He-69 build/support thread. PCB's/kits-available!

[ramshackles]

Traced my problem back to the relays. The input relays aren't switching....it seems like their default position is off/in 'bypass' and powering the unit should switch these to being on.
But it doesnt. So nothing getting through to the input.
This is odd as when I cross the wires I can hear the relays 'click'. But perhaps this doesn't mean that they are actually switching.

So next step I will take is to remove the relays and put a jumper across to hardwire it to 'on'. Then I can see what else I have screwed up!!

 

[taliska]

Hi.

I'm planning on building a pair of these soon (hopefully in igors favoured configuration), and was wondering whether anyone has a/b'd the lundahl LL1524/LL1517 transformers that are recommended for this build?

Just trying to work out whether it's worth importing the preferred one that isn't readily available in the UK (LL1524) or just using the one that is...(LL1517)...

Thanks!

Kaz

 

[zayance]

Traced my problem back to the relays. The input relays aren't switching....it seems like their default position is off/in 'bypass' and powering the unit should switch these to being on.
But it doesnt. So nothing getting through to the input.
This is odd as when I cross the wires I can hear the relays 'click'. But perhaps this doesn't mean that they are actually switching.

So next step I will take is to remove the relays and put a jumper across to hardwire it to 'on'. Then I can see what else I have screwed up!!

Mine is sitting on lab bench for a huge amount of time now, not much time for diy and even less for troublshooting these days :/
I have the same problem with mine, first i had the relay Igor mentionned on farnell codes and it wasn't working well, since it switching was occuring if a minus voltage was applied to the relay (bi-stable iirc the name) so i changed this to the normal relays we use in most of our builds here, and the unit was passing audio and EQ was beeing switched as well, but in bypass mode it was muting the signal, odd.
So mine is still at that state, and while all is soldered at right spot, i know that these work no prob since one forum member has his working good (serviced by igor tough), so it must be a simple mistake or a PCB tweak maybe (cut trace hardwire etc... but didn't look to deep into that) i guess i should move my a.. and try to find my prob as well...

 

[ramshackles]

It's been a while since I did mine and I'd forgotten how I'd left it. It works, but I just took a look at the insides and I can see now that I'd decided I didn't need the insert or bypass (as bypassing can be done at the patchbay) and just left it hardwired to 'on', no relay.


It would be good to get to the bottom of the problem as the BOM still reflects Igors part number; it must be correct if other members have working versions?

I might put out a competition to try and get a good tutorial for these things....

 

[taliska]

It's been a while since I did mine and I'd forgotten how I'd left it. It works, but I just took a look at the insides and I can see now that I'd decided I didn't need the insert or bypass (as bypassing can be done at the patchbay) and just left it hardwired to 'on', no relay.


It would be good to get to the bottom of the problem as the BOM still reflects Igors part number; it must be correct if other members have working versions?

I might put out a competition to try and get a good tutorial for these things....

I guess the ideal person to find would be someone who had the exact same problem with the relays and then managed to fix it, so they know what the exact issue is. Someone with a build that worked first time won't necessarily be able to say why...

Some other thoughts:

Does anyone have a front panel designer file for the face plate? (or have an unassembled one that they can measure up?) I'm happy to extrapolate based upon the images in the first post, but obviously I'd prefer more accuracy over less. The nice thing is that most of the pots and switches are point to point wired, so exact positioning doesn't matter, but the grayhill is pcb mounted, so that's a little bit more critical.

FWIW, if I do end up making a fpd file for myself, I'll make it available here, but obviously it will be use at your own risk!

Kaz

 

[zayance]

Well i guess i Found the prob, need to confirm that, but that was a stupid one if so, so Huge LOL...  :
I used ON-OFF-ON switch (can't see if that's your case as well ramshackles?),  BOM says clearly not to use if not using "Insert" option (Pre) so ON-ON there since i'm not using his albatross pre

 

[ramshackles]

It's been a while since I did mine and I'd forgotten how I'd left it. It works, but I just took a look at the insides and I can see now that I'd decided I didn't need the insert or bypass (as bypassing can be done at the patchbay) and just left it hardwired to 'on', no relay.


