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#1
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Steve Bench's KT88 Matrix Amp
http://members.aol.com/analogengineer/kt88mat.htm
While I've collected all the parts for a possible 5894 version of the original matrix amp, last year I was lucky to acquire 3 nos TT21. I have a marine radio that uses one. I was hoping to get a quartet. (The marine radio TT21 is well worn, but I'm in no hurry to fix it up.) I am now thinking I'd like to make a TT21 version, but not with 6MB8. Or, I do have 4 well-worn KT88, but a top-cap version could be neat! I could use my 12W 7k/3.75-15 Beacon OPT's modularly perhaps! I wonder about using other tubes I have for the front end - 6SN7, 6SL7, even 1629 magic eye too. I have no spice yet. Not sure how to design. Mind you I haven't given it a great deal of attention yet. ~26V drive? Just a thought, logged. Surely it doesn't have to be a pentode driver? While we're on that, and the triode festival - this vacuum state amp looks as though it could be an incarnation of the above - was it? http://www.triodefestival.net/atf200...n/IMG_3375.JPG Ross |
#2
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Ross Matheson wrote: http://members.aol.com/analogengineer/kt88mat.htm While I've collected all the parts for a possible 5894 version of the original matrix amp, last year I was lucky to acquire 3 nos TT21. I have a marine radio that uses one. I was hoping to get a quartet. (The marine radio TT21 is well worn, but I'm in no hurry to fix it up.) I am now thinking I'd like to make a TT21 version, but not with 6MB8. Or, I do have 4 well-worn KT88, but a top-cap version could be neat! I could use my 12W 7k/3.75-15 Beacon OPT's modularly perhaps! I wonder about using other tubes I have for the front end - 6SN7, 6SL7, even 1629 magic eye too. I have no spice yet. Not sure how to design. Mind you I haven't given it a great deal of attention yet. ~26V drive? Just a thought, logged. Surely it doesn't have to be a pentode driver? While we're on that, and the triode festival - this vacuum state amp looks as though it could be an incarnation of the above - was it? http://www.triodefestival.net/atf200...n/IMG_3375.JPG Ross I see you have posted a picture of an Allen Wright designed power amp based on his slightly new idea of PP, for which he claims sonic superiority, which isn't unusual. This is achieved by using a CCS sink to the commoned cathodes of the output tubes, which makes the output stage act as a class A amp only, and incapable of class AB. The first 10 watts are the most important, and they are precious, and need our care and respect, and using a CCS makes sure the turn off current of one output tube exactly equals the turn on current of the other. To find out if Allen's ideas are beneficial to the sound, build one to find out. Meanwhile David Crittle at www.retrovox.com.au might have quite a few TT21 for sale at reasonable prices. Allen Wright's design would have nothing in common with http://members.aol.com/analogengineer/kt88mat.htm Patrick Turner. |
#3
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I wonder about using other tubes I have for the front end - 6SN7, 6SL7,
even 1629 magic eye too. I have no spice yet. Not sure how to design. Mind you I haven't given it a great deal of attention yet. ~26V drive? Just a thought, logged. Surely it doesn't have to be a pentode driver? While we're on that, and the triode festival - this vacuum state amp looks as though it could be an incarnation of the above - was it? Hi Ross, Pentode drivers work better for the Matrix. You're looking for linearity in the local feedback loop. There was a discussion on that topic a while ago in this forum. Although there was a Matrix amp at the triode festival, the pictured KT88 amp from Allen isn't it. The Matrix at the festival was 7695 based and tiny (200 cu inches) producing 3-4 watts per channel from 7695 pentodes. Best Regards, Steve Check my web page .. A HREF="http://members.aol.com/sbench101/"http://members.aol.com/sbench101/A Remove the .gov to EMail me |
#4
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"Steve Bench" wrote in message ... I wonder about using other tubes I have for the front end - 6SN7, 6SL7, even 1629 magic eye too. I have no spice yet. Not sure how to design. Mind you I haven't given it a great deal of attention yet. ~26V drive? Just a thought, logged. Surely it doesn't have to be a pentode driver? While we're on that, and the triode festival - this vacuum state amp looks as though it could be an incarnation of the above - was it? Hi Ross, Pentode drivers work better for the Matrix. You're looking for linearity in the local feedback loop. There was a discussion on that topic a while ago in this forum. Although there was a Matrix amp at the triode festival, the pictured KT88 amp from Allen isn't it. The Matrix at the festival was 7695 based and tiny (200 cu inches) producing 3-4 watts per channel from 7695 pentodes. Best Regards, Steve Check my web page .. A HREF="http://members.aol.com/sbench101/"http://members.aol.com/sbench101/A Remove the .gov to EMail me the website as posted doesnt work http://members.aol.com/sbench101/ look up matrix in the list Doug |
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