B1 Buffer Preamp

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#3,822
B1 Surpassed

Hi Folks,

This maybe the wrong thread for this post, so apologies in advance, but further to my previous post, 23/06/13, about the B1... After many hours of critical listening, I have the concluded that the B1 just does not sound right with my A40 monoblocks. So I built the JLLH buffer with ripple eater PSU's and the sound is mind blowing. This thing just ROCKS!!😀
 

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#3,829
Just out of interest I was Googling the JLH "Buffer" that the previous post was referring to. It seems an elusive beast.

I wonder if this is the buffer that was being referred to. I think the component values may have changed due to obsolescence.
 

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#3,832
The original simple compound buffer by JLH is a well known circuit. Its a low power mixed genre Sziklai. Higher Ygfs JFETs, more bias through better BJTs and an offset balance trimmer take it further. Expect a different sound than a B1 that may compliment different systems and likings better or not.
 
#3,833
NAD equipment used to suffer a similar degredation in sound. A "PURE" NAD system was supposed to sound very good, but if you only had a few pieces of NAD interspersed with other equipment, the results were often disappointing.

I use the B1 with an Aleph 4 and the results are simply outstanding.

My first foray into the DIY world of amplifiers was with my Dad who built one of the Hart JLH 80W Mos-Fet kits. It's still in the loft somewhere but I remember that the sound was somewhat muddied by the regulated PSU. He rebuilt it with an un-reg supply and it was much better. The Pass amps are so much more "Alive" and "Dynamic". Of course loud speakers have come along in leaps and bounds since then too. He was always a B&W man. I can't remember what we had then DM14's I think. I've got his 683's now.
 
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#3,835
JLH Buffer

The circuit that Katie and Dad shows is virtually exactly the one I have just built. The two 150ohm resistors are , instead, a 1k trim pot in the circuit I have. (The circuit I have is in the "Audio Design Amplifier" project in ETI Electronics Digest Winter 1985 / 86). All other components are as specified and were obtained from Cricklewood Electronics. The PSU is from the "low current" section of the ETI 80 Watt power amp PSU with resistor values recalculated to suit my input / output voltages. The ripple eater or "shunt regulator" part is also JLH and was published, again, in ETI April 1994; I just combined them both on a single PCB (well two to make the dual rail supply)! I sure didn't mean to dis the B1 because it sounded very good but, in the end, it just lacked drive and excitement but this JLH arrangement sounds magnificent in my system.
 
#3,839
I just built a B1buffer stage within a box with remote volume pot & input switching. I cannot believe how good this sounds, I've used a TDA1543 to supply two digital inputs and have two additional analogue inputs, the DAC and B1 boards are fed by Teddy Pardo Teddyregs, the volume pot & switching relays from a simple LM317. Despite the messy wiring and budget-level components, it is dead quiet and very transparent. I'm alternating between Ncore and Fetzilla amp stages to see which has the better synergy within the system, both sound good.
I used 200K resistors instead of the 221K - anyone care to let me know if this will make a noticable difference?
It's an elegant design, I like it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
 
#3,840
ajst2duk said:
I just built a B1buffer stage within a box with remote volume pot & input switching. I cannot believe how good this sounds, I've used a TDA1543 to supply two digital inputs and have two additional analogue inputs, the DAC and B1 boards are fed by Teddy Pardo Teddyregs, the volume pot & switching relays from a simple LM317. Despite the messy wiring and budget-level components, it is dead quiet and very transparent. I'm alternating between Ncore and Fetzilla amp stages to see which has the better synergy within the system, both sound good.
I used 200K resistors instead of the 221K - anyone care to let me know if this will make a noticable difference?
It's an elegant design, I like it. (I mean the circuit - not my build which is like a spaghetti bolognase).
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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