2. amps-preamps
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retubing and would like to hear input from others

Hi all,
I recently switched from ss to valve gear and am starting to retube, getting rid of some sovtek and cheap chinese tubes. I picked up a cherry counterpoint sa-500 and a set of coincident mp300b monos. My first quandry is with the rectification and power regulation sections of both the pre and power amps. When choosing tubes for rectification and regulation(5ar4 for rectification on mp300b, 6ca4 for sa-5000 rectification, 12ax7 and 6dj8 for regulation). With these tube sections, is a low noise tube required/beneficial? I would also greatly appreciate some input on other peoples impressions of different 6dj8/6922 used as phono and linestage drivers.

Thanks
maplin
4 responses Add your response
tpsonic
1,092 posts
 
5ar4 rect:Mullard and Tung-sol.Each has its'own sound,with the TS having slightly better bass.
6922/6dj8:Siemens and Amperex (7308,cca).Low noise/microphonics are always beneficial-never know when you may switch units and need them in a different part of the circuit.
saki70
907 posts
 
Try a website called Joe's Tube Lore on Audio Asylum . He has done exactly what you are asking for with the different input tubes . Now he did not do the shootout using your equipment , he used a Thor preamp . So take that into consideration .
http://www.audioasylum.com/audio/faq/joes-tubes.html#12AX7
You could try this link , if it works .

Good luck .
sbank's avatar
sbank
3,378 posts
 
In many circuits, the 5AR4 doesn't have any impact or just very small impact on the sound. Try before you spend big $ on rectifier tubes, if possible.

2nd re: Joe's tube lore. Also another thread this week talked extensively about 6922s. Cheers,
Spencer
rodman99999
6,123 posts
 
In most ANY amplifier, upgrading the rectifier will provide a most definite improvement in sound. The power supply is providing the voltage/current to your speakers, as modulated(YES- that IS the correct term) by the musical signal. Any improvements there are certain to improve the overall presentation. As mentioned; Mullards(especially from the Blackburn Plant) are a very nice(and long life) tube, that will increase your listening pleasure. That topic has been discussed, and verified, in these threads. Go to (http://forum.audiogon.com/cgi-bin/srch_fr.pl?&1&procsrch&3&4&), and type, "Mullard 5AR4" in the Search bar.
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