the Poor Man 660 support thread

[TheGuitarist]

I mean that if it is 30 degrees, 6 positions is 180 degrees, a horizontal line.

With that case design the 1 and 6 don't fall on a horizontal line.

Like the 2 and the 8 on the gain/time constraint are 180degrees from each other, with the time constraint its more like 1 and 6 are more like 160 or 150 degrees apart.

Does that make more sense? It looks like the 1 and 6 would more closely line up with 2.5 and 7.5.

Its not a big issue, i've just seen people with the numbers lining up, maybe those people are using 10k log pots instead of rotary switches.

 

[jdbakker]

I mean that if it is 30 degrees, 6 positions is 180 degrees, a horizontal line.

Nope.

Outside a big government building is a row of ten flagpoles, equally spaced, in a straight line. The distance between neighboring flagpoles is ten meters. What is the distance between the first and the last flagpole?

JDB.
[or was it lampposts along a road? And it's primary school math, so nobody bothered with pole thickness or earth curvature]

 

[ChuckD]

JDB is correct

You are counting from zero and not from one. A common mistake.
The first position is 1 meaning there are only 5 gaps of 30  degrees each

 

[mata_haze]

hello,
I am having troubles with my PM670 precisely on the meters.
I am using a couple of SIFAM AR29 Vu meters and I am noticing the meters interact with the threshold pot.
they are just fine and correctly set up when threshold is on zero, but the deflect (towards -20) when I increase the threshold.
the meter goes down to -5 when the threshold control it's around 5.
also when I change the threshold control on the Right hand side compressor the LHS meter reacts as well even though they are not linked.
weird.

now my question is:
-should I use shielded cable for the VU connection?
-does it matter where I lay down my cable for the meter (from PCB to meter)?. I have noticed that the level seems to change if I move the cable around.

The compressor works absolutely fine in all its aspects: anything else I should be checking?

any help will be much appreciated as usual...

Best,
M.

 

[TheGuitarist]

JDB is correct

You are counting from zero and not from one. A common mistake.
The first position is 1 meaning there are only 5 gaps of 30  degrees each

And thats why maths was my best subject at school.


I'm not kidding it really was. Thankyou for clearing that up! I will now go smack my head against an old maths book

This was for part sourcing because i didn't want to waste money, thats why i hadn't tried it yet.

 

[juanjovincenzo]

Hi guys,  it is a lot infomation and I'm lost,  where I can buy the PM 660 /670 PCBs?? or where is the Link to found the PCBs copper Layout??, sorry I am a beginner. Or maybe the link to acces a  PM 660/670 KIT.
Thank for the patience
regards
Juanjo

 

[TheGuitarist]

Hey just a quick question, what amp rating are the pm660 toroids?

I got mine off a board member... but i don't know what fuse to use with it. I'll be running it 240v (115v primaries in series) if that helps at all.

 

[[silent:arts]]

Hi guys,  it is a lot infomation and I'm lost,  where I can buy the PM 660 /670 PCBs?? or where is the Link to found the PCBs copper Layout??, sorry I am a beginner. Or maybe the link to acces a  PM 660/670 KIT.

http://www.groupdiy.com/index.php?topic=37037.msg455230#msg455230

Juanjo,
I don't know if you mean a forum beginner or a DIY beginner.
if the answer is DIY beginner, I wouldn't recommend the PM as a first project.
Regarding PCBs, they can only be found in the black market at the moment.
Schematic and PCB copper layouts are not available.

 

[TheGuitarist]

Hey just wondering if someone could tell me what current/voltage the meter outputs are putting out. I have a NOS simpson vu meter... that i can't work out if its working or not... but it was bought with other pm660 parts ... but can't work out if its working. I have a thread in the lab about it but maybe this will help if i know that i'm simply not just putting enough current through it.

 

[juanjovincenzo]

thanks for the INFO. Yes I´m a newbie. I am learning about the PM project
regards

 

[tommypiper]

The compressor works absolutely fine in all its aspects: anything else I should be checking?

You're not having the distortion problem during compression that others have reported?  Like KHStudio...?

Just wondering, because it seems to be a lingering mystery here for several builders.

 

[mrclunk]

hey Mata,
I just used unshielded twisted wires for the meters, mines fine.

I seem to remember i had some weird interaction between the threshold and meters when first testing mine.
I'm pretty sure (but not certain sorry...) i'd wired one of the threshold pots incorrectly.
Also have u adjusted RV3, RV6 correctly after fitting all the tubes and the meters?  I was a spaz and didn't re-adjust
after putting the tubes in.

probably of no help, but you never know...
good luck studio!

 

[elektrovolt]

here I am again, still having the same problem.
when turning the unit on, the high voltages (136 and 245V) rise and when the meter starts to move, the voltages drop down and the meter too.
one board fully connected (transformers, tubes, meter, potmeters)

I have completely rebuilt the compressor board and the PSU board multiple times, no help. the voltages stick around 60 volts and 30 volts. when I disconnect the filament power the voltages come up again, slowly and stay at 200v and 100v. still to low, of course. they should be 245 and 136.

can't find a transformer that gives me the extra filament power.

please, I really do not know what to do now ! someone?

 

[shabtek]

@electrovolt:
what power transformer are you useing?
is it capable of the B+ load?
why not get another P.T. dedicated to the heaters?

 

[elektrovolt]

I am using a toroidal transformer from the bernbrue groupbuy. that should be working without problems according to several people around here.
shabtek: as I said, I cannot find a dedicated heater PSU.

is my transformer bad ? when I measure the secundary voltages, the seem to be fine.

 

[tommypiper]

You've got a problem in your Power Supply.  Or downstream maybe... If the secondaries measure correct, then follow the voltage through your PS.  Something is not correct somewhere in your build.  The best way to find it is follow the path and find out where it breaks.  Test test test.:-\

A dedicated PS or heater toroid is not hard to find.  But first... Post for us detailed pictures and follow the electrons through your circuit.  Check everything.  Since you rebuilt it, and have the same prob again, it's probably not something  you will find easily because you repeated the mistake thinking it's correct (if there is a mistake, instead of something broken).  So you need to approach your sleuthing from a new perspective.  Hope that helps...

I shouldn't talk... I have not built this yet.  But it's basic troubleshooting and one always needs encouragement and help at times like that.

 

[jackies]

A number of people commented in this thread that the PM670 sound somewhat lacked and they wouldn't use it on master bus. Also a number of people said that Edcor transformers produce distortion and harsh highs or something...
So, how come nobody tried it with better transformers? I'm sure there have to be people with piles of Lundahls?
Wouldn't take too long to hook some up and see if that'd change the sound considerably.
Myself, I haven't even started building it, you know the drill, too many projects, too little time... However, I have some transformers kicking around... What, I will be the first to try even if takes me forever to get to it?

 

[elektrovolt]

after all the trouble I had with the voltages dropping and such... I replaced the first IRF840 for the 8923th time and now it seems to work.
I will test tomorrow with multimeter and sound.

 

[Kingston]

What, I will be the first to try even if takes me forever to get to it?

I'll race you to it! I'm already eying some lundahls with good specs for the job. But I'll also switch to using these russian alternative tubes that need a bit of PCB rework. Somewhat like this but with 4 instead of eight 6k4p tubes http://www.groupdiy.com/index.php?topic=31788.140

 

[jackies]

Kyllä!

Then, maybe, use 6n6p instead of 5687? RPM - Russian Poor Man?
Now, the transformers - Edcors are rated 2.5w, which is obviously overkill for input/output, except for the sidechain amp. Anybody can tell what exactly kind of power the sidechain amp actually produces? With the boost circuit?