maxlorenz said:Hi Salas,
Avoiding crossover distortion and "coloring" the sound at our liking?
I've been told that some Tube amps do have capacitors on the signal path...
Anyway, I'll soon make that capacitor-less buffer for my TVC
I hope it is not too neutral...
Cheers,
M
this gadget is SE , so there is no any xover dist ;
even in case of (almost any) other buffer I know - there is no any xover dist , because they're all A class
Without being sure, maybe Max refers to alleged capacitor distortions described as ''crossover'' too, maybe you remember the battery bias on caps stuff by JBL etc. In the end, the electrostatically microphonic nature of cap foil following rather high signal voltage as in speakers, seems to stay put by some DC voltage bias IMHO.
JBL paper
JBL paper
capacitorless B1
http://www.diyaudio.com/forums/showthread.php?postid=1591410#post1591410
A reminder of Salas version since its been mentioned.
Is this still the most recent version?
Would any jfet suitable for the Pass B1 also work here?
I was considering building this before but couldn't figure out what I needed to look for in a relay. Does the 12V refer to Coil Voltage? What does the 700R refer to? I didn't see any similar spec to select for at the suppliers I usually buy from.
Is the npn pair literally *any* npn pair? Or any npn pair that makes sense, at least to someone who understands what they're looking at? And it is a Darlington pair right?
Any comments on parts for this circuit would be appreciated. And thank you Salas of for sharing.
salas said:Revised schematic.
http://www.diyaudio.com/forums/showthread.php?postid=1591410#post1591410
A reminder of Salas version since its been mentioned.
Is this still the most recent version?
Would any jfet suitable for the Pass B1 also work here?
I was considering building this before but couldn't figure out what I needed to look for in a relay. Does the 12V refer to Coil Voltage? What does the 700R refer to? I didn't see any similar spec to select for at the suppliers I usually buy from.
Is the npn pair literally *any* npn pair? Or any npn pair that makes sense, at least to someone who understands what they're looking at? And it is a Darlington pair right?
Any comments on parts for this circuit would be appreciated. And thank you Salas of for sharing.
This design made by Salas looks really good. I would say it is an improvement to the "original" Pass B1 design for obvious reasons. I wonder only whether for this design a shunt reg after LM317 would bring some further improvements, especially if you omit large input elco, used for filtering ?
For those of you interested in further improving of this simple B1 design, this is a recommended reading:
http://www.borbelyaudio.com/adobe/ae699bor.pdf
For those of you interested in further improving of this simple B1 design, this is a recommended reading:
http://www.borbelyaudio.com/adobe/ae699bor.pdf
I use this for secondary duty, so I did not change it. Of course symmetric shunt regs instead of 317 will bring benefits. But I don't know if it will seem worthy to all people given their dedication and individual system resolution. Its much more costly for time and space or dissipation.
*12V 700R refer to the particular relay coil characteristics (typical to find).
** Any NPN pair means just a couple of NPN transistors. One used as a diode, the other under the relay to pull its coil.
*** 1k and 330R can be lower, say 220R each if no oscillation is manifesting given the particular input and output cabling. That, makes it more dynamic subjectively.
**** I haven't used other than 2SK170BL
*12V 700R refer to the particular relay coil characteristics (typical to find).
** Any NPN pair means just a couple of NPN transistors. One used as a diode, the other under the relay to pull its coil.
*** 1k and 330R can be lower, say 220R each if no oscillation is manifesting given the particular input and output cabling. That, makes it more dynamic subjectively.
**** I haven't used other than 2SK170BL
I think it is 20mA...but Papa or one of the regulars can confirm.
http://www.enjoythemusic.com/diy/0708/first_watt_b1_preamplifier.htm
"The preamp typically draws fewer that 0.02 Amps, so current is not much of an issue."
http://www.enjoythemusic.com/diy/0708/first_watt_b1_preamplifier.htm
"The preamp typically draws fewer that 0.02 Amps, so current is not much of an issue."
To whom it may concern.
That shunt reg post can be handy for lux B1 builds. Either capacitor coupled or symmetrical.
That shunt reg post can be handy for lux B1 builds. Either capacitor coupled or symmetrical.
New B-1 build
Hey! I just finished a B-1 yesterday. I used a board and transistors from Colin at Pass labs. Worked just fine the first time I fired it up. It sounds Maaahvelous! Deeper and more "solid" bass than my previous preamp. (a Bride of Zen with overkill power supply) Sounds "better" over the rest of the frequency range, too. (Sorry, I don't know how to describe the differences like some golden eared types) Thanks, Nelson!
