[Harp-L] Re: Fender Twin '57

[Dina Janzen <dlj@xxxxxx>]

Nitpicking perhaps, but.....

The RI  57 Twin is based on a 5E8A, not a 5F8 which has four 6L6 tubes.
It uses two 5AR4 rectos, not  5Y3.  One 5AR4 can be pulled for more sag.
A lower gain phase inverter tube will reduce the gain.   The phase 
inverter is a split load inverter that uses one of the two triodes in a 
12AX7.  The other triode functions in a gain stage.
Several list members have have been quite pleased with 5E8A clones.   
The 5E8A is quite similar to the 5E7 Bandmaster, 5E5A Pro and 5F4 
Super.  The basic  circuit design is quite harp-friendly and can be 
powered up with 6L6's, big trannies and big speakers or powered down to 
run 6V6 tubes at 5E3 volumes.

Jim R


On Feb 7, 2005, at 5:22 PM, harp-l-request@xxxxxxxxxx wrote:

> Message: 3
> Date: Mon, 7 Feb 2005 16:14:56 -0200
> From: Matthew Prouty <matthewprouty@xxxxxxxxx>
> Subject: [Harp-L] Re: Fender Twin '57
> To: harp-l@xxxxxxxxxx
> Message-ID: <e8b59240502071014fa475fb@xxxxxxxxxxxxxx>
> Content-Type: text/plain; charset=US-ASCII
>
> The Fender Twin '57 is the model 5F8.  I use a 5D8 which has its
> inputs modified to the 5F8 spec.  This amp is the one that B.B. King
> and Eric Clapton love.  I know BB uses a Black Face most of the time,
> but Eric loves this one.
>
> Its lay is, if it have four inputs.  V1 inputs 1 and 2.  V2 inputs 3
> and 4.  Then these two tubes feed individually a cathode follower V3
> that drives the tone stack.  Any of these tubes can be changed out for
> tubes with less gain.  The last pre amp tube is the V4 phase inverter.
>  The 5F8 has a grounded cathode on the output tubes, if I remember
> correctly.  This gives it a bit more power than the cathode bypassed
> 5D8 which rates at 25 watts.  The phase inverter is calculated to be a
> 12AX7 and should not be changed.  It has little effect on the amplifed
> signal so changing it will not help alter tone or eliminate feedback.
>
> This model, might have two 5Y3GT rectifiers.  You can pull one to get
> a browner, saggy sound, but becareful the 5Y3GT arcs under heavy load
> and you can burn one up fast.  This amp has a sweet tone that is
> comparable to none other.  It is slightly cleaner than most tweeds due
> to the dual rectifier set up, but it has a lot of warmth.  It is a
> push  pull class AB1 or 2, who really knows?  With 6L6 output tubes.
> Great amp and I think the reissue is point to point wired.