Does anyone or even Mr. Pass if he’s watching, know the name for the cascode arrangement of fets in this preamp? I built a two channel version point-to-point for my CD player because it was really hot and I love it. I have made many cascode srpp and tetempoles mostly with tubes some hybrid, but this one is a bit unusual to me. Mr. Pass said it is his favorite. The name anyone? Sorry if I miss it in the previously 255 Pages
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Hello, I got a B1 circuit board from 2015, been collecting dust for quite som time, now up and running, mounted in a metal chassis
Q1
Using a 18V power adaptor, is fuse in circuit a necessity?--If so, what kind of fuse is needed for the B1? 230V mains area...
A battery pack a better option?
Q2
I've tried the B1 with Quad II´s KT66 monoblocks ( modified, with separate earth to chassis, not through the original Quad 2 umbilical chord ) with good results, will I need to protect the B1 from the power amp?
PS:
I know I'm way too late with this build..., with several updated on the unit afterwards, will appreciate any replies...
Q1
Using a 18V power adaptor, is fuse in circuit a necessity?--If so, what kind of fuse is needed for the B1? 230V mains area...
A battery pack a better option?
Q2
I've tried the B1 with Quad II´s KT66 monoblocks ( modified, with separate earth to chassis, not through the original Quad 2 umbilical chord ) with good results, will I need to protect the B1 from the power amp?
PS:
I know I'm way too late with this build..., with several updated on the unit afterwards, will appreciate any replies...
@tralalalala I had a similar experience to yours. I had a B1 sitting in a box with all of the parts for about 10 years and finally got around to building one last year myself. 
I've attached some pictures in case that helps your build.
For the PSU - if you check the article, Nelson says you can feed the circuit 18-24VDC. I personally have been running mine with one of my linear 24VDCs or initially just the Triad 24vdc switcher and using Mark's SMPS filter between it and the B1. I'd say your PSU should have a fuse if its a linear, but if you are using a switcher, make sure it has the auto restart/short circuit protection.
RE: protecting the B1 from the power amp - not sure what you mean . The B1 has output coupling caps which will block DC from being send to the amp. If you are unsure of proper earth grounding or current return paths, there are a couple of excellent articles people have posted on the forums here. If you can't find them, free to DM me and I'll hunt them down. This is something that seems to be a bit of a mystery until you get the facts straight, and then its pretty straight-forward.
--Tom
I've attached some pictures in case that helps your build.For the PSU - if you check the article, Nelson says you can feed the circuit 18-24VDC. I personally have been running mine with one of my linear 24VDCs or initially just the Triad 24vdc switcher and using Mark's SMPS filter between it and the B1. I'd say your PSU should have a fuse if its a linear, but if you are using a switcher, make sure it has the auto restart/short circuit protection.
RE: protecting the B1 from the power amp - not sure what you mean . The B1 has output coupling caps which will block DC from being send to the amp. If you are unsure of proper earth grounding or current return paths, there are a couple of excellent articles people have posted on the forums here. If you can't find them, free to DM me and I'll hunt them down. This is something that seems to be a bit of a mystery until you get the facts straight, and then its pretty straight-forward.
--Tom
Attachments
Hi !
Do I understand you correctly if I say that the power supply needs a fuse, if I build it from scratch, but not the B1 buffer circuit?
Having difficulties finding a switcher / wall wart / power adapter, on net, with a autorestart / short circuit protection...
Thanks for clearifyring my thoughts around coupling caps / DC blocking.
Thank you!
Do I understand you correctly if I say that the power supply needs a fuse, if I build it from scratch, but not the B1 buffer circuit?
Having difficulties finding a switcher / wall wart / power adapter, on net, with a autorestart / short circuit protection...
Thanks for clearifyring my thoughts around coupling caps / DC blocking.
Thank you!
Yes, you should always have some fusing mechanism in the power supply that prevents shorts from letting the smoke out. SMPS PSUs usually have onboard overload (current or temp) protection and will auto-reset themselves rather than blowing a physical fuse but it has the same effect.
--Tom
Actually, I think most wall warts do have the auto restart feature. When I first turned on my B1K, due to large capacitance values, my smps (24V 500mA) wall wart would first illuminate the front panel LED then it would go out for a moment and then come back on permanently. I think it was the smps shutting down due to being unable to support the dead-short nature of the fully-discharged capacitors which, in all, add up to quite a bit of capacitance. I have since modified my in-chassis filtering (+24, +/-15 taken from the one 24V smps) to include relays that close for full connection only after the capacitors have reached partial charge through a current-limiting resistor.
Yes most if not all of the ones I've encountered do, but its a good idea to check because you don't want to find out the hard way by letting the smoke out. If you are using a linear supply, definitely make sure theres a fuse in the AC side of the PSU that is properly rated for what you are using it for.
--Tom
--Tom
Hi Everyone!
I am new to this forum - fresh from building a WHAMMY and chuffed that I can spend $600 on a very decent head-phone amp.
I am now thinking of building a B1 pre-amp. I have a CJ Premier 17LS valve pre-amp now. Whilst I love the smooth sound, I am looking for a bit more slam and bass. I tried the WHAMMY as a pre-amp and it sounded great, with the extra slam and bass, but maybe losing some resolution and soundstage on the CJ.
Is there a B1 "best practice" summary that has the consensus improvements and suggestions all in one place, as opposed to trolling through the history of the forum to find out what worked and what gives the best results?
I am new to this forum - fresh from building a WHAMMY and chuffed that I can spend $600 on a very decent head-phone amp.
I am now thinking of building a B1 pre-amp. I have a CJ Premier 17LS valve pre-amp now. Whilst I love the smooth sound, I am looking for a bit more slam and bass. I tried the WHAMMY as a pre-amp and it sounded great, with the extra slam and bass, but maybe losing some resolution and soundstage on the CJ.
Is there a B1 "best practice" summary that has the consensus improvements and suggestions all in one place, as opposed to trolling through the history of the forum to find out what worked and what gives the best results?
Not to drive you away from the B1 but you may want to consider the BA2018 if you want all the qualities that you are looking for. It's not minimalistic like the B1, but it presents a dynamic soundstage & great resolution as well. The problem that I found with my B1 was that, although it was wonderful for not interfering with the signal too much, in trying to find the right set of caps to use (to match to your particular aural desires and/or matching your other components character) one can spend a lot of money on finding which brand suits your desired listening experience. JMTCs.
Cheers
