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Project Specific Discussions => Dynamic Processors => Topic started by: lolo-m on April 09, 2009, 03:02:16 PM

Title: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on April 09, 2009, 03:02:16 PM
TO SAVE SOME TIME IN TROUBLESHOOTING, PLEASE READ ALL POSTS BEFORE IMPLEMENTING THE SCAB IN YOUR PM660/670. THANKS

Hi,
Here is a build help thread for poeple who choosed to implement my SCAmp Booster on their PM660 or PM670. Just to save some time, let's call it SCAB (SCAmp Booster  ;D)

Schematics :
http://nbns-studio.pagesperso-orange.fr/PM670/boost-analags-sc-amp.gif (http://nbns-studio.pagesperso-orange.fr/PM670/boost-analags-sc-amp.gif)

Just a few soundsamples realised with the same settings using the two different modes . I'm sure the FAIRCHILD setting used in SCAB mode isn't what I would use to master this song but it is revelant of the different compression ways you can have using the SCAB:
Soundsamples :
Uncompressed file :
http://pagesperso-orange.fr/NBNS-Studio/PM670/UNPROCESSED.wav (http://pagesperso-orange.fr/NBNS-Studio/PM670/UNPROCESSED.wav)

Analag's way :
http://pagesperso-orange.fr/NBNS-Studio/PM670/pm670-analag-network.wav (http://pagesperso-orange.fr/NBNS-Studio/PM670/pm670-analag-network.wav)

SCAB Mode using Fairchild Position 2 setting :
http://pagesperso-orange.fr/NBNS-Studio/PM670/pm670-scab-fairchild-pos2.wav (http://pagesperso-orange.fr/NBNS-Studio/PM670/pm670-scab-fairchild-pos2.wav)

SCAB Mode using custom Fairchild type TC network :
http://pagesperso-orange.fr/NBNS-Studio/PM670/pm670-scab-fairchild-custom.wav (http://pagesperso-orange.fr/NBNS-Studio/PM670/pm670-scab-fairchild-custom.wav)

Drum sounsamples :
Uncompressed :
http://pagesperso-orange.fr/NBNS-Studio/PM670/DRUMSNOCOMP.wav (http://pagesperso-orange.fr/NBNS-Studio/PM670/DRUMSNOCOMP.wav)

Analags network :
http://pagesperso-orange.fr/NBNS-Studio/PM670/DRUMSANALAG.wav (http://pagesperso-orange.fr/NBNS-Studio/PM670/DRUMSANALAG.wav)

Fairchild position 2 :
http://pagesperso-orange.fr/NBNS-Studio/PM670/DRUMSFAIR2.wav (http://pagesperso-orange.fr/NBNS-Studio/PM670/DRUMSFAIR2.wav)

Custom TC network 1 :
http://pagesperso-orange.fr/NBNS-Studio/PM670/DRUMSCUSTOM1.wav (http://pagesperso-orange.fr/NBNS-Studio/PM670/DRUMSCUSTOM1.wav)

Custom TC network2 :
http://pagesperso-orange.fr/NBNS-Studio/PM670/DRUMSCUSTOM2.wav (http://pagesperso-orange.fr/NBNS-Studio/PM670/DRUMSCUSTOM2.wav)



Thanks to SaMpLeGoD for the BOM with Banzai codes :
http://pagesperso-orange.fr/NBNS-Studio/PM670/BOM_for_Side_Chain_Amp_Boost_for_PM670.doc (http://pagesperso-orange.fr/NBNS-Studio/PM670/BOM_for_Side_Chain_Amp_Boost_for_PM670.doc)


Thanks to Moby for the wiring guide ! It can be found here :
http://pagesperso-orange.fr/NBNS-Studio/PM670/PoorMan+SCAB-WiringGuide-R1.pdf (http://pagesperso-orange.fr/NBNS-Studio/PM670/PoorMan+SCAB-WiringGuide-R1.pdf)


Or you can read that   ::):

Fill the board  ;D !!!

On the PSU board set RV1 and RV2 to have +17V and -17V.
Connect those +-17 to my board.

If you start filling the PM board, don't solder D1, D2, D3, D4, C4, R16 and R18. Put 2 wire links between C4 pads and R18 pads.
If they're already soldered, solder a wire link between the C4 pins and between R18 pins. I can't honestly say that's it is a good idea to dissolder C4 (even if I did) as it can endomage the PCB if not correctly done. Cut D1, D2, D3, D4 on the middle of the glass tube. Then keeping hot the pin solder, remove the half diodes. This is my tip to remove these diodes easily, without staying hot a too long time on the board.

TR4 output (secondary) goes directly on the SCAB board.

The SCAB "to attack" connector will be connected to the "attack" connector of the PM board.
The SCAB "attack" connector is the 10K pot of Analags network design.
The SCAB "MODEA-L or R" + MODEB-L or R" is where you connect the DPDT switch to change the MODE from "Analag's network" to "Your a la Fairchild network". There's unfortunately a 1 dB overall gain raise when not in "Analag's mode". There are 3 pads added to solve this but we will talk about this later.

Put the SCAB in "analag's mode", set RVx01 so the SCAB "to attack" connector pin to pin reads 0V DC on multimeter.

If you solder a 2uF in Cx03 place, you've got the Fairchild POS 2 setting when switched in "a la Fairchild mode".

Here you are, ready to experiment !

Play, have fun and feel free to post here...

EDIT : Read my "pimping my own pimp" post on second page to have a really well working mod !
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: Moby on April 09, 2009, 07:49:56 PM
Lolo, it will be nice if you can do the wring diagram as Volker did for PM. Or you can add SCAB PCB into existing one . I figure how it has to be connected but I'm sure that there will be a lot of questions about  ;)
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: crisotop on April 10, 2009, 04:23:49 AM
I'd like to konw it it's possible to use the +17V on the PSU PCB for the SCAmp Booster and drop the same voltage via a simple resistor for let's say 12V relais? Is there enough juice for the opamps and four relays?

thanks!
christoph
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: lolo-m on April 10, 2009, 05:17:22 AM
I'd like to konw it it's possible to use the +17V on the PSU PCB for the SCAmp Booster and drop the same voltage via a simple resistor for let's say 12V relais? Is there enough juice for the opamps and four relays?

thanks!
christoph
On the board there's a 7812 to provide the 12V for the relays, lighting... with same KK connector than on the PSU board. All you'll have to do is to plug relays on the SCAB board... Just one warning, try to stay under 500mA of total consumption for lighting and relays. I would suggest to use maximum led lighting (where it is possible SIFAM meters, ON light...)  instead of bulb lighting because leds doesn't eat a lot of current.

Lolo, it will be nice if you can do the wring diagram as Volker did for PM. Or you can add SCAB PCB into existing one . I figure how it has to be connected but I'm sure that there will be a lot of questions about  ;)
Moby you're perfectly right !!! I was thinking to do this... As I won't be connected to the web during the week-end, I will try to do this... More simple and quick !

DON'T BE AFRAID THIS MOD IS TOTALLY REVERSIBLE IF YOU DON'T LIKE IT  ::). This was a part of the hard job !!!
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: Moby on April 10, 2009, 06:38:35 AM
Quote
Moby you're perfectly right !!! I was thinking to do this... As I won't be connected to the web during the week-end, I will try to do this... More simple and quick !
If you need some help I'm here  :)
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: crisotop on April 10, 2009, 10:33:07 AM
Quote
On the board there's a 7812 to provide the 12V for the relays, lighting... with same KK connector than on the PSU board. All you'll have to do is to plug relays on the SCAB board... Just one warning, try to stay under 500mA of total consumption for lighting and relays. I would suggest to use maximum led lighting (where it is possible SIFAM meters, ON light...)  instead of bulb lighting because leds doesn't eat a lot of current.

Genius, should have had a closer look before posting - as always ;)

thanks for clearing this up!
Christoph
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: lolo-m on April 10, 2009, 10:53:21 AM
No problem !  ;)
I have the same bad habbit  ;D !!!
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: crisotop on April 11, 2009, 05:54:05 AM
Do we need proper 'big' heatsinks (similar to the ones used for Q1 on the pm boards) for the 7812 and the TIP transistors, or will something smaller do?

cheers
christoph
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: lolo-m on April 11, 2009, 06:09:56 AM
I would suggest to fix the board on the case INSULATED. This is a simple way to cool everything for the lowest cost possible. If not possible to do that, 7812 can get hot (depend of current consumption of lighting and relays). A heatsink with the same °C/W than the one used for the 317 in the PSU board will do.
But I think that the best is to fix the TO220 to the case...
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: crisotop on April 11, 2009, 07:40:00 AM
Makes sense, thanks again!

Christoph
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: Moby on April 11, 2009, 08:59:28 AM
SCAB WiringGuide is ready  ;D http://www.mediafire.com/file/yfwfyfqv0ww/PoorMan+SCAB-WiringGuide.pdf
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: tommypiper on April 11, 2009, 02:07:45 PM
SCAB WiringGuide is ready  ;D http://www.mediafire.com/file/yfwfyfqv0ww/PoorMan+SCAB-WiringGuide.pdf

It doesn't download on that site.  Is there something I"m missing?  (I'm on OSX, maybe that's why?)
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: Moby on April 11, 2009, 02:26:47 PM
Don't know... works for me..  :-\
edit:works under os x too (me)
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: tommypiper on April 11, 2009, 03:05:22 PM
Don't know... works for me..  :-\
edit:works under os x too (me)

Yes, but you're probably logged in as the owner of that document/account.  Do I have to start an account to download it?
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: Moby on April 11, 2009, 03:16:43 PM
don't have an idea... but I don't know where to upload :-\ BTW, I didn't type any pass under OS x....
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: Moby on April 11, 2009, 03:33:20 PM
OK than.. one more place http://twin-x.com/groupdiy/displayimage.php?pos=-3120
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: tommypiper on April 11, 2009, 04:41:57 PM
http://www.groupdiy.com/Themes/default/images/post/thumbup.gif ;D
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: Moby on April 11, 2009, 04:43:52 PM
great... about avatar try to resize to 60x60  ;D
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: crisotop on April 16, 2009, 10:31:13 AM
allright, here's another one: As far as I've studied the schematic and circuit board, it should be possible to use a 6pos 2pole switch for having analags original 10k pot on the first deck as 6pos á 2k switch and my deisred Fairchild-inspired RC combo on the second deck with wathever cap/resistor values I want, since both circuits are fully independent - did I get this right?

Thanks in advance,
Christoph
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: lolo-m on April 16, 2009, 10:46:41 AM
allright, here's another one: As far as I've studied the schematic and circuit board, it should be possible to use a 6pos 2pole switch for having analags original 10k pot on the first deck as 6pos á 2k switch and my deisred Fairchild-inspired RC combo on the second deck with wathever cap/resistor values I want, since both circuits are fully independent - did I get this right?

Thanks in advance,
Christoph
Yes, you're perfectly right !
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: lolo-m on April 16, 2009, 11:15:10 AM
Edited first post with diferent links and soundsamples...

Eddie, is that what you're looking for ?
Title: Re: LOLO-M SCAmp Booster build and tips help thread
Post by: lolo-m on April 27, 2009, 10:29:59 AM
Changed the soundsamples on first post...  :)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on May 18, 2009, 06:38:31 AM
PIMPING MY OWN PIMP !!!
Waiting the boards to arrive at home, I played with my prototype... And pimped it  ;D ;D ;D.
Here are the results :
   I tried at the begining of this mod to reach the fastest attack times of the Fairchild ( the more difficult thing to reach)... but I forgot one thing : the slower attack times...
   So, playing with the prototype and custom TC network, I realised I forgot one resistor  :-[. But you can easily put it on the board ;D ;D ;D :
On the footprint of the 1N400X diode, solder a 75 ohm serial to the diode on "ring" side of the diode.
With this resistor you'll get :
- approx 0.2ms of attack time with a 2,2uF (no paralleled cap)
- approx 0.4ms of attack time with a 4,4uF (2,2uF paralleled cap)
- approx 0.8ms of attack time with a 6,9uF (4,7uF paralleled cap)
- approx 1ms (or maybe more because it gets difficult to measure this) of attack time with a 15,8uF (2x 6,8uF paralleled caps)

To know what resistor you must parallel for a defined release, use the basic RxC calculation (result is in second). Don't forget you already have a 221K already parralleled...

