank you!


Best regards,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: Monoklang on January 20, 2016, 03:46:38 PM
I haven't started building my two kits yet, but I would love to have the right screws sent to me.

Regards
John Rönnerblad
Title: Re: 500 series Sontec / GML type eq
Post by: onlymeeee on January 21, 2016, 06:55:51 AM
No worries Monoklang..  will post out today.  I've saved your address, so you can remove it now if you wish..

@qmp audio - Yes +-6dB is possible..  easiest way on this unit would probably be to swap out all the R69s for 51k.. 
Title: Re: 500 series Sontec / GML type eq
Post by: buckethead on January 21, 2016, 07:16:34 AM
Hey there!

I got two of those bad boys finished and running for a few months now. The screws were fitting perfectly in my kits.

Thanks for putting this project together, these EQs sound absolutely amazing!

Regards,
Mathias
Title: Re: 500 series Sontec / GML type eq
Post by: rob61 on January 21, 2016, 11:12:15 PM
Just ordered a pair. Had a Sontec 250EX but sold it regretfully. Hope these can get that transparency back. I have a 51x rack and some DOA for 24v. What would the best option be here? Do 24v rails give more headroom? Would it be the same if I used 24v rails only on the discreet DOAs? What are others using?
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on January 22, 2016, 03:21:29 AM
Hi folks!

Finally, after weeks of being too busy, I have finished my unit. Thanks a lot to David for bringing this amazing project and to Udo for his very kind and helpful support!!!
Here's some pics
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on January 22, 2016, 03:22:24 AM
Inside...
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on January 22, 2016, 03:23:04 AM
one last???
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on January 22, 2016, 03:23:59 AM
No! this one is the last: back of the unit  :P
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on January 22, 2016, 06:08:33 AM
Very well done Ben!
So you stuck with the OMEGs,yes?



Now have fun mixing,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on January 22, 2016, 12:06:43 PM
Thanks Udo!
Yes I have OMEGs, it's more simple...

These EQs are absolutly amazing, so sweet, so powerful!!!
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on January 22, 2016, 12:24:49 PM
Thanks Udo!
Yes I have OMEGs, it's more simple...

These EQs are absolutly amazing, so sweet, so powerful!!!
Yes they are indeed!
You used the original mounting holes,right?
This build is teasing me now.....


Best,


Udo ;)
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on January 23, 2016, 08:45:14 AM
Yes, you can see on the inside pic that I use the L-bracket from David's kit. The only thing I hadn't bought was the faceplate, David can managed different type of kit, which is very kind of him ;)
You haven't build one??? I thought you have...

Ben
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on January 23, 2016, 09:03:31 AM
Yes, you can see on the inside pic that I use the L-bracket from David's kit. The only thing I hadn't bought was the faceplate, David can managed different type of kit, which is very kind of him ;)
You haven't build one??? I thought you have...

Ben
Hi Ben,


of course I did two of them,they're in heavy use for months now!
I meant a 19"-version,maybe with seperate controls (non-concentric) and +/-6dB mod. etc.
And I didn't expect the unit to turn out so nice as yours with the standard kit.
Just dreaming atm......


Cheers,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: rob61 on January 23, 2016, 12:30:20 PM
Thanks Udo!
Yes I have OMEGs, it's more simple...

These EQs are absolutly amazing, so sweet, so powerful!!!

Could you comment on the In/Out DOA or chips you used and voltage configuaration? Curious what others are using as I'm going to build a pair.
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on January 24, 2016, 04:24:10 AM
Hi Rob,

I have built it as David did : ICs for in/out and +/- 16V. If it's good enough for the designer, it's good enough for me! And IT IS: very good piece of gear!!!
Good luck for your build.
Best,
Ben
Title: Re: 500 series Sontec / GML type eq
Post by: Dr Gris on January 25, 2016, 02:19:59 PM
Has anybody tried Piere's APP992 in this circuit? I really like that opamp. Haven't built these EQ's yet,
but will soon and gonna try the APP992 in there.

Cheers//M
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on January 26, 2016, 12:01:39 AM
Has anybody tried Piere's APP992 in this circuit? I really like that opamp. Haven't built these EQ's yet,
but will soon and gonna try the APP992 in there.

Cheers//M
Hello,
I'm about to do so soon,it's on my list anyway,and I have a few already assembeled here.Will report back when done.


Cheers,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: Unit7 on January 31, 2016, 05:30:38 AM
Got my pair ready this week. Love this kit/build and I join the choir, they sound great! The only issue I had was that when trimming to ±0V at the testpoints (A-E) at the lowest band (A) on both my units (eq out) it took like 10-15 secs before my DMM settled, just like when there's a cap in the circuit you are measuring. Also the readings never really settled, but fluctuated approx ±2mV. I did email David about this, but I just wanted to check if anybody else had this?

edit: Fluctuation is actually less than ±2mV, and I got word from David that both behaviours described is ok.
Title: Re: 500 series Sontec / GML type eq
Post by: evanbradford on February 02, 2016, 07:07:40 PM
Hi, I built two of these and am almost done, but am having one small issue. I used option D and am consistently getting close to -20 V for the filter rails (usually about -19.8 V, without the ICs). Both positive and negative main rails and the positive filter rails are coming in about 1 V less than this. I know the voltage is going to be a bit higher since the unit isn't drawing much current, but my question is, is -19.8 V too high?

Thanks!

update: David said this should be fine, but to monitor the voltage after installing the ICs and make sure that it dropped. It was still just about 0.5V too high, I had originally set the rails on my 51x supply 0.7V over per Jeff's assembly guide, so I just decided to back those off a bit and everything looks good.
Title: Re: 500 series Sontec / GML type eq
Post by: dribro on February 04, 2016, 08:17:01 AM
Hello guys.
Any news on the DOA options, how do they sound? And what are the opamps everyone's choosing? Are you guys sticking with +-16v rails and opamps suggested by David?
Title: Re: 500 series Sontec / GML type eq
Post by: saxmonster on February 04, 2016, 01:34:44 PM
I think I might get in on this action, I might have to sell my DLA2A.  Such decisions!!!!!!!!
Title: Re: 500 series Sontec / GML type eq
Post by: evanbradford on February 06, 2016, 01:04:29 AM
Hello guys.
Any news on the DOA options, how do they sound? And what are the opamps everyone's choosing? Are you guys sticking with +-16v rails and opamps suggested by David?

