Poor Man's Pultec EQP1-A Build Support Thread

[wave]

I have a film cap for that position. It is 100nF not 100µF!

http://www.mouser.com/Search/ProductDetail.aspx?R=R413N31004000Kvirtualkey64600000virtualkey80-R413N31004000K

Here are the etch files I'm going to use

Dave

 

[dirtyhanfri]

Great!, thanks a lot, that pcb looks easy to etch at home, big tracks and pads...

About the cap, Right now I'm not at the bench, so I can't check it but, I'd swear it's 100uF, so maybe I have misread the schematic sooo long....

Gonna work these days out of my city, I will report my advances the next week...

 

[ruffrecords]

I have a film cap for that position. It is 100nF not 100µF!

Dave

Yes, that should definitely NOT be an electrolytic but a plastic film type rated at 275VAC. The Mouser part Wave pointed to is just what you need.

I am surprised that electrolytic has not exploded! Not surprised you are getting blown fuses.

Cheers

Ian

 

[wave]

Great!, thanks a lot, that pcb looks easy to etch at home, big tracks and pads...

About the cap, Right now I'm not at the bench, so I can't check it but, I'd swear it's 100uF, so maybe I have misread the schematic sooo long....

Gonna work these days out of my city, I will report my advances the next week...

It's definitely 100nF. I just looked at the schematic and the PSU board that Ian designed.

Dave

 

[MatthisD]

It is burning fuses, Is 500mA enough, right? I think I readed it somewhere here, but I'm not sure right now,

Try a 1amp fuse for a single tube gain stage, the heater current draw is 600ma alone.

 

[ruffrecords]

It is burning fuses, Is 500mA enough, right? I think I readed it somewhere here, but I'm not sure right now,

Try a 1amp fuse for a single tube gain stage, the heater current draw is 600ma alone.

DirtyHanfri - is the fuse on the primary or secondary of the transformer??  You should fuse the primary and a 1 amp slow blow should be fine. You need to use a slow blow fuse because the inrush current to the heaters and the HT smoothing caps can be quite high.

Cheers

Ian

 

[ilfungo]

sorry for the stupid question
I'm using a 6.3V DC
When I connect to the H1 and H2 have to respect a polarity?
Thanks

 

[ruffrecords]

sorry for the stupid question
I'm using a 6.3V DC
When I connect to the H1 and H2 have to respect a polarity?
Thanks

No, the tube does not care about the polarity of the heaters. Connect them whichever way is most convenient.

Cheers

Ian

 

[ilfungo]

Sorry I've populated R1 and R2 on Hi PCB...
Jumper on R3?
If I don't use L1 I must use a jumper across it?
Thanks

 

[ruffrecords]

Sorry I've populated R1 and R2 on Hi PCB...

That is is correct.

Jumper on R3?

On Hi PCB there is NO R3 and NO jumper on it. R3 is fitted only on Lo PCB.

If I don't use L1 I must use a jumper across it?
Thanks

Yes, you should jumper L1 if you do not use it.

Cheers

Ian

 

[dirtyhanfri]

Thanks for the advices about the cap, I guess I've been lucky with no cap explosion 

About the fuse, it's on the primary, in the IEC socket, actually it fits 2 fuses, one on each pin (except the earth one).

I will be working on that this weekend, hopefully everything will be fine, thanks again for the tips

Edit: just to say I've etched the psu and it was so easy, great! It was my first etch using my led isolation box, cheap and nice way to get my boards done and looking fine, I'm actually happy with this. I will populate it later and see what happens, thanks!

 

[dirtyhanfri]

Tubes Glowing Nicely  ;D

I connected the psu to one of the Make up gain stages with a tube on it and fired it up, nothing exploded and the tube was glowing, then I unplugged it and measured voltage falling from 250v. to zero slowly (it took about 15 minutes actually). Then I plugged the other tube and everything nice too. Actually, I think the tubes were shining more than when I had only one tube....