If you plan to use the Fairchild's TC network, use the 75 ohm resistor serial to the diode. It will work  :).

I really suggest to use this 75 ohm resistor... Without it it's working, but you will always have approx 0,2ms of attack time with various compression attack figures depending of the caps you'll use in the TC network...

I sould reffer to my note to self a little bit more   ::)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Kingston on May 18, 2009, 09:43:09 AM
Regarding bigger and more flexible networks,

how do you suppose it should be handled, when there will be significant amounts of LARGE film caps for each channel?

with the possibilities you listed there combined, it's going to be one FAT time constant expansion board in an already cramped space.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on May 18, 2009, 12:24:03 PM
Lolo, just checking weither I understand your side chain booster.

Higher voltage in the side chain means that the caps that handle the attack time can recharge faster (or that you can use different value caps that do).
Soo, can this concept be applied to the GSSL side chain as well so we can have ultra fast attack times?

Or can the VCA's not generate them?

Thanks!
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on May 18, 2009, 12:59:09 PM
Regarding bigger and more flexible networks,

how do you suppose it should be handled, when there will be significant amounts of LARGE film caps for each channel?

with the possibilities you listed there combined, it's going to be one FAT time constant expansion board in an already cramped space.

Yes, my TC switch is quite big !!! I used a 12 position, 4 rows switch per channel. I have 6 different release times on each of the 4 different attack times ... If I cannot have what I want with this, I guess I'd better use another comp  ;D !
The switch measure about 8 cm !!! But my case is 40cm deep  :D !!!
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on May 18, 2009, 04:11:44 PM
Lolo, just checking weither I understand your side chain booster.

Higher voltage in the side chain means that the caps that handle the attack time can recharge faster (or that you can use different value caps that do).
Soo, can this concept be applied to the GSSL side chain as well so we can have ultra fast attack times?

Or can the VCA's not generate them?

Thanks!
Yes, I had a look at the TC part of the GSSL... The TL074 isn't a really powerfull op-amp...

I don't know if the VCA can handle ultra fast attack times so I can't say it'll work or not  ???.

Changing this opamp for a more powerfull one, or maybe to had a buffer before the TC network could give faster attack times.

But the network isn't the same at all:

- The Fairchild TC network on position 1 2 3 and 4 is a cap charged by the current of the scamp (attack) and discharged through a resistor (release). To change the attack times, you've got 2 solutions: changing the cap or having a more powerfull scamp. As the release resistor is the grid resistor, it can't be increased at more than 220K to keep the tubes in a safe operation. So, a smaller cap will give you a quicker attack but also a quicker release... The sc-amp ability to charge the cap fast is the main difference between the different varimus. Fairchild is the more powerfull so it is the quicker...

- The SSL network is a cap charged through a resistor (attack) and discharged through another one (release)... The charge resistor and the cap values are certainly the main way to get the attack time changing... I think it would be a lot simpler to reduce the charge resistor or the cap value to have faster attack times. But changing the cap value will change the release value too... But in the GSSL, there's no tubes, no grids, and you don't have the same limits in the release resistor choice...

   So to be clear :D, IMO the pimp on the GSSL to have faster attack times would be more to change the TC cap for a smaller one... and maybe to change the attack resistor, but you may find the TL074 limits :P...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on May 18, 2009, 04:52:13 PM
Thanks Lolo!


I don't know if the VCA can handle ultra fast attack times so I can't say it'll work or not  ???.

I think there will be distortion with faster attack settings. Did some tests with the fastest available attack and release and when compressing heavily I got some distortion in the low end. Faster will probabely be worse...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Kingston on May 18, 2009, 05:40:53 PM
I think there will be distortion with faster attack settings. Did some tests with the fastest available attack and release and when compressing heavily I got some distortion in the low end. Faster will probabely be worse...

AFAIK it's the VCA crapping out. It's not really designed for such fast speeds. I forgot a name of the company, but there's one very recent design SSL "clone" compressor out there that has discrete VCA's to overcome some limitations, a mastering unit.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: crisotop on May 19, 2009, 02:45:22 AM
Vertigo VSC-2
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on May 19, 2009, 07:06:42 AM
Well, that Vertigo VSC-2 has the exact same attack times as the ssl...I would have expected something faster....
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: crisotop on May 19, 2009, 07:21:22 AM
Printed on the panel, it feels a lot faster (not sure if the ssl timeconstants are correct)


Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: analag on May 19, 2009, 07:27:52 AM
Good God...It's time to release my ultimate Mu Compressor...the mind blower...and if you want sound samples I will have my man Volker host some serious crush, attitude, color, tube sound...fer yah. Seriously I don't want to give out that one.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Kingston on May 19, 2009, 07:38:43 AM
Sorry for off topic.

Well, that Vertigo VSC-2 has the exact same attack times as the ssl...I would have expected something faster....

That front panel is only some engineers' definition of what the attack time is. There is much more to attack than what is printed on front panel.

Printed on the panel, it feels a lot faster (not sure if the ssl timeconstants are correct)

Indeed. They probably only used the SSL standard time constants on the panel because their product topology is so heavily based in it.

But the attack shape might be completely different, resulting in far less distortion, and at least the illusion of faster speeds. This might not fit the original SSL designers definition of attack speed at all. He might have labeled a product like this very different.


I think similar needs were the starting point of this whole SC amp thing. Analag posted some pictures showing the much more even exponential slope a more powerfull SC amp could provide for time constants, again resulting to less distortion.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on May 19, 2009, 10:25:21 AM
Good God...It's time to release my ultimate Mu Compressor...the mind blower...and if you want sound samples I will have my man Volker host some serious crush, attitude, color, tube sound...fer yah. Seriously I don't want to give out that one.
Do you have a problem with mods done on your stuff ?
I thought we were in a DIY forum  ::)... Or maybe my poor english is a problem to understand  what you mean...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: analag on May 19, 2009, 01:57:29 PM
Good God...It's time to release my ultimate Mu Compressor...the mind blower...and if you want sound samples I will have my man Volker host some serious crush, attitude, color, tube sound...fer yah. Seriously I don't want to give out that one.
Do you have a problem with mods done on your stuff ?
I thought we were in a DIY forum  ::)... Or maybe my poor english is a problem to understand  what you mean...

I love it, but if you step up the design I'll come up with something else...and we keep it going. I push you and you push me, and in the end who knows.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: SUPERMAGOO on May 25, 2009, 09:32:32 AM
you could do some tests with drums?.
I would like to hear the different mods with Buss-drums or just
bassdrum+snare.

eso lo grabaste en españa? saludos!
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on June 03, 2009, 12:56:33 PM
you could do some tests with drums?.
I would like to hear the different mods with Buss-drums or just
bassdrum+snare.

eso lo grabaste en españa? saludos!
Here it is ! On first post  ;D...
Sorry for being so slow to release those samples, but I had to fix a hum problem. This is out topic, but have a look with a scope at what's happening in the filament PSU. Push-pull technology is meant to cancel filament hum problem, but in mine it isn't  :'(...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Moby on June 03, 2009, 01:12:18 PM
Quote
This is out topic, but have a look with a scope at what's happening in the filament PSU. Push-pull technology is meant to cancel filament hum problem, but in mine it isn't  Cry...
Did I understand you correctly? You had a hum issue caused by filament supply? Did you solve that? How?
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on June 03, 2009, 01:46:44 PM
Quote
This is out topic, but have a look with a scope at what's happening in the filament PSU. Push-pull technology is meant to cancel filament hum problem, but in mine it isn't  Cry...
Did I understand you correctly? You had a hum issue caused by filament supply? Did you solve that? How?
Yes, you did understood correctly.
 I tried all the possibilities I had. Unregulated and regulated. Regulated was better but not perfect. The transformer is roughly used on filament PSU. We are pumping 5,2A constantly, and the caps haven't got enough guts to handle that. There is something like 2 or 3 volt sawtooth on the DC...
 The drums sounsamples are made with a regulated PSU based on 2 LM350. I had to add a cap (330uF) to the adjust resistor and went with four 4700uF caps ( and not 2 ) to limit the oscilation. Of course, I played with the transformers place and put a metal shield between the toroid transformer and the electronics...
  And the hum is still here  :-\, small but here...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: SUPERMAGOO on June 04, 2009, 04:24:00 AM
do not worry about the hum!.
I just want to hear about how a strong
compression on rock-drums.
if necessary installing the power transformer in an external case.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Kingston on June 04, 2009, 07:38:39 AM
I tried all the possibilities I had. Unregulated and regulated. Regulated was better but not perfect. The transformer is roughly used on filament PSU. We are pumping 5,2A constantly, and the caps haven't got enough guts to handle that. There is something like 2 or 3 volt sawtooth on the DC...
 The drums sounsamples are made with a regulated PSU based on 2 LM350. I had to add a cap (330uF) to the adjust resistor and went with four 4700uF caps ( and not 2 ) to limit the oscilation. Of course, I played with the transformers place and put a metal shield between the toroid transformer and the electronics...
  And the hum is still here  :-\, small but here...

Interesting, did you use the Moby/silentarts regulator board, or rolled something of your own? Certainly using 5,2A of a 6A supply with filters is pushing it.

I haven't actually had my PSU toroid made yet, but I already specified it with 2X 9VAC 3A windings, for two separate rect/regulator/filters (pulling 2,6A each). I expect that would be easier on the transformer, compared to one BIG 6A winding... we'll see.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on June 04, 2009, 09:45:13 AM
do not worry about the hum!.
I just want to hear about how a strong
compression on rock-drums.
if necessary installing the power transformer in an external case.
The drums samples were made with around 7 to 10 dB compression (depends of the network). I didn't change any setting (input and threshold), the only change is the type of TC network used, and of course the modes (analag's and SCAB)...
I did go up to 20dB compression without problem, the sound was still clean, but on SCAB mode the attacks were completely smashed and a huge pumping effect created... You have this pumping effect on the samples, but it's still musical.
Note: the ring of the drums is a lot more present and some details are appearing  :)...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on June 04, 2009, 12:15:15 PM
Thanks for the samples Lolo. Are all files normalised? / Do all files have the same volume?
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on June 04, 2009, 12:22:49 PM
Thanks for the samples Lolo. Are all files normalised? / Do all files have the same volume?
All the files are as they get out of the comp. No normalisation, no tricky thing. I also resample the file in bypass mode to be sure the AD/DA conversion to be on all files to compare  :). They are more or less the same volume but I cutted the end of the files after recording quickly, so they don't have exactly the same weight.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on June 04, 2009, 01:51:03 PM
ok thanks...on my computer speakers the uncompressed file was rather loud in comparison to the compressed files.

Have not loaded them in my DAW yet...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on June 04, 2009, 02:13:29 PM
It's possible there's some level changes between compressed and uncompressed files. I didn't bother levels  ;D...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Freddy G on June 18, 2009, 08:42:00 PM
Does anyone have part numbers for the connectors shown in this photo? The green one as well as the white ones, and the female mates for the white ones too.  Having a heck of a time trying to find them, I don't know exactly what they're called! Mouser or digikey would be good...



(http://pagesperso-orange.fr/NBNS-Studio/PM670/proto2.jpg)

Thanks ;)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: idylldon on June 18, 2009, 10:59:59 PM
Does anyone have part numbers for the connectors shown in this photo? The green one as well as the white ones, and the female mates for the white ones too.  Having a heck of a time trying to find them, I don't know exactly what they're called! Mouser or digikey would be good...

They're called Molex connectors.  "Molex" is a brand name, but it's kind of like Kleenex these days because most folks refer to these type of connectors as Molex connectors even though there are other mfgs. (Cinch, Kobiconn, Tyco, etc.).  