I'm curious about this as well. I used the suggested opamps and went with scheme D so I could use the 24V rails of my 51x supply... in the preliminary tests I've done, the EQs sound absolutely fantastic, I'll be starting my first session with them tomorrow so I'll have more of a feel for what they can do after that. If they end up being as awesome as I think they're going to, I'll probably build another pair and would love to experiment with some different ICs/DOAs. Has anyone done any comparisons, and if so, is the difference fairly pronounced or subtle?
Title: Re: 500 series Sontec / GML type eq
Post by: Monoklang on February 08, 2016, 03:49:10 AM
I have finished the soldering and are mounting them.

Should the "red" shelf switches not go through the face plates holes?

Mine aren't 100% aligned with holes, but it seems right in other ways.

I tried to put on the big pots (gain), how do I get them closer to the face plate? They like stop halfway down.

Kind regards
John
Title: Re: 500 series Sontec / GML type eq
Post by: Monoklang on February 08, 2016, 03:49:54 AM
The red switches.
Title: Re: 500 series Sontec / GML type eq
Post by: Unit7 on February 08, 2016, 05:01:55 AM
I have finished the soldering and are mounting them.

Should the "red" shelf switches not go through the face plates holes?

Mine aren't 100% aligned with holes, but it seems right in other ways.

I tried to put on the big pots (gain), how do I get them closer to the face plate? They like stop halfway down.

Kind regards
John
That's how my shelf/bell switches ended up too
Re gain knobs, me too asked about that, and was instructed to cut shafts.
Title: Re: 500 series Sontec / GML type eq
Post by: rob61 on February 08, 2016, 06:37:51 AM
I'm getting ready to start my build of these. It would probably be easier to hacksaw these shorter before soldering. Can anyone who has done this comment on the length that needs to be cut off?
Title: Re: 500 series Sontec / GML type eq
Post by: Unit7 on February 08, 2016, 08:43:58 AM
I'm getting ready to start my build of these. It would probably be easier to hacksaw these shorter before soldering. Can anyone who has done this comment on the length that needs to be cut off?

I cut mine (only the plastic shafts) just inside the groove, like 2-2.5mm. Accidentally cut one shaft a bit deeper so had to attend a little extra to get knob at same distance from faceplate as the others, but it still worked out fine.

BTW I cut mine assembled, holding unit laying on bubble wrap on edge of desk. Got a lot of plastic dust on faceplate and I was very careful to not scratch it and not use too much force to break anything, but doing it with unit assembled made it easier for me as I don't have a proper vise to hold those tiny things. But if I'd do it again I guess I'd do it without the faceplate on, assembled on the L-plate.
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on February 08, 2016, 11:51:19 AM
The red switches.
Same here,it's allright for my taste.
For the shafts,yes,cut them down if you want them shorter.
Haven't done this on mine,but if I want it some day I'd simply dremel them assembeled,just cover the rest to prevent it from dust.


Best regards,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: rob61 on February 08, 2016, 01:25:27 PM
Is it the plastic or metal shafts that need to be trimmed?
Title: Re: 500 series Sontec / GML type eq
Post by: Monoklang on February 09, 2016, 06:59:06 AM
Finished! Both units sounds amazing!

Thanks David for a great kit!
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on February 09, 2016, 03:36:52 PM
Is it the plastic or metal shafts that need to be trimmed?

It's the plastic ones. Very easy to do with a Dremel, just be careful to not cutting to much, 3mm max is cool. I've done accidently 5mm, it's very short!!!
Title: Re: 500 series Sontec / GML type eq
Post by: rob61 on February 10, 2016, 08:53:26 PM
Starting my build. For DOA 4 and 5 I plan to use the OPA134PA and later experiment with the PPA992 OpAmps. I'm not sure if I install the 12pf Ccomp 4-5 (listed as Compensation cap for audio amps) or not. Can someone tell me would I install these for my intended OpAmp selection using 16v rails?

Also, for C18, the silkscreen shows each lead pad with a "+" sign on mine. Should I then assume the square pad is the positive?

Title: Re: 500 series Sontec / GML type eq
Post by: rob61 on February 12, 2016, 01:11:03 PM
Finished my pair. They sound fantastic. Thanks so much for making this extrordinary kit available!
Title: Re: 500 series Sontec / GML type eq
Post by: living sounds on March 06, 2016, 07:14:08 PM
Great project, I'm really tempted!

Do the 5pf caps have to be mica? At almost 3 EUR a piece (mouser) these are rather pricy, especially for a very small feedback cap. Wouldn't a COG ceramic do the job just as well?
Title: Re: 500 series Sontec / GML type eq
Post by: tonedude on April 17, 2016, 07:24:34 AM
Got my kits on friday and they are now finnished. But, unfortunately I seemed to have had really bad luck with the quality of the tripple deck pots I got from David...

One of the pots had two 4.7k decks instead of two 100k (it was 4.7k - 4.7k - 100k, instead of 4.7k - 100k - 100k...)

The other faulty pot had a middle deck that have a bad connection in some way, it is therefore impossible to get a stable measurment out of it (it measures an unstable 120k, moving uppwards, instead of the specd 100k.) Most of the 100k decks did measure somewhere around 90k to 95k, witch should be ok, I quess. So my stereopair now have the higest and lowest freq band tracking somewhere inbetween, bad to exceptionally bad...

The really sh*tty part is that i allready had them mounted before finding out that I got pots of bad quality.  So, one tip of advice is to meassure and test them out, before soldering them in place... Maybe also match them for stereo use. Could spare you some valuable time and eliminate frustration...

I have contacted David about it.
Title: Re: 500 series Sontec / GML type eq
Post by: petermontg on April 22, 2016, 09:24:36 AM
Anybody put together any audio samples for this
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on April 26, 2016, 01:02:25 PM
Got my kits on friday and they are now finnished. But, unfortunately I seemed to have had really bad luck with the quality of the tripple deck pots I got from David...

One of the pots had two 4.7k decks instead of two 100k (it was 4.7k - 4.7k - 100k, instead of 4.7k - 100k - 100k...)

The other faulty pot had a middle deck that have a bad connection in some way, it is therefore impossible to get a stable measurment out of it (it measures an unstable 120k, moving uppwards, instead of the specd 100k.) Most of the 100k decks did measure somewhere around 90k to 95k, witch should be ok, I quess. So my stereopair now have the higest and lowest freq band tracking somewhere inbetween, bad to exceptionally bad...

The really sh*tty part is that i allready had them mounted before finding out that I got pots of bad quality.  So, one tip of advice is to meassure and test them out, before soldering them in place... Maybe also match them for stereo use. Could spare you some valuable time and eliminate frustration...

I have contacted David about it.
May I ask how this issue worked out,any solutions?
Could be interesting for others around here too I think.


Thank you in advance,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: Sinkia on April 27, 2016, 04:17:56 AM
Awesome !

I'm really thinking about ordering a couple !

