BPPBP - Bruno Putzey's Purist Balanced Preamp (well a balanced volume control really)

[sq225917]

Oh yeh that modern 1979 jensen opamp....

 

[mrjayviper]

is there are "replacement" for the hypex discrete voltage regulator? thanks

 

[gorso69]

is there are "replacement" for the hypex discrete voltage regulator? thanks

It is not a replacement, but a pin-compatible regulator with LM 317 and a capacitor on the ADJ pin were made.

 

[sq225917]

Any 3 pin reg with correct pin out will work, just without the kelvin sense

 

[gorso69]

It was done with remote sense, here are the pictures

 

[DAZER]

How do you think which design will have better sound?
AMB α24+δ1 (or Quad Goldpoint) vs. BPPBP (Purist by Bruno Putzey)?
Anyone compared both?

 

[cowanaudio]

If either option sounds different to the BPPBP, it's a faulty design.

 

[atohmdiy]

Hello,
I have a BPBP for a few years, i built it with hypex reg, and it's power by a 13v transfo. Can it take DC ?

 

[sq225917]

Yes you can feed dc straight into the +/- pins, it'll just pass through the diodes to feed the regs. That's how mine is wired.

 

[atohmdiy]

Thank you for your answer, i will maybe take this route when i rebuild mine in a proper case. Meanwell have a psu block that output +-15v and 5v. The +-15v for the BPBP is ok, but the 5v for my maya controller is not enough, or i will need to bypass the maya psu to feed directly the 5v to the board.

 

[killie99]

Should the selector switch for the BPPBP be a make before break?

 

[sq225917]

It's only open/closed, there's no bounce to worry about.

 

[zabloc]

I have a question,
I'm thinking of making this preamplifier, what are the experiences of people who have made it?
Can I make a parallel output (XLR and SE) and connect the amplifier to the XLR and the subwoofer to the RCA, or do I have to make a balanced to SE conversion on the SW output?
And how can I limit it so that it does not exceed +16.6dBu

 

[Hans Polak]

Have another look at the circuit diagram and you will see that the output is not differential, but made balanced by inserting a resistor in the gnd line of equal value as in the hot line.
An SE output would mean to tap the ground line right before this resistor.

Hans

 

[zabloc]

Thanks Hans, I understand now.
And how should I limit it to +16.6dbu, as far as I understand, this concerns the pot resistance, what is math?
Sorry, I'm not a professional but a slightly advanced hobbyist.

 

[Hans Polak]

Pot is 10K and gain is Rout/(10K-Rout), so when Rout is 10K gain will be infinite.
When you want to limit gain, you will have to insert a resistor in series with the pot.
A 1K resistor as an example will limit gain to 10K/1K = 10x or 20dB.

Hans

 

[viltsone]

Have anybody tried or changed on this preamp OP amps to some newer ones like OPA16xx, OPA828? Would it be doable? Anybody have this preamp KiCad files or other editable PCB files to make small changes?

 

[cowanaudio]

What aspect of performance do you think needs improving with an opamp change?

At unity gain I'm unable to distinguish this preamp from a piece of wire.

 

[viltsone]

I am reading positive feedback that OPA2828 opens new territory on lower distortion and sound quality with a transparency and details in music. I love to use this preamp also with BAL in and SE out and SE in BAL out/SE out.

 

[cowanaudio]

It does all this already.