The power header (the one with the screws) can be found on pages 1519 and 1522 of the current Mouser catalog.  You need to know the pin spacing on the PCB to make sure you get the right one.  To find more, just do a search for "terminal blocks."

The other ones are usually Molex KK Series and you can find the "headers" (the "pin" part usually mounted on the board) and the "crimp terminal housings" on pages 1450-1453.  Again, you need to know the pin spacing on the PCB to get the right ones.  You'll also need the "crimp terminals," which are also on these pages.

There are special crimping and insertion tools, but I've never needed them and I've put a LOT of these things together.  I use a small pair of channel lock pliers (we used to call them "points" pliers back when cars had mechanical points in the distributors) to do the crimp and then I CAREFULLY solder them as well.  Too much solder will ruin the spring part of the "crimp terminals" because it solders the spring part to the stationary part.  I have never had a problem assembling them in this manner.

You can view those pages online at Mouser's website or just download the .pdf of the catalog.

Hope this helps.

Cheers,
--
Don
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on June 19, 2009, 03:13:22 AM
Does anyone have part numbers for the connectors shown in this photo? The green one as well as the white ones, and the female mates for the white ones too.  Having a heck of a time trying to find them, I don't know exactly what they're called! Mouser or digikey would be good...

Thanks ;)
They are the same connectors used by Silent Art for the PM and PSU boards. I tried to make the mod as easy to do as possible  ;).
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: SIXTYNINER on June 24, 2009, 07:11:15 AM
HI
some molex code and source
try to check
 ;)

Digikey WM4201-ND
Digikey WM4203-ND
Digikey WM2012-ND
Digikey WM2014-ND


Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Freddy G on June 24, 2009, 09:06:22 AM
Thanks fellas! :D
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: SIXTYNINER on June 24, 2009, 09:59:57 AM
Thanks fellas! :D

........no problem freddy
have fun with your "diy"

WHY A FORUM IF "NO SHARE" ?
 ;)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: SaMpLeGoD on June 30, 2009, 08:08:33 PM
The -17 supply for the main board was taken? is this right? +17 and -17 goes directly to SCamp Board?
Just to be sure ;)

I'm finally wiring mine!!!

Eddie :)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 01, 2009, 03:32:49 AM
The -17 supply for the main board was taken? is this right? +17 and -17 goes directly to SCamp Board?
Just to be sure ;)

I'm finally wiring mine!!!

Eddie :)
Yes, set the +17/-17V of the PSU660 board to +17V and -17V. The 7812 on the board will give you the needed +12V for relays, lights...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: SaMpLeGoD on July 01, 2009, 07:08:46 AM
The -17 supply for the main board was taken? is this right? +17 and -17 goes directly to SCamp Board?
Just to be sure ;)

I'm finally wiring mine!!!

Eddie :)
Yes, set the +17/-17V of the PSU660 board to +17V and -17V. The 7812 on the board will give you the needed +12V for relays, lights...

Hello Lolo,

Yeah I understand that, but what I'm asking is: when conecting the SCamp boost to the +17V / -17V, do we need to disconect the -17V from the main board?
I know that the +17V on the SCamp Booster will be regulated to +12V for the relays and stuff... but the wiring for -17V that went to the main board, is no longer needed?

Cheers,

Eddie :)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Kingston on July 01, 2009, 07:27:56 AM
you still definitely need the -17V wired to the main board! You will wreak serious havoc if you remove the connection.

It is used to bias the many tubes of PM.

Note that +17V is not actually required at all in a plain poorman. You don't really NEED relays and light, and meters. they are just luxury.

[edit]

now that I look at it, isn't there an error on the SCAMP wiring guide? the -17V connection is missing for the main board.

[edit2]

and ground!
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: SaMpLeGoD on July 01, 2009, 07:41:45 AM
you still definitely need the -17V wired to the main board! You will wreak serious havoc if you remove the connection.

It is used to bias the many tubes of PM.

Note that +17V is not actually required at all in a plain poorman. You don't really NEED relays and light, and meters. they are just luxury.

[edit]

now that I look at it, isn't there an error on the SCAMP wiring guide? the -17V connection is missing for the main board.

[edit2]

and ground!

Yes, there's missing the -17V and GND conection to the main board on the wiring guide!
Thanks a lot!!

Eddie :)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 01, 2009, 08:03:51 AM
you still definitely need the -17V wired to the main board! You will wreak serious havoc if you remove the connection.

It is used to bias the many tubes of PM.

Note that +17V is not actually required at all in a plain poorman. You don't really NEED relays and light, and meters. they are just luxury.

[edit]

now that I look at it, isn't there an error on the SCAMP wiring guide? the -17V connection is missing for the main board.

[edit2]

and ground!

Yes, there's two missing wires on the wiring guide  ;D. It was an evidence to me, but I agree it isn't !!!
The PSU feeds the PM660 board with GND and -17V and SCAB Board with -17V/GND/+17V.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Moby on July 01, 2009, 08:49:45 AM
Quote
Yes, there's two missing wires on the wiring guide  Grin. It was an evidence to me, but I agree it isn't !!!
The PSU feeds the PM660 board with GND and -17V and SCAB Board with -17V/GND/+17V.
Sorry, my mistake  :-X Here's the revised file  ;D
http://www.mediafire.com/file/mzzwzmmwhy2/PoorMan+SCAB-WiringGuide-R1.pdf
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 01, 2009, 10:02:15 AM
Moby, lightening fast, as ever  ;)...

Updated 1rst post with new wiring guide   :).
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: dagoose on July 02, 2009, 03:43:03 PM
I'M in the middle of implemeting the scab-board in my pm670 and i was wondering about a few things.

Is it correct that the -17v and ground to the PM boards are both disconnected? i can imagine the -17v but the ground= earth or am i missing something here?

I dind't realize that the 10uf on the scam board is replacing one 10uf of the PM board.
I have wima's on the PM boards but i have a cheaper epcos poly cap (191-2948 RS) installed on the scab and so i'm wondering if it's better to desolder the wima and stuff it on the scab board.
It will be a bit harder and a lot more work because the wima's are a lot higher then the epcos caps and i have to put the scam board on a different place in the case. Now it fits above my XLR connectors with the transistors isolated mounted to the case. So.. will it make any difference if i use the epcos?

Is it a problem if i leave the discontunued 10uf wima on the pm board or shall i remove it anyway?

Can't wait to hear the scab mod! i only need some switches for the scab but i was also thinking of using the same switch as the bypass but with relays swithing in the 2 modes. you just need 12v to swith in the relay in scab or analag mode so 2x relay will do the job, will save some wiring.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Moby on July 02, 2009, 03:56:15 PM
I don't think there will be any difference between wima or epcos poly caps. This is sidechain and no audio is running through. Just DC time constant network. I will remove wima's and use it on some more critical place  ;)
Regarding wires check the revised wiring guide.
Quote
Can't wait to hear the scab mod!
hehe, "SCAB MODE", sounds awful  :P
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Kingston on July 02, 2009, 03:56:24 PM
Is it correct that the -17v and ground to the PM boards are both disconnected? i can imagine the -17v but the ground= earth or am i missing something here?

oh come on! read like the two posts before you!  ::)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 02, 2009, 04:37:23 PM

I dind't realize that the 10uf on the scam board is replacing one 10uf of the PM board.
I have wima's on the PM boards but i have a cheaper epcos poly cap (191-2948 RS) installed on the scab and so i'm wondering if it's better to desolder the wima and stuff it on the scab board.
It will be a bit harder and a lot more work because the wima's are a lot higher then the epcos caps and i have to put the scam board on a different place in the case. Now it fits above my XLR connectors with the transistors isolated mounted to the case. So.. will it make any difference if i use the epcos?

As you can see I put a lot of holes to fit any 10uF cap you'll find  ;)... My answer is on the board ! But to be clearer and honnest, Silent Art says there's some difference (Wima's the best 10uF for him) but as Moby, I really do think that you won't hear any difference. We're in the sidechain, we're charging a cap with low voltages, slowly (audio spectrum is a really low frequency in electronics world  ::) ). So if the epcos fits better, use it  ;).

Is it a problem if i leave the discontunued 10uf wima on the pm board or shall i remove it anyway?

Well that's a waste to leave them, but that's better to leave them than to destroy the board  ;D. If you're not sure you'll manage to disolder properly the wima, don't do it and just strap it.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: dagoose on July 03, 2009, 02:44:58 AM
you still definitely need the -17V wired to the main board! You will wreak serious havoc if you remove the connection.

It is used to bias the many tubes of PM.

Note that +17V is not actually required at all in a plain poorman. You don't really NEED relays and light, and meters. they are just luxury.

[edit]
ok... looks like i missed this (how could i..) and saved the wrong, old, wiring guide.  :-\
I think that after the weekend i will have it done!

now that I look at it, isn't there an error on the SCAMP wiring guide? the -17V connection is missing for the main board.

[edit2]

and ground!

Yes, there's two missing wires on the wiring guide  ;D. It was an evidence to me, but I agree it isn't !!!
The PSU feeds the PM660 board with GND and -17V and SCAB Board with -17V/GND/+17V.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: SaMpLeGoD on July 03, 2009, 11:50:34 PM
Hello,

Just some rookie's questions... what's for that two 4k7 trimmers on the SCamp board? How can I regulate them?
Thanks

Eddie  ???
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 04, 2009, 06:08:50 AM
Hello,

Just some rookie's questions... what's for that two 4k7 trimmers on the SCamp board? How can I regulate them?
Thanks

Eddie  ???
Hi Eddie,

Set the 2 PM660 boards trimmers as described in the 660 support thread.
Then, switch the SCAB in analag's mode.
Measure the voltage between the 2 pins of the SCAB "TO ATTACK-X" connector. Set the 4K7 trimmers to have 0 Volt there.
Here it is, the SCAB is set and ready to play in both modes  :D !!!!
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: SaMpLeGoD on July 06, 2009, 12:43:58 AM
Hi Eddie,

Set the 2 PM660 boards trimmers as described in the 660 support thread.
Then, switch the SCAB in analag's mode.
Measure the voltage between the 2 pins of the SCAB "TO ATTACK-X" connector. Set the 4K7 trimmers to have 0 Volt there.
Here it is, the SCAB is set and ready to play in both modes  :D !!!!

Hello Lolo!

Thanks for the explanation! I already did it!
I had a problem in on of my channels before I install the SCamp PCB, and I still have it with the board installed...
One channel compress, normally, althrough some strange behaviours in the extreme positions... but the other one, has some problem in the main board... still don't what what is happening...
With the new board (SCamp) I feel more the compression... but everything is still light to me... I didn't put that 75Ohm resistor that u said on your "pimpin' my pimp..." Will it rise my attcack to 0,4ms as I read? as long as I have some 2.2uF caps on it?
I really will love to have my compressor all working... but so far have some problems to solve...
Cheers,

Eddie  :-\
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 06, 2009, 04:14:12 AM

Thanks for the explanation! I already did it!
I had a problem in on of my channels before I install the SCamp PCB, and I still have it with the board installed...
One channel compress, normally, althrough some strange behaviours in the extreme positions... but the other one, has some problem in the main board... still don't what what is happening...

Hi Eddie !
I had a problem with one of my channels too, and I solved it changing finally the tubes. The PM660 handles mismatched tubes but not really mismatched tubes. If one of the 6BC8 isn't matched at all (with huge difference between the two triodes), you'll have really weird problems appearing in their grid bias (I can't understand why but it did on mine)!!! On one of my channel I had a few volts appearing between the legs grid resistor with no compression... I changed the tubes and now everything is good...

