Nelson does it! Not across a relay but across a switch, what should be similar.
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Thanks to Papa Nelson and Salas:
This is my first post on DyiAudio. I just finished a B1 with a 20 volt single pole power supply using an LM317T after a CLC filter (6,800 micofarads, 10milliHenry/7 ohm, 6,800 micofarads). On Input 2, I installed a six relay input selector kit I found on eBay.
The B1 is incredible and exceeds my fondest expectations. On my speakers (circa 92 dB) it is absolutely silent. In my living room the B1 satisfatorily drives either my Conrad-Johnson MV-55 tube amplifier or Dyi 2006 JLH Clas A to any level I care to listen to. Driven by the B1 each amplifier exhibits the strengths of its particular typology. The low output impedance of the B1 appears more compatible with each amplifier than the output from my prior preamplifier, a tube-based model.
I cannot thank Nelson Pass enough for making this design available to us. It can be implemented for less than $200, including boards and NJFETs from PassDyi, all other parts, and a low-cost chasis. Its performance exceeds anything I know of that is commercially available for many multiples of its cost. The B1 has provided me with the confidence to order the F-5 boards and parts for my next project. I urge anyone who is contempating building a B1 to hesitate no longer and do so. As Papa has indicated, the standard version works extremely well!
I also want to thank Salas for his patience and unstinting guidance regarding all of the questions asked about the B1. Even though I built a standard version, Salas' advice helped me to gain a deeper understanding of the design and appreciate the various iterations possible. As one of my next projects I intend to build the Salas simplified 36 dB NJFET RIAA for installation in my B1 chasis. Experience with the B1 has made me a true believer in the miracles which the 2SK170 is capable of producing.
Deepest and sincere thanks.
This is my first post on DyiAudio. I just finished a B1 with a 20 volt single pole power supply using an LM317T after a CLC filter (6,800 micofarads, 10milliHenry/7 ohm, 6,800 micofarads). On Input 2, I installed a six relay input selector kit I found on eBay.
The B1 is incredible and exceeds my fondest expectations. On my speakers (circa 92 dB) it is absolutely silent. In my living room the B1 satisfatorily drives either my Conrad-Johnson MV-55 tube amplifier or Dyi 2006 JLH Clas A to any level I care to listen to. Driven by the B1 each amplifier exhibits the strengths of its particular typology. The low output impedance of the B1 appears more compatible with each amplifier than the output from my prior preamplifier, a tube-based model.
I cannot thank Nelson Pass enough for making this design available to us. It can be implemented for less than $200, including boards and NJFETs from PassDyi, all other parts, and a low-cost chasis. Its performance exceeds anything I know of that is commercially available for many multiples of its cost. The B1 has provided me with the confidence to order the F-5 boards and parts for my next project. I urge anyone who is contempating building a B1 to hesitate no longer and do so. As Papa has indicated, the standard version works extremely well!
I also want to thank Salas for his patience and unstinting guidance regarding all of the questions asked about the B1. Even though I built a standard version, Salas' advice helped me to gain a deeper understanding of the design and appreciate the various iterations possible. As one of my next projects I intend to build the Salas simplified 36 dB NJFET RIAA for installation in my B1 chasis. Experience with the B1 has made me a true believer in the miracles which the 2SK170 is capable of producing.
Deepest and sincere thanks.
Hello,
For R1 is ok a Vishay-sfernice 1 Ohm 6W wirewound resistor? (I have a lot of them).
Cheers
For R1 is ok a Vishay-sfernice 1 Ohm 6W wirewound resistor? (I have a lot of them).
Cheers
It will work fine. And you will be sure that it doesn't ever get close to it's dissipation!! 🙂
Agreed. You will really think this even more when the F-5 is complete.
Russellc
I have to agree with comments about the B1. Mine goes from 5hz to 780khz with good voltage swings. It has the most open, raw and revealing sound of all my preamps to date, SS and tube. For me though I need more gain, even some gain so I'm building my third BoZ. This time with no input caps to be driven by my new Oppo BDP-83SE.
If you like the B1 then build the simple BoZ. In front of a pannel of hard core listeners they voted BoZ over B1 as the better preamp. I'm still a big fan of the B1.
If you like the B1 then build the simple BoZ. In front of a pannel of hard core listeners they voted BoZ over B1 as the better preamp. I'm still a big fan of the B1.
