the Poor Man 660 support thread

[DerEber]

And don´t get the 1:4 and 4:1 transformer mixed up.

 

[radiance]

Ok, situation is as follows:

The 24V relays I'm using for time constant switching need at least 18V  (75% of 24V) to work.
Somehow they did work on 17V but sometimes, after being on for several hours, they fail,  so I want a bigger margin.

Best solution would be to replace them with 12V ones + voltage drop resistors.

However, there are other, less elegant but more easy solutions that might work.

How about raising the +17V to +18,5V? This way, the relay's are fine. Only downside is that the OPA604's on my side chain booster are fed with assimetrical voltages (-17V & +18,5V)

Other option might be to raise both the -17V AND the +17V to -18,5V and +18,5V. Downside is that Q1 will see -18,5V (instead of -17V) on pin 2. Also, I will have to readjust both RV3 and RV6 trimmers.
Would this extra -1,5V do any harm ??

Any other thoughts?

Thanks!

 

[Moby]

Best solution would be to replace them with 12V ones + voltage drop resistors.

Maybe the 12V relays plus additional 7812 regulator 

 

[radiance]

Best solution would be to replace them with 12V ones + voltage drop resistors.

Maybe the 12V relays plus additional 7812 regulator 

Yes...thanks for that.

However, replacing 10 relays will be a last resort option...rather do the voltage raising.
Just don't know if this -1,5V raise will do any harm to the 6n5P tubes...the enclosed data sheet was in russian..;-)

 

[radiance]

So I did raise both -&+ 17V to 18,5V and it works ok.
It seems to get a little hotter after a while but it can also be due to the hot weather we're having here (no airco in my room).
Don't know what the long term effects on the tubes will be though....
We'll see...

 

[lolo-m]

If you did reajust the bias I think it is perfectly safe... The transistors don't have to handle a lot of curent.

 

[radiance]

If you did reajust the bias I think it is perfectly safe... The transistors don't have to handle a lot of curent.

That's what I did...seems to work fine indeed.
Thanks!

 

[duantro]

Hello. I picked up partially stuffed pcbs for this project from a board member in the black market, and am going to try to give this a go. After reading this 147 page thread I must say wow....what a journey! Hopefully I can learn from all of the issues that some of you have had. This is my first tube build...gulp
These pcb's did not come with schematics. Volker, is it possible to get these?
edit: I have the EU group buy Rondo toroid. Upon looking for a second larger 9v transformer, would this Triad Magnetics VPT18-5560 9V 11.12A parrallel be a decent addition?
http://www.mouser.com/ds/1/410/VPT18-5560-2773.pdf

 

[radiance]

Sure, that would work, although a little over specced...I'm using a 8A toroid for this...

 

[duantro]

Where did you find your 8A at? I'm not having much luck finding anything over 6A, besides the 11A that a posted.

 

[radiance]

RS components

 

[tommypiper]

No.
Look again at the wiring guide. >http://www.silentarts.de/DIY/PM660/PoorMan-WiringGuide.pdf

What apps are you guys using to create these wiring guides?  They are great.  Is it a version of Adobe Acrobat, or did you use Illustrator?

 

[duantro]

I am realizing that my parts lot didn't include the bypass relay boards. Are these pcbs long gone Volker?
I searched and saw Igor sells some, which I guess I could get also. However, I'm hoping to get them sooner than later.

 

[prescott]

Hello!

I have a problem:

I connected the psu to the 660 board.
All the voltages are correct.
When i plug the main r10(330r) and rv6 is smoking...
Where can be the mistake?

Heater is working, the problem comes if i connect the other voltages...

 

[prescott]

The problem comes when i connect the 250V.
The other voltages are without smoke :-\

I tried the same with my other board (with no tubes) and there is no problem with anything.

I use only mono for the first try.

Please help me!

 

[[silent:arts]]

I am realizing that my parts lot didn't include the bypass relay boards. Are these pcbs long gone Volker?

yes. they are gone.

 

[prescott]

Problem solved

 

[duantro]

Thanks Volker, I've ordered Igor's boards.
Prescott-What was the problem?

 

[prescott]

Me trimmer made a sort, I dont know how....
It melted, I changed to a new one, and no problems

But I have an other audible problem, that my comp eats some of the transients of the music...
Ok, its smoother, but there is too much to my ears...
Maybe the tubes are not the best.
I have 6n5p tubes, and some 5687 (dont know the brand)
Can someone suggest me some tubes for clean, full of transients sound?

Or is it because of the Edcors?

I also founded that its sounds better when I try different positions on the trimmers...
The -4.5v I dont like, its almost 0 where I like the sound... wondering why...

 

[radiance]

Me trimmer made a sort, I dont know how....
It melted, I changed to a new one, and no problems

But I have an other audible problem, that my comp eats some of the transients of the music...
Ok, its smoother, but there is too much to my ears...
Maybe the tubes are not the best.
I have 6n5p tubes, and some 5687 (dont know the brand)
Can someone suggest me some tubes for clean, full of transients sound?

Or is it because of the Edcors?

I also founded that its sounds better when I try different positions on the trimmers...
The -4.5v I dont like, its almost 0 where I like the sound... wondering why...

Did you match your 6n5p tubes?

Also, I suggest that you read this whole thread, yes it's 147 pages long by now, but it will answer all your questions.