Drip Pultec V2

[AusTex64]

1. Has anyone used the Hammond power supply choke that is mentioned on the PCB? There's no choke on the original schematic, but it could have also been omitted due to cost.

2. Regarding the 1K resistor on the inductor PCB, I notice Greg and othe pics I saw on the Net used a 3W metal film Vishay there. The Mouser cart includes a 1K 1W carbon film, which I used, thinking it will sound better. And the PCB nor instructions call for a 3W there. I understand this resistor is important for the low freq simultaneous boost/cut trick to work.

Hope to post some pics, comments and things I've learned about this build here soon.

 

[Bonsaimaster]

I did not have a choke on mine. and I did use the 1K 1W carbon film resistor. Sounds great.

 

[AusTex64]

Thank you!

It's not real clear to me where one would wire up hs choke anyway. Guess I'm gonna try it without it.

 

[AusTex64]

I'm wondering why Drip reversed the placement of the power supply and transformer in relation to the original? On the original, as well as the Cayacosta and new Pulse units, the power supply is located directly behind the power switch, on the right hand side (looking at the front panel). On the Drip, it's on the left hand side, which requires running 120VAC across the audio section, or at least very near it, to get power to the front panel AC switch. I've tried to minimize potental issues by running the AC to the front panel power switch at the very top of the chassis, as far away from the XLR's and transfomers as possible, and using twisted pair, foil shielded 22AWG wire. Some manufacturers like Pendulum Audio won't even put an AC switch on the front panel, claiming it affects signal to noise, much less running AC right next to the audio section....

Guess we'll see what happens when I power up. Still waiting for my English transformers.....

 

[Khonnor]

Hi! I'm having some doubts about the main wiring (international) it's not clear at all in the manual, any help? thanks a lot!

 

[AusTex64]

Khonnor,

Which mains transformer are you using - Hammond, Sowter?

Also, see this http://www.dripelectronics.com/sitedocs/pultec_manual.pdf

It's the manual for the rev 1 boards, but he covers wiring the 220V transformer pretty well.

Good luck!

 

[bundy]

I am currently in the process of building a pair of these.

As there is no definitive Bill of Materials, I'm having trouble figuring out exactly what some of the resistors need to be.
Can all of the resistors (apart from the bleed resistor) be of type: metal film 5% 2-watt (e.g. PR02)?

Much of my confusion comes from the v1 manual, where many of the resistors are specified to be 3-watts.
There's also a 1% resistor, and even a couple of 0.1% resistors.
There is no explanation given and to make matters worse, there are no specific part identifiers to know which part is being referred to.

Secondly, can the bleed resistor be a PR03, or does it need to be specifically a metal oxide type?

Thirdly, what is the story with resistors "A", "B", "C", and "D"?
Are they always 1 kOhm (2 watt), 220 Ohm (2 watt), 220 Ohm (2 watt), 1 kOhm (2 watt) respectively (as marked on the PCB)?
My specific build will be using the Sowter 9527 power transformer configured for 240V operation.
I'm also curious to hear from anyone who installed a 10H choke for "A".