I'll keep read this post !

Great job
Title: Re: 500 series Sontec / GML type eq
Post by: tonedude on April 28, 2016, 01:58:52 AM

May I ask how this issue worked out,any solutions?
Could be interesting for others around here too I think.


Thank you in advance,


Udo.

I recieved two new pots from David and my EQ's are now up and running, both sounds marvelous!

I did however have som problems with one of the new ones. First of it does not have the same quality feel as the other pots I got. And after contacting David about it, and also after doing my own research... we found out that the lack of "qualitiy feel" when turning the pot, is dependant on some sticky oil/grease that makes the pot smoth/hard to turn (in a god way...), and that hard/smoth feeling was lacking in one of my pots. And that "feeling" is gone because the sticky oil is absent on the outer shaft on that one. The same pot also had a contact problem on one pin (middle/wiper pin on middle deck), but I gave It a light squeeze with a plier and have had no problem with it since.

 // Mattias
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on April 28, 2016, 11:02:34 AM
Hi Matthias,


thanks for explaination,glad you got it solved now.
Happy mixing,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: qmp audio on April 28, 2016, 11:57:37 AM
does not have the same quality feel as the other pots I got.

One of my LF pots has this issue.  It's much 'looser' to turn than the others.
Title: Re: 500 series Sontec / GML type eq
Post by: jona on May 17, 2016, 04:54:50 PM
i finished a pair as well and i am very happy with the sound.. so much that i think about building another pair with stepped controls..
how can i calculate the resistors for frequency, q and gain ?
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on May 26, 2016, 03:55:38 AM
i finished a pair as well and i am very happy with the sound.. so much that i think about building another pair with stepped controls..
how can i calculate the resistors for frequency, q and gain ?
Hi,


yes,a nice idea,had this in mind too.Sad to say I don't know the how-to calculate this (except for the gain pots of course  ;D ).
One way might be to derive the values from real potentiometers in circuit prior to building a stepped version.


Did you find a solution?


Best regards,


Udo.


P.S.:In the "Igor Days" member Harpo helped us with excellent excel charts to make a sontec.
He's a math genius.Maybe he wants to chime in.....?
Title: Re: 500 series Sontec / GML type eq
Post by: [silent:arts] on May 26, 2016, 06:53:43 AM
fc = 159000 / ((R73+R75) * C27 * (R74+R76) * C28)^0.5

I did an Excel sheet for this years ago, maybe someone has saved it?
Can't find it anymore.
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on May 26, 2016, 08:10:11 AM
fc = 159000 / ((R73+R75) * C27 * (R74+R76) * C28)^0.5

I did an Excel sheet for this years ago, maybe someone has saved it?
Can't find it anymore.

Wow,thanks Volker!But I seriously fail when it comes to it.So I will bake some banana bread instead.Cheers,Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: Harpo on May 27, 2016, 02:25:46 PM
P.S.:In the "Igor Days" member Harpo helped us with excellent excel charts to make a sontec.
He's a math genius.Maybe he wants to chime in.....?
He's not. Some quick&dirty banana bread (http://www.hausverwaltung-heger.de/al_leck_trick/SontecCalc_Onlymee.xls) for frequency ...
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on May 27, 2016, 03:02:28 PM
P.S.:In the "Igor Days" member Harpo helped us with excellent excel charts to make a sontec.
He's a math genius.Maybe he wants to chime in.....?
He's not. Some quick&dirty banana bread (http://www.hausverwaltung-heger.de/al_leck_trick/SontecCalc_Onlymee.xls) for frequency ...
Wow!!!
Thank you very much indeed,it is good to have you here!
This teases me to do a stepped version for me too (although I already have the 500 version).
Let´s see if I can open the charts somehow (I´m on a mac).If not I have some other Windows based computers at work.
And eat some banana bread of course ;D


Great stuff Harpo!


Best regards,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: bruno2000 on May 27, 2016, 03:50:11 PM
P.S.:In the "Igor Days" member Harpo helped us with excellent excel charts to make a sontec.
He's a math genius.Maybe he wants to chime in.....?
He's not. Some quick&dirty banana bread (http://www.hausverwaltung-heger.de/al_leck_trick/SontecCalc_Onlymee.xls) for frequency ...

Thank you!
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on May 28, 2016, 06:10:41 AM
Question for Harpo:


I have now installed Open Office on my mac,your Calc opens up nicely.
Opted for 23 positions.
So I went through it and found the frequency choice quite nice for the first four bands.
On the high(shelf) the end at roughly 60kHz was a bit high for me. ;D
Although I´m totally unexperienced with excel and the likes (I was born in the chalkboard times….) I gave it a try and altered the end frequency to 26,5kHz to make it more useful and to follow the original onlymee-design.
Gave me a ratio of 13,15.
All good so far,but at the end position (switch fully cw) the chart "adding series resistor values" gives me a value of 4,530(E96) and 4,640(E48)kilo-Ohms .
Since all other bands end at zero ohms,am I right to add this value as a series resistor at the cw end (23rd position)?


Thank you in advance,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: Harpo on May 28, 2016, 07:30:54 AM
Udo, if you substitute the high band formerly 3K3s R73 and R74 in cell E9 with parts value 7K867 resistors as the closest match for your new target frequency (3300+4530=7830) with keeping caps values, the CW end of the chart will return to zeroes (ignoring, the pots/rheostats resistance might not be 0 ... 100K but maybe 17ohms ...98K3, so you could measure their real world value and update the cells in chart rows 11...14 for more realistic filter response numbers). You could play with cap values as well ... just sayin'
Harpo
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on May 28, 2016, 08:24:03 AM
Thank you very much Harpo!
This is going to be a real fun,so many variables,hahaha…….
Changing R73 and R74 is a great hint indeed.
I think I will get the kits,the parts and then with the real caps in hands put their values into your Calc,then start from there to have a good "fundament" to start with.I might order multiples of C27 & C28 to match them for stereo operation in pairs.


Thanks again and have a nice weekend,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: Zander on May 28, 2016, 08:46:10 AM
Hi Udo,


What brand of switches will you be using?


Zander
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on May 28, 2016, 08:54:46 AM
Hi Udo,


What brand of switches will you be using?


Zander
Hi Zander,


not sure yet,ELMA is out of my range.
I asked URALTONE for 24 pos. switches,but the downside is that they're BMM types.
So I'm hunting for parts atm.


Best,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: Harpo on May 28, 2016, 10:14:05 AM
not sure yet,ELMA is out of my range.
I asked URALTONE for 24 pos. switches,but the downside is that they're BMM types.
When you join the switches CCW end (1st.pos) in the adding series resistors config with the BBM type switch pole, you prevent an open connection while switching, otherwise (single switched resistors) put a high value resistor in parallel to the switched rheostat ends ...
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on May 28, 2016, 01:28:16 PM
Hello Harpo,


thank you,
although I´m a bit confused now.


