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Post subject: Amp Sqealing
Posted: Tue Aug 09, 2011 12:50 pm
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I just bought a Hotrod Deluxe III. I notice the amp sqeals on the drive and more drive channels when turned up past a moderate level. I replaced both preamp 1 and 2 with a Tuglnsol and JAN Phillips 5751 respectively and still get the sqealing. The tone is nicer and the sqealing is less, but still there. Everything else works fine on the amp. Any ideas on what's causing the sqealing?

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Post subject: Re: Amp Sqealing
Posted: Tue Aug 09, 2011 12:53 pm
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V3

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Post subject: Re: Amp Sqealing
Posted: Tue Aug 09, 2011 12:55 pm
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shimmilou wrote:
V3

Really? Bad tube maybe or are you just kidding around? The V3 is a phase inverter section, right?

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'13 Standard Strat
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Post subject: Re: Amp Sqealing
Posted: Tue Aug 09, 2011 12:59 pm
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No, I'm serious. :) Correct, V3 is the pi and can be microphonic also, just like the other preamp tubes. The squealing could be output tubes or some other problem, but the most likely, and easiest to try, would be the pi since you already changed V1 and V2. :idea:

Of course, I presume that you aren't talking about the normal feedback that can occur if you stand too close to the amp at loud volume.

BTW, you can use any of the same 12AX7 type tubes in the preamp for the pi also, including 5751 or 12AT7, etc. So either of the stock tubes that you removed from V1 and V2 will work. You won't get much effect on the tone with different pi tubes, but a lower gain tube in the pi position can have a positive affect on distortion/headroom. :idea:

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


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Post subject: Re: Amp Sqealing
Posted: Tue Aug 09, 2011 6:22 pm
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It took me a while to find that one of my HRDeluxe preamp tubes had gone microphonic.
I kept assuming it was the hollowbody squeal until I did the pencil tap test in between sets.
If I may add to shimmilou's advice, buy AND bring back up tubes in your road cases.


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Post subject: Re: Amp Squealing
Posted: Tue Aug 09, 2011 7:45 pm
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shimmilou wrote:
No, I'm serious. :) Correct, V3 is the pi and can be microphonic also, just like the other preamp tubes. The squealing could be output tubes or some other problem, but the most likely, and easiest to try, would be the pi since you already changed V1 and V2. :idea:

Of course, I presume that you aren't talking about the normal feedback that can occur if you stand too close to the amp at loud volume.

BTW, you can use any of the same 12AX7 type tubes in the preamp for the pi also, including 5751 or 12AT7, etc. So either of the stock tubes that you removed from V1 and V2 will work. You won't get much effect on the tone with different pi tubes, but a lower gain tube in the pi position can have a positive affect on distortion/headroom. :idea:

Thanks for the info. Just when I thought I understood this amp... I switched a bunch of tubes all around to find the best compliment. The original PI tube got left out of the equation. I was running the Analog Delay through the effects loop and using the footswitch and drive channel. After yanking that and putting it in a chain with some other pedals I found some nice tones. THEN I yanked the footswitch out (a BadMonkey was basically duplicating the footswitch drive channel). Yanking the footswitch seemed to change the tone AGAIN!

...for the better IMO. Pretty cool amp all in all. It was between this and the Deluxe VM. I think I made a good decision. I still haven't used it in practice or a gig but I'm pretty sure it will cut it nicely. I was a little concerned about the squeal, but after moving the delay into the chain, swapping out the microphonic tube and yanking the footswitch it seems tamed.

Wow - I spelled "Squeal" wrong in the title. Oops! :mrgreen:

_________________
-Kirk

GUITARS
'12 Sonoran Acoustic - black (dated 10/31/12)
'13 Standard Strat
AMP
Vox ac4c1-bl
PEDALS
Compressor
Big Muff
Vox Stomplab 1G
Carbon Copy Delay


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Post subject: Re: Amp Sqealing
Posted: Tue Aug 09, 2011 8:44 pm
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vinscag wrote:
It took me a while to find that one of my HRDeluxe preamp tubes had gone microphonic.
I kept assuming it was the hollowbody squeal until I did the pencil tap test in between sets.
If I may add to shimmilou's advice, buy AND bring back up tubes in your road cases.


I forgot all about the pencil test. These Groove Tubes (Sovtek?) are not the prettiest tubes I've heard. I will eventually swap them all out and keep as backups.

_________________
-Kirk

GUITARS
'12 Sonoran Acoustic - black (dated 10/31/12)
'13 Standard Strat
AMP
Vox ac4c1-bl
PEDALS
Compressor
Big Muff
Vox Stomplab 1G
Carbon Copy Delay


Top
Profile
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