Anyone here have/build a Pass B-1 buffer?
- Thread starter 240sx4u
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I run one in my main rig. I like it a lot but paired with an F5 I need a bit of gain somewhere. My speakers are ~89-90dB@1W1m and if I play an older CD, before loudness became an issue, max volume sometimes isn't quite enough. Haven't tried running 2 amps though.
240sx4u
Lunatic Member
Right, which is why I am asking... it's a bit beyond my knowledge base.
There's a bit of output difference between an F5 and your Classe'...like a factor of 10.
If you have access to a passive pre, either one in the closet or a loaner, you can try that and see if the gain issue will be a problem.
sachu888
Spare the tigers, kill me
I have built the Pass B1 and using it since last 2 years.Its great.I don't find any problem with gain.You can see some pic of my build here http://audiokarma.org/forums/showthread.php?t=395040 and here is a very long thread still running http://www.hifivision.com/diy/21036-pass-b1.html
Regards,
Sachin
Regards,
Sachin
Double Decker PASS B1
This is another version from previous one where I used SSP at the input to accept selected source and drive LSA within PASS B1 where B1 driving output power amp.
By boundry at 2012-05-15
By boundry at 2012-05-15
Recent modifications
Another B1 being planned to replace frontal SSP. Observe the soldering of taller components at the other side by keeping pin numbers same. I excluded power caps in second B1 and tapped Gnd, V+, and V/2 from existing B1.
By boundry at 2012-08-18
This is how it looks from different angles -
By boundry at 2012-08-18
By boundry at 2012-08-18
From top -
By boundry at 2012-08-18
Changes in sound:
Now some may call it clinical sound, too transparent. This made everything available from 1.2Hz onwards and flat response without any coloration. Low has definitely got more punch and original. HF are clean and overall dark as always. SSP with AD823 was nearby but not that much. One of my friends used this for one weekend and he wanted me to sell this to him immediately. I did not do so. Enjoying it..
Edited: all source including crappy FM to vinyl LP and Maranz CDP, sound detailed as never before. No gain but no loss in terms of volume level.
This is another version from previous one where I used SSP at the input to accept selected source and drive LSA within PASS B1 where B1 driving output power amp.
By boundry at 2012-05-15
By boundry at 2012-05-15
Recent modifications
Another B1 being planned to replace frontal SSP. Observe the soldering of taller components at the other side by keeping pin numbers same. I excluded power caps in second B1 and tapped Gnd, V+, and V/2 from existing B1.
By boundry at 2012-08-18
This is how it looks from different angles -
By boundry at 2012-08-18
By boundry at 2012-08-18
From top -
By boundry at 2012-08-18
Changes in sound:
Now some may call it clinical sound, too transparent. This made everything available from 1.2Hz onwards and flat response without any coloration. Low has definitely got more punch and original. HF are clean and overall dark as always. SSP with AD823 was nearby but not that much. One of my friends used this for one weekend and he wanted me to sell this to him immediately. I did not do so. Enjoying it..
Edited: all source including crappy FM to vinyl LP and Maranz CDP, sound detailed as never before. No gain but no loss in terms of volume level.
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Billyk
Active Member
Big fan of the B1 buffer here. Was going to say you could use two but omishra took care of that. There is also the AMB LAbs (no affiliation) alpha 20 line stage based on the JISBOS (JFET Input Stage, BJT Output Stage). It can be configured for gain. Then there is th "souped-up" version of the B1, the DCB1 that is direct coupled and uses a Salas designed shunt power supply.
I use and love the B1 and the DCB1, I have the alpha 20 on deck to be built for my next project, it is going to drive my F5T and will have a bit of gain.
I use and love the B1 and the DCB1, I have the alpha 20 on deck to be built for my next project, it is going to drive my F5T and will have a bit of gain.
Billyk
Active Member
I love them both, the B1 is built into a little integrated that has the B1, NP designed "Amp-Camp" monoblock 5 watt class A amps and an ODAC. Which by the way drives the amps and an active sub with no problem. I use it in my office at work, the only problem, I have to stop and listen sometime 'cause it just sounds soo darned good. Interestingly enough, as you asked about powering it, I power the B1 to 20VDC with a 12volt wall wart and a DC-DC boost I got off eBay for $5.00. The power draw is very light and Papa designed a nice widget that does not seem to mind the power supply. I had planned on replacing it with a more conventional "proper" power supply, but it sounds great as is, so...