It would be good to get to the bottom of the problem as the BOM still reflects Igors part number; it must be correct if other members have working versions?

I might put out a competition to try and get a good tutorial for these things....

I guess the ideal person to find would be someone who had the exact same problem with the relays and then managed to fix it, so they know what the exact issue is. Someone with a build that worked first time won't necessarily be able to say why...

Some other thoughts:

Does anyone have a front panel designer file for the face plate? (or have an unassembled one that they can measure up?) I'm happy to extrapolate based upon the images in the first post, but obviously I'd prefer more accuracy over less. The nice thing is that most of the pots and switches are point to point wired, so exact positioning doesn't matter, but the grayhill is pcb mounted, so that's a little bit more critical.

FWIW, if I do end up making a fpd file for myself, I'll make it available here, but obviously it will be use at your own risk!

Kaz

Front panels and L-brackets will soon be available from my site

 

[taliska]

Front panels and L-brackets will soon be available from my site

Awesome! FWIW, it would be nice if the brackets and fronts were available separately, as I've recently just used schaeffer for the first time for a couple of front panels for the 9k500 project, and they turned out really nicely and not too expensive, so I'm more inclined to do custom front panels to differentiate a little bit! Seems fitting for a project with more options than normal...

 

[zayance]

Allright, well little update, my last discovery, on last post was a quick and futile ignorance ha, not much concentrated these days, too many things in the head, anyway...
I have two of these, one as said before had the bypass not working, but when ON (XLR mode) it was passing signal and EQ was working etc..., but on the second i have, while the bypass was working i wasn't getting any good signal when ON  , and found out that it was because of a bad LL7101 (bad contact), had another one in stock, changed it and now at least one works no prob, on-off-on switch etc....
The first one, even if beeing an exact copy, still gives same prob, bypass mutes signal etc..., for now i leave it as is, and will further check things, but it could be a slight connection prob or maybe a bad connection, and as said can bypass an DAW or patchbay anyway just a quick update...

 

[ramshackles]

Front panels and L-brackets will soon be available from my site

Awesome! FWIW, it would be nice if the brackets and fronts were available separately, as I've recently just used schaeffer for the first time for a couple of front panels for the 9k500 project, and they turned out really nicely and not too expensive, so I'm more inclined to do custom front panels to differentiate a little bit! Seems fitting for a project with more options than normal...

They would be available separately.
FYI, all the docs (downloadable from the site) have corel draw files for the front panels, so you could get them and your l-brackets made by whoever you like (and customise them etc)

 

[taliska]

It's been a while since I did mine and I'd forgotten how I'd left it. It works, but I just took a look at the insides and I can see now that I'd decided I didn't need the insert or bypass (as bypassing can be done at the patchbay) and just left it hardwired to 'on', no relay.


It would be good to get to the bottom of the problem as the BOM still reflects Igors part number; it must be correct if other members have working versions?

I might put out a competition to try and get a good tutorial for these things....

Hey Ramshackles, got a couple of questions if you've got time... (I'll be building my he69s soon)

Did you ever get to the bottom of your relay problems?

Was the relay switching the only major issue you came across?

Cheers,

Kaz

 

[ramshackles]

I skipped out the relay and 'hardcoded' it.

I've heard from a couple of other people who had relay problems that they replaced their relays with these:

http://uk.farnell.com/jsp/search/productdetail.jsp?sku=9913890&CMP=i-bf9f-00001000

and it worked fine.

As I've seen in other threads, the cascode opamp that can be used with this project is easy to mess up due to it's tiny size. You should also be careful with the pin numbering of replacement transistors (dont just stick them in!)

 

[taliska]

I skipped out the relay and 'hardcoded' it.

I've heard from a couple of other people who had relay problems that they replaced their relays with these:

http://uk.farnell.com/jsp/search/productdetail.jsp?sku=9913890&CMP=i-bf9f-00001000

and it worked fine.

