About to start building my F4 (stereo) and now looking down the road on how to drive my F4. Options are Pumpkin or Impasse preamp or keep my hotrodded DCB1 and feed that into BA.
From some of the comments in threads, it can be done but I only know of 1 member that has done this. TimBarnes setup his BA in different chassis with its own transformer. So here are my questions:
1. Can I keep the BA gain stage in the same chassis as my F4 and use the existing transformer and Universal Power supply v3 board? (Antek An-5218)
2. Is there a preference to which BA revision I should use? v2 or v3
3. Is there anything I would need to change on the F4 to implement BA gain stage?
4. To wire it up, I would take one of the available V++,V-- & G from power supply board and connect to BA. Take the input from the chassis and direct to BA and the output of BA to input of F4.
This might be over simplistic and a given to most, but I want to make sure I have everything covered.
Thanks in advance
Neville
From some of the comments in threads, it can be done but I only know of 1 member that has done this. TimBarnes setup his BA in different chassis with its own transformer. So here are my questions:
1. Can I keep the BA gain stage in the same chassis as my F4 and use the existing transformer and Universal Power supply v3 board? (Antek An-5218)
2. Is there a preference to which BA revision I should use? v2 or v3
3. Is there anything I would need to change on the F4 to implement BA gain stage?
4. To wire it up, I would take one of the available V++,V-- & G from power supply board and connect to BA. Take the input from the chassis and direct to BA and the output of BA to input of F4.
This might be over simplistic and a given to most, but I want to make sure I have everything covered.
Thanks in advance
Neville
1. Yes.
2. No, your choice.
3. No and yes, Standard F4 or crippled F4, both will work but crippled for best performance.
4. Yes.
Question, you are going to make an F4, then possibly cripple it to make a push pull BA output, why not just make a BA2/3 instead.
If you decide you want an F4 later on, swap the front end for a B1.
2. No, your choice.
3. No and yes, Standard F4 or crippled F4, both will work but crippled for best performance.
4. Yes.
Question, you are going to make an F4, then possibly cripple it to make a push pull BA output, why not just make a BA2/3 instead.
If you decide you want an F4 later on, swap the front end for a B1.
Thanks for your input Itsmee....... I already have all the parts and pcb and going to start this weekend on my F4. F4 appeal was also because I could run it in balanced mode. Detailed build guides are available for F4 and F5 - this is the major driving factor, because I am new to amps......and (gulp) dont shoot me.......new to diy Pass amps.
I know the BA is pretty modular and maybe that was the route I should have taken, but without a build guide.... I am very hesitant.
I know the BA is pretty modular and maybe that was the route I should have taken, but without a build guide.... I am very hesitant.
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Welcome to the Pass class A addiction; build one and you can't stop.
I have no doubt that you will eventually get round to the BA series, with one or more detours along the way.
I wish you well with your F4 build, if you have any questions, post them in the F4 thread.
I have no doubt that you will eventually get round to the BA series, with one or more detours along the way.
I wish you well with your F4 build, if you have any questions, post them in the F4 thread.
1. No problem putting them in the same chassis if you want to. Just make sure you have the space. There's an argument that separate power supplies are better, but it's probably marginal. If I was putting them in the same chassis I would use a shared power supply.
2. I don't have any experience of anything except the version I built (boards from diyaudio.com), so I can't comment.
3. You can build a stock Ba-3, and connect it to a stock F4 with no modifications. That's what I have done, and it works fine. If you search for "crippled F4" there are a lot of discussions of what can be left out of the F4 if you have a BA-3 front end. I haven't done it so I won't comment any further.
4. Your wiring plan looks OK to me.
tim
Thanks Itsmee, I already have an F5 on the way and now I can see me ordering the BA as well.
Hey Tim, thanks for your input. From your posts in earlier thread it looks like you built BA-3 gain stage - is that right? Any tips or suggestions after the fact? I really want to keep the F4 stock so I am glad to hear from you and Itsmee that it can be done. I want to be able to use them in any amp without having to rebuild them. I should have purchased the Deluxe 5U for expansion...oh well at least the Deluxe 4U has ability to mount pcb on front plate.
Hey Tim, thanks for your input. From your posts in earlier thread it looks like you built BA-3 gain stage - is that right? Any tips or suggestions after the fact? I really want to keep the F4 stock so I am glad to hear from you and Itsmee that it can be done. I want to be able to use them in any amp without having to rebuild them. I should have purchased the Deluxe 5U for expansion...oh well at least the Deluxe 4U has ability to mount pcb on front plate.
The BA-3 with a volume control and input selector forms a complete linestage preamp. That's how I'm using it. So I can use it with my F4, a gainclone, or any other amp. I built it into a separate case (cases) for the maximum flexibility.
The other application for the BA-3, and the original intended use, was as a front-end to the BA-1 and BA-2 back end stages, neither of which have voltage gain. If I was building one of those (and I'm looking at building a BA-1 because I have the transistors), I would feed it from the BA-3, just as I feed the F4.
For amps with voltage gain, like the F5, Honey Badger, and gainclones, you may not need the gain that the BA-3 provides, depending on the efficiency of your speakers and the size of your room. I have a big room, but efficient horn-loaded speakers, and the BA-3/F4 has just enough gain.
It sounds as though you're on the right track - just build the F4, and build the BA-3 as a front end, either in the same case or separately.
tim
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