Let me see if I got this right.
I want to go for adding series resistors.
So if I get it right the circuit "sees" the full resistor chain when in open condition using a BBM type switch,correct?
Looking at the schematic there already is a connection between the wiper (which will be the pole) and one end.
Isn´t that a rheostat configuration already?
If so I only have to run two wires per wafer,one will be the joined ccw end/pole directly at the rotary switch and the other is the cw end,right?


Here´s the schematic for your reference (although I´m sure you have it):
http://www.thedonclassics.com/schematics/250EQ_schematic.pdf


Please excuse my noob questions,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: Harpo on May 28, 2016, 02:46:23 PM
So if I get it right the circuit "sees" the full resistor chain when in open condition using a BBM type switch,correct?
yupp, about 100K per deck, a lot less than infinity and known working.
Quote
Looking at the schematic there already is a connection between the wiper (which will be the pole) and one end.
Isn´t that a rheostat configuration already?
If so I only have to run two wires per wafer,one will be the joined ccw end/pole directly at the rotary switch and the other is the cw end,right?
correct, a rheostat is a two legged device.
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on May 28, 2016, 02:59:34 PM
Excellent Harpo,you made my day!
This way I can go for 24positions plus save some money,great!


Thanks a lot,


best,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: SOLO on September 26, 2016, 12:45:08 AM
Hey i was contacting you to ask how much would you charge to make another pair of your 500 series Sontec / GML type eq
Im looking to spotlight a lot of boutique 500 series modules and designers and my upcoming YouTube show
Thanks again
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on September 26, 2016, 12:05:55 PM
Hey i was contacting you to ask how much would you charge to make another pair of your 500 series Sontec / GML type eq
Im looking to spotlight a lot of boutique 500 series modules and designers and my upcoming YouTube show
Thanks again





Don't get it,who do you refer to?


Best regards,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on November 18, 2016, 10:25:10 AM
Another pair up and running.


Best regards,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: mysticmerlin on December 19, 2016, 06:18:50 PM
Just finished 4 using opa134 and 24v. All worked first time, easy build.
The sound is wonderful, very clear and surgical yet smooth.

These kits are a steal.
I have a couple of GML channel strips and these sound just as good .

Thanks David

Title: Re: 500 series Sontec / GML type eq
Post by: john12ax7 on December 20, 2016, 01:40:30 AM
Just finished 4 using opa134 and 24v. All worked first time, easy build.
The sound is wonderful, very clear and surgical yet smooth.

These kits are a steal.
I have a couple of GML channel strips and these sound just as good .

Thanks David

Isn't 24v a bit much for opa134? Might work for a bit but long term probably burn up.
Title: Re: 500 series Sontec / GML type eq
Post by: mysticmerlin on December 20, 2016, 02:00:08 AM
Isn't 24v a bit much for opa134? Might work for a bit but long term probably burn up.
With the Zeners I have 18v .  I have a mix of 16v / 24v modules in my racks and using the 24v  rails balances out with  the rest.
Title: Re: 500 series Sontec / GML type eq
Post by: evilcat on January 16, 2017, 11:05:40 AM
Hi there,
Small problem here! I have a pair of these EQ, working great for a year now. Recently a problem appears: my 2 channels are saturated and one of them is something like 12dB hotter than the other.
I've opened the case (BTW I've racked them with JLM PSU on +/-16V) checked voltages and continuity and there's something weird: voltages are ok BUT there's continuity between +V and 0V!!!
I've disconnected the PSU and the modules, checked the PSU alone and find the same problem. There's continuity between +V and 0V BUT only when the unit is turned ON. When I turn it OFF there's no continuity anymore.
When I say "continuity" it's my DMM ringing. As for the impedance between ground and 0V with the chassis it's 13 ohms and between +V and chassis it's 68 ohms.
Any ideas?
Thanks

Ben
Title: Re: 500 series Sontec / GML type eq
Post by: thomasdf on February 11, 2017, 06:38:44 PM
Hi guys
This project looks amazing, how can I get my hands on a pair of kits?
Thanks
Title: Re: 500 series Sontec / GML type eq
Post by: kosi on February 11, 2017, 07:04:08 PM
http://www.thedonclassics.com/#all-kits
Title: Re: 500 series Sontec / GML type eq
Post by: thomasdf on February 13, 2017, 12:01:26 PM
Stupid me! Thanks!!
Thomas
Title: Re: 500 series Sontec / GML type eq
Post by: Studio Mollan on July 26, 2017, 11:57:47 AM
I just finished my two kits and they do sound amazing!

There's two things though i cant get my head around.

 1.  A few of the trimpots, the ones in the filter section, won't zero out the voltage across the test points. I'm between 4 and 50mv on a few of them. The filters sound good though after a very short first test.

2. the Modules are about 2mm to deep to properly fit my desk. An vintage API 2488. Anyone else had this issue? The modules are floating above the top of the adjacent modules when the connector is fully in. I have double, and triple checked that I've assembled the front panel as in the manual. If i moved the top nuts to the other side of the front panel i might get a snug fit. Also the knobs are all about 2mm above the face plate when pushed in fully.

Also i had to connect pin 5 with pin 13 to get it working. Don't know if this is related to me using them in a desk as opposed to a 500 rack.

/
Emil
Title: Re: 500 series Sontec / GML type eq
Post by: jensenmann on July 26, 2017, 05:33:26 PM
Did you use 25turn precision trimmers or single turn versions. With precision trimmers I could calibrate the servos down to the 10uV region.
Title: Re: 500 series Sontec / GML type eq
Post by: Studio Mollan on July 26, 2017, 06:02:40 PM
Hi,
I used the ines from the BOM. 25 turns seem right from what I remember. They are not single turn. At least 10 turns.

Did you use 25turn precision trimmers or single turn versions. With precision trimmers I could calibrate the servos down to the 10uV region.
Title: Re: 500 series Sontec / GML type eq
Post by: Rogy on October 01, 2017, 11:39:10 AM
Deleted...

My issue appeared to be a measurement setup issue; my four units are working flawless!

Best Rogy
Title: Re: 500 series Sontec / GML type eq
Post by: benewell on January 16, 2018, 03:46:23 PM
Hi There,
Long time lurker, first time poster, I purchased 2 kits last summer and they are absolutely Wonderful!

Unfortunately only the BOOST function for each band works on one EQ... I'm not able to cut at all. Has anyone experienced this, or have any hints I could try to isolate the issue?

