Re: [Harp-L] controlling amp feedback

["Splash" <celtiac@xxxxxxxxxxxxx>]

Try a 12AU7 in V1.  And keep the push/pull knob switches pushed in.
V3 is the effects and reverb drivers.  Not in the pre-amp circuit.

There's a manual here:
http://www.seymourduncan.com/images/84_40.pdf


PEACE
Scott
Believe in Magic!
----- Original Message -----
From: "John Kerkhoven" <solo_danswer@xxxxxxxxxxxx>
To: <harp-l@xxxxxxxxxx>
Sent: Friday, July 06, 2007 10:55 PM
Subject: [Harp-L] controlling amp feedback


> A question for the amp-savy listers.
>
> I just got my first serious amp, a second hand Seymour Duncan 84-40 tube
> amp. It's a guitar amp, not a harp amp. I got it at a good price, and at
low
> volume I can get some very sweet sounds on the distortion channel with
> reverb. Tried it loud in a small rehearsal space with drums, bass and
guitar
> and had to rely on the clean channel as I could not get the volume I
wanted
> without feedback on the dirty channel.
>
> Tubes: 3 12AX7s. According to http://www.harpamps.com/ampg/ampg4.html this
> is probably part of the problem. He says: "The more 12AX7 tubes, the more
> preamp stages. This is good for a guitar player, but bad for a harp
player.
> The feedback demon thrives in the preamp stages of an amp. One or two
12AX7
> tubes are enough. Three is the maximum."
>
> The other tubes are 4 EL-84s.
>
> Microphones I use: Madcat Shaker and an old SM58.
>
> I'm just starting to use this amp and I know a lot depends on the room and
> where you stand. I have not tried micing the amp yet and may try that in
due
> course. And I know that too much reverb can bring on the feedback.
>
> I have zero experience with tube amps. Should I swap some or all of the
> preamp tubes? Is this safe to do?
>
> Any other ideas?
>
> Thanks,
>
> John
> Montreal
>
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