With the new board (SCamp) I feel more the compression... but everything is still light to me... I didn't put that 75Ohm resistor that u said on your "pimpin' my pimp..." Will it rise my attcack to 0,4ms as I read? as long as I have some 2.2uF caps on it?
I really will love to have my compressor all working... but so far have some problems to solve...
Cheers,

Eddie  :-\
With the 75 ohm resistor added, you'll have about 0,2ms with 2,2uF on the SCAB board and no other cap paralleled. To have those 0,4ms you're talking about, you need to have the 2,2uF on the board and another 2,2uF parralleled on the TC switch.
I really think the PM670 is really nutral. To ear the attack compression human ear needs a few ms, you'll ear only the release clearly with a really fast varimu.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: dagoose on July 09, 2009, 04:16:54 PM
dammit... the scab board turned out to be a crap mod..  :-\
Both channels have distortion like hell, one channel is blown up in some kind of way (think the 6107 transistor, not sure) and everything is connceted the way it should..
Removed the c4, bridged it, removed r18, bridged it and removed all 4148's on the pm board but shouldn't there be some kind of bridge in there as well?

So far.. it sucks big time, i had a working pm670 but now it's dead..  >:(
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 10, 2009, 06:34:47 AM
dammit... the scab board turned out to be a crap mod..  :-\
Both channels have distortion like hell, one channel is blown up in some kind of way (think the 6107 transistor, not sure) and everything is connceted the way it should..
Removed the c4, bridged it, removed r18, bridged it and removed all 4148's on the pm board but shouldn't there be some kind of bridge in there as well?

So far.. it sucks big time, i had a working pm670 but now it's dead..  >:(
:o :o :o OUCH !!!
FIRST ANSWERS:
You don't need to make any bridge on the 1N4148 on the PM660 boards. Those diodes are now on the SCAB board.

SECOND SIMPLE QUESTIONS:
1°) The wiring guide only shows one channel. Did you do the mod on both ?
2°) The first wiring guide didn't shows the -17V link to the PM660 board...Did you wired it with the new wiring guide you can find on the first post of THIS THREAD ?
3°) check any shorts you could make with the solder on the SCAB (the pads are sometimes really close).
4°) Finally did you set the SCAB trimmers as described a few post earlier ?

This mod can't destroy the PM660/670 as nothing changes on the board. CV amplitude is the same,  voltages are the same, it is just a unity booster of the CV voltage.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: rrs on July 10, 2009, 10:19:58 AM
Hello,

Just some rookie's questions... what's for that two 4k7 trimmers on the SCamp board? How can I regulate them?
Thanks

Eddie  ???
Hi Eddie,

Set the 2 PM660 boards trimmers as described in the 660 support thread.
Then, switch the SCAB in analag's mode.
Measure the voltage between the 2 pins of the SCAB "TO ATTACK-X" connector. Set the 4K7 trimmers to have 0 Volt there.
Here it is, the SCAB is set and ready to play in both modes  :D !!!!

Just checking if when measuring between the two attack pins the Attack switch can be disconnected (for easier measurement). I ask this because it was mentioned in the 660 support thread that all connections should be made when firing up.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 10, 2009, 10:49:57 AM
Hello,

Just some rookie's questions... what's for that two 4k7 trimmers on the SCamp board? How can I regulate them?
Thanks

Eddie  ???
Hi Eddie,

Set the 2 PM660 boards trimmers as described in the 660 support thread.
Then, switch the SCAB in analag's mode.
Measure the voltage between the 2 pins of the SCAB "TO ATTACK-X" connector. Set the 4K7 trimmers to have 0 Volt there.
Here it is, the SCAB is set and ready to play in both modes  :D !!!!

Just checking if when measuring between the two attack pins the Attack switch can be disconnected (for easier measurement). I ask this because it was mentioned in the 660 support thread that all connections should be made when firing up.

Unfortunately, the SCAB and the PM board must be connected together to make this setting.

PS: I would suggest to connect the SCAB TC NETWORK switch on "R-X" connector or "C-X" connector.
     Analgs pot or switch will be connected to SCAB's "ATTACK-X" connector.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: rrs on July 10, 2009, 11:12:32 AM
I only meant disconnect the "To Attack X" switch.
It's these two pins that should measure 0V between them right. Is it safe to disconnect the attack switch connector to measure the two pins?
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 10, 2009, 07:35:25 PM
I only meant disconnect the "To Attack X" switch.
It's these two pins that should measure 0V between them right. Is it safe to disconnect the attack switch connector to measure the two pins?
I don't understand what switch you're talking about  :-\. To me the SCAB "TO ATTACK-X" is a connector with 2 wires connected to PM660 "ATTACK" connector. There's no switch there.
This connector MUST be connected. The link is necessary to acheive proper setting.
The only switch I see is the "MODE" switch and it must be connected too to toggle the SCAB into analags mode (anyway, it wouldn't help to have this one unconnected).

Check back the wring guide and use the labels you see on it. I will answer more clearly to your questions  ;).
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: rrs on July 11, 2009, 05:38:02 AM
I only meant disconnect the "To Attack X" switch.
It's these two pins that should measure 0V between them right. Is it safe to disconnect the attack switch connector to measure the two pins?
I don't understand what switch you're talking about  :-\. To me the SCAB "TO ATTACK-X" is a connector with 2 wires connected to PM660 "ATTACK" connector. There's no switch there.
This connector MUST be connected. The link is necessary to acheive proper setting.
The only switch I see is the "MODE" switch and it must be connected too to toggle the SCAB into analags mode (anyway, it wouldn't help to have this one unconnected).

Check back the wring guide and use the labels you see on it. I will answer more clearly to your questions  ;).

Sorry I mean rotary switch. You have answered my question though tha the connection must be made when measuring this.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: rrs on July 12, 2009, 08:24:49 AM
OK fired this thing up and got a very disturbing crackling sound? Switched off imediatly, sounded like something was shorting.

Did some searching arround. One thing I noticed was the LM7812 pin 2 and 3 both seemed to be connected to ground. Does this seem right or do I have a faulty component?
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Moby on July 12, 2009, 08:46:48 AM
Quote
One thing I noticed was the LM7812 pin 2 and 3 both seemed to be connected to ground. Does this seem right or do I have a faulty component?
Pin 3 should be on ground but 2 no. Desolder the 7812 and check did you shorted 2 pin pad somewhere to ground and check 7812 too . I presume that you made some soldering mistake somewhere  ;)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: rrs on July 12, 2009, 09:39:25 AM
Quote
One thing I noticed was the LM7812 pin 2 and 3 both seemed to be connected to ground. Does this seem right or do I have a faulty component?
Pin 3 should be on ground but 2 no. Desolder the 7812 and check did you shorted 2 pin pad somewhere to ground and check 7812 too . I presume that you made some soldering mistake somewhere  ;)

have disconected LM7812 and no short between 2 and 3. When 12 V is connected to meters and relays I can buzz with my multimeter pin 2 and 3.

powered up with 12V disconnected and still here the crackling sound. With no power to SCamp all is fine. All was fine before installing SCamp.

Let me know if anyone spots a problem here.
(http://i248.photobucket.com/albums/gg161/rrs12/P1010003.jpg)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on July 12, 2009, 11:04:15 AM

have disconected LM7812 and no short between 2 and 3.

You mean, no short between pins 2 and 3 from the LM7812 right?
Did you check if there was a short on the board as well? It seems there must be a short on the board right?
Also, I see your diode's are mounted tightly on your board. Did you put steel clamps on them when soldering them? To release some heat while soldering?
Maybe you've a faulty diode. They can't handle much heat.

I always mount them 5 to 10mm off the board so there's enough space for a steel clip while soldering them....
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 12, 2009, 11:47:23 AM
have disconected LM7812 and no short between 2 and 3. When 12 V is connected to meters and relays I can buzz with my multimeter pin 2 and 3.

powered up with 12V disconnected and still here the crackling sound. With no power to SCamp all is fine. All was fine before installing SCamp.

Let me know if anyone spots a problem here.
(http://i248.photobucket.com/albums/gg161/rrs12/P1010003.jpg)

Thanks for the photo, it's always better to see if there's something wrong or not :
The thing I can't see but I suppose you did it, is the strap close to the first big WIMA...
Another thing I can't see is : what do you use as "MODE" switch ? It must work like a dual ON/ON switch. "MODEA-X"switch and "MODEB-X" switch are mechanicaly linked... This switch should operate as a short between MODEA-X pin2 and pin1 (or pin3) and at the same time MODEB-X pin2 should short pin1 (or pin3).

Stupid question, but sometimes they're needed  ;D: did you set the PSU660 to +17V / -17V before installing the SCAB ?

PS: I see you've done the mod the right way (75R before the diode)  ;)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 12, 2009, 11:56:47 AM
rrs,
Other idea, if everything on the previous post is correct:
1°) What's connected to the 12V rail ? Keep under 500mA current consumption here....
2°) Check if the BYPASS PCB roll-off diodes don't make a short when connected...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: rrs on July 13, 2009, 02:28:18 AM
Thanks guys. I will get a chance shortly to do more teasting.
One thing is the short only happens when the 12V connector is connected.

It runs the meter lights and relays. There was no problem before the mod with this. Also the crackling sound occurs still when 12V is not connected so it may be something else also.

Anymore testing ideas are more than welcome expecialy the obvious ones.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 13, 2009, 05:14:22 AM
Thanks guys. I will get a chance shortly to do more teasting.
One thing is the short only happens when the 12V connector is connected.
This makes me think about the BYPASS PCB roll-off diodes... Are the relays working ? If not, try the opposite connection on the 12V connector (quickly)...

It runs the meter lights and relays. There was no problem before the mod with this. Also the crackling sound occurs still when 12V is not connected so it may be something else also.
You seam to have a problem on the +17V/-17V rail...
Safe test you can do :
- Disconnect the "ATTACK" connector on the PM660 boards... Tell us what's happening (you won't have any compression BTW)...

Anymore testing ideas are more than welcome expecialy the obvious ones.
On the SCAB, check if the electrolytics are the right way because it's impossible to see the orientation on the photo. Check also if the +17V/-17V is present where it should be (op-amps, transistors...)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: rrs on July 13, 2009, 07:48:15 AM

- Disconnect the "ATTACK" connector on the PM660 boards... Tell us what's happening (you won't have any compression BTW)...



No crackling sound  :)(12v is connected also).

I guess were onto something. It could be coming from the PM660 board.
Where to from here?
(http://i248.photobucket.com/albums/gg161/rrs12/P1010009.jpg)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 13, 2009, 08:01:40 AM
Your PM660 board's fine, cool  ;D.

Unplugged like this did you checked voltages on the SCAB board (OPamp and transistor supply) ?
If everything is fine :
1°) Try to see if the link between SCAB and PM660 is not twisted...
If it's OK:
2°) Replug the connector, and redo the setting operation, trying to see if the voltage between "TO ATTACK-X" connector pins can become negative or positive. SET it to 0V, of course, in analag's mode  ;D...

I'll be back on the web in about 2 hours...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Kingston on July 13, 2009, 08:06:41 AM
rrs,

why have you nothing connected to your poorman PCB ground and -17V?

Please people! READ THE WHOLE THREAD BEFORE DOING ANYTHING THAT CAN BREAK YOUR UNITS!

then read them again! all of them!

 >:(
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: rrs on July 13, 2009, 08:18:42 AM
rrs,

why have you nothing connected to your poorman PCB ground and -17V?

Please people! READ THE WHOLE THREAD BEFORE DOING ANYTHING THAT CAN BREAK YOUR UNITS!

then read them again! all of them!

 >:(

Moby's wiring diagram shows no connection. Is Mobys diagram wrong?
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Kingston on July 13, 2009, 08:35:11 AM
What did I just say?

There's only 5 pages. Is it really too much to ask?  :(
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: rrs on July 13, 2009, 09:09:27 AM
What did I just say?

There's only 5 pages. Is it really too much to ask?  :(

Well looks like the wiring guide was updated in the last 13 days. I am sorry if my not re-reading this thread every two weeks has offended anybody. Then again if you had just alerted us to the fact the wiring guide had changed I would be giving you a big thanks.
I will see if this makes a difference.

[Edit] Well actually that seems to have done the trick so I guess I do owe you a big thanks anyway. :-*
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 13, 2009, 09:38:25 AM
Thanks Kingston !!!!
 
