the Poor Man 660 support thread

[[silent:arts]]

I used IFR820 and IRF840, and so far I have all the voltages with correct values and working... do you think I'll have problems if I don't sawp the IRF820 by the IRF840?

since it is working I don't see any reason to change it.
there other units running with this combination without problems.

some people had problems and changing the IRF820 to 840 helped.
may be there are some bad or underspect IRF820 arround ?

 

[analag]

Hi,
as Mata_haze told, we have solved the problem with the PSU (the PM we are working on is the same unit),
so the voltages are OK without LOAD , but when i plug-in the two boards there is a huge drop:

245V -> 77V
136V ->36V

The heater is perfect at 6,35V

May i suspect the IRF regulators not working properly ?

PM670 is a complicated beast !)

Many thanks for your help

What makes you think the PSU is the problem. Sounds like the boards might be shorting somwhere. Check if R1 is getting hot or too warm. If there is too high a current draw after the regulator R1 is there to drop the voltage among other things.

analag 

 

[mata_haze]

Hello,
the following are the results after an afternoon of tests:

the 670 got tested without VU meters in the circuit and the following is the behavior:
-at start up all the voltages reach NEARLY correct level ie=245 it's instead 230
-after 30 seconds 245V drops down to 136. and the 136 branch drops to 64.
  -with VUs in circuit the voltages drop as follows 245->77 and 136->30.

we cheched R1 on the PSU and is not hot at all, the voltage drop across it it's 0.18 VDC

then we tried to twick RV3 and RV6 and the voltages bumped as follows:
245-> 180 (previously 136)
136-> 90 (previously 64).

any hint?

many thanks,

Best,
Mattia.

 

[AW_music]

Now the situation is this:

PSU alone is:
245-> 254
136-> 138

With  Boards:
245->is 158
136->is 83
??? ???

What we have done:
-tweaked RV3 and Rv6 at correct values (-2,4   -4,5)
-checked  for current drop across R1 : 0,73 VDC
-checked ALL trafos (one pin of T1 was broken_ Edcor !!  : FIXED !)
-checked the PSU alone with no boards and without R8 _ after Q4 we have 254V perfect !

Any suggestion ? Any idea?

Many thanks

Best regards
Nico

 

[[silent:arts]]

first, test it with one channel.
if one channel is working, swap the channels.

 

[analag]

Plug out the 6BC8's and power up. Check if the voltage to the GR (5687) is stable now.

 

[AW_music]

Ok,
the struggle goes on !!!

So i've pulled out 6BC8's, and measured 5687's :
On valve pin 1 / 9 -> 202V
On valve Pin 2 / 7 -> 0V
On valve Pin 3 / 6 -> 15V

The PSU  now shows:
245-> 204
136-> 108

---
Yes Volker,
I have already tested channel by channel , but they do the same ! ???
----
I wanna see the "light" with this project !!!
Any direction ?

Nico

 

[skal1]

hi
[silent:arts]

anyone can i connect the 50w resistor to power supply without the pm660 modules been attached?


thanks

skal1

 

[[silent:arts]]

you can

 

[skal1]

;D  hi
[silent:arts]


skal1

 

[skal1]

hi

What value is a good starting place for r15  the 50w resistor , with the rectified 9v from the tx i am seeing 13.35v. can someone help me with this please

thanks in advance.


skal1

 

[SaMpLeGoD]

Hello all,

I finally finished my PM670 and I'm having some questions that I can't really understand...

1) Why, even I'm not in link mode, if I move one threshold (left or right) both VUs move? it's supposed to move indepoendently, right?

2) Is the SIFAM AL20SQ that slow? I think they have a excessive release time... can I do something? or is just VU caratheristic and that's it?

3) I just can only "hear" the compression at the extreme hard CW gain + threshold, so only at this time I understand what the TConstants are doing... I'll get the Lolo-m mod as soon as possible, because this is not a behaviour I expected and like

4) In "Link" stereo mode, should I move the ontrols in "parallel"? or only the controls of one channel takes place? I ralize that the gains re independent, but the threshold don't... how about the TC?

5) why in CCW or CW pos the VU's get nuts without any signal? like: no input signal put the threshold hard CW or CCW the VU goes far left? it is norlmal?

Sorry for all the questions, the comp It sounds really nice, but do what I didn't expect from a compressor... maybe with the new TC network... thanks in advance!

Cheers,

Eddie :-\

 

[lolo-m]

Hello all,

I finally finished my PM670 and I'm having some questions that I can't really understand...

