the Poor Man 660 support thread

[Silvas]

The vu resistor have to be choosen well to track correctly the gain reduction. The movement is showing you some compression but maybe not the real amount of compression.

Hey Lolo, can you elaborate a bit more on this ? as i mentioned before, my meter is showing approx 1/2 of the real and measured gain reduction. Of course i would love to have a bit more accurate tracking, but i hadn´t played with the 22K VU resistor yet and my paralell trimmer is 5K. At first i wanted to take the 22K completely out and see...but i´m sure there´s a better way to select the resistor, then zeroing it with the trimmer.

As the thread is a bit long ;D, I re-found that. I hope it can help you:

You've got to understand how's the VUmeter is tracking gain reduction (maybe you already understood that but some of us can be interrested) :
A vu meter is a AC voltmeter (with the rectifier build in). Through R6, the current pumped by the 6BC8 creates a voltage you measure. As the tubes are pumping less current when compressing the voltage drops and the needle goes left. Some little maths : If we call Ib the DC current pumped by the tubes and Ia the current pumped by the tubes to create audio signals voltage on R6 can be calculated with this : Ur6 = [Ib + (Ia - Ia)] x R6.

You can use nearly any Vu or voltmeter here to track compression. On mine, I left R6 on the board and connected on parallel a 500 ohm pot (with 2 points wired together to react as a single resistor). One point of the pot is connected directly to the vumeter, the other point feed the Vu through a 3K6 or 3k9 ohm resistor. It works ! And my Vumeter is an old PEKLY (french brand unfortunately disapeared a long time ago)...

Try this if you didn't and tell us what's happening  .

PS: the needle reacts weirdly only when the 6BC8 are overdriving audio (I mean with no compression).

This setting works or not depending of your 6BC8 curves...

Seems it doesn´t work with my Nissei VU´s...that was exactly my initial setup. The nissei VU´s has the 3K9 internally. Have to try it again now that my PM is working nicely. Thanks !

 

[lipcriminal]

Hi all

I've read the whole thread twice but I still haven't found what I'm looking for...
I have a couple of questions I need answered

- What fuse should i use for the pm670, using a Edcor Tx @ 220V?
- How exactly do i wire the bypass, using a 2x6 pos Lorlin? (a diagram would help a newb out)
- How do i wire the TC switch, using a Lorlin 2x6 pos?

Oh, and i don't know if this has been overlooked but the tubesockets listed in the BOM from tubedepot (SK-9PINPC2) aren't ceramic. It's some kind of high temperature polymer, but reading this thread I'm guessing ceramic is the only way to go...Got me some de-soldering later on  

thanks for a cool project, hopefully I'll be firing it up within the next couple of weeks!

/Richie

 

[tomcat]

This one is the ceramic/gold contact version: SK-9PINPCG

 

[lolo-m]

This one is the ceramic/gold contact version: SK-9PINPCG

You posted on the wrong thread  !

 

[tomcat]

Oh yes. Im still gaga from reading trough 106 + 20 or so pages of the PM 660 thread. Sorry  ;D

EDIT: No im really gaga. Its the correct thread. Read the post before mine  

EDIT AGAIN: Ok, will go to sleep soon. Now i know what you meant. Very slow compress.. ahem computation my brain has now. A little bling can be also nice for poor men and as you know with gold everything sounds even better  ;D

 

[lolo-m]

Oh yes. Im still gaga from reading trough 106 + 20 or so pages of the PM 660 thread. Sorry  ;D

EDIT: No im really gaga. Its the correct thread. Read the post before mine  

EDIT AGAIN: Ok, will go to sleep soon. Now i know what you meant. Very slow compress.. ahem computation my brain has now. A little bling can be also nice for poor men and as you know with gold everything sounds even better  ;D

Have some sweet dreams and everything will sound better than gold  !

 

[lipcriminal]

Hi all

I've read the whole thread twice but I still haven't found what I'm looking for...
I have a couple of questions I need answered

- What fuse should i use for the pm670, using a Edcor Tx @ 220V?
- How exactly do i wire the bypass, using a 2x6 pos Lorlin? (a diagram would help a newb out)
- How do i wire the TC switch, using a Lorlin 2x6 pos?

