Date This Amp!

[plexi50]

I just worked on a Gibson Skylark GA5T amp. Tube compliments is a 5Y3-12AX7- and the power tube is unknown. Looks like a 7199 / /6BQ5 but not sure. Not a 6V6 tube as i have seen on some GA5T model schematics. I can find nothing online that come close to this GA5T faceplate. The speaker code is 285416. Rola 6th week of 1941. I looked at the pots but no numbers stamped on the back. There are number on the side but they are so small i can not see them very well even with a magnifying glass. The wire is not cloth. I have seen amps that used the PVC wire in the early 60's but this cab and chassis looks much older. Brown bakelite chicken knobs

Have you seen this model Gibson Skylark and do you know the year it was made?

[FYL]

I'd say a ca. 1961 GA-5T with a replaced speaker. Tube complement should be 12AX7, 6BM8, 5Y3GT. A similar version was sold as the GA-1RT Maestro reverb unit.

[plexi50]

Thanks FYL. I told the owner that the speaker probably was replaced long ago. It had a Craftsman two prong power cord on it from the 60's that has those fine lines on it. I tell ya it sounded like a dam 6V6 tube though with nice breakup.

[VMS]

Hi,

here's few links that might be useful:

http://www.angelfire.com/blues/rockinjohn/skylark_ga_5.html

http://www.0rigami.com/gg/amps.html

http://www.chambonino.com/work/work7.html


VMS

[eleventeen]

couple of questions: (I have NEVER worked on nor seen the insides of a little Gibson tweed amp of that era)

That fuseholder is stock? Doubt it!

Was the amplifier originally built on a tag board as pictured?

[FYL]

That fuseholder is stock? Doubt it!

The square fuse assy is typical of late '60s/early '70s. All the gibbies I've seen used round fuseholders.

Was the amplifier originally built on a tag board as pictured?

The original was a messy point to point build.

[eleventeen]

Thanks, FYL. From the tag-board and the Blue Sprague cap, this looks like it could be a near-total gut job, with essentailly NO (original) internal date-coded parts remaining. 'Cept maybe that brown electro next to the blue Sprague? Or the trannies.

[plexi50]

I found the site i was looking for. 1957-61 if i am reading this right
http://www.angelfire.com/blues/rockinjohn/skylark_ga_5.html

[rafe]

I have one 106xxx so it's earlier " tag board looks stock" .....I replaced some of the caps on mine ...yours looks dead stock the fuse holder on mine is round screw on so I don't know if that was replaced on yours ....yours is stock other than blue sprague or close inside   .....Tremolo work? yours is most likely 61
It's one of my favorite amps......

[supro66]

I don’t think the clock and soldering iron looks good on the face plate

I see it was a quarter to twelve lunch break?????? 

That is why I like tube amps

No mystery just trace the road map and fix it

Like the old cars I worked in the 60’s

Everything was the same

NO COMPUTERS BACK THEN

[plexi50]

rafe that 6BM8 tube sure breaks up nicely. I could almost swear it is a 6V6 in a blind test. The clock came with the amp but it has faded over time. I didnt notice that until you pointed it out 
It is almost impossible to take pics with a shiny face panel like that. With my camera anyway

[FYL]

rafe that 6BM8 tube sure breaks up nicely.

The 6BM8/ECL82 is quite close to a 6AQ5 + 1/2 12AT7. Nice small bottle.

It is almost impossible to take pics with a shiny face panel like that. With my camera anyway

You need a light box, and even then the results will be very variable.

[softwarejanitor]

The speaker code is 285416. Rola 6th week of 1941.

I'm not so sure about that...  my guess on the code would be Rola 16th week of 1954.  Usually if those date codes are 3 digits they only have a 1 digit year code and you have to make an educated guess at the decade.  The Jensen Special Design sticker is interesting.  Possibly the original speaker was the Jensen and whoever replaced the speaker peeled and re-stuck the label.

[sluckey]

A speaker made in 1941 would probably be a field coil speaker rather than a PM speaker. You missed the code conversion. Code 285416 converts to Rola, 16^th week of '54 or '64. See below...

http://www.webervst.com/codes.html

or this pic...

[plexi50]

Your right Steve. I have been doing all kinds of backward thinking latley. Ever take the band off the Bologna and throw the Bologna away and you find yourself standing there with the red band in your hand?

[sluckey]

Yes! But I beat the dog to it. Came in under the 5 second rule too! 

[plexi50]

Man you must have been starving. Dogs pretty quick!