:D :D :D :D :D :D :D :D :D
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Kingston on July 13, 2009, 10:04:47 AM
I am sorry if my not re-reading this thread every two weeks has offended anybody.

you only needed to read new posts. in the last page. 2 minutes.

compare that to the amount of time you spent troubleshooting.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 13, 2009, 12:55:30 PM
I am sorry if my not re-reading this thread every two weeks has offended anybody.

Nobody has been offended, but it's always stupid to waste time...
Tell us about your progress...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: dagoose on July 14, 2009, 02:21:20 PM
Ok, finally had some time to test some things.
First i wanted to make sure that my pm board itself was ok and so added the 4148's again, 120r res and 10uf, standard. then.. still not working.. dammit.. Then i measured the voltages from the psu and i had both 17v lines but... the -17v was + 17v and so i have 2x +17v lines!  :o
Then i disconnected the -17v from the scabboard (not the pmboards) and everything worked fine again, even the channel with the scabboard came alive.. but without the -17v connected to the scabboard. Of course that channel is not working as it should but at leadt it gives sound and does compress a bit in both modes... weird..

How can a voltage which should be -17v become +17v?  ???
Anyone? i don't see the logical part of this.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on July 14, 2009, 02:56:03 PM
Ok, finally had some time to test some things.
First i wanted to make sure that my pm board itself was ok and so added the 4148's again, 120r res and 10uf, standard. then.. still not working.. dammit.. Then i measured the voltages from the psu and i had both 17v lines but... the -17v was + 17v and so i have 2x +17v lines!  :o
Then i disconnected the -17v from the scabboard (not the pmboards) and everything worked fine again, even the channel with the scabboard came alive.. but without the -17v connected to the scabboard. Of course that channel is not working as it should but at leadt it gives sound and does compress a bit in both modes... weird..

How can a voltage which should be -17v become +17v?  ???
Anyone? i don't see the logical part of this.

So you're saying that without the scabboard connected all your voltages are fine right? You meassure -17v & +17v from your PSU with the scabboard disconnected?
If yes, problem is on the scabboard. Did you check all transistors on the scabboard? No mix-ups here?
No shorts to ground on the -17v or +17v traces?
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: dagoose on July 14, 2009, 04:43:39 PM
OK.. when i checked the board i didn't see anything wrong but when i connected it again the voltages where ok and it worked.
The only thing was that one channel was faulty, the 5534 got hot and it wasn't working so i changed all tip's and it works  ;D
So it looked like i had some faulty tip transistors, they where not mixed up or something and i didn't see a short, it just did some really weird things.
The only thing is that i blew up one of the 2n6107's on the pm board now while calibrating the voltages again..  >:(

Another question about the calibrating of the scamp board; you say that you have to put it into analag mode and then calibrate to 0v between the 2 pins of the attack connecter to the attack pot, am i right here? so you do that without the potmeter (stepped switch) connected or with? i have some voltrages going on there but they are hard to get to 0, it looks like i see discharge of a cap when i measure the voltage, it's really not possible to calibrate. The only thing that happens is that the VU meter is changing it's 0 position.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 14, 2009, 09:37:11 PM
Another question about the calibrating of the scamp board; you say that you have to put it into analag mode and then calibrate to 0v between the 2 pins of the attack connecter to the attack pot, am i right here? so you do that without the potmeter (stepped switch) connected or with? i have some voltrages going on there but they are hard to get to 0, it looks like i see discharge of a cap when i measure the voltage, it's really not possible to calibrate. The only thing that happens is that the VU meter is changing it's 0 position.
Happy to know you made such progress  :)...
The 0 Volts DC must be between the SCAB "TO ATTACK" pins with no signal applied in Analag's mode... My fault. I noticed and corrected my error yesterday on the first post... I'm definitively human, with all the mistakes a human being can do  :-[...  All my apologies...
You'll see, calibrating is really easy... But not to make any error be sure you can see a change turning the trimmers CW or CCW. And definitely, set it to the 0V position.

PS: As the SCAB "TO ATTACK" connector is linked to PM660 "ATTACK" connector, you can make you measures on both. They carry the same voltages.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: rrs on July 15, 2009, 08:47:27 AM
Wow thanks lolo-m.

This works a treat. Definitly worth doing as the original was a little slow for my taste.
Thanks for the help also.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 15, 2009, 08:56:57 AM
Wow thanks lolo-m.

This works a treat. Definitly worth doing as the original was a little slow for my taste.
Thanks for the help also.
:) :) :)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: dagoose on July 17, 2009, 03:15:05 PM
ok.. the board itself is working in analag mode.. but still not at scamp mode.
I think the 5534's are blown (they got hot with the weird voltages) but i don't have any in stock right now so i have to wait to get some.
What happens now is that when switched to scamp it works for a few seconds (it compresses) and after like 3 seconds it sounds like a cap discharging and it starts to distort because of the rising level and meters that go positive (From 0 to + 2db) instead of negative (from odb to - ..db)
Does that sound like blown 5534's? guess so..
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 17, 2009, 03:42:44 PM
If you've got a TL071 (or OPA604 or any pin compatible opamp) it does work too (maybe a bit slower with a TL071).
Check again your connections of the +/-17V on both PSU and SCAB... If you use connectors there, it's sometimes difficult to be sure the connection is really good (it happened to me) and your previous voltage changes make me think about this kind of problem...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: dagoose on July 21, 2009, 02:36:18 PM
Picked up some 5534's today and it's up and running!  8)
It sounds good, at least faster then the analag mode to my ears though i haven't really tested it yet but i'm happy with the result.
I used the bypass switch for in/out (2 relays and 2 pole switch), it now has bypassmode, analag mode and scamp mode so 3 steps and it works great and i didn't have to drill extra holes!
To make it more visible i added a red led to the back of the meter when in scamp mode so that it has a bit more like a red glow from behind. Not shocking but it adds something.  ;D
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 21, 2009, 04:59:28 PM
I glad to read this !!! I prefer this to your first post  ;) !
Really happy you sorted out  :D !
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: dagoose on July 22, 2009, 01:50:22 AM
I will post some interior/beaver shots later on but it's already racked up now, it has to work hard today.  ;D
I was a bit sceptical at first mainyl because i didn't really understand what it was doing but now i do and it's so simple, i was really thinking the hard way.  :-\
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: crisotop on July 25, 2009, 08:28:22 AM
C3 on the main PM670 board is only used when in analag mode am I right?
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on July 25, 2009, 10:45:08 AM
C3 is used in both modes. Except if you don't want to use analag network at all, you need it. If you want both modes and stick to Fairchild network, use a 1,8uF. But trust me a 2,2uF is fine and doesn't make a real change in the release (and attack of course)  ;).
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: crisotop on July 25, 2009, 10:49:02 AM
that's all I wanted to hear (since a 2u2 is all I have at the moment ;)

cheers lolo!
christoph
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: khstudio on August 27, 2009, 06:31:20 PM
Please forgive me for posting in 2 different threads but I'm not sure the main help thread gets enough visitors from complete builds.

Anyway...
Has anyone done any Full Frequency sweeps on their PM670 (with or without the SCAmp)
 with & without compressing?

I don't have the SCAmp installed so mine is stock. I just did some sweeps & it looks pretty flat but when compressing it looks normal until it gets to about 1k - then it ramps down about -4 dB more or so  :o

http://www.khstudio.us/DIY/PM670/PM LR Sweep.bmp (http://www.khstudio.us/DIY/PM670/PM LR Sweep.bmp)

If anyone has or could sweep their working unit... that would be GREAT!

Thanks.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: ChuckD on October 04, 2009, 04:11:37 AM
Hey Lolo or anyone else

I am confused does the SCamp board use the same 10K Attack pot as the Analag version just making the time constants quicker?
Or do I have to have values for C* and R* in Scamp mode?

I am confused what to connect if I want to switch between both modes. The wiring diagram shows the R* and C* not hooked up but a 10K pot.

Also , this has been asked a few times, can someone put down what they recommend for values for both C* and R*?

Hey Thanks Guys!

Chuck
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on October 04, 2009, 04:28:02 AM
Hey Lolo or anyone else

I am confused does the SCamp board use the same 10K Attack pot as the Analag version just making the time constants quicker?
Or do I have to have values for C* and R* in Scamp mode?

I am confused what to connect if I want to switch between both modes. The wiring diagram shows the R* and C* not hooked up but a 10K pot.

Also , this has been asked a few times, can someone put down what they recommend for values for both C* and R*?

Hey Thanks Guys!

Chuck



The 10K pot is used only in Analag's mode....
C* and R* are the "a la Fairchild" TC network. If you want to have closer specs to the Fairchild use a 2 or 2,2uF as C* and copy the rest of the Fairchild TC network... Just don't forget that the 2uF and 220K of the Fairchild are already connected in the PM670 + SCAB.
Connect the switch mode as described in the wiring guide (one dual switch per channel)...
I hope I'm clear enough   ;D ...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: ChuckD on October 04, 2009, 04:35:07 AM
No Sorry I still don't understand


Quote
to have closer specs to the Fairchild use a 2 or 2,2uF as C* and copy the rest of the Fairchild TC network... Just don't forget that the 2uF and 220K of the Fairchild are already connected in the PM670 + SCAB.

This statement seems to contradict itself.
So what do you recommend for the values for both C* and R*? For a True Fairchild? Can you just list the 6 values for me that may help a lot.

Thanks by the way for the quick response Lolo!

Chuck
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Moby on October 04, 2009, 07:01:57 AM
Just copy the network from real F670. Or do your custom one if you want.Or read the PM pimp page....
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on October 04, 2009, 07:49:44 AM
Copy this network without R137 (it's already on the PM660 board) :

(http://i52.photobucket.com/albums/g8/mobidik/660-time-constant.jpg)

The network is composed by : R137, R138, R139, R140, R141, C109, C110, C111, C112, C113.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: ChuckD on October 04, 2009, 01:07:29 PM
Thanks Guys

On the FC 670 schematic it shows C values and R values wired in series with respect to each other. Then each position is a R/C value put in parallel with the circuit.
With the SCAMP board it has two connections C* and R* that look simply in parallel with each other. Are the C* and R* already joined in series and then parallel WRT the circuit on the SCamp board or should I do that on the switch?

Do you have a schematic for the Scamp board that you could post? That would clear this up maybe.
Do you understand why I am confused?


Chuck
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on October 04, 2009, 01:25:53 PM
Looking at the Fairchild TC network:
- Consider that R137 is already on the PM660 board,
- C109 can be connected to C* on the SCAB board.
- The rest of the network will be on the switch connected on R* for example.

I originally put those footprints to let people try different possiblities of C and R in the TC network... I apologies if it's a bit confuse for some of us  ;D...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: ChuckD on October 04, 2009, 02:51:28 PM
Lolo,

Thanks for the replies and patience !

I thought you said the C109 was already on the board?  But here you said to put it on connection C*
I really need to draw out this schematic I guess if you don't have one handy.

I will put the network as drawn on R* then But which side is which? In case I use electrolytics?
Hopefully I can clear this up for others. Or I am I the only one .... sorry if so.

Chuck
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: ChuckD on October 04, 2009, 03:18:27 PM
OK now I understand

1) On the Scamp Board C103 and C203 correspond to C109 on the FC670 schematic.
2) R17 on the Poorman Board Corresponds to R137 on the FC670 schematic.
3) Leave C* connectors empty.
4) Build the network in the FC670 Schematic by hand using a 2pole 6position switch connect that to R* connector.
5) The poles of the switch connect to the RED side of the wiring diagram while the shorted side of the network connects to the Brown Side.
6) If using electrolytics then the Negative terminal of the cap should go towards the Brown shorted connection


Is this correct?

Chuck
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on October 04, 2009, 03:35:18 PM
ChuckD spot on  ;) ! You've got it perfectly right !