I've:
- reseated the ribbon cable
- made sure TPS 1-TPS 2 read 0mv
- tested all switches and pots work mechanically, and are easy to switch/rotate
- tried different slots in 500 series rack

And I still have the same issue of not being able to cut with any band. My other EQ works flawlessly however. Any help or suggestions are greatly appreciated!

Best,
Brian


other notes: I also swapped R69's for 51k as per suggested earlier in the thread, getting a nice gentle +-, instead of the full 12dB. The only other issues I noticed are the mv's at each frequency band test point are slightly off (anywhere from 2-50ish similar to another user), but that doesn't seem to affect the functionality of the unit.
Title: Re: 500 series Sontec / GML type eq
Post by: Zander on January 17, 2018, 02:50:09 AM
For those who used Pier Paolo's APP992, did you adjust or leave out some components.


Zander
Title: Re: 500 series Sontec / GML type eq
Post by: Studio Mollan on January 18, 2018, 04:24:22 PM
Hey,
There must be an issue round about here in your EQ.
Check for cold solder joints or missing, faulty components. the ribbon cable is a candidate,. Try the one in the functioning unit, or check for continuity with a DMM. Truly great eq's!


Hi There,
Long time lurker, first time poster, I purchased 2 kits last summer and they are absolutely Wonderful!

Unfortunately only the BOOST function for each band works on one EQ... I'm not able to cut at all. Has anyone experienced this, or have any hints I could try to isolate the issue?

I've:
- reseated the ribbon cable
- made sure TPS 1-TPS 2 read 0mv
- tested all switches and pots work mechanically, and are easy to switch/rotate
- tried different slots in 500 series rack

And I still have the same issue of not being able to cut with any band. My other EQ works flawlessly however. Any help or suggestions are greatly appreciated!

Best,
Brian


other notes: I also swapped R69's for 51k as per suggested earlier in the thread, getting a nice gentle +-, instead of the full 12dB. The only other issues I noticed are the mv's at each frequency band test point are slightly off (anywhere from 2-50ish similar to another user), but that doesn't seem to affect the functionality of the unit.
Title: Re: 500 series Sontec / GML type eq
Post by: benewell on January 22, 2018, 09:15:26 PM
Thank you for the response!

Unfortunately I have been busy, but will try those suspects you suggested soon! I'm noticing that on my working EQ I added the optional C18a, as well as ccomp4 and compIC5. As I am a bit of a novice with circuit design and it was mentioned as optional/TBC, I wasn't sure if they were necessary... but am considering adding them to the non-functioning EQ.

Would it be beneficial to have those as well?

EDIT: Found the issue! There was a nick along the top of the Top PCB preventing signal from CCW on the Ribbon Cable to R48. Good news, everything looks neat and all solder issues/mv problems are gone with done soldering, I just wish I noticed this earlier hah Bad News is now I have to repair the trace alone the top, which shouldn't be too hard but I guess there's a first time for everything!

Thanks Studio Mollan for pointing me in the right direction!

[/quote]
Hey,
There must be an issue round about here in your EQ.
Check for cold solder joints or missing, faulty components. the ribbon cable is a candidate,. Try the one in the functioning unit, or check for continuity with a DMM. Truly great eq's!


Title: Re: 500 series Sontec / GML type eq
Post by: Spino on January 28, 2018, 06:15:08 AM
bump this.

and also, nobody commented on the sound of the 250eqs with those in.

For those who used Pier Paolo's APP992, did you adjust or leave out some components.


Zander
Title: Re: 500 series Sontec / GML type eq
Post by: Studio Mollan on January 29, 2018, 10:26:20 AM
Hi,
Yes you should fit them all. C18a isn't crucial, but recommended, but the Ccomp4 and compic5 should be fitted.

Thank you for the response!

Unfortunately I have been busy, but will try those suspects you suggested soon! I'm noticing that on my working EQ I added the optional C18a, as well as ccomp4 and compIC5. As I am a bit of a novice with circuit design and it was mentioned as optional/TBC, I wasn't sure if they were necessary... but am considering adding them to the non-functioning EQ.

Would it be beneficial to have those as well?
Title: Re: 500 series Sontec / GML type eq
Post by: benewell on January 29, 2018, 02:51:26 PM
Good to know!

I've fitted Ccomp4, compic5, and C18a, as well as found the issue (broken trace at the top of the PCB before R48). Both EQ's are back up and working flawlessly  ;D

Thank you Studio Mollan!


Hi,
Yes you should fit them all. C18a isn't crucial, but recommended, but the Ccomp4 and compic5 should be fitted.
Title: Re: 500 series Sontec / GML type eq
Post by: Studio Mollan on January 30, 2018, 01:10:36 PM
No problem dude, Glad they're working now!
Good to know!

I've fitted Ccomp4, compic5, and C18a, as well as found the issue (broken trace at the top of the PCB before R48). Both EQ's are back up and working flawlessly  ;D

Thank you Studio Mollan!
Title: Re: 500 series Sontec / GML type eq
Post by: Zander on February 06, 2018, 01:39:00 AM
SOLVED. David suggested to try this under its intended load. So I used a 600 Ohm (he calculated that for me :) ) resistor to ground from the negative filter rail. The zener is working just fine. Thank you David.

I have both my sontecs set for +/-24v for the main doa and +/-18v for the filter rails. In both Vcc- is too low. -19.5 and -18.7. Vcc+ is fine. Combined this is over the max supply voltage of 36v.
I suspect the 6V2 zeners 5% tolerance. I changed them out with a few others. Which were all giving me to little voltage drop.
I think I have two options: 1) changing the zeners for new ones or order 7V5 zeners. 2) use the +/-16v voltage rails.

Am I overlooking something? Anyone here set up the power rails like I did? It’s option C in the manual.

Zander
Title: Re: 500 series Sontec / GML type eq
Post by: baslotto on April 26, 2018, 03:54:20 AM
Hey guys!

Not sure anyone is still hanging around here but I just finished 2 of these great units and all the voltages and measurements were right before I passed music through them.

Once I did that I realized  that for one of the channels the BLUE gain knob won't do anything.

Can anybody help me figuring this out? It looks like all my soldering has been done correctly, I don't see any missing points.

I swapped the gain knobs modules to see if that affected the other module but it's not the knob module.

Any other measurements to help me identify where to start?

Thank you for any help.

Stefano
Title: Re: 500 series Sontec / GML type eq
Post by: Studio Mollan on April 26, 2018, 04:40:22 PM
try using the ribboncable from the working unit. It might be a bad cable.


Hey guys!

Not sure anyone is still hanging around here but I just finished 2 of these great units and all the voltages and measurements were right before I passed music through them.

