I always wanted to do the B-1 driving a 45 SE amp into a F4. F4 replicating source sound of 45 SE amp, but 25 watts....sold my 45 SE project 95% done and never built the F4 boards. Always sort of regretted that.
Russellc
Russellc
Tubelab TSE was originally designed for a 45, 45/F4 must be great combo, but check the nutube offer from Nelson while still open...
F4 fed with 2.5W sissy toob amp is nothing more and nothing less than 2.5W amp with big cojones
except if you use 16R output on tube amp , and F4 is loaded with less ohms
or if you use interstage xformer in between toob amp and F4
except if you use 16R output on tube amp , and F4 is loaded with less ohms
or if you use interstage xformer in between toob amp and F4
No proposals for a super-symmetrical balanced solution ?
Like e.g. Allen Wright's gain stage plus a circlotron buffer with Semisouth's ?
Vacuum State - High End Hifi Equipment
Build The Amazing FET Circlotron | Pass DIY
(Fig.5, so no need for unobtanium 2SJ74's)
🙂
Happy New Year,
Patrick
Like e.g. Allen Wright's gain stage plus a circlotron buffer with Semisouth's ?
Vacuum State - High End Hifi Equipment
Build The Amazing FET Circlotron | Pass DIY
(Fig.5, so no need for unobtanium 2SJ74's)
🙂
Happy New Year,
Patrick
I recently finished Michael Abdullah's KT-88 amplifier and it sounds really good with my horn speakers. For cost, simple to build and great sound with efficient speakers it is hard to beat. Here is a guy that recently built this amplifier on youtube with a detailed build guide and parts he used. YouTube I started with part 10 showing the results he obtained. I have many tube amplifiers, SE 300B, SE45, tube lab SSE, plus 5 or 6 more along with 7 up and running Papa clones. There are a lot of similarities to FW amplifiers and tube amplifiers. Papa has talked about this a lot himself. Simple circuits with few parts. It all becomes whether you want a SS or tube amplifier on which one prefers. I like all of my amplifiers.
Attachments
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From us :
Interest for genuine Semisouth SJEP120R100 curve tracer matched pairs & quads
But of course you can equally well use other MOSFETs, such as the equally excellent 2SK1530.
2SK1530-Y Japan-Transistor von Toshiba | eBay
Or even the IRFP240 in the original article.
Just need to use more in parallel.
🙂
Patrick
Interest for genuine Semisouth SJEP120R100 curve tracer matched pairs & quads
But of course you can equally well use other MOSFETs, such as the equally excellent 2SK1530.
2SK1530-Y Japan-Transistor von Toshiba | eBay
Or even the IRFP240 in the original article.
Just need to use more in parallel.
🙂
Patrick
I'm afraid you've missed it.
That was Papa's Christmas present of Korg B1 boards. As a surprise, after
the offer signup closed, Papa threw in matched jfets:
https://www.diyaudio.com/forums/pass-labs/313612-b1-korg-triode-76.html#post5645233
That was Papa's Christmas present of Korg B1 boards. As a surprise, after
the offer signup closed, Papa threw in matched jfets:
https://www.diyaudio.com/forums/pass-labs/313612-b1-korg-triode-76.html#post5645233
Wow, what a generous man. I will look forward to whatever becomes available at the DIY Audio Store.
The set up I am talking about is #3 in the F4 manual.
http://www.firstwatt.com/pdf/prod_f4_man.pdf
Maybe I am misunderstanding, but wouldnt the flea amp drive an F4 to full output? I would have B-1 or some pre before the flea amp...Seriously, not the old "will it drive F4 routine" LOL. I figured this would result in a 25 watt amp that had the sound signature of the flea amp. I was going to use a SE 45 amp. If it wont drive F4 as I thought, guess I'm glad I sold that project off!
Russellc
you know that F4 has no voltage gain
flea amp can throw out only as much volts it can throw out ....... so if you have volts for 3W , F4 will "just" add cojones, not watts (volts missing for that, actually)
flea amp can throw out only as much volts it can throw out ....... so if you have volts for 3W , F4 will "just" add cojones, not watts (volts missing for that, actually)
Well I had that wrong, guess it doesnt matter since I am divested of the 45 amp now.... Where's the benefit of driving the F4 with the flea amp? Or put more accurately, in what case does "cajones" help here? There must be some reason, just not the one I thought, i.e. 25 watts output...Driving lower ohm type speakers? (but still with flea watts)
Somehow I thought flea amp would drive F4 to full output.....lots I dont know! Curiosity: how much volts typical 45 amp put out?
Russellc
Somehow I thought flea amp would drive F4 to full output.....lots I dont know! Curiosity: how much volts typical 45 amp put out?
Russellc
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Well, no mathematician am I. I'm still trying to digest the materials you gave me on calculating cascode information. Looks like "not enough" to drive F4 to full output is short answer.
For a given speaker driven by flea amp with given preamp and source, what utility practically speaking is placing, F4 between flea amp and speakers? I think the answer is it may drive load a little easier? But only because of increased "cajones" not because more output in watts thing? Plus fact F4 doesn't add much sound change itself of course.
Silly me figured, well if given pre will drive F4 to full output, then surely that output from flea amp driven by said preamp would drive F4 to full output...obviously dead wrong. But that would be sweet if it were only possible....oh well. At time the 45 amp driving F4 would have been for Altecs...which would have worked just not the way I envisioned it would. No free lunch.
Thanks,
Russellc
For a given speaker driven by flea amp with given preamp and source, what utility practically speaking is placing, F4 between flea amp and speakers? I think the answer is it may drive load a little easier? But only because of increased "cajones" not because more output in watts thing? Plus fact F4 doesn't add much sound change itself of course.
Silly me figured, well if given pre will drive F4 to full output, then surely that output from flea amp driven by said preamp would drive F4 to full output...obviously dead wrong. But that would be sweet if it were only possible....oh well. At time the 45 amp driving F4 would have been for Altecs...which would have worked just not the way I envisioned it would. No free lunch.
Thanks,
Russellc
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well , yes
simply - flea amp is having own voltage envelope on output and that's exactly maximum voltage you can use to drive F4
pretty much same thing - you're having 36Vct Donut in F4 ; with same xformer , you can add trillion output mosfets in parallel to existing ones , but you'll still have 25W amp on 8R load ........ being limited with voltage envelope , given by rails value
simply - flea amp is having own voltage envelope on output and that's exactly maximum voltage you can use to drive F4
pretty much same thing - you're having 36Vct Donut in F4 ; with same xformer , you can add trillion output mosfets in parallel to existing ones , but you'll still have 25W amp on 8R load ........ being limited with voltage envelope , given by rails value
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