Now, I'll start passing audio.

Thanks for all your advices!!!

 

[wave]

Tubes Glowing Nicely  ;D

I connected the psu to one of the Make up gain stages with a tube on it and fired it up, nothing exploded and the tube was glowing, then I unplugged it and measured voltage falling from 250v. to zero slowly (it took about 15 minutes actually). Then I plugged the other tube and everything nice too. Actually, I think the tubes were shining more than when I had only one tube....

Now, I'll start passing audio.

Thanks for all your advices!!!

Did you end up using my etch file for your PSU? I would love to see a pic of it and the rest of the unit!

Dave

 

[dirtyhanfri]

Yes, I used it, thanks, very nice layout btw

This is the picture I have from the psu, I will make a better one when I dissasemble everything for clean everything inside

The closed unit (and my left foot, just noticed)

Almost everything inside

Another View

Tubes on

Trimmers in a little piece of perf board, for easy access

Ground Star

This two last pictures really like me, two detaills that makes the build nicer .

I'm having some troubles, gonna work hard on the wiring, I just noticed there are 2 eq hook up schemes, gonna look that tomorrow...

The unit passes audio, both in bypass and eq in mode, but the eq doesn't work propperly (the High cut switch seems to be reversed, with max cut at pos 1.

Also, the trimmers look strange too...

I'm actually so happy, my first tube project, and everything looks better than expected (as opposed to my gssl...) also I have some new tools, like a Proxxon minidrill with an amazing vertical stand and my cheap and self made pcb isolation box wich makes me want to build more thigs...

This wouldn't be possible without all the wise advices I got in this forum, thanks!

 

[ruffrecords]

It's great to see pictures of a project coming together. Congratulations.

Cheers

Ian

 

[ruffrecords]

Just updated the documentation for the new 3 band Pultec PCB to include a BOM. New pdf is here:

http://www.ianbell.ukfsn.org/EzTubeMixer/docs/EzTubeMixer/3BandPultec/P3bandDoc.pdf


Cheers

Ian

 

[wave]

Hey dirtyhanfri,
Nice unit. Good job so far. I made this diagram to help me out as well as others. I took it down earlier as I was going to add the mid section but I don't think you're using that so feel free to check it out

Dave

 

[dirtyhanfri]

It's great to see pictures of a project coming together. Congratulations.

Thanks, you can feel so proud, without your advices i probably would have a electrical shock, for sure, also, nice EQ Ian!, it's being a funny and instructive project.

Hey dirtyhanfri,
Nice unit. Good job so far. I made this diagram to help me out as well as others. I took it down earlier as I was going to add the mid section but I don't think you're using that so feel free to check it out

Dave

Thanks, It's so clear, I will try it. I think I have reversed the pots wiring (I'm using stepped switches), maybe I'm misunderstanding something, just to be sure, fully counteclock wise, means pin 12, right? So, in the hook up diagram v2 by Ian (posted in the first post of this thread), the little dots are pin 12?

Also, In the input I have no transformers, will etch a balancing / unabancing amp based on 5532s I've seen in this forum, but at the moment just using the pin 2 of the input xlr's, 3 to gnd..Also I've found some wiring issues in my oeps, so right now, my unit is fully unbalanced, gonna focus on the eq and the in that kind of things.

I noticed the eq was so quiet with no audio going though it, almost no hum (again as opposed to my gssl), what I was worried about...

 

[ruffrecords]

I think I have reversed the pots wiring (I'm using stepped switches), maybe I'm misunderstanding something, just to be sure, fully counteclock wise, means pin 12,

Fully counter-clockwise usually means pin1.

Fully clockwise usually means pin 12.

Cheers

Ian

 

[dirtyhanfri]

I reversed connection in pins 1 and 12 on one channel and it seems to be working fine as far as I can tell listening in my bench monitor...  ;D