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

Hi, I’m a novice diyer and I’m very interested in BPBP. I’ve seen that unfortunately the last GB for this project is now closed and tfboy doesn’t know if/when he will open a new one. So my question is if and how is possible to turn an idea in a real device, which I could couple to my new Hypex class d power amp. Sorry if I can seem silly in my request, but it is the only way I can follow to reach my aim (good listening to good music)
Thank in advance,
Gaetano.
 
Maplins do a 12-0-12 250mA for about £6. I get 13.7v out on my slightly high 242V mains.

12V 250mA Miniature Transformer | maplin

Just a heads up for anyone still needing transformers in the UK. Now Maplin are sadly in administration ... :sigh: .... these transformers are £3.20 ea now online (don't think they stock them in store).

EDIT: - They DO do them in store! 2 in each of my local stores (well, they are NOW, won't be tomorrow ).
 
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Hi, my BPPBP drives two NC400 in full range mode. My problem , I would like to drive a Hypex PSC 2.400 as well , which needs +18dB input level.
I think about building a 2nd BPPBP to put it behind the 1st one.

BPPBP----------------------------------------------NC400(2x)
\-----------BPPBP-----PSC2.400------subw.

Can someone tell me whether I have to expect any kind of trouble with impedance, distortion, CMRR, R4/32 R15/42 or anything else?
 
18 dB is quite a lot. There are gain setting in PSC2.400!

//
I asked Jos Wolthuis (Hypex Electronics) for help, he told me there is no possibility to change the input sensivity. The manual doesn't help either.
If you're using the psc 2.400 as two way system, you can lower the high channel
in relation to the low channel.
I'd like to use it in bridged mode to drive my sub.
By the way, I forgot to say, my preamp system is fully balanced.
 
Hi, I would like to build the BPBP and include it in my DAC project. Is there perhaps anyone who still has the PCB lying around and willing to sell? If including the Hans Polak volume control option, that would be even greater! Or anyone considering to start another group buy....
 
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Hi, I would like to build the BPBP and include it in my DAC project. Is there perhaps anyone who still has the PCB lying around and willing to sell? If including the Hans Polak volume control option, that would be even greater! Or anyone considering to start another group buy....

Maartn, I have a unpopulated board left, send me a PM if you want it...
 
Has anyone tried a mechanical stepped attenuator instead of the pot?

Short answer: Yes works fine. And you can even avoid the very high gain by inserting a resistor in series with the stepped attenuator, witch you cannot with a pot. And you can use a logaritmitc attenuator with non of the issues related to a log. pot.
Only drawback: No remote control and fancy displays :p
 
Only drawback: No remote control and fancy displays :p
That's not necessarily true! (ok, depends on how "fancy" a single dot matrix LED grid is to you... ).

Are ladder types ok? If so...

Khozmo used to do a step-motor stepped attenuator but now look at this: relay driven with an optical encoder to switch. Surely that is the most ideal you can get? Solves the possible wiper lifting or make before break problems with a normal one?

High Quality Audio & Industrial Attenuators

After I've got one going with Maya, I might investigate this further! Up to six channel versions...

Could this then go in the same place as the pot rather than Hans' attenuator position solution?
 
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Here's a commercial amp/preamp using it (not with bppbp of course), Valvet:

s2_netzteil_black_green.jpg