Here is SCAB's schemo :
http://pagesperso-orange.fr/NBNS-Studio/PM670/SCAMPBOOSTERdefinitive-sch.pdf
 (http://pagesperso-orange.fr/NBNS-Studio/PM670/SCAMPBOOSTERdefinitive-sch.pdf)
You can connect electrolytics as caps, but electrolytics are getting old quickly and unpolarised caps are not expensive when you're dealing with less than 63V (in our case it's max 17V). If you want to connect some lytics be carefull with polarity, the pin connected to the diode is the most negative pin.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: ChuckD on October 04, 2009, 03:50:47 PM
Quote
If you want to connect some lytics be carefull with polarity, the pin connected to the diode is the most negative pin.

If this is true then my instructions (5&6) are Wrong?

Can you check it for me?

Chuck

Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: ChuckD on October 04, 2009, 04:01:03 PM
Ok sorry I do not know this old way of marking the electrolytics and I have my + and - switched in my instructions !!!

It should read:


1) On the Scamp Board C103 and C203 correspond to C109 on the FC670 schematic.
2) R17 on the Poorman Board Corresponds to R137 on the FC670 schematic.
3) Leave C* connectors empty.
4) Build the network in the FC670 Schematic by hand using a 2pole 6position switch connect that to R* connector.
5) The poles of the switch connect to the RED side of the wiring diagram while the shorted side of the network connects to the Brown Side.
6) If using electrolytics then the Negative terminal of the cap should go towards the resistor and Positive connects to the Brown shorted side of your hand built switch network
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: jyrki3101 on October 22, 2009, 05:46:20 PM

HI, could this TC network board w/ 2p6pos rot.switch work in analag's and fairchild mode. Here is the pic. ( if I succeded in attaching
an image )
  - jyrki3101-















Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on October 23, 2009, 06:33:33 AM

HI, could this TC network board w/ 2p6pos rot.switch work in analag's and fairchild mode. Here is the pic. ( if I succeded in attaching
an image )
  - jyrki3101-

I looked at it fastly and I didn't notice any error... It should work properly. Nice work  ;) !!!
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Nele on October 23, 2009, 07:32:19 AM
maybe add some extra pads for the caps so larger types will fit as well ( 7.5, 10, 12.5 and 15mm)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: jyrki3101 on October 23, 2009, 09:07:43 AM
Thanks, I just want to check one more thing :
1. 50-63V is enough for the voltage rating of caps in the TC network(scab mode), because the voltages in SCamp are not more than 17V ! 
please correct me if I'm wrong
    -jyrki3101-
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on October 23, 2009, 09:21:54 AM
You're perfectly right. PM670 doesn't use huge CV voltage swing anyway even in Analag's mode... 63V is already overkill. we don't deal with the real Fairchild's CV voltages.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: TheGuitarist on December 06, 2009, 08:43:06 PM
I'm just sorting out how to wire up my TC switch.


Just checking that this sounds right to everyone (desoldering this may be a pain so i'd prefer to get it right the first time)


I'll be using a 6 pos 2 deck switch (or only 6 of a 12 etc)

for one deck it will be either resistors in series or just 2k 4k 6k 8k 10k

For the second deck, which will be the fairchild mode, it will be like from the 6th position. capacitor from the input to output tabs (hope that makes sense.. where you would normall solder resistors.) then use a diode to link the input of 6 to the input of 5. Then repeat that process.

I think that should work and paralell the caps. What sort of voltage/current is going through the switch. Just need to work out what diode to use (unless someone wants to point me in the right direction :D)


EDIT:

After looking at jyrki3101's board... i'm wondering.. is it even possible to do this without a seperate board? I think i'm in over my head electronic wise. Just getting veeryyy confused as to how to implement the FC TC. Not too worried about going custom.

Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: mrclunk on January 26, 2010, 02:52:35 PM
Hi guys,
I have a question for anyone who's experienced the small amounts of distortion (under compression) in the normal 'analag' TC mode.

After you added the SCAB sidechain amp does this still happen or does the added balls alleviate the problem?

Just finished tweaking my standard PM670 and noticed a little distortion on a piano solo in a test track, the distortion only occurs on quite hard hit parts. (But its not a signal overload problem)
Just thought perhaps the added power of the SCAB mod would help the SC 'keep up' with the faster transients of the piano. (programed midi piano, with high velocities)
I do have a SCAB pcb waiting to go in btw so when added i'll see for myself, just wondered if it helped?

Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Moby on January 26, 2010, 03:14:52 PM
Quote
After you added the SCAB sidechain amp does this still happen or does the added balls alleviate the problem?
Adding SCAB board makes PM totally different regarding TC network, so it of course sounds different  ;) .
Quote
Just finished tweaking my standard PM670 and noticed a little distortion on a piano solo in a test track, the distortion only occurs on quite hard hit parts. (But its not a signal overload problem)
From my experience distortion is caused mostly bu "Varimu" tubes, then by transformers . First U must match them and when you do that there is still  a problem because it's not really Vmu tube. It will never work as  6BA6 or 6386 ! Adding SCAB helped a bit to catch faster so "headroom" improved a bit.
Anyway, that's my 0.2 cent's.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: mrclunk on January 27, 2010, 05:34:52 AM
Thanks Moby,
I'll try some different tube combo's and take it from there.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Moby on January 27, 2010, 07:20:02 AM
Thanks Moby,
I'll try some different tube combo's and take it from there.
But have in mind that 4 6BA6 or similar wired in triode mode must have a "rich" at least 10K / 600 ohm . I would rather say 15K . Also, capability of SCAMP is max -17V CV so maybe tweaking the PM to another beast is not a good idea. I'm not desperate with PM sound at all , (with close matched tubes and transformers) but it has strong character and maybe is not best compressor for mastering purpose. Also, nobody mentioned that when you match tubes in CH1 you have to match another channel close to that if you want to use it in link (stereo) mode. So, order some more 6BC8's and match them in dynamic mode. It will sound great for vocals, guitar and some kind of drums smashing  ;D. For mastering wait a bit for some more sophisticated design  ;)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: ChuckD on February 07, 2010, 11:50:14 PM
I wanted to post here since this is where I got the wiring guide (first page).

Is there a ground loop on the wiring guide?
Does the Green/Yellow wire and Blue Wire on the Bypass PCBs both go to Ground through different paths?
Would this cause a loop?

Chuck



Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on February 10, 2010, 01:25:18 PM
I wanted to post here since this is where I got the wiring guide (first page).

Is there a ground loop on the wiring guide?
Does the Green/Yellow wire and Blue Wire on the Bypass PCBs both go to Ground through different paths?
Would this cause a loop?

Chuck
If you want to be sure there's no ground loop you can star ground every board (I mean one point on the chassis leading ground to every single board). But hum in the PM670 comes mainly from an unregulated filament supply, bad matched tubes and magnetic field provided by a too hardly used power transformer. Check also a post of Moby about wiring the filament to cancel a lot of hum due to electrostatic field effect in the PM660/670 thread.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: ChuckD on February 11, 2010, 04:37:22 PM


Hey Lolo

I have another issue :

When I try to calibrate one channel I cannot make both Your Timing circuit and Analag's circuit equal to -4.5.  When I tweak yours to -4.5 then flip switch Analag's reads -4.99. Same goes if I try the other way they are always -0.4V apart.
So when I flip the meter is now not at 0 GR

This is not true for the other channel which I can get them 0.04V apart. Which tracks very well on the meters in either mode.

What could cause this gap between the 2 circuits ?


Thanks Again

Chuck




Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on February 11, 2010, 05:53:29 PM
Did you follow exactly the procedure in my first post ?
This is the only way to get the mod working properly.

The PM660 board should be set to the normal setting first. Then the SCAB can be attached and set as explained in first post.

I had problems too when I did the mod and finally find that procedure to have a good tracking in both modes.

Hope this helps.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: ChuckD on February 11, 2010, 06:12:47 PM
Ok Sorry

I think I did this wrong then!
It still kinda works though ?  Here is what I did

1) setup RV3 for -2.5 V and RV6 for -4.5V at right side of R17 (middle pin of pot) .
2) Then set RV201 for -4.5  middle pin to GND (in both modes)
3) Set RV101 for -4.5 middle pin to GND   (in both modes)

So this is wrong then??

I think you said to :

1) setup RV3 for -2.5 V and RV6 for -4.5V at right side of R17 (middle pin of pot) .
2) set mode to Analag's , set RV201 and RV101 so that their corresponding "To Attack" connectors have 0VDC across them???

Is this correct?

Chuck







Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on February 12, 2010, 01:26:45 AM
Ok Sorry

I think I did this wrong then!
It still kinda works though ?  Here is what I did

1) setup RV3 for -2.5 V and RV6 for -4.5V at right side of R17 (middle pin of pot) .
2) Then set RV201 for -4.5  middle pin to GND (in both modes)
3) Set RV101 for -4.5 middle pin to GND   (in both modes)

So this is wrong then??

I think you said to :

1) setup RV3 for -2.5 V and RV6 for -4.5V at right side of R17 (middle pin of pot) .
2) set mode to Analag's , set RV201 and RV101 so that their corresponding "To Attack" connectors have 0VDC across them???

Is this correct?

Chuck
Between the 2 pins of each "to attack" SCAB connector you must read 0V, in analag's mode with no compression and no signal.
It isn't easy to measure this but it is the only way.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: ChuckD on February 28, 2010, 03:54:35 AM
Nope this still did not work for me.

I have done what you said but the one side does not match in 2 modes
I my way of doing it I had it much closer but it was a compromise between the two.

What is strange is it only happens on one channel. The other channel this method works perfect.
Any ideas what could cause the two modes to be so far from each other on one channel only??


Chuck

Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on February 28, 2010, 04:16:54 AM
Nope this still did not work for me.

I have done what you said but the one side compresses way more then the other. In both modes.
In the Analag Mode the meters seem to match but in SCAMP mode they do not at all.

As the SCAMP is a basic voltage follower I can't understand what's happening.
If tracking is "OK" in analag mode and not in SCAB mode, maybe you have to check again if you didn't make an error in the resistors around the opamp. It must have a gain of 1. If everything is OK, you maybe have a problem of solder short somewhere in the SCAB. Have you tried to swap the channels of the SCAB ? Does the problem changes too ? If it does, the problem is on the SCAB, if it doesn't the problem is somewhere else.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: ChuckD on February 28, 2010, 05:05:27 AM
Yes if I do this the problem does switch sides. So it is something on the right 20X side of my SCAMP board is screwy.
I tried swapping the opamps since they were in sockets and thought I'd give that a quick try. It did not make a difference.

Tomorrow I will have to unhook the SCAMP board and start looking at the bottom solder joints.

Chuck
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on February 28, 2010, 06:10:13 AM
Chuck,
Another easy test you can do is to swap the Mode switches from one side to the other if you wired them with connectors on the SCAB. An error in wiring can do tricky things there. Just an idea...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: ChuckD on February 28, 2010, 09:09:12 PM
No I tried that it is the one side as mentoned before.
I took out the board which was really difficult in mine. It is so tight.

I checked all the connections and added the 75ohm resistor since I never did that.
Everything looks good.

Problem is still there.

Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: SIXTYNINER on April 14, 2010, 04:35:00 AM
hi moby
if the pdf in mediafire is the right one
that in the first page ?
 ;)

Quote
Yes, there's two missing wires on the wiring guide  Grin. It was an evidence to me, but I agree it isn't !!!
The PSU feeds the PM660 board with GND and -17V and SCAB Board with -17V/GND/+17V.
Sorry, my mistake  :-X Here's the revised file  ;D
http://www.mediafire.com/file/mzzwzmmwhy2/PoorMan+SCAB-WiringGuide-R1.pdf
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: dagoose on April 14, 2010, 05:17:28 AM

What happens now is that when switched to scamp it works for a few seconds (it compresses) and after like 3 seconds it sounds like a cap discharging and it starts to distort because of the rising level and meters that go positive (From 0 to + 2db) instead of negative (from odb to - ..db)
Does that sound like blown 5534's? guess so..