As I've seen in other threads, the cascode opamp that can be used with this project is easy to mess up due to it's tiny size. You should also be careful with the pin numbering of replacement transistors (dont just stick them in!)

Great, thanks for the info. Those relays are the same ones as used in the F76 by the looks of it...

Regarding the cascade opamp, yeah, that was me! I put in my 2n2484s with their collectors and emitters swapped due to not noticing the different pinouts on the central semi versions. I've ordered some replacement ones (multi comp) from farnell which have the same wrong pinout though, so hopefully with a bit of fiddling things my F76s will be running before too long! ;-)

Kaz

 

[Grummy77]

I don't suppose Igor is still kicking around this thread?

Igor - I know it's been well over a year since your offer but I'm hoping it still stands. On 30NOV12 you said to fix my fried components and we'll fix the rest together. I believe I've finally fixed my fried components. All of which I believe we're actually in my powersupply. I also had an underrated power transformer in that power supply for 51x capabilities. With my power supply issues resolved it cleared up my biggest issue with these EQs. Which was no headroom. They now take line level perfectly.

My only real remaining issue is that I seem to have a permanent highpass filter happening. Every other eminent of the EQs seems to work as I'd expect based on graphs I've seen on these EQs. It's jus as though there's a permanent HPF at around 50-100Hz (perhaps more of a low shelf heavily cut). When I switch the EQ to use the existing HPF it too behaves like I would expect. Just does it on top of my permanent low cut issue.

As is, in certain scenarios it's actually very useful. Good for things where I'd cutting down there anyways. Vocals (love them on group vocal bus), acoustic guitar, stuff like that. But it would be nice to have them functioning properly. Then I could try them on drum bus or even the whole mix sometime.

Thanks.

 

[taliska]

Hey all,

Random question to anyone who might know:

Earlier in the thread, it is suggested that non-shorting grayhills can be used in the two positions that are designated as requiring shorted grayhills.

Does anyone know what the practical difference between the two will be when used on this board? I understand the difference is BBM or MBB, but I'm rather asking which is the correct one for this board and what the real-world difference will be?

The only other experience with grayhills I have is in full kits and Peter P's EQN, which used non-shorting switches, but then he had lots of little resistors on the board which which were used for smoothing the pops out I believe. I can't see anything approaching the same function on Igor's pcbs...

Cheers,

Kaz

 

[taliska]

Not sure there's anyone paying attention to this thread, but here goes... 

I'm just in the process of wrapping up my mouser order for my components and not being a genius when it comes to this stuff wanted to state my understanding of the less well documented parts of this build for clarity's sake.

The output transformer can be setup for 1:1 or 1:2. At some points in this thread I thought that the choice was completely arbitrary, but it seems to be now, that the correct thing to do is to use 1:1 when the input transformer is included, and 1:2 when the balanced line receiver is being used.

It's my understanding that there is a 6db loss when using the balanced line receiver, as the That1246 is a 1240 series component, and the 6 means -6db of gain. There are other 1240 series ics available, but the 1246 seems to be the best for input headroom.

Because I'm using the cascode amp from Igor's F76, I'm using R12 : R15 == 2k49 : 511R, which Igor states is suitable for his amp for 1:2 operation (are these the only things required for 1:2 operation?). Additionally, when those values are used, it's also mentioned that C7 should be 330 pf.

R17 is dependent upon the relays used. It's recommended that 12v relays are used instead of the original 5v ones that were specified.

The following ones were recommended: http://uk.farnell.com/jsp/search/productdetail.jsp?sku=9913890&CMP=i-bf9f-00001000 and they have a 1K coil resistance.

According to the SCHEM_PS_IO_RELAYS.png file, to calculate the resistance required for R17 when using relays with 200R coil resistance, the following should hold true:

r17 = (voltage required at r17 / (voltage required at relays / coil resistance));

r17 = (1.25 / (5 / 200)) = 50R.

It should be noted that I just played with the numbers until they made sense, as I find the words in the schematic less than clear personally.

Also worth noting is that the schematic says..."possible to use 12v relays with 9v on each relay".

