Bright Cap mods

Van_Muddlestein · Post by **Van_Muddlestein** » Mon Jan 21, 2013 12:13 pm

My Ampeg v50h is supposedly a NMV Plexi clone of sorts. I'm very curious about doing the bright cap mod to it. Someone clue me in on how to do that. Or walk me through it. I can't even find a schematic so if anyone could help me do that, too...anyone?
Thanks.

GuitarBilly · Post by **GuitarBilly** » Mon Jan 21, 2013 12:20 pm

hmmm.... it will be hard to tell without a schematic. On the Plexi Ri the bright cap is labelled C5 and it's a 4700pf capacitor. For the mod, you just clip one of the legs and you're good to go.

Now, with the Ampeg, even if it's a clone, I doubt the PCB layout/labeling is exactly the same.

100 watt · Post by **100 watt** » Mon Jan 21, 2013 12:24 pm

When you figure out out what cap it is, try using smaller value caps, before going without one. Some amps sound better with a bright cap just of a smaller value.

On my plexis, I have bright caps on BOTH channels.

If you have a place to put it, you can put the bright cap on a switch, to bring it in & out of the circuit. i had mine on a switch for a while on a hacked up JMP I had.

GuitarBilly · Post by **GuitarBilly** » Mon Jan 21, 2013 12:34 pm

100 watt wrote:When you figure out out what cap it is, try using smaller value caps, before going without one. Some amps sound better with a bright cap just of a smaller value.

On my plexis, I have bright caps on BOTH channels.

If you have a place to put it, you can put the bright cap on a switch, to bring it in & out of the circuit. i had mine on a switch for a while on a hacked up JMP I had.

Yes that is true. I had done the C12 mod on my DSL but ended up reversing it to stock. The amp lost punch without the cap. I will try different values eventually.

100 watt · Post by **100 watt** » Mon Jan 21, 2013 12:41 pm

guitarbilly74 wrote:
100 watt wrote:When you figure out out what cap it is, try using smaller value caps, before going without one. Some amps sound better with a bright cap just of a smaller value.

On my plexis, I have bright caps on BOTH channels.

If you have a place to put it, you can put the bright cap on a switch, to bring it in & out of the circuit. i had mine on a switch for a while on a hacked up JMP I had.

Yes that is true. I had done the C12 mod on my DSL but ended up reversing it to stock. The amp lost punch without the cap. I will try different values eventually.

I'll have to look, but theres a mod that uses a resistor in place of the bright cap, that some guys like to do on the plexi reissues. That may be something to look at that may work out well with your amp. I'll have to dig around over @ Metro amp & see what value it is.

I have a book I hade with a bunch of different Marshall mods Ive found & printed out. Hopefully before too long, I can get my stuff out of storage. Theres some stuff Ive saved that isnt online any more.

100 watt · Post by **100 watt** » Mon Jan 21, 2013 12:56 pm

here we go

http://www.thegearpage.net/board/showth ... p?t=439303

TurboPablo · Post by **TurboPablo** » Mon Jan 21, 2013 1:01 pm

I cliiped the bright cap on my JCM2204 and it made a hell of a difference. The amp always had a kind of "shrill" feel. Lifting the cap smoothed it out. I have a Traynor YBA-1 Bassmaster that I may do the same thing to. But first, it needs a trip to my tech for some love. Not that that will happen anytime soon. Since I bought the DSL, everything else is collecting dust.

I may just sell the Traynor.

100 watt · Post by **100 watt** » Mon Jan 21, 2013 1:08 pm

paul88lx wrote:I cliiped the bright cap on my JCM2204 and it made a hell of a difference. The amp always had a kind of "shrill" feel. Lifting the cap smoothed it out. I have a Traynor YBA-1 Bassmaster that I may do the same thing to. But first, it needs a trip to my tech for some love. Not that that will happen anytime soon. Since I bought the DSL, everything else is collecting dust.

I may just sell the Traynor.

IMHO, it's a "must do" thing, in a 50 watter. I dont know if its the less of headroom a 50 has ...compared to a 100, or if it's something else, but 50's always seem way brighter than 100's. I've always dropped the Slope resistors down a bit in my Broe's 50's abit to. That seems to thicken them up some. (along with playing with the NFB). Simple stuff that yeilds good results.

IMHO, "voicing" mods sound better than gain mods, in Marshalls. When you get to adding a bunch of gain, things can get nasty. Adding some "oomph" sounds better to me

Dave · Post by **Dave** » Mon Jan 21, 2013 1:09 pm

Billy VM, I couldn't find shit on the layout of your amp. Just trace the volume pot area to find a cap between two of the lugs on the volume pot.

Are the pots PCB mounted or flying leads?

Van_Muddlestein · Post by **Van_Muddlestein** » Mon Jan 21, 2013 1:43 pm

Chuck Nutz wrote:Billy VM, I couldn't find shit on the layout of your amp. Just trace the volume pot area to find a cap between two of the lugs on the volume pot.

Are the pots PCB mounted or flying leads?

I haven't even opened it up yet. That's going to happen tomorrow. I just was kind of putting a feeler out for getting ideas on what to do. I really like the way the amp sounds but it can get a bit harsh for my tastes and it has a large impact on the sound with pedals. :-?

100 watt · Post by **100 watt** » Mon Jan 21, 2013 1:57 pm

What pre amp tubes are in it? it may help to go with a lower gain tube

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