Help with AOR 100 mod

[capncrunch]

The saga continues...lol! I realised today the amp sounds great-but only when Im using the FX loop! Its still pretty fizzy otherwise. Im wondering should I mod the amp to sound good without the FX loop being used? And if I do will it sound too dark when I use the loop? FWIW I always have my pedalboard plugged into the loop. Thoughts? Bob

Mine does that too. I think thats because the loop is a poor design that it accidentally adds some resistance that rolls off some top end. I put a passive loop in a 2204 and it does the same thing to it. Kind of improves the lower volume tone a bit. Incidentally there is a mod for the 2204/03 where you install a 100K or larger resistor between the volume pot and the PI to knock down some buzzy high end. I wonder if that would work on an AOR?

Oh, and BTW, does anyone know how to tighten up the lows in the AOR amps? My AOR sounds great on the upper strings but, the E and A strings really get muddy.

Thanks

[rockon1]

Mine does that too. I think thats because the loop is a poor design that it accidentally adds some resistance that rolls off some top end. I put a passive loop in a 2204 and it does the same thing to it. Kind of improves the lower volume tone a bit. Incidentally there is a mod for the 2204/03 where you install a 100K or larger resistor between the volume pot and the PI to knock down some buzzy high end. I wonder if that would work on an AOR?

Oh, and BTW, does anyone know how to tighten up the lows in the AOR amps? My AOR sounds great on the upper strings but, the E and A strings really get muddy.

Thanks

Ive come to realise its an amp that just sounds "right" when its loud whether theres something in the loop or not. at lower volumes something in the loop definately helps cut the high fizz. The bass response on mine seems good-just dont engage the boost at lower master volumes or the windows will blow out! Ive never heard an amp capable of so much bass!
Ive developed a problem with mine though. For the first minute or two after I turn it on the volume is full on with no response from the MV. After that it works fine. Im wondering if its just a bad pot or something else. Bob

[capncrunch]

Rockon1: Yeah, I don't know a lot about amps and stuff but, that does sound as though you've got a bad pot.

I can't play with the volume very high in my band. Probably the wrong amp for me.
I'm going to try to run an EQ in the loop at lower volume levels with the bass boost off to see if I can dial in a more definitive low end. Seems like with the boost off there is now lowend at all and with the bass boost on it gets too muddy and undefined.

[rockon1]

Rockon1: Yeah, I don't know a lot about amps and stuff but, that does sound as though you've got a bad pot.

I can't play with the volume very high in my band. Probably the wrong amp for me.
I'm going to try to run an EQ in the loop at lower volume levels with the bass boost off to see if I can dial in a more definitive low end. Seems like with the boost off there is now lowend at all and with the bass boost on it gets too muddy and undefined.

It really depends how you use the amp. Its a bit tricky. If you dont use the AOR channel then yeah you cant pull the bass boost out(unless you turn it up). If your using the AOR channel then you can turn down the pre volume 1 and turn up the master to 4-5 and the bass boost isnt as extreme. Of coarse you will have a tough time balancing the volumes between channels like this. An attenuator cutting just a few db's off would be great.FWIW- The amp kicks a** with the AOR off and both pre gains up and all the (TMB)boosts on. Of coarse you need to push the volume to at least 5 on the master or its too bassy. Im going to borrow a friends THD hotplate to mess with it with. Bob

[CRU JONES]

The AOR looks alot like the Ampeg VTL50/100 series of amps designed by Lee Jackson(!). I have a buddy with the vtl50 and it is very kickass! You should check those schematics out for some comparisons.

Also, Matt's idea with grid stoppers is a very good one. try bigger values than 68k, 220k, 330k, or even 470k. The grid stoppers create a RC rolloff with the interelectrode capacitances. They will kill the fuzzyness bigtime.

[rockon1]

The AOR looks alot like the Ampeg VTL50/100 series of amps designed by Lee Jackson(!). I have a buddy with the vtl50 and it is very kickass! You should check those schematics out for some comparisons.

Also, Matt's idea with grid stoppers is a very good one. try bigger values than 68k, 220k, 330k, or even 470k. The grid stoppers create a RC rolloff with the interelectrode capacitances. They will kill the fuzzyness bigtime.

In the end I used a 470k input grid stopper resistor. Works well. Bob