geoffbyrne Posted February 27, 2012 Share Posted February 27, 2012 (edited) tests run on JJ 803S valves [url="http://la-economy.blogspot.com/2012/02/tube-test-jj803s.html"]http://la-economy.bl...est-jj803s.html[/url] & Tung Sol 12AX7 http://la-economy.blogspot.com/2012/02/tube-test-12ax7-tung-sol-reissue.html G. Edited February 27, 2012 by geoffbyrne Quote Link to comment Share on other sites More sharing options...
Dood Posted February 27, 2012 Share Posted February 27, 2012 Ahhh superb. I've e-chatted with Myles before about valves. He's been a great help and incredibly knowledgeable. This makes for very interesting reading. Quote Link to comment Share on other sites More sharing options...
bertbass Posted February 28, 2012 Share Posted February 28, 2012 I replaced the JJ ecc83s in my Mywatt 200 with a trio of Tung Sol 12AX7 and I did actually notice a difference for the better. In my opinion that is. Tighter bass and less middle which I like. Quote Link to comment Share on other sites More sharing options...
bigbottomend Posted March 6, 2012 Share Posted March 6, 2012 Good info , thanks Quote Link to comment Share on other sites More sharing options...
REDLAWMAN Posted March 6, 2012 Share Posted March 6, 2012 Terry, Hi mate, hope you're well? Daft question probably, but why did you replace only 3 of the 4 and did you retain the 4 JJ powertubes? Incidentally- and slightly off beam- have you ever tried running it on 2 instead of 4 power tubes and if so, did you take out the 2 central ones or 2 end ones? Quote Link to comment Share on other sites More sharing options...
charic Posted March 6, 2012 Share Posted March 6, 2012 [quote name='dood' timestamp='1330383877' post='1556746'] Ahhh superb. I've e-chatted with Myles before about valves. He's been a great help and incredibly knowledgeable. This makes for very interesting reading. [/quote] Did you ever try those other valves in the kilo? Quote Link to comment Share on other sites More sharing options...
Dood Posted March 7, 2012 Share Posted March 7, 2012 Not yet mate! It's a job to do at some point to see how it sounds, but i've been pretty busy elsewhere! I'll start by rotating around valve one,the 'critical' position and see what difference it makes with my 'magic' valve and my rather spesh 5751. Quote Link to comment Share on other sites More sharing options...
geoffbyrne Posted March 7, 2012 Author Share Posted March 7, 2012 Latest epistle from Myles: [url="http://la-economy.blogspot.com/2012/03/vacuum-tubes-today.html"]http://la-economy.blogspot.com/2012/03/vacuum-tubes-today.html[/url] G. Quote Link to comment Share on other sites More sharing options...
geoffbyrne Posted March 16, 2012 Author Share Posted March 16, 2012 Another interesting instance of Amp Blueprinting: http://la-economy.blogspot.com/2012/03/bit-of-amp-blueprinting-from-past.html G. Quote Link to comment Share on other sites More sharing options...
bertbass Posted March 16, 2012 Share Posted March 16, 2012 Sorry, a bit slow with this reply but only just seen it. I only replaced 3 because stupidly, I didn't realise that there were 4 preamp valves and only ordered 3. The only reason that I changed them in the first place is that I'd read that the Tung Sol 12AX7 were supposed to be better valves so I thought I'd give it a go. I haven't changed the KT88s as the JJs are new and it would have cost a lot of cash to replace them as well. Never tried running an amp with only 2 of the 4 output valves and doesn't the output impedance change with only half the output valves? Quote Link to comment Share on other sites More sharing options...
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