"If you like the B1 then build the simple BoZ. In front of a pannel of hard core listeners they voted BoZ over B1 as the better preamp. I'm still a big fan of the B1."
Thanks for the feedback, Russellc and mhouston. When I finish the F-5, I will definitely look into the the BOZ.
Thanks for the feedback, Russellc and mhouston. When I finish the F-5, I will definitely look into the the BOZ.
As much as I like the concept of BOZ, I don't think it was
as good as the balanced version, and that seems to be
the prevailing opinion out in the world. Of course neither
of those is a neutral as the B1.
😎
as good as the balanced version, and that seems to be
the prevailing opinion out in the world. Of course neither
of those is a neutral as the B1.
😎
Hi folks.
Hoping someone can help with a problem I have matching JFETs for the B1. I have copied exactly the following simple circuit for N-channel JFET matching described in the link below:
Transistor matching
For the 9V supply I am using one of those rectangular (6LR61) batteries which I read elsewhere should be up to the task.
Trouble is I get no reading at all on my DMM. The lowest setting on the DC scale is 200mV, which I assume on that setting measures everything up to 200mV?
Have I made some simple error here? It's driving me nuts!
Many thanks,
- John
Hoping someone can help with a problem I have matching JFETs for the B1. I have copied exactly the following simple circuit for N-channel JFET matching described in the link below:
Transistor matching
For the 9V supply I am using one of those rectangular (6LR61) batteries which I read elsewhere should be up to the task.
Trouble is I get no reading at all on my DMM. The lowest setting on the DC scale is 200mV, which I assume on that setting measures everything up to 200mV?
Have I made some simple error here? It's driving me nuts!
Many thanks,
- John
If you are using a resistor between V+ (battery) and Drain, you can read some mV, otherwise you must set your DMM for current (mA) and place the probes between V+ and D.
I'm using the circuit exactly as described in that link, so no resistor... And my DMM is set to the 200mV (max) setting. I get a zero reading.
An externally hosted image should be here but it was not working when we last tested it.
mV(volt) or mA(amp)? One measures voltage one measures current. The circuit is measuring current... EDIT: Which means the meter needs to be in series with the circuit.
Last edited:
As I told you, you must set the DMM for MILLIAMPS, not millivolts!
Red probe to V+, black one to D
If you look carefully the pics you linked, you will notice DC mA close to in meter. 😉
Red probe to V+, black one to D
If you look carefully the pics you linked, you will notice DC mA close to in meter. 😉
Point is, you don't want to measure voltage, will be zero, except your cables have a very high resistance, but you want to measure current. IDSS of your parts will be around 6-20mA, so you should turn your DMM to something within this range.
//Edit: bit too slow...
//Edit: bit too slow...
DOH yep quite right it was on the Volts setting - I definitely need to call it a day today making simple mistakes 🙄
Thanks for setting me straight folks, and shhhh not a word of this to anyone 😉
Ahem.
- John (losing his marbles at 37!)
Thanks for setting me straight folks, and shhhh not a word of this to anyone 😉
Ahem.
- John (losing his marbles at 37!)
Right after my little mistake (slaps forehead) measured the JFETs without trouble.
I have in my small batch of 2SK170's:
9.5 (1)
9.6 (1)
9.8 (3)
9.9 (1)
10 (1)
10.1 (1)
10.2 (1)
10.3 (2)
I assume from what I have read that out of that bunch, best to have a pair of 9.8s for the CCS, and a pair of 10.3s for the follower transistors?
Cheers,
- John
I have in my small batch of 2SK170's:
9.5 (1)
9.6 (1)
9.8 (3)
9.9 (1)
10 (1)
10.1 (1)
10.2 (1)
10.3 (2)
I assume from what I have read that out of that bunch, best to have a pair of 9.8s for the CCS, and a pair of 10.3s for the follower transistors?
Cheers,
- John
Been reading more posts about the JFETs and now a little confused as to which is the best configuration:
1) Pair of 9.8's for CCS, and pair of 10.3's for the follower transistors
OR
2) 9.5 (CCS) and 9.6 (follower) for one channel, and 9.8 (CCS) and 9.9 (follower) for the other?
Any difference or doesn't it matter?
Cheers,
- John
1) Pair of 9.8's for CCS, and pair of 10.3's for the follower transistors
OR
2) 9.5 (CCS) and 9.6 (follower) for one channel, and 9.8 (CCS) and 9.9 (follower) for the other?
Any difference or doesn't it matter?
Cheers,
- John