the Poor Man 660 support thread

[analag]

Ok, new baby has born. 

I want to thank you Analag, [silent:arts] and everyone in this great great forum making this possible.

I bought this unit premade from Elektrovolt and today I finished it. During building time I've played lot's of different kind of music and instruments through it and it totally rocks! It can be really soft, almost unnoticeable or really hard and crunchy compressor.

It is almost "stock" unit. Exceptions are found in input and threshold gain, custom timing network and 6N5P tubes instead 6BC8 as suggested in thread.
I've measured fastest attack time nearby 2ms which I feel fast enought and I don't feel unit needs scamp board. Anyway there's no room left for it  ;D

Your appreciation is noted and accepted...enjoy.

My not so good english skill limits me to tell more details, so pictures tells more than thousend (bad finnglish) words:

Long live DIYing,
Paavo

 

[lewilson]

I wonder what type of mods were done to the input and threshold gain?  

 

[ChuckD]

Hey Paavo


What is that handy "false bottom" with the pre drilled holes? Where did you get that?
I want a bunch of those. I move stuff around so much that the bottoms of my units are full of holes.

Chuck

 

[Grooveteer]

Chuck,

I think Paavo got it from Modushop in Italy.  http://www.modushop.biz/ecommerce/cat096_l2.php?n=1

Cheers,

G

 

[kilmister]

I wonder what type of mods were done to the input and threshold gain?  

I ment values of input and threshold are what I wanted instead values suggested earlier in thread which I found to be "stock" values. Basicly no mods there.

Bottom plate is indeed from Modushop. It's really handy and keeps surface clear. I run AC power lines under it so it offers also nice extra shielding against hums.

-Paavo

 

[tomcat]

I hope the mods dont kick me, but i believe it fits best here.

If anybody needs 6n5p tubes, there some on ebay right now (not mine!)

http://cgi.ebay.com/XRARE-LOT-4-TUBEs-6N5P-NEW-BOX-06-1970-MILITARY-/300424473297

 

[tomcat]

It is almost "stock" unit. Exceptions are found in input and threshold gain, custom timing network and 6N5P tubes instead 6BC8 as suggested in thread.
I've measured fastest attack time nearby 2ms which I feel fast enought and I don't feel unit needs scamp board. Anyway there's no room left for it  ;D

Cool. Maybe you can tell us more about the mods, would be very nice

 

[Kingston]

whoah! prices have seriously come up. like tripled! Am I just paranoid or should I simply keep my mouth shut about less known tubes in the future.

 

[tomcat]

Well, after he sold the last 3 8packs so quick he decided to sell the 4packs for the same price

 

[lewilson]

I had  an idea this would happen, so before I mentioned the 6n5p ,I bought a few hundred

 

[tomcat]

Ah, and you didnt sell me some So you forced me to go the russian route (before he raised the price)  ;D

 

[TheGuitarist]

Well so i finally finished wiring up my pm660 today. Fired it up, set it up so all the voltages were correct (except one thing i'll mention later). Got bypass happening, got the Scamp booster all wired in as per moby's guide.

Plugged it in, the bypass relay is working great, flip it on and BUZZZZZZZZZZZZZZZZZZ. Gain, threshold and attack times have no effect, but the scamp booster switch to switch between the two attack modes does make it pause or something momentarily. So my thinking is there must be a problem on the board itself or with the tubes, which leads me to my question that i mentioned before. I'm using the slow heater board, but i couldn't find any info as to what to change the trimmer to. The tubes seem to be running pretty hot, but i've never used those tubes so they might glow that much ordinarily.

Any thoughts or help before i jump back into this would be great. I should note that i have not put in the earth point or secured the transformers yet, didn't think it was important, i just wanted to get everything working before i screw everything down.

 

[Kingston]

i have not put in the earth point

That's your buzz-zzzzzzzzzz right there.

for safety reasons alone, please hook up your grounds ALWAYS before firing up the first time.

Your heaters should be around 6.3VDC (non-critical). Measure with multimeter and set the trimmer accordingly.

Then maybe read through all the forum poorman material once more.

 

[TheGuitarist]

Just for what its worth, there was buzz and it passed no audio at all.

Yeah, that was my next step. Just need to find the time to do it.

 

[radiance]

Maybe try to get it working without the SC booster first...

 

[kilmister]

Cool. Maybe you can tell us more about the mods, would be very nice

I made timing network with 1x10 Grayhill switch I had allready. It's locked up to 6 positions.
Positions 1 to 5 has resistor and capacitor parallel instead "stock" units series 10k pot and 10uF.

Values are
1 - 100k / 220nF
2 - 100k / 1uF
3 - 330k / 1uF
4 - 67k / 4.7uF
5 - 150k / 4.7uF

Position 6 is "Auto attack" There is 2uF and 2.2k in series.

I really suck in documentation. Hope this clarifies a bit

-Paavo

 

[Freddy G]

Well, I've read and studied this whole thread twice now. I have all the parts on my bench and i will finally begin to build this monster. I am very worried
All of the potential pitfalls that are out of my control deeply concern me. Matching tubes, bad tubes, bad edcors, underspec'ed power transformer, distortion. I wanted a mastering compressor, but many people who have built this say that it's a colour box and not clean enough for mastering.
I have to ask....Doug (emrr) where are you? You had so many insights and input, did you ever finish your 670? How did it turn out? What do you think?

 

[[silent:arts]]

Freddy, just build it and try it out

 

[emrr]

I have to ask....Doug (emrr) where are you? You had so many insights and input, did you ever finish your 670? How did it turn out? What do you think?

Life has gotten in the way of most electronics action in the last few years.  Very little has been built around here, due to other work.  I've been reduced mostly to commentary.  My boards have been built for almost 2 years now, and been in a box with the rest of the parts.  I still have a large backlog of repairs for other people that must get finished before I get to touch any of my own stuff, unfortunately.    :-[ :-\ :'(

The 670's potential problems are pretty well documented now (if scattered; we need a new document itemizing the problem experiences, with various troubleshooting procedures), and if you have decent troubleshooting skills it shouldn't be too hard to sort out.  Some of your list, like the Edcor QC, you can answer yourself in 2 minutes with a multimeter, then it's off your list. 

Heat is an issue; build big.  Use a fan if you can.  Put the power trans outside, if you can.  Or even better, build the PSU in a separate box, like analag advised.  Filament voltage issues are extremely simple; I am all astonishment that it's been perceived as this giant obstacle.  Buy another filament transformer if it proves necessary. 

Do the circuit boards freak you out, when looking at the list of issues, and what it will take to make changes on the fly?  Then don't use them, and build point to point, or with terminal strips.  There's not that much there ITFP.  You could go with off the shelf PSU's also, if you needed to punt:

http://internationalpower.com/cgi-bin/htmlos.cgi/004.1.091947711612676064

 

[Freddy G]

Hey Silent Arts,
I'm glad you are still around to support this.....OK I'm gonna dive in now. Here's a photo of what I've got.
And while I was typing Doug replied too. Thanks for chiming in.
I'm going to build this totally stock to begin with (with 25k dual pots). I have Lolo's scamp stuffed but I'm not going to impliment it until the stock build is problem free. Who knows, I may like it stock! If I like it then I will use elmas and maybe try some pimps and mods...wish me luck, and I hope I don't have to bother you guys too much during the build ;D

Click on this link to see large photo.
http://home.cogeco.ca/~freddygabrsek/PM670%20start.jpg