OK, reposting my old post because it seems that i have the same problem again.
It runs fine in analag mode but when i switch to scanb mode it works for a few seconds and then it sounds like the compression slowly fades away and after about 10 seconds there is no compression.
When i switch back to analg mode again the meters peg and it's distortin because of high gain and after a few seconds it is working fine again and it stays that way.
I checked voltages and they all seem right, any idea where this could be coming from?
I was thinking.. could it be that the 5534's don't like the 17v?
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Kingston on April 14, 2010, 05:49:05 AM
5534 runs fine on 17V rails. The way it behaves now sounds like some cap, probably in the time constant network is connected wrong. Check your time constant networks.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: dagoose on April 14, 2010, 01:19:05 PM
Please call me stupid... ::)
i recently did some experimenting for what i had to unplug the scamp board i because it was in the way of the trannies i was working on.. since then i didn't really test/use it, just put it back into the rack and it stayed there doingnothing.
I accedentily swapped the ''to attack'' and ''attack''.  :-\
Strange thing is that it is working quite ok in analag mode when you do that (time constant ofcourse not) but in scamp mode it doesn't.
I found out because when i tried to re-adjust the 0v on the attack i could try anything but it stayed 0v. Then i got suspcious and check the wiring.

It's up and running again!  ;D
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: imo on October 29, 2010, 04:07:40 AM
just getting back to my PM670 after a loonngg tour. Anyway, it looks like it has been a while since there was any action here, but i had a couple of questions.
1. The 75r resistor is connected to the anode side of the 4007's on the SCAMP board?
2. Where are R* and C*? Are you guys referring to to 'C-L' and 'R-L'? Then according to Chuck's diagram would you plug the time constant 2 pole switch to the R-L pads, with the 'brown' side meaning  pad of R-L that connects tothe left side of the 'to attack R' pads?
3. If you build the 2 pole switch with the 15 and use a DPDT switch as well, then you are replacing the 10k 'attack' pot with the 1st pole of the 6 position switch?

Just wanting to confirm as a lot of connections on this beast, and no comprehensive schematic.
Thanks
Ian
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on November 09, 2010, 08:45:10 AM
Ok, found some time for the poorman. I've read this whole thread, studied all schematics plus guide.
I'm figuring out what's the best way of implementing the time constant switch, or maybe switches.

One question: The "attack" pot does nothing when switched in "fairchild" (non analag) mode right?
The idea is to make your own time constant network by connecting various caps and resistors to the C and R terminals right?

Due to my lack of time the pauses in between working on this poorman are so long that I have to re-read all info every time.
Must be working for more than two years on this project. I keep saying to myself...enjoying the road is more important than the final destination...although it would be nice to eventually finish this project   :D
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on November 10, 2010, 05:59:42 AM
Is this thread still alive?
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: loopermc5 on November 10, 2010, 11:16:13 AM
Is this thread still alive?
I'm also just getting to my scamp. Im going to use  switches with 2 decks so in each mode I have my seperate t.c's for each. i will also be wiring the release as a seperate switch. I got the board in and wired just need to complete the switches.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: tomcat on November 10, 2010, 11:47:20 AM
Is this thread still alive?

I hope so ... will start my build next week ... hopefully :)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on November 10, 2010, 12:47:27 PM
Is there maybe an updated schematic available? The one I have is dated 13-3-2009 and on that schematic it seems the attack pot is only working in analag mode.
I don't want a pot that's only working in 1 mode. More something like a big rotary switch with 12 presets (taken from both analag & Fairchild (scamb) mode).

Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: tomcat on November 10, 2010, 12:58:41 PM
Have the same + wiring guide from 1.Jul 2009
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on November 10, 2010, 01:04:08 PM
I'm also just getting to my scamp. Im going to use  switches with 2 decks so in each mode I have my seperate t.c's for each. i will also be wiring the release as a seperate switch. I got the board in and wired just need to complete the switches.

Can you elaborate? Is the release switch done by different value resistors connected to the "R" terminal in the scamb pCB?

Also, will you be using the attack pot at all? Or just switching between different cap values in BOTH analag and fairchild mode?
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: loopermc5 on November 10, 2010, 02:13:32 PM
well im going to combine jyrki3101 layout on page 7? of this thread and what Veermaster did here
http://www.groupdiy.com/index.php?topic=28274.0  I havnt actually sat down to figure out details yet but it's the basic idea of where i'm going
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on November 10, 2010, 04:30:15 PM
Re-read the whole thread (plus the pimp thread) once more and all's clear now.
One question though: is there a reason we should keep the analag mode at all?
In other words, is there anything special about the time constants from the analag mode or can we get these with the scamb mode as well?
Having these two mode's makes things unnecessary complex on the frontpanel if you ask me....
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: loopermc5 on November 10, 2010, 05:45:33 PM
 
Re-read the whole thread (plus the pimp thread) once more and all's clear now.
One question though: is there a reason we should keep the analag mode at all?
In other words, is there anything special about the time constants from the analag mode or can we get these with the scamb mode as well?
Having these two mode's makes things unnecessary complex on the frontpanel if you ask me....
Thats the cool thing about it is you can just go nuts finding the  t.c's that work best for you. I kept the analag tc because I like it no other reason
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on November 15, 2010, 03:49:23 PM
Re-read the whole thread (plus the pimp thread) once more and all's clear now.
One question though: is there a reason we should keep the analag mode at all?
In other words, is there anything special about the time constants from the analag mode or can we get these with the scamb mode as well?
Having these two mode's makes things unnecessary complex on the frontpanel if you ask me....
I kept the analag mode as poeple asked for this... You can recreate it with the SCAB but it will be dificult and certainly never be exactly the same. Power to charge the caps in SCAB mode isn't the same than analag's stock sidechain.
Ps: Sorry not to be very active, but I started one year ago the hugest DIY work I can do. I bought an old factory build in 1850 and started to repair it to make a "huge" complex of 6 rehearsal places and my studio inside the 760 square meters I bought... I'm more confortable with hammer and concrete-mixer than with solder-iron at the moment  ;D ! To be honest, my body has never been that painfull...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Kingston on November 16, 2010, 06:30:10 AM
I built time constant networks so that in some of the range you can have roughly equal timing on both scamp and the plain mode. They don't sound the same at equal time settings because they have different attack and release shapes. Scamp has a much more abrupt discharge of the cap so even if calculations say "equal" they are not.

I would advice to keep both modes available for flexibility. Most of the time the plain mode is fast enough and sounds very "natural", say 2-4uF (medium attack) with 50k-150k in parallel (fast/medium release). With scamp it becomes harder to tell settings at that range apart as they will always be very fast.

Thanks lolo-m for the scamp board again, it really helps with flexibility.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on February 21, 2011, 10:42:03 AM
For experimental reasons I have now the release resistors replaced with a 470K pot.
When doing clean compression I can't hear any fine adjustments but when things are a little distorting these fine adjustments are very nice to have for tone shaping.
Any reasons why I should NOT go for a pot instead of fixed resistors?
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on February 25, 2011, 05:56:37 AM
I see the Fairchild time constants uses resistors in series with caps on two positions. Does this give a longer attack time?
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on February 25, 2011, 01:56:54 PM
No, on position 5 and 6 the resistor just slow the release.
With Fairchild's TC network you have to think current. The current coming out of the SCamp charges the network. You'll see and understand that it will fill the smaller resistive element first (the smaller cap) then the most resistive element will make the cap's discharge. On position 5 and 6, there's an additional resistor+cap that will be charged by the current of the SCamp , then by the cap's charge and it have a really really long discharge. Honestly position 5 and 6 are nearly unusable now. They have a super fast attack time and a crasy long release (more than 2 minutes if I remember well). They were made to maintain the level whatever could happen in broadcast (mad DJ, poeple talking too loud or too low, sleeping engineer...) not to saturate the emiter.
I hope I've been clear enough  ::).
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on February 26, 2011, 09:17:03 AM
Thanks Lolo!

One more thing...is there a limit on how small the parallel resistance can be?
In the original Faitchild time constant section the smallest is 68K.
So, the smaller the resistor the faster the release time...why not make it even smaller, say 10K,  or even no resistance at all?
I like very fast release times ;-)
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on February 27, 2011, 02:19:43 AM
I don't exactly know the limit for the parallel resistor but 10K is working for approx 20ms release time. I've got this setting in my TC network : 2,2uF // 10K.

...  or even no resistance at all?
I don't understand what you mean there but :
- No resistance (only the cap) will mean no release
- A wire parralleled to the cap will mean no attack and no release = no compression.

Another thing, if you want to slow the attack you've got a few options :
- you can use bigger caps : if you double the caps value you approximatively double the attack time or,
- you can use a little serial resistor added to the 75 ohm I forgot on the SCAB board (Read PIMPING MY OWN PIMP page 2). As it'll make the SCAmp output impedance higher, the caps will charge slowlier and attack time will be longer BUT be carefull with this resistor value as you create a voltage divider with the release resistor so the max compression will be affected.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: pacemaker on February 27, 2011, 05:40:20 AM
hi lolo,
I'm currently building my PM670,
and i would like to put your scamp booster in.
not sure it's the right place,
but i can't find a thread for the boards only,
Was it a one shot run of boards or are they still available somewhere ?
best regards,
Francois
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on February 27, 2011, 06:37:43 AM

- A wire parralleled to the cap will mean no attack and no release = no compression.


Strange, I had a 470K pot wired parallel to the cap and still got some compression when turned all the way cw which resulted in 0 resitance...well, maybe the resistance was 18R or so due to the pot being not very acurate...but still.
It did sound quite nice...I'll experiment some more with this.

Thanks again for chiming in on this old thread...
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Kingston on February 27, 2011, 07:39:50 AM
Are you sure you don't have the 221k resistor of the old time constant network still there?
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: radiance on February 27, 2011, 11:01:12 AM
Are you sure you don't have the 221k resistor of the old time constant network still there?

It's still there yes...but that does not matter since the pot I use is parallel to that resistor as well is it?

..Or am I missing something?
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Kingston on February 27, 2011, 12:39:18 PM
Oh I see, close to 0 resistance. Don't know what is going on then.
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on February 28, 2011, 03:53:34 AM

- A wire parralleled to the cap will mean no attack and no release = no compression.


Strange, I had a 470K pot wired parallel to the cap and still got some compression when turned all the way cw which resulted in 0 resitance...well, maybe the resistance was 18R or so due to the pot being not very acurate...but still.
It did sound quite nice...I'll experiment some more with this.

Thanks again for chiming in on this old thread...
You're right you may have some compression...
Looking at the schematics the 0dB point (6BC8 tube bias) is made with a cap parralleled to a resistor. The SCAmp if loaded with a shunt (0 ohm load) is charging the bias cap. This is why you've got some compression.

This is not really safe for the comp so avoid this by using a minimum of 4K7 in the TC network (about 10ms release with a 2uF cap). If you want to use a pot put a minimum resistor (4K7 or best IMO 10K serial to the pot). Every thing will be a lot more predictable that way  ;).
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on February 28, 2011, 04:20:22 AM
hi lolo,
I'm currently building my PM670,
and i would like to put your scamp booster in.
not sure it's the right place,
but i can't find a thread for the boards only,
Was it a one shot run of boards or are they still available somewhere ?
best regards,
Francois

Hi François !
The black market topic vanished for some reasons (I don't know).

First, like I said many times :
Have a working STOCK PM660/670. Test it, listen to it.  If what you hear don't please you enough, PM me. There's a few SCAB boards left somewhere...

