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Possible B4 Buffer Improvements

As regards section 2 of my anove description. I avoided a possible ground loop by connecting just one earth to the star ground from the signal input, as all input signal ground share the same ground at the input kit
I've changed input & output caps (provisionally) from the setting that appeares in photos above. The input caps are old 3.uf proppylene Wonder caps that I had lying around from the times of yore. The output caps are pros as well but new Mundorf stuff (2.7uf) I'm waiting to try polysterenes kindly offered by our fellow Pinkfish SQ225917 But I don't like the result much when comparing the sound I get from B4 with the other pres (by order of preference:Supercharged 72, Neil's Minimotherboard and Superregged 32.5) The sound seems rolled off in the heights and a bit hard. I don't know whether to trust Neil's generous view as to prefer B4 to his own design. So far at least.
I'm going to try one direct input signal bypassing the selector kit , just in case it should be the culprit. Who knows.
I welcome your wise viewa

PD.I have tried bypassing the selector kit with not much improvement though.
 
Hardhold,

I'm interested interested in the time-constant at the input of your B4. What resistor value are you using for R5?

Ben
 
I've just changed from 10k to 22k and find it to sound better now.
Next step would be to wire out the output and run a dance ball of input caps.
Cheers
 
Hi Harthold,

What source are you using?
Have the high frequencies opened up since changing to 22k? Is it a big difference?
On par with your supercharged 72?

Ben
 
It's opened up clearly. I've done the bypassing/wiring of the outpu cap too. It's now playing loud loud. Do the comparison against the 72 when I can.
Thanks for your interest. I'll keep on posting
 
The sound is much better.I run only a single ground wire from the signal input kit to the signal input pin -as the selector kit melts the stereo ground of all signals into one. The input cap is now a 2.7uf M-cap and no output cap in place. I'm looking forward to fit the 1uf polysterene when it comes on the post Defenitely it is precise and refined to a point. The image/sound stage (or whatever you call it) is not as tall and large as the one gets out of my Supercharged 72 ( fuelled from a 300VA Rcore and Hackernap, of course). So I might expect some improvement when I get a slightly larger trafo (R-core) next month, perhaps. I'm also waiting for a tray/sled to fit the lot in a Naim shoebox but in due time.
Cheers
 
Going to start building mine in just over a month's time, with an R-core. Slightly worried I might lose some PRAT compared to my 32.5, but I'm keen to give the B4 a go!
 
New improvement found using a laminated trafo of about 60va. An old piece salvaged many many years ago from a amp found in the bin which, oddily enough, has 3 windings : 15-0-15, 12-0 and (the not usable)17-0. I have powered the input Kit (12-0) and the B4. The sound is better (3d) although I have to allow in less signal to get same sound level.o.c.
As I now have to order an R-core.my question is whether there's consensus on whether to use 12-0-15 or 15-0-15. Laminated tx probably sound better by itself in this pre whether 12 or 15-0-15. even an old piece like this.
Photo to follow, whenever my Photobucket lets me upload it.



P.D. By the way Bennyboyph asked what source I was using: 1.- Wadia transport 3200 and Audionote DacII (output txless),2.- Yamaha tuner -my bodge-, and even tried my 3.-Linn Walhalla, Naim-Avondale Phonopre with SuperTeddyRgs
 
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