You do realise F6 has it's own buffer built in. There's absolutely nothing wrong with putting a volume pot onto the front end of it.
The only reason to build a B1 would be if you have more than one source and want to switch between different sources. Or maybe you just like having separates.
I would suggest building the B1 revision 2 not the original, as the new revision is better at driving difficult loads which could be handy if you are planning on building other amps that might need that.
The Revision 2 is also capacitor free.
The only reason to build a B1 would be if you have more than one source and want to switch between different sources. Or maybe you just like having separates.
I would suggest building the B1 revision 2 not the original, as the new revision is better at driving difficult loads which could be handy if you are planning on building other amps that might need that.
The Revision 2 is also capacitor free.
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Nope.. not a clue .. Newbie Here 😀
Have a pot in front.. seems to work 'fine'.
Was only wanting to attach my TT /phono.. eventually.
Thought it might need an interface.. dunno if that's even true.. yet.
Nothing else on the immediate horizon.
No desire to collect boxes without genuine reason.
Erm Where do I find B1.2 ?
Not planning on a 'better' amp.. but I'm starting to understand how these are addictive rascals.
Previously it was all about getting an Amp that didn't dissapoint.
No longer.
Have a pot in front.. seems to work 'fine'.
Was only wanting to attach my TT /phono.. eventually.
Thought it might need an interface.. dunno if that's even true.. yet.
Nothing else on the immediate horizon.
No desire to collect boxes without genuine reason.
Erm Where do I find B1.2 ?
Not planning on a 'better' amp.. but I'm starting to understand how these are addictive rascals.
Previously it was all about getting an Amp that didn't dissapoint.
No longer.
If you look at Sony V1 article you will find a very simple buffer circuit.
You will also start to notice it has a very strong resemblance to the 1st stage of the F6 amp.
😉
You will also start to notice it has a very strong resemblance to the 1st stage of the F6 amp.
😉
I guess the dcb1 from tea bag should foot this criteria right?
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It was a long long time since I looked at that but from memory he uses the original B1 circuit but with a bipolar power supply with a direct coupled output.
If so, that will do the job driving just about every amp.
The push pull version of the buffer (revision 2) has a twice the class A current capability though, all things being equal which is beneficial for driving something like Burning Amp Mu Follower.
If so, that will do the job driving just about every amp.
The push pull version of the buffer (revision 2) has a twice the class A current capability though, all things being equal which is beneficial for driving something like Burning Amp Mu Follower.
Interesting. Thanks for the explanation. I have two dcb1 built already. Would be interesting to try the B2 at some point
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Sent from my ONE A2003 using Tapatalk
It's still called B1 but the circuit has been revised/changed.
The original B1 including DCB1 are absolutely great circuits.
Tricky to find info about B1 ..there are variants/mutants seemingly everywhere.
Threads intertwine and branch off, trying to retrace the development /info is no trivial task.
Cryptic answers, likely the result of the same questions repeatedly asked, are unfortunately not overly informative to non acolytes either 😉
Clearly the easiest choice is the Pass labs diy version .. which does include the increasingly iffy to source 170's.
IMO.. Small risk in trusting the Master.
Threads intertwine and branch off, trying to retrace the development /info is no trivial task.
Cryptic answers, likely the result of the same questions repeatedly asked, are unfortunately not overly informative to non acolytes either 😉
Clearly the easiest choice is the Pass labs diy version .. which does include the increasingly iffy to source 170's.
IMO.. Small risk in trusting the Master.
I have no info on any revision of B-1. Neither does Firstwatt, or they are keeping mum about it.😀 Like you say, I have seen many off shoots, mainly the Hypnotize and Mezmorize, but those are not FirstWatt revisions. I also recall someone adding a small gain circuit to it as well, IIRC it also used a few added Toshiba J fets.
If one needs gain, the BA3 front end sounds better to my ears, when compared to my B1......sounds better even if you don't need the gain...again, to my ears. I do have both on hand.
http://www.firstwatt.com/prod.html If you scroll down to B2 and B3, maybe these (or one of them) is what some refer to?
Russellc
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I have personally spoken (in writing) with Papa about this.
The B1 circuit is now different.
You would learn something by carefully studying the Sony V1 article.
The original B1 circuit is fine but it will struggle driving some of Papa's new circuits eg BAF mu follower circuit.
If you don't intend on building that then the original B1 will probably drive 90% of Papa's circuits (including F6) without any issue what so ever.
The benefit I see of the new B1 circuit is in the long run you will save on jfets. Eg you can drive F6, M2, F4, etc directly without the buffer input stage.
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Hi Guys,
Here is an interesting finding made at the expense of my poor F6. I had already blown one set of input JFETs on one channel, repopulated the board, back up and running, no problems. Yesterday the other channel just blew the input JFETs on startup, just a pop when I turned on the power after the preamp had been on for ~ a minute or so. So either the batch of semisouth parts that I got are especially fragile, or something else must be going on. I'm using an aikido 9 pin all in one preamp to drive the F6 and it sounds really great, and I ran it into an Aleph J that uses the same JFETs for years without problems. I decided to see if there was a voltage spike at turn on/off. I hooked my multimeter to the pre out set to VDC, When I turned on the pre I measured a wild spike ranging up to 10 vdc and swinging into the - 5 vdc range for several seconds before settling out to ~ 20 mV. Tried the same test on a dual mono aikido that uses tube PSU's, same behavior. Then I took A SS preamp reran the experiment, no voltage swing at all, rock steady ~ 2 mV. I've used the Aikidos for years with a variety of gear and have never had a problem. I'm not an EE so I'm not sure what to make of this unless the F6 topology leaves the JFETs particularly vulnerable to damage from this phenomenon. In any event I'm puling the Aikido out of the chain for now. Anyone with more knowledge care to comment ?
PJN
Here is an interesting finding made at the expense of my poor F6. I had already blown one set of input JFETs on one channel, repopulated the board, back up and running, no problems. Yesterday the other channel just blew the input JFETs on startup, just a pop when I turned on the power after the preamp had been on for ~ a minute or so. So either the batch of semisouth parts that I got are especially fragile, or something else must be going on. I'm using an aikido 9 pin all in one preamp to drive the F6 and it sounds really great, and I ran it into an Aleph J that uses the same JFETs for years without problems. I decided to see if there was a voltage spike at turn on/off. I hooked my multimeter to the pre out set to VDC, When I turned on the pre I measured a wild spike ranging up to 10 vdc and swinging into the - 5 vdc range for several seconds before settling out to ~ 20 mV. Tried the same test on a dual mono aikido that uses tube PSU's, same behavior. Then I took A SS preamp reran the experiment, no voltage swing at all, rock steady ~ 2 mV. I've used the Aikidos for years with a variety of gear and have never had a problem. I'm not an EE so I'm not sure what to make of this unless the F6 topology leaves the JFETs particularly vulnerable to damage from this phenomenon. In any event I'm puling the Aikido out of the chain for now. Anyone with more knowledge care to comment ?
PJN
Isn't this what is confusing B1 v2. Papa posted it a few weeks (months) ago, here on DIYAudio
Attachments
That LDR version of the buffer has 1K at the output as did the original B1, so still might not drive the more difficult loads.