Hey! I just finished a B-1 yesterday. I used a board and transistors from Colin at Pass labs. Worked just fine the first time I fired it up. It sounds Maaahvelous! Deeper and more "solid" bass than my previous preamp. (a Bride of Zen with overkill power supply) Sounds "better" over the rest of the frequency range, too. (Sorry, I don't know how to describe the differences like some golden eared types) Thanks, Nelson!
I have a nice chassis lined up with a beefy Tx and PS already built in. The whole thing is giving me rails of +/-28VDC unregulated. So I planned on adding regulation, maybe using a jung type regulator. For those whole have gone this regulated route, have you tried out a simple 317/337 reg compared to a super regulator? Is it worth it do you think?
Fran
Fran
b-1 psw
Fran I'm running a simple 317/377 and am happy with it
-my reasoning was that the buffer draws so little power(.2amps if I remember correctly) that I didn't think over the top was necessary
perhaps there would be some gain in focus & snap with a faster with less bounce type regulator-perhaps someone who has heard both could quantify
rob
Fran I'm running a simple 317/377 and am happy with it
-my reasoning was that the buffer draws so little power(.2amps if I remember correctly) that I didn't think over the top was necessary
perhaps there would be some gain in focus & snap with a faster with less bounce type regulator-perhaps someone who has heard both could quantify
rob
John Broskie has a nice 0/+ regulated supply fore tube heaters
Normally the regulated supply fore tube heater are 6-12V
But this one is designed fore a 24V tube preamp
I suppose it could work with 18V too
Or maybe the SuperRegulator, Per Anders Sjoestroem have some printboards, but there are others I cant remember
A small switchmode, maybe
Its funny, but THEL in Germany, who also sells several regulated supply, still suggest that a traditional supply with multiple small caps will be really hard to beat
According to him a regulated supply have drawbacks
I am considering a CLC choke supply
I will also try to avoid toroids
Normally the regulated supply fore tube heater are 6-12V
But this one is designed fore a 24V tube preamp
I suppose it could work with 18V too
Or maybe the SuperRegulator, Per Anders Sjoestroem have some printboards, but there are others I cant remember
A small switchmode, maybe
Its funny, but THEL in Germany, who also sells several regulated supply, still suggest that a traditional supply with multiple small caps will be really hard to beat
According to him a regulated supply have drawbacks
I am considering a CLC choke supply
I will also try to avoid toroids
B1 Regulator
I am planning on using a Linear Technology LT1083 to bring the 40 VDC outboarded supply that is already routed to my chassis for my Pearl Phono boards, down to 25V for the B1 board. (Given the generous real estate on Pass's board, I think I can ad this on a small perf board above the B1 PCB without too much trouble......maybe Pass could add a regulator section to "Rev. A" of the PCB, someday.) This should work pretty well. I am told that the LT regulators are faster and sound better than the LM317 types, but who knows. I'm not sure my old ears could tell the difference......
BTW - be careful which version of the Panasonic TSHA caps you buy from Digikey - this board wants the 25 mm D "skinny" ones !! I've got a couple "fat" ones now looking for a project !!!
I am planning on using a Linear Technology LT1083 to bring the 40 VDC outboarded supply that is already routed to my chassis for my Pearl Phono boards, down to 25V for the B1 board. (Given the generous real estate on Pass's board, I think I can ad this on a small perf board above the B1 PCB without too much trouble......maybe Pass could add a regulator section to "Rev. A" of the PCB, someday.) This should work pretty well. I am told that the LT regulators are faster and sound better than the LM317 types, but who knows. I'm not sure my old ears could tell the difference......
BTW - be careful which version of the Panasonic TSHA caps you buy from Digikey - this board wants the 25 mm D "skinny" ones !! I've got a couple "fat" ones now looking for a project !!!
Re: New B-1 build
I am a new builder and am trying to construct the B-1 as my first serious audio project. I have read the Pass materials but am having trouble find the PN55D resistors and the capacitors referenced in the DIY article. Might anyone have a suggestion on a source?
Thanks for your help.
Decker said:
I am a new builder and am trying to construct the B-1 as my first serious audio project. I have read the Pass materials but am having trouble find the PN55D resistors and the capacitors referenced in the DIY article. Might anyone have a suggestion on a source?
Thanks for your help.