PS : Le bonjour d'Avignon, tu es où en France ?
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: pacemaker on February 28, 2011, 08:46:51 AM

merci pour tes conseils Lolo,
je suis a angers dans le maine et loire !
a bientot peut etre,
francois
Title: Re: PM660 / PM670 SCAmp Booster build and tips help thread
Post by: dingo on March 14, 2011, 02:37:40 PM
hello! :)
I am interested on scamp booster
I am building pm670
read all thread and...
would like to add the scamp booster option
are boards available? or maybe some etch file!
thank you!
dingo.
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Moby on February 09, 2012, 11:11:32 PM
Yes. Few left. please contact Lolo-m and I will send it to you .
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Freddy G on January 07, 2013, 10:19:19 AM
I have a nicely working stock PM670. I have my scamp board stuffed and ready to go. I've read this thread a few times and am still completley confused about how to hook up the TC network. Verbal descriptions and theorys are going over my head!  Reading Chuck D's posts, I have similar questions. Really what I would like to see is a clear list of components for the TC network and a clear diagram on how to hook it up. I have Lorlin 2 pole, 6 position switches.
Help will be much appreciated!
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Freddy G on January 09, 2013, 04:47:15 PM
OK, I think I finally have a handle on this. I've been studying this switch from page 6:



(http://www.groupdiy.com/index.php?action=dlattach;topic=32965.0;attach=1775;image)



I was so confused because I didn't understand the values...but now I see that the cap values are paralleled to make up the values as shown in the fairchild TC network.  And on the other pole of this switch I just couldn't figure out what the 2k resistors were doing and where did they come from? they are not in the fairchild tc schematic. Then it dawned on me.... that pole with just the 2k resistors is the Analag mode!..is that correct?
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on January 09, 2013, 07:26:46 PM
I was so confused because I didn't understand the values...but now I see that the cap values are paralleled to make up the values as shown in the fairchild TC network.  And on the other pole of this switch I just couldn't figure out what the 2k resistors were doing and where did they come from? they are not in the fairchild tc schematic. Then it dawned on me.... that pole with just the 2k resistors is the Analag mode!..is that correct?
You're right. This switch is to get both modes on only one switch : analag's and fairchild's tc networks are on that switch.
I don't remember and don't have time to dig but it may need one more switch to toggle between the 2 differents modes...
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Freddy G on January 09, 2013, 07:32:03 PM
I will likely not even use the Analag mode ....we'll see though
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: alexc on January 10, 2013, 12:34:39 AM
Here's an novel use for the SCAmp pcb - I'm using it not in my poorman builds, but rather, in a diy franken build.

I had some neumann fader modules which I ripped all the transformers from.
The faders were discrete vca module type driving lowZ faders.
So I have taken the neuman discrete vca modules and am hooking them up to the SCAmp pcb as the sidechain.

Don't see why it won't work!

Am using this in a 3RU build with a pair of Tesla channel strips.

A combo of traffo/fet DI with Tesla early discrete/semi preamp+inductor eq and I'm adding Haufe active  transformer  main and  aux outs.

This will be the last of my franken-strips! 

All my parts used up then :)
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Freddy G on January 10, 2013, 09:49:09 AM


Hi,
Here is a build help thread for poeple who choosed to implement my SCAmp Booster on their PM660 or PM670. Just to save some time, let's call it SCAB (SCAmp Booster  ;D)

If you start filling the PM board, don't solder D1, D2, D3, D4, C4, R16 and R18. Put 2 wire links between C4 pads and R18 pads.
If they're already soldered, solder a wire link between the C4 pins and between R18 pins. I can't honestly say that's it is a good idea to dissolder C4 (even if I did) as it can endomage the PCB if not correctly done. Cut D1, D2, D3, D4 on the middle of the glass tube.

Just need to clarify...are you saying to remove R16? or to jumper it? In the Scamp wiring guide R16 is still shown.
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on January 11, 2013, 02:45:33 AM
Just need to clarify...are you saying to remove R16? or to jumper it? In the Scamp wiring guide R16 is still shown.

Look at the PM660-670 schemo and after a few seconds you should understand  ::)...

Isn't R16 a little lonely ?
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Freddy G on January 11, 2013, 07:52:50 AM
Umm, thanks. I guess you're saying it should be removed then. Looking at the scamp schematic R*01 takes the job of R16 from the PM circuit right?
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on January 12, 2013, 08:44:20 AM
Umm, thanks. I guess you're saying it should be removed then. Looking at the scamp schematic R*01 takes the job of R16 from the PM circuit right?
If you cut the diodes (and you should have), R16 is connected now to : nothing... You just losse a resistor if you leave it there. Connected to nothing a resitor doesn't hurt, and except if you've got real horrible money problems, you'd better leave it there  ;D ...
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Freddy G on January 12, 2013, 09:05:53 AM
I've got it working. WOW! Now this sounds like the kind of compression I was hoping for. Thanks lolo-m! Your Side chain amp booster did the trick!
I will not be using Analag mode.
I have to say I don't know what I would ever use Fairchild TC postion 5 and 6 though!

Any suggestions for different R/C networks for position 5 & 6 that are more usable than the Fairchild.
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on January 12, 2013, 09:36:01 AM
Thanks  8)  8)  8)
On the 2nd page, 3rd post gives you all the tips to calculate a "a la Fairchild" TC network to get the attack and release you want... This is better to make your own as anyone likes different settings...
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Freddy G on January 15, 2013, 04:09:22 PM
OK! Got my TC networks in place and it sounds good.
I'm having a problem on one side of the Scamp board though. Hopefully someone can help me through this.
It's definately the one side of the scamp board because I switched everything from one side to the other and the problem remains on the same side of the Scamp.
The VU meter is getting pinned all the way to the left. Voltages on the problem side are higher than the working side. If I unplug the connectors from ModeB-R and ModeA-R the meter goes back to zero.
Any help appreciated...what should I check?
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Freddy G on January 17, 2013, 05:09:00 PM
Oh man! I've been trying to figure this out with no luck. Looks like I will end up taking the scamp board out and just going back to the Analag mode :-[
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Moby on January 18, 2013, 06:13:13 AM
Oh man! I've been trying to figure this out with no luck. Looks like I will end up taking the scamp board out and just going back to the Analag mode :-[
Why? If you have one channel working you just have to compare voltages from point to point and find the faulty one. Then you will probably find some wrong value or misplaced component on "bad" side ;)
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Freddy G on January 19, 2013, 05:49:04 PM
Ha! I think I found it....bad TIP42C.

Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: creal on February 28, 2013, 12:03:51 PM
Hi all
I finished my PM670 and it work nice.
Now it's time to play with TC network...
I have all my SCAB stuffed except the 12pf caps on (c101,201).

I don't have any 12pf at home, can i replace this caps by 10, 22, 33pf?
what's the best value? I will use a OPA604s

So other questions,
If i understand well, the R* connector is used for the release time res and the C* for the attack time caps?
I'll like to use 2 switches on my unit, one for the attack and the other for the release.
It is correct?

Cyril
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on March 05, 2013, 04:03:54 AM
I have all my SCAB stuffed except the 12pf caps on (c101,201).

I don't have any 12pf at home, can i replace this caps by 10, 22, 33pf?
what's the best value? I will use a OPA604s
For c101/201 use anything between 10pF and 47pF and you'll be fine !
If you use OPA604 don't stuff c102, c202 as they are not compatible with the 604...

So other questions,
If i understand well, the R* connector is used for the release time res and the C* for the attack time caps?
I'll like to use 2 switches on my unit, one for the attack and the other for the release.
It is correct?
You're right. BTW notice that they are paralleled. You can only use one if you prefer and feed the attack switch (caps) and release switch (resistors).
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: skal1 on March 17, 2013, 09:55:32 PM
Hi lolo-m

hopping you've got 1 scamp board lying around

cheers

skal1
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: creal on March 18, 2013, 05:37:10 AM
Hi Lolo,
it's works perfect now, i like what the scamp add. it is very differrent of the analag mode.
I tested the fairchild network and it's great.
Now i play with different values for caps and res on a separate switches before order the front panel.
Thanks for this great addon.

Cyril
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: Studio Mollan on February 06, 2014, 10:14:26 PM
Hi.
Any chance there's more pcbs around for sale? I took over a project and would like this mod.
I can't find schematics?
/
Emil
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: duantro on February 26, 2014, 01:30:29 AM
I'd take another one also. I've got enough spare parts to build another M670 down the road and honestly couldn't imagine using it without the scamp, or something similar.
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: lolo-m on February 26, 2014, 04:34:36 AM
Sorry for being away during such a long time, but days are only 24 hours long and I need about 48 hours each days to acheive what I started...

Anyway, I won't do another run of SCAB PCB's as there's nearly no demand. You can find the schematics and everything to etch the boards yourself in this thread :
http://groupdiy.com/index.php?topic=45556.msg570789#msg570789 (http://groupdiy.com/index.php?topic=45556.msg570789#msg570789)

Have fun, give me time  ;D

Laurent
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: marcus4audio on May 16, 2014, 04:21:21 PM
Hi guys. I finally finished my PM670 build and I'm happy with it but I have a problem with timing network in SCAMP mode. I would like to have separate attack/release controls. Can somebody share successful "working" values? I read all the pages related to this build and at the end my brain hurts  :o
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: duantro on May 30, 2014, 12:51:27 AM
Hi guys. I finally finished my PM670 build and I'm happy with it but I have a problem with timing network in SCAMP mode. I would like to have separate attack/release controls. Can somebody share successful "working" values? I read all the pages related to this build and at the end my brain hurts  :o
I know your brain pain from all of this up and down train ride. My m670/ pm670 uses the same time constant network for with and without scamp booster. Look back for Lolo's pimping the pimp comment (reply #22 in this thread), Bluebirds comments on the pm670 thread, or on Kingston's m670 thread for starting values to experiment with. http://groupdiy.com/index.php?topic=51478.0.
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: marcus4audio on May 30, 2014, 05:31:57 AM
Thanks Duantro. So If I choose to go with values of caps like Lolo's (reply #22) can you suggest value for "universal" release pot? I understand that release will depend from capacitors values so for every possition it will need to be trimmed again. Right?
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: duantro on June 13, 2014, 12:19:31 AM
Thanks Duantro. So If I choose to go with values of caps like Lolo's (reply #22) can you suggest value for "universal" release pot? I understand that release will depend from capacitors values so for every possition it will need to be trimmed again. Right?
Sorry for the delayed response, I guess I don't get notifications from this thread. I used a dual 6 pole switch for the time constant, but you could easily make a switch for attack and one for release. Check out Bluebird's original values and experiment.
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: marcus4audio on June 13, 2014, 06:33:18 AM
Thanks :)
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: prescott on June 12, 2015, 05:32:09 AM
Hello!

I've just inserted the SCAB and I like it a lot.
My only problem:

How can I have slower attack time? (5ms, 10ms, 30ms)
I'd like to have slower attack even with fast release if it is possible...

Thanks!
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: duantro on August 25, 2015, 05:27:32 PM
Hello!

I've just inserted the SCAB and I like it a lot.
My only problem:

How can I have slower attack time? (5ms, 10ms, 30ms)
I'd like to have slower attack even with fast release if it is possible...

Thanks!
Probably should have posted this in the pm660 thread, but the way I understand it is smaller capacitors in the time constant section = quicker attack times. Experiment here for taste.
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: ojiban on May 02, 2016, 08:44:34 AM
Hi diyer's

First of all thanks for this threat...
I'm starding my build of the pm670 with scamp, i hope, soon.
Now is my question: is it smart to build thisone with te germanium resistors? I know it will influence the sound.

Thanks in advance.
Gr ojiban
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: crisotop on April 18, 2017, 09:58:34 AM
I've just started working on my PM670 after a long break and having troubles adjusting RV*01 to 0V. I'm using 5k trimmer, might that be a problem? If I'm reading the schematic correctly that shouldn't really be an issue...

thanks in advance,
Christoph
Title: Re: [BUILd] PM660 / PM670 SCAmp Booster build and tips help thread
Post by: duantro on April 22, 2017, 11:03:10 PM
I'm finally getting around  to try to implement Kingston's Psu mod from the m670 thread, and was wondering if anyone had thoughts on if the scamp board would run happily at 12.6v? I know the ne5534's look to be within range here, not sure about the tip41/42's and thought I'd check if there were any thoughts on implementing this in the m670 mod.
Link for M670 info: https://groupdiy.com/index.php?topic=51478.0

Edit: no response, so I decided to keep the existing +-17v supply in there also.