gibson falcon ga-19rvt

[DummyLoad]

anyone want to build one? looks like 1/2 of V3 is not used. maybe another switched gain stage?  use 6AN8 in place of 7199?


http://el34world.com/charts/Schematics/files/gibson/Gibson_GA-19RVT.pdf



it is a cool sounding little combo amp.


1964 Gibson GA-19 RVT Falcon amp


skip to 1:30

Gibson Falcon GA-19RVT Screen-Tested At RaxTrax Recording


forgive the tele...
1963 Gibson Falcon Tremelo!!!!


Gibson GA-19RVT Falcon amp demo


-pete

[TIMBO]

Hey DL, The old amps really have a COOL sound.

[Fresh_Start]

Interesting reverb circuit. Two triodes in series driving it and a pentode recovery stage. That drawing had me confused for a while but I think it makes sense now.

Cheers,
Chip

[chocopower]

All those videos you post are for that schematic:

http://i142.photobucket.com/albums/r106/capnjuan/gibson%20falcon/GibsonGA19MaestroM216.jpg


the schematic you post is for the previous version.

[DummyLoad]

link does not work.


--pete

[DummyLoad]

The '61 tweed GA-19RVT and '62-'63 brown Crestline version are the same electronically (these are the 6C4 versions).

The later '64-'65s are the 7199 versions (easily ID'd by the knobs and black tolex)...

And FWIW - the Maestro M-216 is the same as the '61-'63 Falcons, just came with a Jensen C-15-N.

i posted the correct schematic. 

--pete

[chocopower]

link does not work.


--pete

Sorry


Fixed.

[kagliostro]

Which Tube can be used instead of the 6EU7 ? (it is an expensive tube)

The spech of the tube say same gain factor (100) but dufferent plate resistance and transconductance

so the two triodes are similar but not exactly the same, it will be interesting to know the correct pinout

on the circuit, but the schematic didn't report it

Is this difference very important for the final result ?

Thanks

Franco

[DummyLoad]

Which Tube can be used instead of the 6EU7 ? (it is an expensive tube)

The spech of the tube say same gain factor (100) but dufferent plate resistance and transconductance

so the two triodes are similar but not exactly the same, it will be interesting to know the correct pinout

on the circuit, but the schematic didn't report it

Is this difference very important for the final result ?

Thanks

Franco

the 6EU7 is a 12AX7A with a different pin-out and no filament CT. pin 3 is open. please read datasheets from same manufacturer.   
both triodes are identical. you are reading a set of conditions at 100V B+ and another set of conditions at 250V B+: both of those conditions are the same for either triode. 

http://tubedata.milbert.com/sheets/093/6/6EU7.pdf

http://tubedata.milbert.com/sheets/093/1/12AX7A.pdf

pin orientation is dictated by layout. i doubt that it matters much. i can't find any pictures of of the internals of high enough quality to reverse engineer. if you find any, please post links. 

the 6EU7 was introduced by RCA in the late 50's to facilitate cleaner layouts for audio circuits. RCA marketing engine...  notice that pinning is clockwise from the bottom, K-G-A and A-G-K. 

on the other hand there is one for sale close by...

http://austin.craigslist.org/msg/4691049881.html 

this one looks like a 1961-1963 model - in one of the pics, it looks like there is a 7 pin tube (third in from the right): that would be the 6C4 (6C4 is 1/2 12AU7) reverb tank driver. the one i want is the 64-67 model that has the 7199 reverb driver and recovery. i may give the guy a call, but i'd really rather have the later model or replicate it with modern and higher quality parts.

--pete

[kagliostro]

Many thanks Pete

if I find photo I'll post it for sure

Franco

[kagliostro]

Here is what I've found












Franco

[DummyLoad]

chocopower is correct. the 6C4 version is all the black and brown amp. the 7199 are the original tweed amps.

don't believe everything you read. thanks for setting me straight. 

found a sound clip of the tweed version.

https://www.youtube.com/watch?v=RyG9lojGSNQ

thank you for the pics franco!    

--pete


 

[TIMBO]

THAT IS GREAT, got a bit of GROWL about it

[DummyLoad]

it does have some nice tone.   


--pete

[chocopower]

I found that time ago. Everything is explained here.


http://letstalkguild.com/ltg/showthread.php?153711-Gibson-GA19RVT-Tweed-v-Crest-compare-contrast&highlight=ga19rvt

[mmaguire9]

Hello all;

I recently repaired this amp. Except for the tube socket I replaced and the 3 prong cord, it is 99.9% stock.
It was 100% stock when it came in.
When play testing for an evening, I was blown away by the tone and the lush different from Fender reverb.
Definitely going to build me one. 12AX7s and a 6U8 for the 7199.
Reverb tank readily available but the reverb transformer only from Mercury Magnetics. I hate paying 200% for MM magic dust so if anyone else knows of a replacement reverb transformer, let us know.
I dated this amp 1961 but it was advertised as a 1962. Could be but I'm sure it was a '61 which would make it first year. Very nice sound.