Re: Fender 40W Blues Deluxe Amp Opinion

[Russ Bradley <wbradley@xxxxxxxxxx>]

Are these pretty standard mods to a harp amp for reducing feedback?
Are these mods recommended for any harp amp?
This looks similar to some recommended mods by Gerald Weber I found on 
the web.


Markburness@xxxxxxx wrote:

>Hi Larry,
>
>This can be a good harp amp and plenty loud. With all the bells and whistles 
>turned down/off it is basically a bassman style circuit with an extra stage 
>of gain. The 12" speaker breaks up pretty good. These amps are great value 
>for money, pity they're not as light as you might imagine.
>
>The one I looked at had very poor fidelity due to greatly mismatched 5881's 
>(17 & 28mA). I put in a matched set, dropped the bias current to 15mA, 
>dropped preamp voltage and increased to input load resistor to 5.6Meg and the 
>result is a very useable harp amp. Next time I get hold of it I intend to 
>bump up the cathode bypass cap value on V1 and add a  bypass cap to V2 
>(100uf?).
>All these things could be done by a tech very cheaply.
>
>A 12AY is an option for V1 but I wouldn't sub out either of the 2 preamp 
>tubes nearer the power tubes. I liked it best with a ceramic Astatic, a very 
>high gain mic may be too harsh without further mods.
>
>Regards, Mark.
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>