As I understand it, relays are switched by the current passing through the coil and magnetising the switch. For the 12v relay, that means that the switching current is (found the formula on a random electronics site, but it makes sense to me...):

coil current = (supply voltage / coil resistance), so:

blah = (12v / 1000R) = 0.012 Amps.

Looking at the lm317 data sheet, it looks like this one is setup as a precision current limiter. Where limit current i = 1.2 / R.

So if the coil needs 0.012 amps to trigger it, then that must mean:

R = 1.2 / i, which is:

R17 = 1.2 / 0.012, which gives 100R.

Performing the same calc using the schematic formula, and substituting the coil resistance in for the 12v coils and also substituting the 9v for the 5v gives:

r17 = (1.25 / (9 / 1000) = 138.8888889R

which is ok if 9v is an acceptable voltage, but obviously if 12v is used instead, then it matches up with my other result...

r17 = (1.25 / (12 / 1000) = 104R.

(well near enough...the discrepancy is 1.2 vs 1.25).


So, after all that, I've just got one simple question (and congrats for reading this far!):

If I go ahead and use those 12v relays, should I use:

a) 100R.
b) 138.8888889R.
c) 104R.

Answers on a postcard.

Kaz

 

[ramshackles]

I only have limited knowledge, so this might have mistakes (makes sense in my head anyway). Here goes:

The suggested relay has a coil resistance of 1.028Kohm and a coil voltage of 12V, this gives a current of 0.01167 A from ohms law.

We know the voltage across R17 should be 1.25V - that is the output voltage of the LM317 (actually, some of them are 1.25V, some are 1.2V - it says on the datasheet).

So, ohms law gives us a value for R17 of 1.25/0.01167 = 107 ohms or (103 ohms for 1.2V).

That is a bit of an awkward value, but if we look at the datasheet, we see that the operating range is not a single number, but anything between a couple of numbers. So going with a 100 ohm resistor will be fine.

 

[taliska]

I only have limited knowledge, so this might have mistakes (makes sense in my head anyway). Here goes:

The suggested relay has a coil resistance of 1.028Kohm and a coil voltage of 12V, this gives a current of 0.01167 A.

We know the voltage across R17 should be 1.25V - that is the output voltage of the LM317 (actually, some of them are 1.25V, some are 1.2V - it says on the datasheet).

This gives us a value for R17 of 1.25/0.01167 = 107 ohms or (103 ohms for 1.2V).

That is a bit of an awkward value, but if we look at the datasheet, we see that the operating range is not a single number, but anything between a couple of numbers. So going with a 100 ohm resistor will be fine.

That's awesome ramshackles! Thank you for taking the time to check my numbers (and approximating less than I did!). Should finally be able to submit my mouser order with some level of confidence now.

Kaz

 

[ramshackles]

No problem. Your logic in the first part seems fine as well. The THAT1246 gives -6dB of gain, so to get back to unity at the output, a 1:2 transformer makes sense as dB = 20log(V/V0)  = 20log(2/1) ~= 6dB

 

[taliska]

No problem. Your logic in the first part seems fine as well. The THAT1246 gives -6dB of gain, so to get back to unity at the output, a 1:2 transformer makes sense as dB = 20log(V/V0)  = 20log(2/1) ~= 6dB

Great. Good to know that my brain isn't completely broken!

I suspect I'm the only person building these at the moment, but just in case, I thought I'd clarify on one of the first posts in this thread.

Early on in this thread, someone asked about the which orientation the carnhill 9048 inductor should go in, and Igor suggested looking at the data sheets and the numbers printed on the back of the board. If you're a bit like me, it's quite tempting to think that the "start" pin on the inductor (the one with the white dot on it), should go approximately somewhere near the start text that's printed on the board. However, this would be an incorrect conclusion and luckily I decided to do some probing with my continuity tester before soldering as it would have been backwards! It turns out that the pins are routed pretty much to the opposite sides for the 9048 footprint.

Anyway, just thought it was worth mentioning, as I hadn't seen anyone state it explicitly for the less gifted of us around here! I've included a picture to show the correct orientation...hope it helps someone!

Cheers,

Kaz