Once I did that I realized  that for one of the channels the BLUE gain knob won't do anything.

Can anybody help me figuring this out? It looks like all my soldering has been done correctly, I don't see any missing points.

I swapped the gain knobs modules to see if that affected the other module but it's not the knob module.

Any other measurements to help me identify where to start?

Thank you for any help.

Stefano
Title: Re: 500 series Sontec / GML type eq
Post by: baslotto on April 26, 2018, 04:54:36 PM
try using the ribboncable from the working unit. It might be a bad cable.

OMG it was the ribbon!!!!!!!! These things sound insane!!

THANK YOU!! YOU NAILED IT!!!!!!!!
Title: Re: 500 series Sontec / GML type eq
Post by: Studio Mollan on April 27, 2018, 11:37:36 AM
Glad to be of help! they are indeed fantastic!


OMG it was the ribbon!!!!!!!! These things sound insane!!

THANK YOU!! YOU NAILED IT!!!!!!!!
Title: Re: 500 series Sontec / GML type eq
Post by: Blackdawg on June 17, 2018, 01:44:46 AM
Eyeing these hard. But my racks only do 16v..is that okay??

Edit: read the manual. Looks like I'll be good, however, does that mean I can still use DOA? or just ICs?
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on June 17, 2018, 02:26:46 AM
Eyeing these hard. But my racks only do 16v..is that okay??

Edit: read the manual. Looks like I'll be good, however, does that mean I can still use DOA? or just ICs?
Hello,


yes,it´s in the manual.You have choices from running them on both dual rails at the same time if you want,e.g. eq on +/-16vdc and doas on +/-24vdc.It is „programmed“ by jumpers/ptcs close to the card edge connector.
Also you can run doas on the 16vdc rails,they will have a bit lower headroom then,but don ´t become „bad“ soundwise.

Best regards,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: Blackdawg on June 17, 2018, 12:34:31 PM
Hello,


yes,it´s in the manual.You have choices from running them on both dual rails at the same time if you want,e.g. eq on +/-16vdc and doas on +/-24vdc.It is „programmed“ by jumpers/ptcs close to the card edge connector.
Also you can run doas on the 16vdc rails,they will have a bit lower headroom then,but don ´t become „bad“ soundwise.

Best regards,


Udo.

Thanks for Clarifying Udo.

Part of me is regretting not having a 24v rail in my TAC racks..but too late now!  I haven't had issues with 16v, but then again, haven't experienced 24v so I don't know what I'm missing  ;D

Will have to get a pair of these!
Title: Re: 500 series Sontec / GML type eq
Post by: Blackdawg on June 18, 2018, 01:22:32 AM
Has  anyone had any luck making these stepped controlled for recall?
Title: Re: 500 series Sontec / GML type eq
Post by: Cool711 on September 11, 2018, 11:01:24 AM
Hey guys,

First time posting here; trying to figure out if to get these.

My main question is: what is the difference quality / components wise to these and the GML 8200?

Why does the GML cost > $6000, and these so much less? I'm having some cognitive dissonance with the fact that these are more than $5000 cheaper without there being some major difference (and find it hard to believe that the difference is just based on the name. Sure; $2-$3000 would be one thing, but this much of a difference?)

Thanks!
Title: Re: 500 series Sontec / GML type eq
Post by: r2d2 on September 12, 2018, 05:43:27 AM
Has  anyone had any luck making these stepped controlled for recall?

(..hoping  to not bore someone, repeating things written in previous posts)

some year ago i seen a diy project with rotary switch on frequency selector and +/- gain pots
all resistors for steps positions , selected and matched minimum at 1%
(check how many hours of work it require , all the rest apart .. , opamp match included )

for the recall automation it is possible use motorized rotary switches…
but seem that only very expensive type can be used for a quality professional Eq

expensive cost apart  , it is necessary write the software for control and re-call (… C+ protocol ?)
and build the circuit for make it run too .…

much cool as "easy" ?  ???

Hey guys,

First time posting here; trying to figure out if to get these.

My main question is: what is the difference quality / components wise to these and the GML 8200?

Why does the GML cost > $6000, and these so much less? I'm having some cognitive dissonance with the fact that these are more than $5000 cheaper without there being some major difference (and find it hard to believe that the difference is just based on the name. Sure; $2-$3000 would be one thing, but this much of a difference?)

Thanks!

stepped expensive hi quality rotary switches apart ,
and all the time required to hand match the resistors for the frequency selectors and +/- gain pots
the GML opamps are  designed , made/assembled  and matched by GML (@ Manley Labs Factory)

The Sontec by Igor can be build also with hi quality (and cost) IC opamp ,
and DOA for a more "analog" type ,

The original sound  of Sontec Eq  come from the type of  the IC opamp
today no more available on the market ,

why a transparent clean analog EQ
with actual DAW full of digital transparent EQ plug ins  ?

it is not better an analog-tube-inductors  EQ with cool  "color" and harmonic distortion/saturation  ?
(……. "dry & wet blender" included as well … )

a new diy "challenge"  ?   ;)

cheers



Title: Re: 500 series Sontec / GML type eq
Post by: SIXTYNINER on September 19, 2018, 12:39:52 PM

why a transparent clean analog EQ
with actual DAW full of digital transparent EQ plug ins  ?

it is not better an analog-tube-inductors  EQ with cool  "color" and harmonic distortion/saturation  ?
(……. "dry & wet blender" included as well … )

a new diy "challenge"  ?   ;)

+ 1 here
Title: Re: 500 series Sontec / GML type eq
Post by: Cool711 on September 29, 2018, 02:48:31 PM
Thanks for the reply, and sorry, but I found it was a bit hard to understand.

To be clear, the multi-thousand $ difference in cost is because GML makes their own match Op-Amps?

And that's it?

Title: Re: 500 series Sontec / GML type eq
Post by: OTRM on October 16, 2018, 02:53:08 PM
Been following this thread with great interest. Thinking about putting a pair to use in the mastering chain. I do have a few Qs....

- How would you classify the sound/character of this EQ?
- Do you consider it to be mastering quality? IE: transparent, clean, not too colored, etc...
- Read earlier about possibly using stepped controls. Anyone done this successfully? For all controls - gain, freq and Q...?
- Also would want to knock the max gain down to +- 6dB in 0.5 dB steps. Anyone figured out the components for this?

Also would like to hear users chime in on the sonic qualities.
Thanks for any help.
OTRM
Title: Re: 500 series Sontec / GML type eq
Post by: benewell on October 22, 2018, 05:07:51 PM
Been following this thread with great interest. Thinking about putting a pair to use in the mastering chain. I do have a few Qs....

