Gemini Ampeg amps

["James D Rossen and Dina Janzen" <dlj@xxxxxx>]

Excellent price for a Gemini in decent shape. 

Probably mid 60's

Potential for great harp tone is probably high.

The amp needs some servicing play its best- should have the power supply filter
capacitors replaced, tubes tested on a tester, and grounded line cord installed.
At a minimum, the cord should be installed for safety. I believe that this amp
uses a multisection can capacitor that sticks down from the chassis like a tube
prehaps a 4/20/20.  These are now available for about $30 and are a better
solution than using individual caps.  The exact cap values need not be
duplicated with the replacement.

Tube replacement may not be needed.  7591 were previously rare and expensive but
are now being made and are about $40 a set.  Get a spare set now if you keep the
amp.

The "wax' transformer is probably the a paper interleaved output transformer,
perhaps original.  Do not replace it unless it is bad, and in this case retain
the old transformer.

The reverb and tremolo in these old Ampegs are sweet.   The reverb might be
improved for harp by getting a short delay tank. These are available direct from
Acutronics for about $40 shipped.

12AU/Y7 tube subs should be fine.  It appears that the 12AX7 closest to the 7199
is the first stage for the reverb channel and the next one over is first stage
for the normal channel if the schematic below is correct.  These would be the
best ones to start with for tube subs.

The unofficial Ampeg web page has a schematic of a similar amp-

http://users.aol.com/bluemuse/ampegmain.html
http://members.aol.com/portaflex/schems/g12.gif

Contact me if you want to unload it......

Jim


- ----------
>From: owner-harp-l-digest@xxxxxxxxxx (harp-l-digest)
>To: harp-l-digest@xxxxxxxxxx
>Subject: harp-l-digest V10 #59
>Date: Sat, Jan 18, 2003, 1:34 PM
>

> Date: Sat, 18 Jan 2003 14:23:33 EST
> From: Cljdm@xxxxxxx
> Subject: Gemini Ampeg amps
>
> - --part1_13.16bc562f.2b5b03b5_boundary
> Content-Type: text/plain; charset="US-ASCII"
> Content-Transfer-Encoding: 7bit
>
> Hi,
>
>     I just Bought a Gemini 1 Ampeg amp, Model G12. Appreciate any information
> from anyone owning one. Harp sounds great through it. It looks to be about 40
> years old. Picked it up for $175 (good buy?).The amp plays well looks decent.
> Has a 12" speaker that seems not to be the original (no identification
> marks). Two channels. One works the bass, treble, vibrato/intensity/speed and
> the echo. Two is just volume,bass, and treble. There are two plugs for each
> channel. One for guitar and one for the accordian on each channel (four
> inputs). I really like the accordian plugs.
>
>      What year is this amp approximately from? And, can I  change the 12ax7
> tubes with au's or ay's?
>     The tubes left to right are:
>    7591 7591 7199 12ax7 12ax7 6cg7 12ax7
>    Should I go for a whole new set of tubes? Also, the amp has a wax
> tranformer. Should I just leave it alone?
>
>   I am hoping to get this amp singing real nice, since it seems to have the
> capacity to be a great harp amp. Any information or help would be greatly
> appreciated.
>
>                                     Best of everything,
>                                                 chris