Re: [Harp-L] Amp Mods

[Boogieman Peeps <boogiemanpeeps@xxxxxxxxx>]

Keep the 12AX7 for the reverb.  Start off with a 12AY7 in the first stage
and see what you get.  12AY7 in the other preamp positions is probably
going to get you where you want, but use as few as you can to get there.



On Sat, Jun 22, 2013 at 8:34 AM, MARK BURNESS
<markwjburness@xxxxxxxxxxxxxx>wrote:

> Hi Robert,
>
> Can you scan the schematic and post a link to a hosting site?
>
> If it's anything like the G40V it would probably do with a few internal
> component changes. The G40V aimed to keep the preamp signal a little
> cleaner than a lot of other amps because of the additional gain stage.
>
> In the short term, I'd try a 12AU7 in V1 maybe an 12AY7/12AT7 in V2?
>
>
>
> I wouldn't worry too much about avoiding the Chinese tubes, getting the
> right balance in tone & response with the preamp valves will depend more on
> the gain structure, rather than where those tubes were made. Buy whatever
> you can afford/gives you best peace of mind, but no 12AX7 from anywhere
> will have the same gain as a 12AU7 from China. I wouldn't worry too much
> about changing the power tubes unles you can rebias the amp/get it rebiased
> easily locally...bias will be more relevant than tube brand.
>
>
> ________________________________
> From: Robert <harmonicaman1968@xxxxxxxxxxx>
> To: harp-l@xxxxxxxxxx
> Sent: Friday, 21 June 2013, 22:51
> Subject: [Harp-L] Amp Mods
>
>
> I'm wondering if anyone here has ever done any mods on a Pignose G60VR.
> It's a 60W tube amp using 2 - 6L6's in the final amp stage and 4 12AX7's
> before that. One of the 12AX7's is for the spring reverb. I'm not sure what
> each of the other 3 do, besides pre-amp stuff, but I do have a schematic,
> and can understand it to some extent.
>
> Eventually, I want to swap out some of the original Chinese parts, like
> the tubes and the speaker.
>
> It's got a high-low switch that cuts out half of the first pre-amp tube on
> low, and jacks for an effects loop. 4 and 8 ohm outputs for different
> speaker combos. One twelve inch speaker in the box.
>
> I'm not up on which tubes would be most advisable, or which speaker. It's
> a very clean amp, not much breakup as designed from the factory. For
> guitar, it's great. For harp, not as much, yet.
>