- How would you classify the sound/character of this EQ?
- Do you consider it to be mastering quality? IE: transparent, clean, not too colored, etc...
- Read earlier about possibly using stepped controls. Anyone done this successfully? For all controls - gain, freq and Q...?
- Also would want to knock the max gain down to +- 6dB in 0.5 dB steps. Anyone figured out the components for this?

Also would like to hear users chime in on the sonic qualities.
Thanks for any help.
OTRM

Hi ORTM,
I'd be happy to give my personal opinion fwiw. I've used a few EQ's, and had the pleasure to hear a Sontec with original opamps in the past.

- Using the suggested opamps in the BOM on +-16v rails, I noticed that it is clean, yet musical, while being unobtrusive. At no point could I "hear" the EQ as an additional layer, as it sounds very natural without having as heavy a vibe as a Sontec. Not overtly surgical, but excellent for doing what it's supposed to.

- Yes. Especially as you can mod it to +-6db easily (see note below) and it is fairly transparent. I find myself using more of this EQ to gently shape where other EQ's may be a little too forward or obvious.

- You *can* however, it looks as though that would require a different housing, as the PCB's are designed to fit within the 500 series format. It is doable, but may need a different chassis, PSU, cabling to pots/switches, etc. This may require lots of work to come up with your own solution depending on your needs.

- @Onlymeeee describes this on page 14, reply #276,  simply by swapping out R69s for 51k. You can incorporate stepped log switches for gain, as long as you have the same total value (50k?) as the center tapped pots... but the maths to figure out the +-.5db steps is beyond me.

Best,
Brian
Title: Re: 500 series Sontec / GML type eq
Post by: OTRM on November 02, 2018, 05:15:22 PM
Hi ORTM,
I'd be happy to give my personal opinion fwiw. I've used a few EQ's, and had the pleasure to hear a Sontec with original opamps in the past.

- Using the suggested opamps in the BOM on +-16v rails, I noticed that it is clean, yet musical, while being unobtrusive. At no point could I "hear" the EQ as an additional layer, as it sounds very natural without having as heavy a vibe as a Sontec. Not overtly surgical, but excellent for doing what it's supposed to.

- Yes. Especially as you can mod it to +-6db easily (see note below) and it is fairly transparent. I find myself using more of this EQ to gently shape where other EQ's may be a little too forward or obvious.

- You *can* however, it looks as though that would require a different housing, as the PCB's are designed to fit within the 500 series format. It is doable, but may need a different chassis, PSU, cabling to pots/switches, etc. This may require lots of work to come up with your own solution depending on your needs.

- @Onlymeeee describes this on page 14, reply #276,  simply by swapping out R69s for 51k. You can incorporate stepped log switches for gain, as long as you have the same total value (50k?) as the center tapped pots... but the maths to figure out the +-.5db steps is beyond me.

Best,
Brian
Thanks for the input Brian
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on November 03, 2018, 01:44:51 AM

Hello,
you wrote:
You can incorporate stepped log switches for gain, as long as you have the same total value (50k?) as the center tapped pots... but the maths to figure out the +-.5db steps is beyond me.


The gain as well as Q is the easy part to make them stepped switches,they are linear,not log.!
For a series string („adding“) switch just divide 50k by the number of steps (minus 1),and that‘s it for the gain.
So for a -say- 23 steps switch it is 2k273 for each step.
In +/-6dB mode the steps will roughly be 0.55dB then,not too bad I‘d say!

Choose the closest value you can find.The goal is to get the overall resistance of roughly 50k.



For Q I‘d take just 5 or 6 steps,a high resolution Q is not necessary in my opinion,plus the switch is less expensive.


For frequency I had the same questions,to calculate the steps was beyond my capabilities.
Reading this thread carefully answers your question.It is all here.
Member Harpo has been so kind to calculate it for us!Again!
Either you search for „banana bread“ here or go back two pages to reply #320.


Hope to have helped,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: stickybeats on December 18, 2018, 05:22:00 PM
Hi Udo-

I'm curious, did you ever complete the +/- 6dB version with the stepped pots? If so, which pots did you end up using?

It looked like you were going to build it but I couldn't tell if you ended up doing it.
Thanks!
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on December 18, 2018, 07:57:07 PM
Hi Udo-

I'm curious, did you ever complete the +/- 6dB version with the stepped pots? If so, which pots did you end up using?

It looked like you were going to build it but I couldn't tell if you ended up doing it.
Thanks!


Hello and welcome to the forum,


still not fully completed,but the audio works fine on the bench.Have still to do a final frontpanel layout because I might implement some extra features.I might tweak the high frequency band a bit too.
For now I don‘t have the time to work on it.But it is a very nice and fun project.
For the pots.....I didn‘t use any.....you mean rotary switches,yes?
Lorlin are o.k. for now for the Q,for the rest I used the blue ones sold by Uraltone.You can find them in the bay too.
It depends on what quality you want and if you can find or need 23 or 24 or even higher (!) position switches.
If you have your house for sale go for Elma etc...... ;D


Best regards,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: john12ax7 on December 18, 2018, 08:18:39 PM
Are Lorlin switches really that bad compared to Grayhill and Elma? Have never used them.

Are you keeping things 500 series with the switches?  I've considered putting the pcbs in a rack case and then make it switched.
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on December 18, 2018, 08:26:59 PM
Are Lorlin switches really that bad compared to Grayhill and Elma? Have never used them.

Are you keeping things 500 series with the switches?  I've considered putting the pcbs in a rack case and then make it switched.
Lorlins are o.k. for now,I used some „encapsuled gold contact“ types that I had here.
If you have the money then yes,go for Elma or Grayhill.
I basically left the 500 series pcbs as they were,just used the small pot pcbs for wire distributing instead.Easier than soldering on the IDC connectors/-pads.I also went for 24vdc for DOAs.
All will reside in a 19“ rack (I make it stereo),impossible to cram this amount of switched pots into 500 format.


Hope to have helped,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: john12ax7 on December 18, 2018, 08:51:54 PM
Yes,  thank you.

Do the Lorlin have reliability issues due to the plastic construction?

I've also been looking at some rotarys from C&K and E-switch.  Mostly I've used Grayhill in the past,  but the pitch on the right angle leads is really small which makes for a tougher soldering job.
Title: Re: 500 series Sontec / GML type eq
Post by: stickybeats on December 18, 2018, 09:27:05 PM
Hello and welcome to the forum,
Thanks! Glad to be here. I've been a longtime lurker and finally decided I want to try building some of these wonderful projects.