1) Why, even I'm not in link mode, if I move one threshold (left or right) both VUs move? it's supposed to move indepoendently, right?

2) Is the SIFAM AL20SQ that slow? I think they have a excessive release time... can I do something? or is just VU caratheristic and that's it?

3) I just can only "hear" the compression at the extreme hard CW gain + threshold, so only at this time I understand what the TConstants are doing... I'll get the Lolo-m mod as soon as possible, because this is not a behaviour I expected and like

4) In "Link" stereo mode, should I move the ontrols in "parallel"? or only the controls of one channel takes place? I ralize that the gains re independent, but the threshold don't... how about the TC?

5) why in CCW or CW pos the VU's get nuts without any signal? like: no input signal put the threshold hard CW or CCW the VU goes far left? it is norlmal?

Sorry for all the questions, the comp It sounds really nice, but do what I didn't expect from a compressor... maybe with the new TC network... thanks in advance!

Cheers,

Eddie :-\

Eddie,
For the full CV / CCW problem :
Try to measure the voltage on the two sides of the diode bridge with no signal and your "pots" on mid position... If there's 0,1 or 0,2V it isn't normal... I had this problem on one side of mine : ... There was something wrong with the diode bridge but I didn't go farer in my searches as I implement my mod on it and this mod needs the bridge to be removed... I would like to know why there was this problem anyway  :
The link problem is certainly a result of this problem...

Analag loves high level signals... definitely  ;D !!! I agree, you've got to push hard the comp... Some of our digital workstations are falling on their knees with a less than 1K loads...

The slow release isn't that slow... There's two release times in Analag's network, one quite fast ( about 300ms IMO ) and one slow... If the needle moove fast for attack, you haven't got an problem.

 

[skal1]

can some one point me to the self etch slow start heat psu, being look for a couple of days for this .


regards

denis

 

[[silent:arts]]

can some one point me to the self etch slow start heat psu, being look for a couple of days for this

http://www.groupdiy.com/index.php?topic=28274.msg371412#msg371412

 

[dagoose]

I'm in the middle of building this beast (can't wait to finish it) but i have one question about the zener diodes.
i have ordered zener diodes at RS and i'm not sure if they are the right one's and before i stick 'm on board i wanted to make sure.

RS pn. 625-6518,  100V Zener diode,1N5378B 5W
RS pn. 812-538,  20V Zener diode,BZX85C20 1.3W

Will these do the job or do i need other zeners? I'm pretty new to zener diodes so i'm not sure..

 

[SaMpLeGoD]

Eddie,
For the full CV / CCW problem :
Try to measure the voltage on the two sides of the diode bridge with no signal and your "pots" on mid position... If there's 0,1 or 0,2V it isn't normal... I had this problem on one side of mine : ... There was something wrong with the diode bridge but I didn't go farer in my searches as I implement my mod on it and this mod needs the bridge to be removed... I would like to know why there was this problem anyway  :
The link problem is certainly a result of this problem...

Analag loves high level signals... definitely  ;D !!! I agree, you've got to push hard the comp... Some of our digital workstations are falling on their knees with a less than 1K loads...

The slow release isn't that slow... There's two release times in Analag's network, one quite fast ( about 300ms IMO ) and one slow... If the needle moove fast for attack, you haven't got an problem.

Hello Laurent!! your explanation helps me a lot! thanks!!! I'll measure the diode bridge just to be sure, althrough I'm looking forward your board to boost the Side Chain Amp
About the VU's needle, it is moving correctly, just the release is a little bit slow... I think there's no problem with that
The comp is preety clear, but I need to feel the compression, maybe is a bad habit, hehehe, but I move the threshold in this comp and it sound like lowering the volume, I don´t really feel the compression acting... maybe with your mod I'll start to feel this... hope so!  :-\

In link mode witch control assume both os channels regulation? only the threshold?
Thanks a lot!

Eddie

 

[[silent:arts]]

In link mode witch control assume both os channels regulation? only the threshold?

look at the schematic / block diagram
the stereo link is done like in the original fairchild: combining the control voltage of both channels.
the control voltage in the block diagram is the line which goes from the "time constant" block to the "input gain".
you can easily see this is behind all controls.
for stereo operation it is best to have set all controls to the same value.

 

[btproductionsaustralia]

hey Guys,

is any one selling pcb's for the 660/670 or do you have to make your own?

I'm in australia...

BT

 

[[silent:arts]]

is any one selling pcb's for the 660/670 or do you have to make your own?

the PCBs are sold out.
watch the black market, from time to time somebody sells a set.