My REDD47 P2P build

[Ilya]

I wanted to share my last experience of making a P2P version of REDD preamp.

I've learnet a lot throuout the process of building this preamp. I've also managed to get rid of all hum completely. The key to this is proper grounding techniques (surprise!  ;D).

This beauty is very quiet. It measures approximately -90dB (with all knobs cranked up) on my FF800. To put this in perspective, solid state pres measure at -95dB - -100dB. I'm very impressed with this. I was hoping for -80dB, frankly.

 

[ruffrecords]

That is an interesting power supply board. Where did you you get it?

Cheers

Ian

 

[Ilya]

Ian,

I've designed all PCBs myself and ordered them locally.

P2P board is also a self made thing. P2P layout is available somwhere on the forum, although I've made minor adjustments to it.

 

[TomTomDeluxe]

My first post, jeah!
Ilya, it looks great! I already ordered some parts to start my Redd47 build.
Which schematics did you use? Your power section looks huge with all that heatsinks and coddock resistors . Do you have a schem for that?
I wanted to try the nice p2p layout from guitarmaker. There is no big spends on the power section like you did. Will I miss something when I do the minimalistic p2p layout. I want to use the hammond 370bx PT. Sorry for my unawareness...
Thx

 

[Ilya]

TomTomDeluxe, welcome to the Lab!

The heatsink is a bit overkill, I agree. But this was what I had at hand, and cooler is better, you know

These are not Caddocs, just regulators. Schematic for HT and heaters is taken from Orange86 project. 12V and 48V are pretty standard. Btw, roughly half a PSU PCB is taken by HT section.

Guitarmakers layout is a way to go. There's a small mistake there (missing connection) - check it against the schematic carefuly.

Can't comment on this particular Hammond. I've ordered custom power toroid with 290V secondary and I'm using bridge rectification. If Hammond has something like 270-0-270V secondary, you'll need a half-wave rectifier with CT tied to ground.

 

[MartyMart]

Very nice build

Well done, Marty.

 

[mitsos]

Nice layout! 

Is that a DIY heater windin? 

 

[Ilya]

Is that a DIY heater windin?

Well, sort of. The 7V AC secondary turned out to be too low (the regulator didn't even began to regulate), so I had to compensate that "manually".

 

[mitsos]

Nice! That's DIY...

 

[dirty1_1garry]

Very sweet project! Congrats!

Could you describe what is the relay pcbs near input and output transformers?
And what transformers do you use?)

 

[Ilya]

Could you describe what is the relay pcbs near input and output transformers?
And what transformers do you use?)

Thanks for kudos.

Relay on the input activates DI (when the jack is inserted). Relay on the output changes polarity. I didn't want to move audio signals to front panel switches. Audio paths are kept as short as possible.

Another subtle thing is: the client requested silver wire hookup. So most of the build is hooked up with solid core 1mm silver wire

Trafos are Cinemags (both in and out).

Enclosure is from diy-racked guys. Custom silkscreening. Very good quality.

 

[mitsos]

nice touch.  If you don't mind, which output?  And 80%, 50% or steel?  thanks!

 

[Ilya]

nice touch.  If you don't mind, which output?  And 80%, 50% or steel?  thanks!

Output is CM-9661A-H. This is high the nickel one.

 

[mitsos]

must sound very nice. I think I talked to dave geren once and he mentioned a nickel output that people used to love for the redd47. I think it might be what john hinson was using also, not sure about my memory though.

 

[Ilya]

Yeah, I talked to David and he told me that HiNi core were preferred by most engineers.
Mr. H rarely discloses what he uses in his gear. But I remember that he hinted HiNi Cinemag trafo in one of REDD threads. He told it was custom, but you never know with John...

 

[mitsos]

I could be wrong, but I think the input was hinson's design, sort of an improved trafo for the UA610.  I believe it's pretty much confirmed that's what he used in his redd47s, but yeah you never know.  The info on the output I'm less sure of, I may be remembering the same thread you are.