For the pots.....I didn‘t use any.....you mean rotary switches,yes?
Oops, yes. I meant rotary switches.  That's what I get for reading through the entire thread in one sitting. Ha.

Thanks so much for the information, I am considering a 2u rack mount stereo version using rotary switches and modifying the boost/cut to a +/- 6dB range.  It'll probably be fairly slow, but I'll post updates if I decide to go for it.
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on December 19, 2018, 01:56:26 AM
Yes,  thank you.

Do the Lorlin have reliability issues due to the plastic construction?

I've also been looking at some rotarys from C&K and E-switch.  Mostly I've used Grayhill in the past,  but the pitch on the right angle leads is really small which makes for a tougher soldering job.
Hello again,


Lorlins are definetely not super reliable,though the before mentioned types did their job so far.For my final build I consider to swap them to Grayhills or other more reliable types.
Soldering wires to Grayhills is no fun,promised!Have done that before......
But there are small pcbs existing which can hold the switches plus resistors.
If you‘re in the US e.g. look here (scroll down a bit):


http://capi-gear.com/catalog/index.php?cPath=51_133 (http://capi-gear.com/catalog/index.php?cPath=51_133)


For the EU maybe ask in the forum here,I‘m not sure if member ruffrecords (Ian Thompson-Bell) did something like that a while ago.....?


Best regards,


Udo.



Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on December 19, 2018, 02:08:06 AM
Thanks! Glad to be here. I've been a longtime lurker and finally decided I want to try building some of these wonderful projects.
Oops, yes. I meant rotary switches.  That's what I get for reading through the entire thread in one sitting. Ha.

Thanks so much for the information, I am considering a 2u rack mount stereo version using rotary switches and modifying the boost/cut to a +/- 6dB range.  It'll probably be fairly slow, but I'll post updates if I decide to go for it.
Hello,


yes,take your time,patience is the key.
The kit is straight forward and easy to build,Adjustments are clearly described and no vodoo.
For the switches just be patient and prepare the resistors well,especially match them for good stereo tracking.
You can make the single bands‘ gain/cut switchable between say +/- 6 or +/- 12dB,it is just one resistor per band.


Have fun,


best regards,


Udo.
Title: Re: 500 series Sontec / GML type eq
Post by: saxmonster on February 07, 2019, 09:16:00 PM
Hi Everyone,

Just built two of these and I am now putting power though them and doing my initial testing.  I built it using the Letter C configuration and my voltage numbers looks ok but just curious if I am using IC's in DOA4 and DOA5 should I still be getting a little over 24vdc on pins 4 and 7?  Or do I want it to be down to 18vdc?  I just don't want to fry my IC's in the DOA4 and DOA5 spots.  The filter rails, I think thats what they are called, are reading a little above 18vdc.  Should put in my IC's?

Thanks in advance. 
Title: Re: 500 series Sontec / GML type eq
Post by: saxmonster on February 09, 2019, 12:01:12 AM
Well I took a chance and plugged in my IC's.  I was able to test all the filter channels and set them to zero and was able to do all the other calibrations perfectly.  Was pretty easy and was the funniest part.  Everything is working great, no hums, all knobs work as well as switches, etc.  This was my 6th or 7th project I built and I am really having a blast building these projects.  This was a fun one except for the knobs.  These things are a pain in the ass.  I have lifted the little knobs almost to the edge of the bigger knobs cause some of them for what ever reason are rubbing on the larger knobs causing the larger knobs to spin when they are already set,  I think I remember somebody giving some tips on getting the knobs setup properly I will just have to revisit the thread later on. 
Title: Re: 500 series Sontec / GML type eq
Post by: jensenmann on February 09, 2019, 04:07:29 AM
Congrats! Pictures, or it didn´t happen  ;)
Title: Re: 500 series Sontec / GML type eq
Post by: saxmonster on February 09, 2019, 10:56:05 AM
Congrats! Pictures, or it didn´t happen  ;)

Added a pic, lol.
Title: Re: 500 series Sontec / GML type eq
Post by: ncl|usl on March 12, 2019, 09:59:30 AM
hello everyone
i would love to build one of this beautiful eq
where can i find the pcb and parts?
thanks
nick
Title: Re: 500 series Sontec / GML type eq
Post by: kante1603 on March 12, 2019, 11:46:28 AM
hello everyone
i would love to build one of this beautiful eq
where can i find the pcb and parts?
thanks
nick
Welcome to the forum Nick,


here we go:


http://www.thedonclassics.com/#all-kits (http://www.thedonclassics.com/#all-kits)


Have fun,


Udo,
Title: Re: 500 series Sontec / GML type eq
Post by: EarthTone on April 18, 2019, 03:42:44 AM
If you just build a pair of these in stock form with +/- 12db and normal non-stepped pots, can you get away with using them in your mastering chain? I'm really wanting a pair, but they'll go into my 2-bus chain for mastering... Can you get away with it as-is? I'd rather build a pair without tweaking the design first before changing anything... But should I build them for +/- 6db if I'm planning to use them only on 2-bus? Just looking for opinions from people who have built them here already... Thanks!

ET
Title: Re: 500 series Sontec / GML type eq
Post by: benewell on May 12, 2019, 09:30:12 PM
If you just build a pair of these in stock form with +/- 12db and normal non-stepped pots, can you get away with using them in your mastering chain? I'm really wanting a pair, but they'll go into my 2-bus chain for mastering... Can you get away with it as-is? I'd rather build a pair without tweaking the design first before changing anything... But should I build them for +/- 6db if I'm planning to use them only on 2-bus? Just looking for opinions from people who have built them here already... Thanks!

ET

Hi Earthtone,
Currently using mine for mastering with +/-6db, and the non stepped pots. Absolutely love it. You most certainly can get away "as-Is" however, you won't have much wiggle room for minute adjustments. Even when I first tried +/-12 to start I wasn't using more than 4db or so during a mix. A little really went a long way.

I am tempted to try adding stepped pots in a different enclosure... but I'm so happy with the non stepped version that I don't foresee myself investing in that adjustment for a while.

Best,
Brian
Title: Re: 500 series Sontec / GML type eq
Post by: Rogy on May 30, 2019, 04:08:54 AM

You can make the single bands‘ gain/cut switchable between say +/- 6 or +/- 12dB,it is just one resistor per band.

Udo.

Hello Udo, Could you explain this in a little more detail?

[Ah, found it on Pg14, post 276: @qmp audio - Yes +-6dB is possible..  easiest way on this unit would probably be to swap out all the R69s for 51k..  ]

I have four of these EQ's, and I'm super happy with them (using them for live sound work like you), but would love to limit their gain to +/-6dB per band for finer resolution on the gain pots.

Many thanks!

Best,
Rogy