I think I have one more question concerning my Pultec clone (see picture :-) after that I will be able to finish them and finally use them. Quite excited about hearing them...
I used a universal Hammond 370CAX transformer (http://www.hammondmfg.com/300series.htm). I connected the primary windings for 240V, but I don't know what to do with the other primary wires (100V, 110V, etc...). Should I just cut them of and put some heat shrink over them? Or...?
Also with the secondaries I have a question: every filament has a CT wire, even the yellow ones to power up the on/off light. What should I do with them? Just solder them to the ground? Just like the violet (50V) wire, which is also a CT?

Hope anyone can help me out in this final stage.

Thanks!


ruffrecords

Re: Almost finished PTP Pultec clone - transformer question
« Reply #1 on: May 28, 2012, 11:13:19 AM »
Assuming you wired the primary as detailed in the Hammond primary wiring table at the bottom of the page you linked, then yes, all you need do is insulate the spare leads and tuck them somewhere tidily.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

ncoak

Re: Almost finished PTP Pultec clone - transformer question
« Reply #2 on: May 28, 2012, 04:59:36 PM »
neat job. what are those boards/posts called?

Walrus

Kevin.

ruffrecords

Re: Almost finished PTP Pultec clone - transformer question
« Reply #4 on: May 28, 2012, 06:06:05 PM »
Where do you get that lovely hook up wire?

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Re: Almost finished PTP Pultec clone - transformer question
« Reply #5 on: May 28, 2012, 07:25:36 PM »
I got the hook up wire from Tube Depot, but it's actually a bit too thick so it's not really easy to work with. Next time I go for a thinner hook up wire.

fazer

Re: Almost finished PTP Pultec clone - transformer question
« Reply #6 on: May 29, 2012, 12:24:46 PM »
Your build looks very old school.    I like it very much. 

Your wire does look thick like 14ga.    I get that from Lord valve in Denver.  It comes in 20ga and 18ga.   The wire is solid core which makes it great for bending into place on PTP.  Its Cloth covered and he sells it for old fender amp type builds.   Much neater than stranded. 

The old fenders (blackface) had a layout to keep the parasitic coupling down.   By using solid core you keep the routing in place.   Also when you cut wire, don't strip the ends as you know,  you just push the cloth cover back to expose the solid wire.  If you try to strip it, it will fray badly.

Works great on these tube builds.   You also see wire like this in old RCA tube gear.

Re: Almost finished PTP Pultec clone - transformer question
« Reply #7 on: May 29, 2012, 02:19:08 PM »
Just to get back to my question: I already sorted out the primary wires from my Hammond 370CAX transformer (http://www.hammondmfg.com/300series.htm), but still need to know where the secondary VIOLET, RED/YEL and YELLOW/BLACK need to be soldered. Refering to the pdf here (http://www.hammondmfg.com/300sch.pdf) those three wires are CT wires. Does this mean I can just solder them to the ground lug?

Hope anyone can help me so I can finish my Pultecs.

Thanks!

PS: here is an other picture of the back of one of my Pultecs, check out the original HS56 ;-)

ruffrecords

Re: Almost finished PTP Pultec clone - transformer question
« Reply #8 on: May 29, 2012, 06:25:47 PM »
Just to get back to my question: I already sorted out the primary wires from my Hammond 370CAX transformer (http://www.hammondmfg.com/300series.htm), but still need to know where the secondary VIOLET, RED/YEL and YELLOW/BLACK need to be soldered. Refering to the pdf here (http://www.hammondmfg.com/300sch.pdf) those three wires are CT wires. Does this mean I can just solder them to the ground lug?

The violet I don't think you need. it is intended for a bias supply for power amps.

As far as the others are concerned it depends on what you are using to rectify the HT. Are you using a tube rectifier or semiconductor diodes?

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Re: Almost finished PTP Pultec clone - transformer question
« Reply #9 on: May 29, 2012, 06:39:22 PM »
I'm using a 6X4 rectifier tube. I've already put the GREEN/YELLOW secondary to the ground (that's what the Cayocosta layout AND the original Pultec schematic says), which I think is the CT. Does this imply the heathers are non-floating? Still don't really know what the "floating heathers" means... The Hammond website also says "Units can be run full wave bridge or full wave C.T." Any ideas?

Thanks for your help!

Bram


plumsolly

Re: Almost finished PTP Pultec clone - transformer question
« Reply #10 on: May 29, 2012, 06:48:53 PM »
Assuming you are you using the the original EQP-1a schematic: red/yellow goes to ground, float (heat shrink and connect to nothing) violet and yellow/black. The schematic that I have (attached) does not show the 6.3V center tap connected to ground.

Best,

Ben

Re: Almost finished PTP Pultec clone - transformer question
« Reply #11 on: May 29, 2012, 08:14:26 PM »
You're right Ben, sorry, I was confused. I meant GREEN/YELLOW goes to the point where resistors 270k and 62k come together (according to Cayocosta's layout), is that right?
And for the rest: cut off VIOLET and YELLOW/BLACK
and put RED/YELLOW to ground

That way I will be able to finish my Pultecs correctly, right?

Thanks for confirming!

plumsolly

Re: Almost finished PTP Pultec clone - transformer question
« Reply #12 on: May 29, 2012, 08:35:50 PM »
You're right Ben, sorry, I was confused. I meant GREEN/YELLOW goes to the point where resistors 270k and 62k come together (according to Cayocosta's layout), is that right?
Yes.
And for the rest: cut off VIOLET and YELLOW/BLACK
I wouldn't cut them off. Just heat shrink the ends and put them somewhere tidy. If you leave a little heat-shrink off the end of the wire and squeeze it together with pliers when it is hot, it makes a nice little seal. I know leaving them can seem untidy, and your build so far is gorgeous, but you just never know - you may want to elevate the heaters and reference them to that 50v bias winding some day...
and put RED/YELLOW to ground
Also yes.

Best,

Ben

rafafredd

Re: Almost finished PTP Pultec clone - transformer question
« Reply #13 on: May 31, 2012, 09:43:31 PM »
WOW, did you actually have a 217D in there?

CJ

Re: Almost finished PTP Pultec clone - transformer question
« Reply #14 on: June 01, 2012, 12:09:12 AM »
dang, where in tierra del fuego hasve you been?

did you get  picked up by a giant condor?

hey, did you back up any vacuumbrain stuff?

good to see ya!

buenos con via mis dios, :P
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

rafafredd

Re: Almost finished PTP Pultec clone - transformer question
« Reply #15 on: June 13, 2012, 08:16:06 PM »
right there in tierra del fuego, getting married and having a son. killed some condors there. Four years old now. Lot's of hard DIY work it has been, and still is. But now I am back, so it seems.

I probably have all vacuum brain in my backup hard drive. Are you looking for something?

CJ

Re: Almost finished PTP Pultec clone - transformer question
« Reply #16 on: June 13, 2012, 08:25:45 PM »
now thats good news!   ;D

let me see about some free web space,

If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html


 

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