The DCB1 I use as a input switch/volume control for various projects so don't have it in critical listing environment as such, but I do find it very revealing of all of the rest of the components in the system. Hey! I guess it's my reference!! Never thought of it that way. It is clean, very clean and easily reflects the changes. I like it a lot and would not hesitate to recommend it.
I planned on the alpha 20 because folks say the f5 needs a touch of gain and it uses the jfets I love from the B1 and adds the BJT to the circuit and can be configured to add the gain I need. The circuit resembles a lot of the circuits on diyAudio hat folks have put forth for use with the F5. Can't wait to put it all together. Will be using LDRs (think Lightspeed) as the volume control and Salas shunt low voltage regs for the PS...
Oh my I am starting to ramble again sorry... I really love this stuff!!
The DCB1 I use as a input switch/volume control for various projects so don't have it in critical listing environment as such, but I do find it very revealing of all of the rest of the components in the system. Hey! I guess it's my reference!! Never thought of it that way. It is clean, very clean and easily reflects the changes. I like it a lot and would not hesitate to recommend it.
I planned on the alpha 20 because folks say the f5 needs a touch of gain and it uses the jfets I love from the B1 and adds the BJT to the circuit and can be configured to add the gain I need. The circuit resembles a lot of the circuits on diyAudio hat folks have put forth for use with the F5. Can't wait to put it all together. Will be using LDRs (think Lightspeed) as the volume control and Salas shunt low voltage regs for the PS...
Oh my I am starting to ramble again sorry... I really love this stuff!!
Now for my usage, it is like: Source -> (B1->[LSA->B1])->Power amplifier F5 turbo V2.
in above statement, PS is not shown but present there and
() - inside preamplifier
[] - second B1
This made input impedance of B1 exposed to source (1MΩ) and first B1 drives to LSA. LSA (light speed attenuator) is LDR based volume control which is hidden from input as well as output because B1 is in between. Second B1 shows output impedance of 50Ω, drives power amplifier. This make it B1 buffer at both the ends, make any source in the world happy by means of very high input impedance. All power amps are drivable with very low output impedance and LSA in control of volume level.
This made no loss of frequency response and adequate driving of source and power amp made life easy with net result cleanest possible I listened in my setup.
After my recent build of pearl2 phono and F5 turbo v2 as power amp, I am finding it difficult to switch off the system. Just listening more music and listening ...
Other components in my system - I have G R research LS Encore bookshelf speakers. Sources are TT with phono (CNC and pearl2), Maranz CDP CD6003 and Tandberg TPT 3001 FM tuner.
in above statement, PS is not shown but present there and
() - inside preamplifier
[] - second B1
This made input impedance of B1 exposed to source (1MΩ) and first B1 drives to LSA. LSA (light speed attenuator) is LDR based volume control which is hidden from input as well as output because B1 is in between. Second B1 shows output impedance of 50Ω, drives power amplifier. This make it B1 buffer at both the ends, make any source in the world happy by means of very high input impedance. All power amps are drivable with very low output impedance and LSA in control of volume level.
This made no loss of frequency response and adequate driving of source and power amp made life easy with net result cleanest possible I listened in my setup.
After my recent build of pearl2 phono and F5 turbo v2 as power amp, I am finding it difficult to switch off the system. Just listening more music and listening ...
Other components in my system - I have G R research LS Encore bookshelf speakers. Sources are TT with phono (CNC and pearl2), Maranz CDP CD6003 and Tandberg TPT 3001 FM tuner.
What SB do you have 240sx? I think the touch has the lowest output at 2Vrms, and you can check your specs but that's probably sufficient to drive each of your amps into clipping. So, all you need to do is calculate the input impedance of your two amps in parallel, and make sure the B1 is okay with that.
P.S. However, if you are intending to use the volume control on your SB for this setup, no preamp or buffer is necessary. If using the B1, you'd want disable the volume on the SB or keep it near 100% and only use it for fine-tuning the volume.
P.S. However, if you are intending to use the volume control on your SB for this setup, no preamp or buffer is necessary. If using the B1, you'd want disable the volume on the SB or keep it near 100% and only use it for fine-tuning the volume.
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