Moderator: kabubi
tony wrote:2 pairs of tubes.....
kabubi wrote:Sir Tony,
what is a better tube for audio application:
one that is high current or low voltage or one that is low current but high voltage?
tony wrote:After the HiFi show at the Dusit Hotel, i have received numerous inquiries about push pull tube amps...when asked
about how much they were willing to spend, all of them came up with low figures giving me the impression that most
folks think that DIY was a cheap way to acquire a tube power amp...could they be correct? let us find out...we will
not consider boutique parts in this discussion, only those that are available from usual sources....
this is my pp EL34 amp...
2. next comes the power tubes....
2.1 JJ seems to be a reliable new production tubes and is available here:i found a local source, their service is
top notch, http://www.epektos.com/catalog/90270c5d ... 4af81.aspx
2.1.1 quad prices for new tubes are as follows, EL34----P3,000; 6L6GC----P3,300, note that you will have to add 150
for shipping......
2.2 Balik-bayan Handicrafts is also a good place to get tubes, large discounts from time to time...
2.3 I also buy from the states NOS TV tubes, these are U$1 each, i find TV tubes as good sounding as the other so
called audio tubes, unfortunately local folks are slow to recognize their virtues nor use them....
2.4. Russian tubes are a revelation to me, they are awesome....and very cheap....
2.4 Gerry Sta Maria, 400-2762 is the other one of my unsung heroes, he can smell tubes a few kilometers away ;D
2.5 the small tubes can set you back another P1000 for a pair of 6CG7, and the 6J9's another P500 for a pair
tony wrote:
depends on what you aim for....for me it is not the tubes per se, but what you do with the tube that matters....
high voltage low current tubes implies high plate resistances necessitating high impedance OPTs that required elaborate OPT designs because of the higher required inductance for decent low frequency response...
low voltage high current tubes OTOH have lowish plate resistance like for the 6C33 that has typically 150 ohm plate resistance thus making designs of the OPT very easy and less critical....the challenge with low voltage tubes is in the drive circuitry.....
but one thing is sure, working with high voltages is scary, i still bear scars on my hands from injuries suffered a long time ago......
alexg wrote:tony wrote:
depends on what you aim for....for me it is not the tubes per se, but what you do with the tube that matters....
high voltage low current tubes implies high plate resistances necessitating high impedance OPTs that required elaborate OPT designs because of the higher required inductance for decent low frequency response...
low voltage high current tubes OTOH have lowish plate resistance like for the 6C33 that has typically 150 ohm plate resistance thus making designs of the OPT very easy and less critical....the challenge with low voltage tubes is in the drive circuitry.....
but one thing is sure, working with high voltages is scary, i still bear scars on my hands from injuries suffered a long time ago......
I will not DIY any amp with B+ more than 500VDC. First, it is scary, one mistake and you are toast (literally) and second, parts, like capacitors, resistors are more expensive on voltages higher than 500VDC.
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