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What to replace my B4 Buffer with?

L

locky

pfm Member
Looks like my DIY B4 Buffer preamp has finally died and I'm thinking of replacing it with a simpler switch/attenuator device that will take 4 analog inputs and give me a single output to the power amp. I don't need any gain, just a clean adjustable signal. Any recommendations? Am happy to go for something DIY if necessary.
 
Whats wrong with the B4? Fixing it will be easy!

Do cross-post into the DIY sub-forum with more detail about what appears wrong for all the help you could want.
You will not come close to what this 'simple' but special PFM-DIY item offers if you want both low-distortion, and a low source impedance to drive your power amp(s), at anything like the original low cost of entry.

ATB.
 
martin clark said:
Whats wrong with the B4? Fixing it will be easy!

Do cross-post into the DIY sub-forum with more detail about what appears wrong for all the help you could want.
You will not come close to what this 'simple' but special PFM-DIY item offers if you want both low-distortion, and a low source impedance to drive your power amp(s), at anything like the original low cost of entry.

ATB.
Click to expand...
Want to build me one then ha ha
 
If you want fancy buy a neurochrome buffer board, strap -/+ 15v rails to it and switch gear and attenuator of you choice.
 
martin clark said:
Whats wrong with the B4? Fixing it will be easy!

Do cross-post into the DIY sub-forum with more detail about what appears wrong for all the help you could want.
You will not come close to what this 'simple' but special PFM-DIY item offers if you want both low-distortion, and a low source impedance to drive your power amp(s), at anything like the original low cost of entry.

ATB.
Click to expand...

Thanks. I think I'll open it up again, take a look and see if I can diagnose the problem with help from the DIY section. I assumed without the need for any gain I'd be able to replace it with something that would perform as well but n ot cost too much, perhaps with an attenuator rather than the Alps pot I currently have.
 
Managed to get the B4 running again. There must gave been an issue with the output caps as things sorted themselves out when I removed them. I do like the look of the neurochrome though with an attenuator. Wondering how it compares to the B4?
 
About 40db quieter and offers balanced to se conversion both ways or straight through without change. At some point I'll build one with a decent relay attenuator.
 
sq225917 said:
About 40db quieter
Click to expand...
I'd call less than half that at best / barely 20dB (and of course it depends significantly on what the reference is - say, 1v out or max output); iow -both are beyond contention as a limitation on line-level inputs. In fact , depending on what you choose upstream as an attuanator and its output impedance, can have as much effect on SNR @ 0.1v output wher emost will be used, as worrying about which route to take.

(infact - this 'snr' as a value f goodness' prob needs a separate discussion -it's a wide-open wormhole of claims, measurements, and marketing misinformation.
and - that's utterly no disparagement against the Neurochrome products: simply a wider observation)

Good points on the other things offered elsewhere though.
 
Less noise mo better, always. All other things being equal. The thd spec is line level, 2v, fair for any cd player, dac and most phonostages. But yes, what comes before and after the fact is critical, for sure.
 
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