Silvertone 1448 Amp Case & Guitar Find

[plexi50]

Picked a up a 1448 with guitar amp and case. I looked at the schematic to confirm the tube compliment and found that i have a 12AB6 in the preamp vs a 12AU6 which the schematic calls for.

I can find little to no data on the 12AB6. Do not see it as a sub either. Volume is less than i was expecting. Could the 12AB6 be the wrong tube period for the 1448. Franks tube data does not have a listing for a 12AB6 tube. I am reading the tube correctly/

The 12AU6 tube though does have 2 other subs. 6AU6-A & 3AU6

[sluckey]

Here's a little info on the 12AB6...

     http://www.radiomuseum.org/tubes/tube_12ab6.html

But since the schematic calls for 12AU6 why not use the correct tube?

[plexi50]

Here's a little info on the 12AB6...

     http://www.radiomuseum.org/tubes/tube_12ab6.html

But since the schematic calls for 12AU6 why not use the correct tube?

It was in the amp when i got it this morning. I think i may have one laying around. I just was wondering why the 12AB6 was in there in the first place. Let me go digging/

[sluckey]

The 12AB6 is pin compatible with the 12AU6, so maybe they are interchangeable. I don't know. Actually, I've never heard of a 12AB6 (don't mean much  ), but 12AU6 was very common back in the '60s.

[plexi50]

The 12AB6 is pin compatible with the 12AU6, so maybe they are interchangeable. I don't know. Actually, I've never heard of a 12AB6 (don't mean much  ), but 12AU6 was very common back in the '60s.

I know i have seen one years ago in a box. Which box? Oh boy.

[sluckey]

12AU6 was used in most all of those cheap, cheap amps that used series filaments. Think Kay, Harmony, Silvertone, etc.

[plexi50]

12AU6 was used in most all of those cheap, cheap amps that used series filaments. Think Kay, Harmony, Silvertone, etc.

I found more (12BA6 Edit) 12AB6 tubes. No luck finding a 12AU6 so far. I know there's one here some where.

[sluckey]

Hey! You switched tube types! We've been talking about 12AB6 up until your last post. Now you're talking about 12BA6.

Will the real tube please stand up?

[plexi50]

Hey! You switched tube types! We've been talking about 12AB6 up until your last post. Now you're talking about 12BA6.

Will the real tube please stand up?

I edited my previous post of 12BA6. My night error. Found more 12AB6 tubes. No 12AU6 to be found. 

[sluckey]

AES has them. Cheap.

[plexi50]

AES has them. Cheap.

 I ordered one NOS RCA 12AU6. $3.50.  I wish there was some data on the 12AB6 tube. I wanted to see what the gain factor was in relation to the 12AU6. The volume is not super low after more hearing of the amp. It is after all a 6" speaker i believe.

[PRR]

It's a CHEAP amp. It is remotely possible the Silvertone factory got a lot of AB tubes at low-low price and didn't care as long as it "worked".

Look for circuit variance. I would wonder if the G2 resistor had to be changed for the different tube (a fair sign this was a factory job). OTOH maybe some TV repairman thought the AB was close-enough (or mis-boxed), and since it played better with an OK AB than with a dead AU, he got paid, everybody happy.

[plexi50]

It's a CHEAP amp. It is remotely possible the Silvertone factory got a lot of AB tubes at low-low price and didn't care as long as it "worked".

Look for circuit variance. I would wonder if the G2 resistor had to be changed for the different tube (a fair sign this was a factory job). OTOH maybe some TV repairman thought the AB was close-enough (or mis-boxed), and since it played better with an OK AB than with a dead AU, he got paid, everybody happy.

Now that's a cool way to look at it. I will check the V1 socket for any resistor variations.

[uki]

Cool stuff man !!

[plexi50]

Cool stuff man !!

I have never owned one before. Like the Silvertone Bobcat the short scales can be fun to play. It came up on CL and it was raining so hard here today that i almost didn't bother to go look at it. But the price was so low (i wont say) that i did not think it was a real legit sale. I took my time and finally split out of the house and only had to drive 1 mile to it. Dam frets and rosewood board is like new. There are not as many finds like this anymore on a consistent basis so when i do see guitars and amps at low prices generally i dismiss them as people collecting email address's and phone numbers for scammers and spam city. It turned out to be a very good day after all! 

[plexi50]

The amp is much louder and better defined with the NOS RCA 12AU6 i received today. Also recapped the PS. I work backwards Steve