[thomas]

Found a cheap old console on a curb, nothing special. But I'm having
trouble IDing the output tubes. There are two little 5 watt OTs, 10K
primary, 4 ohm secondary. Since I'm just about to move in a few weeks,
I don't want to open the thing up just yet to trace the wiring back
from the OTs. The two tubes closest to the OTs are a 6BE6 and a 6BA6.
Could those be the power amp tubes? I haven't found any other
candidates. There is one EL80, but nothing that matches it for the
other channel.

[thomas]

Bret Ludwig wrote:
thomas wrote:
Found a cheap old console on a curb, nothing special. But I'm having
trouble IDing the output tubes. There are two little 5 watt OTs, 10K
primary, 4 ohm secondary. Since I'm just about to move in a few weeks,
I don't want to open the thing up just yet to trace the wiring back
from the OTs. The two tubes closest to the OTs are a 6BE6 and a 6BA6.
Could those be the power amp tubes? I haven't found any other
candidates. There is one EL80, but nothing that matches it for the
other channel.

As you know from Mr. Tube Manual.....you DO have a Tube
Manual!!!!!.....the 6BA6 and 6BE6 are (in no particular order) an RF
amp and a pentagrid mixer/oscillator for the tuner. They nearly always
go together and were used in most serious radios.

Thanks. I am moving. My books are packed and my knowledge of this stuff
is rudimentary at best. Given that this is a stereo receiver, with two
OTs, I expected to find two matching output tubes, but no such luck.
There are two metal boxes on the chassis, each with a tube barely
protruding, but I presume those are more radio parts.

The only two identical tubes are 12AX7s, which are widely spaced apart
on the chassis, and I doubt they would be used as power amp tubes
anyway.

BTW, I have an old Silvertone guitar amp that uses a little 6BE6 as the
preamp tube driving a 6V6. The tone is rather vanilla right now, but I
have yet to restore it.

[robert casey]

thomas wrote:

Found a cheap old console on a curb, nothing special. But I'm having
trouble IDing the output tubes. There are two little 5 watt OTs, 10K
primary, 4 ohm secondary. Since I'm just about to move in a few weeks,
I don't want to open the thing up just yet to trace the wiring back
from the OTs. The two tubes closest to the OTs are a 6BE6 and a 6BA6.
Could those be the power amp tubes?

Those are tubes usually used in radio receiver circuits. Maybe someone
stuck them in random sockets. Neither of those tubes would be able to
do audio output duty. Something like a 6AQ5 might be the kind of tube
for audio amps. That's a 7 pin tube.

[Tom Bavis]

On 18 Dec 2006 08:50:08 -0800, "thomas" wrote:

Found a cheap old console on a curb, nothing special. But I'm having
trouble IDing the output tubes. There are two little 5 watt OTs, 10K
primary, 4 ohm secondary. Since I'm just about to move in a few weeks,
I don't want to open the thing up just yet to trace the wiring back
from the OTs. The two tubes closest to the OTs are a 6BE6 and a 6BA6.
Could those be the power amp tubes? I haven't found any other
candidates. There is one EL80, but nothing that matches it for the
other channel.

I once saw a Bradford (W. T. Grant) stereo console that used a single
ELL80 for the two output channels. That's a dual power pentode,
essentially two EL95s in one bottle.

[thomas]

Tom Bavis wrote:
On 18 Dec 2006 08:50:08 -0800, "thomas" wrote:

Found a cheap old console on a curb, nothing special. But I'm having
trouble IDing the output tubes. There are two little 5 watt OTs, 10K
primary, 4 ohm secondary. Since I'm just about to move in a few weeks,
I don't want to open the thing up just yet to trace the wiring back
from the OTs. The two tubes closest to the OTs are a 6BE6 and a 6BA6.
Could those be the power amp tubes? I haven't found any other
candidates. There is one EL80, but nothing that matches it for the
other channel.

I once saw a Bradford (W. T. Grant) stereo console that used a single
ELL80 for the two output channels. That's a dual power pentode,
essentially two EL95s in one bottle.

Thanks, that must be the answer. The tube's ID is too worn off the
glass to say for sure, but it does appear to have a symmetrical
structure inside, consistent with two equivalent sections, one on each
side. I got so curious that I was going to take the chassis apart and
trace the wiring back to the OTs, but the darn thing requires a flat
head screwdriver to disassemble, which are all packed away in my
obsolete toolbox.

Tubestore.com wants $50 for a NOS ELL80. Is there really a market for
this bottle? I doubt I'll use it for anything. I'll probably strip this
receiver all the way back, and use the chassis, the PT, and one of the
OTs to make a low-power guitar amp. If anyone wants to trade me for the
ELL80 let me know.

It was an experience picking this thing off the curb. I am a gentrifier
on a nice block of 1920s Craftsman houses that are situated in a
working class minority neighborhood (ghetto, slum, whatever). The
console's former owner came out to chat me up as I was removing the amp
from the console. I think he was bemused to see a middle class white
man picking through his garbage. I know him a little bit. Like about
50% of the poor people who live down here, he's got a job, owns his
house, takes care of his kids and animals, and is a decent guy. It
burns me up when politicians and libertarians demonize the poor. Some
of them fit the negative stereotypes, but most don't.