the Poor Man 660 support thread

[dagoose]

Hey, that´s a nice one. I like the white touch very much. Haven´t I seen this frontpanel layout before?? !!   ;D ;D
regards
Bernd

No.. i think you must have had a really good dream about that frontpanel.  :
I printed a PDF file from your design in frontpaneldesigner and used that as a base for the lasertran prints.
I used 2x a4 prints, there is a small line where the 2 sheets meet but not like really noticable, certainly not disturbing and almost gone with the lacquer.

 

[skal1]

Hey [silent:arts]


have you got a spare psu for a poor man  just burnt a big hole in  board and carpet  .


skal1

 

[[silent:arts]]

... have you got a spare psu for a poor man  just burnt a big hole in  board and carpet  .

ouch  :'(
how did you manage that?

unfortunately I don't have anything left right now.
I will do some more, but this will take some weeks.

 

[skal1]

oh well that's diy for you, shorted some thing while i was testing  :-[


skal1

 

[[silent:arts]]

oh well that's diy for you, shorted some thing while i was testing  :-[

glad you are still alive.
this PSU could kill you ...

which part burned?

 

[skal1]

As far i can see  r1 r5  and all transisors are gone, r1 did the most damage and r 5 ..

skal1

 

[giltmastering]

here it is! another living poorman!  ;D



Some minor issues, i can't get the heater voltages higher then about 5,9 volt,

Looks like you still have C23 & C24 on the PSU board......  does this matter?

 

[dagoose]

here it is! another living poorman!  ;D



Some minor issues, i can't get the heater voltages higher then about 5,9 volt,

Looks like you still have C23 & C24 on the PSU board......  does this matter?

Yep, they are still on but it doesn't matter because the heater part of the board is not doing anything, it's simpy not connected at all.

I did some other measuring this morning; when all tubes are in i have about 8.8v right after the rectifier (so input of the board) and after about an hour i still have 5,9v at the outputs of both boards. It's not reall hard to to get 6.3v then at the other output where no tubes are in. So it looks like the regulator can't handle the power consumption of the tubes in some kind of way and so the voltages drop.

 

[Moby]

Can you please measure the voltage drop across R1?

 

[lolo-m]

here it is! another living poorman!  ;D



Some minor issues, i can't get the heater voltages higher then about 5,9 volt,

Looks like you still have C23 & C24 on the PSU board......  does this matter?

Yep, they are still on but it doesn't matter because the heater part of the board is not doing anything, it's simpy not connected at all.

I did some other measuring this morning; when all tubes are in i have about 8.8v right after the rectifier (so input of the board) and after about an hour i still have 5,9v at the outputs of both boards. It's not reall hard to to get 6.3v then at the other output where no tubes are in. So it looks like the regulator can't handle the power consumption of the tubes in some kind of way and so the voltages drop.

If you've got a scope, do a test with it... You may understand better what hapens.

 

[khstudio]

Sorry guys, I try to keep up with the thread but work has been demanding.
Remember IRF820 for mono and IRF840 for stereo.

analag

Finally getting my STEREO unit together & found this post...

Do I need to change my Q4 from IRF820 to IRF840 ?

( I already have an IRF840 at Q5 )

Thanks

 

[[silent:arts]]

Do I need to change my Q4 from IRF820 to IRF840 ?

try first if it works. there are enough working stereo units build with this combo.
but if you have high voltage problems exchange the IRF820 to IRF840.

 

[khstudio]

Thanks man  ;D

I could use a little advise: I have
2x 24 position switches
2x 12 position switches

Were do you think the 24 position switches would work best?
Input or Threshold?

I was thinking Input - but thought I'd ask beforehand.

Also,
I plan on dB steps for the input but want to ask you guys that have built units - which do you feel is better for the the Threshold?
Log or Lin taper?

I'm sure there's a "sweet spot"

 

[Kingston]

read what I wrote just two pages back, then the rest of the thread.

 

[khstudio]

read what I wrote just two pages back, then the rest of the thread.

I've been doing nothing but READING... but there's a **** load of info to sift thru.
I'm not a newbie here bro. 

I'll look back a few pages.
thanks.

 

[khstudio]

Apparently a log (pot or rotary switch series) will work best with the "threshold/compress" switch as well. Someone in this thread tested it and with linear it apparently only "digs" at the audio (with modern levels) at about half or one quadrant of the pot/rotary. With log you get more even spread.

Great info... sorry I missed it.

 

[[silent:arts]]

I have added a link to Kingstons rotary contribution to the first post

 

[JoleFIN]

Apparently I've missed something that I can't find with the search function, but a dull question regarding the basic things... What are the differences between PM670 and original Fairchild 670?

I'm about to start the PM project soon, gathering the parts here

 

[MartyMart]

Apparently I've missed something that I can't find with the search function, but a dull question regarding the basic things... What are the differences between PM670 and original Fairchild 670?

I'm about to start the PM project soon, gathering the parts here

It's 10 tubes different for a kick off !!

Supposed to sound great though

MM.

 

[Kingston]

What are the differences between PM670 and original Fairchild 670?

You should really ask, what is similar between a PM670 and Fairchild 670. And the answer is: the general topology to achieve Vari-mu compression, and nothing else.

I have found it extremely odd that so many people here have labeled their poormans with the Fairchild logo. It's like you build a really nice custom chopper from the ground up and stick a Rolls Royce logo on the gas tank.