Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => AmpTools/Tech Tips => Topic started by: DummyLoad on February 12, 2012, 04:15:20 pm
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love the 'lil fellers...
i started a matrix of types grouped by base type.
the types in bold are what i would or might consider suitable for AF amp use. Mu and transconductance are specified for triodes - transconductance is in Siemens - mA/V
please feel free to suggest additions, comments, etc...
spreadsheet attached in PDF format. if you have interest, send me a PM with email addy and i'll send you the spreadsheet as .XLSX attachment.
respectfully,
--DL
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DL, what is it you like about these tube types? And what sets them apart from the more common 9-pin and octals?
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smaller
lower operating voltages
less heat
lower output power and lighter iron
more compact designs/chassis
extremely rugged
high reliability
nearly roadie-proof; some were made for missile use, some were even designed to survive being shot out of a cannon, the remainder seem to be, at the very least, rated for industrial use.
they're cool lookin'!
+ they also make great pedals without the need for the 200V+ to wake up 12A(x)7 types.
i got hooked on them when PRR jokingly (maybe not?) suggested i use one to drive a 125W RF pentode in SE configuration a-la champ layout. i chose the 6948 - rare tube, but makes great tone.
the down, aside from the tubes being rare, is that sockets are even more so rare - to circumvent, i use 8 pin DIP wire-wrap IC sockets that have milled-pins.
--DL
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Cool beans. Thanks!
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Very cool compilation. Making some sort of subminiature based preamp and/or teeny tiny power amp is on my todo list. I'm wondering if you have a key for the codes used with the pentodes?
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http://pacifictv.ca/socket.htm#submin (http://pacifictv.ca/socket.htm#submin)
odd sockets
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PBP - power beam pentode
SCO - sharp cut-off pentode
RCO - remote cut-off pentode
SRCO - semi-remote cut-off pentode.
RF - radio frequency
AF - audio frequency
--DL
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http://pacifictv.ca/socket.htm#submin (http://pacifictv.ca/socket.htm#submin)
odd sockets
appreciate the the link ray.
i have bought stuff from john - a very pleasant man. mostly i've bought compactrons and the last few chassis mount sub-mini sockets he had.
i found 20 or so on ebay last fall for about $3.50 each so i sprung for them - i'll probably end up using them in custom pedals and some for a mini princeton reverb.
--DL
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i use 8 pin DIP wire-wrap IC sockets that have milled-pins.
that's a darn good idea...
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smaller
lower operating voltages
less heat
lower output power and lighter iron
more compact designs/chassis
extremely rugged
high reliability
nearly roadie-proof; some were made for missile use, some were even designed to survive being shot out of a cannon, the remainder seem to be, at the very least, rated for industrial use.
they're cool lookin'!
+ they also make great pedals without the need for the 200V+ to wake up 12A(x)7 types.
i got hooked on them when PRR jokingly (maybe not?) suggested i use one to drive a 125W RF pentode in SE configuration a-la champ layout. i chose the 6948 - rare tube, but makes great tone.
the down, aside from the tubes being rare, is that sockets are even more so rare - to circumvent, i use 8 pin DIP wire-wrap IC sockets that have milled-pins.
--DL
+1 DL. Thanks for the compilation. There are several SE and P-P schemo floating around the web if you don't want to start from scratch; Google '5902 tube' for starters. Easy enough to build a JTM"4.5" that sounds quite a bit bigger than it looks. Regards
dennis
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thanks zendragon & will do.
--DL