Oh, and i don't know if this has been overlooked but the tubesockets listed in the BOM from tubedepot (SK-9PINPC2) aren't ceramic. It's some kind of high temperature polymer, but reading this thread I'm guessing ceramic is the only way to go...Got me some de-soldering later on  

thanks for a cool project, hopefully I'll be firing it up within the next couple of weeks!

/Richie

Anyone? 

 

[tomcat]

Sorry to ask ... i forgot it and another search trough 113 pages will make me pull my hair

The 6BC8 should be mathced in quads (even if its not possible, 6n5p, blah...)

But i forgot, what about the 5687? Do they need a matching too?

 

[tomcat]

Btw any source for the 6n5p known? At the moment i can just find some new chinese tubes

 

[DIYnoob!]

Just for the record...does anyone know if the BOM on page one updated? I'm on page 46 at the moment and its almost been 2 years since this project started, just want to get some light on this. Thanks

 

[[silent:arts]]

I'm not aware of any more errors, thus it hasn't been updated.
(I did that first when errors where detected)

Replace any IRF820 with IRF840 and you should be fine.

 

[DIYnoob!]

I'm not aware of any more errors, thus it hasn't been updated.
(I did that first when errors where detected)

Replace any IRF820 with IRF840 and you should be fine.

Thanks volker  ;D

for tubes try http://www.tubedepot.com

 

[DIYnoob!]

volker are the pcb sets available to order? I know you're a busy guy around here, but I've been itching to get this one done.  ;D ;D

 

[Silvas]

Finally finished mine ! well, actually, i finished it a while ago.

Nice comp. "stock".  A bit slow release for my taste, but quite good.

I´m running 1 5687 per channel for now. All my problems were due to low heater voltage. I have great mains variations over here, so for the power resistors i chose (i had to run a couple in paralell to get close to 6.3v) i´m getting 6.8v. My next plan is putting in an LM338k-based heater supply to help with my mains variations. Right now, i´m mixing some jazz, and the PM is inserted on the guitar amp and bass DI.

The edcor power TX is mounted on the back. with all tubes in, it gets quite hot. for now it´s warm.

I put that (variable speed with 317 regulator) fan to help a bit with the temperature.

Relay boards are my own design. As the original ones were stolen with a lot of other parts...i had to design a PCB and i ordered some units for the PM and other projects.

I need some 6k5p tubes to test, and i need to put back that 5687´s ! (when i´m satisfied with my heaters voltages)

Please remind me next time of putting the VU zeros on the front panel !

And, some of my DIY mixing gear, the PM next to the D-LA2A, D-AOC, couple GSSL´s, modded ART pro VLA, Scully 280, distressor, 4x gain brains, the dolbys, the lynx...i know. I need a proper rack for all the stuff. I´m moving these across our 3 rooms.

Now it´s time for the dual pultec i always wanted.

Thanks, Volker, Rowan and everyone else here for sharing their experiences with this build. It is by far the most complex build i´ve ever done. 

 

[kazper]

Thats a sweet rack full of DIY goodies... I've always wondered if those 24 position switches off eBay have end stops or adjustable end stops?

 

[[silent:arts]]

fascinating
very nice and clean work, inside and outside.
I really like how you did the 3 heater resistors ...
good work my friend, you really found your own design and style.

 

[Silvas]

Thats a sweet rack full of DIY goodies... I've always wondered if those 24 position switches off eBay have end stops or adjustable end stops?

It has end stops. But you can dissasemble it and put your own stops if you want.

fascinating
very nice and clean work, inside and outside.
I really like how you did the 3 heater resistors ...
good work my friend, you really found your own design and style.

Thanks Volker ! such a pleasure to stuff the white boards. I'm loving my banner, as usual !

 

[[silent:arts]]

I'm loving my banner, as usual !

now, watching your banners together you know what I mean with your own style ;D

now I think I need more tube projects for you  ;D ;D ;D

 

[bernbrue]

Very cool, really "pro" style, your work. Did you realize, that Volker loves to play around with these banners?!
.
regards
Bernd

 

[Silvas]

now I think I need more tube projects for you  ;D ;D ;D

Bring it on !!!