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Gibson G105 Help

Started by intocarsoncity, July 22, 2010, 05:21:38 PM

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intocarsoncity

hey everyone new to these forums, looking for some tips.  i found a gibson g105 2x12 at a local pawn shop thats in great condition and sounds fantastic, but its missing the reverb tank.  the RCA hookups are just dangling, i touched them, they buzzed, they seem to be working ok.  i was wondering if anyone could tell me what sort of spring reverb tank would work, wondering if its worth picking up....i need a decent solid state amp to replace my wonderful but road weary music man 4x10...i found the schematic, but i'm not very tech savvy and it didnt give me much insight into how easy/difficult putting a new tank would be, or what sort i would need, or if thats even a good idea.  ive attached the schematic.  any and all responses would be appreciated!

DJPhil

Greetings,

Sounds like a good find! There's a bit better schematic here, the one you posted is a bit blurry. The schematic lists the tank as a model 4FB2A1A. You should be able to use that part number to find an exact replacement ([urlhttp://cgi.ebay.com/PAIR-ACCUTRONICS-REVERBERATION-REVERB-TANK-FENDER-/350375068243]ebay is one option[/url]). To install it all you should need to do is bolt it on, plug it in, and try it out. The tank itself is basically a microphone and a speaker glued to each end of a spring, so all the electronics are in the chassis. There's no other adjustments necessary that I'm aware of, though you might wait to get a second opinion from one of the pros just to be sure.

Hope that helps. :)

intocarsoncity

#2
thanks!  i was also wondering if there are any currently manufactured tanks that would work?  should i not be able to locate the exact replacement...like the current accutronics type 4, type 8, type 9 tanks you can get on ebay?

J M Fahey

Hi.
Nice find !!
I bet it must be LOUD too.
Of course, forget about that puny "harmonic multiplier", just stick a good pedal in front of it.
The power amp owes something to Randalls (cough cough) of that era; absolutely loved the Phaser.
The tank suggested,
Quotemodel 4FB2A1A
*is* a "Type4" ; just get into Accutronics (or Google accutronics reverb tank) to learn what the other letters mean.
Besides the "4", you must also match the letters that indicate impedance and connector wiring, the others indicating more or less damping, etc. are not that critical.
Post some pictures.

phatt

Hi,
    Agree with JMF,, You folks need to get out more it's called Google. :lmao:

It's a HiZ Tank.

For Accutronics Tank *4FB2A1A*
Drive Z = 1.5k
PU Z = 2.2k

If you get a DC reading of around 200 Ohms with a DMM then you are close enough.
(likely a similar DC reading from both transducers)

Any Tank close to that will work just fine.
Be aware that some of these rev circuits are nothing special.

Here is how to to make a REAL Reverb circuit.
http://sound.westhost.com/articles/reverb.htm

I think I'm actually partly the reason for this Page as I kept hassling Rod Elliot for more DRIVE as most circuits are gutless at the drive ability.

Rod was a great help to me in my endless struggle to build a decent Reverb circuit.
Have fun, Phil.

Jack1962

you can find a replacement tank for it at Antique Electronic Supply : http://www.tubesandmore.com

                                               Rock On

teemuk

QuoteBe aware that some of these rev circuits are nothing special.
Yeah, with many old amps it can be hit or miss, but if the reverb is anything like in this G-70 amp I'd be hesitant to alter the circuit without trying out the original one first.
http://www.youtube.com/watch?v=t5gtYKN2DBA