JCM 800 owners - did ya clip the bright cap?

[schwa]

I have an 80's 2204 that I'm loving these days. I have it in the shop to get some Seimens EL34's biased and a check up. (Seems to be working pretty good though.

I've read about clipping the bright cap, which seems to be almost "the appendix" in this amp. Cranked, it's pretty much out of the circuit, but at lower levels, some think it adds undesirable treble.

My tech though good, isn't much for advice when it comes to tone. He'll do a mod, but doesn't have an opinion on tone.

Can anyone share any before/after experience with a bright cap mod?

[jj jafar]

This will vary from person to person.I like the cap there,adds a nice bite on top of the strings.If you have a top endy guitar and/or speaker situation you may opt to remove it.Then again you can always turn down the treble knob a hair.Although the treble knob and cap are not exactly the same.Best bet is to clip one leg,play without it for awhile,solder it back on,play with it for awhile and then decide what you like better.
JJ

[stratburst]

It's subtle but noticeable. If you're pushing the amp with the Master around 7-8, the sweat spot on this amp IMO, then it's really not going to matter. Don't cut it, it's easy enough to de-solder it and leave in place out of the circuit. That way it can be easily be re-added into the circuit if you deside you don't like it. Awesome amp, enjoy!

[jj jafar]

Clipping one leg or desoldering it is basicly the same thing.Resoldering it will be be exactly the same,lol.Don't want to confuse him:D
JJ

[Rod]

I played those amps for many years and always clipped the bright cap...But I think most guitar amps have to much treble anyways...The bright cap works at low volume...at higher volume it has less effect...
The Soldano SLO I had I did the same thing to..later called the Warren Haynes mod...

[cisspcism]

I have an SLO 100 and clipped the cap but put it back. I think the cap is good for some added sizzle.

I think the problem with JCM800 amps isnt so much the bright cap but the huge upper nasal mids that are present that kind of cause the harshness.

I find I get better results by lower tha mids and the treb a tad. Lowering the mids really smooth out these amps and it doesnt sound scooped or anything.

[cram]

There are some mentions of this in several threads that can be found in this thread -
(as well as this one now!)
Mods Section:
JCM800 TGP Research (http://www.thegearpage.net/board/showthread.php?p=8064048)

FWIW - I would experiment with different speakers rather than mod the amp. In the last couple years I've really had my eyes opened to how different my amp sounds with a variety of speakers.

[Cleet Mongaire]

I have a '79 2204 and haven't felt the need to clip the cap. I play mostly p90 guitars though and don't use alot of gain and roll back on the treble both on the amp and the guitar. Sounds killer to me.

[Miracle Man]

Are we talking the 1n bright cap on the pot, or the 470pf treble peaker next to the jacks? I clipped both about two years ago, but last month I did some experementing using aligator clips. In the end I put the 470pf treble peaker back in. It adds that upper midrange and harmonics 800s are famous for and sound's dull without it. I still find the 1n bright cap on the pot too much though, but clipping it flattens the tone at lower gain settings, so I replaced it with a 330pf cap. Now it's nice and sparkly at lower gain settings, and gets fater when you turn the gain up.

So, IMHO, don't remove it! Spend an hour at the tech trying different value caps and go for the one you think sounds best. :beer

[Rex Nomad]

You could have your tech install a rotary switch with a couple different values -including no cap. Then you'll have the best of every thing. This can be done easily (if you only use one speaker cab you can use one of the speaker output jacks as a spot for the switch - so no extra holes) and is completely reversible.

I cut the bright cap on mine and did the above mod to my mids cap.

[Gnarlly]

I desoldered the cap on the preamp volume pot briefly, and ended up putting it back to stock; the amps sounded more alive to my ears with it in the circuit, even with the preamp maxed (supposedly the cap doesn't have any effect when the preamp is on 10). It does get more trebley when the preamp is lower, but I just compenstate with the treble and presence controls.

If you are getting some annoying high-end, try some different speakers. I really like G12-65 speakers with JCM 800s. A less expensive "greenback"-style alternative that also sounds great and can handle some power without a flubby low end are the 50 watt Eminence GB12 speakers. The 16 ohm versions are sometimes hard to find, but the 8 ohm versions are easily available.

[mmorse]

Are we talking the 1n bright cap on the pot, or the 470pf treble peaker next to the jacks? I clipped both about two years ago, but last month I did some experementing using aligator clips. In the end I put the 470pf treble peaker back in. It adds that upper midrange and harmonics 800s are famous for and sound's dull without it. I still find the 1n bright cap on the pot too much though, but clipping it flattens the tone at lower gain settings, so I replaced it with a 330pf cap. Now it's nice and sparkly at lower gain settings, and gets fater when you turn the gain up.

So, IMHO, don't remove it! Spend an hour at the tech trying different value caps and go for the one you think sounds best. :beer
I did the same thing. Ended up putting the treble peak circuit back in. Haven't tried a different value for the bright cap though. Maybe I'll give that a try.

[Alvis]

Outa there...!

[SlyStrat]

No bright cap on any Marshall I ever owned. Turn up the treble and presence if you need more high end. A friggin' No Brainer.

[dcooper830]

I have an SLO 100 and clipped the cap but put it back. I think the cap is good for some added sizzle.

I think the problem with JCM800 amps isnt so much the bright cap but the huge upper nasal mids that are present that kind of cause the harshness.

I find I get better results by lower tha mids and the treb a tad. Lowering the mids really smooth out these amps and it doesnt sound scooped or anything.

Oh my God!!!!! You're the first person besides me who I've seen do this.

I tell people I turn the TREBLE and MID down on my Marshalls and they think I'm an idiot.

But you're so right!! It really does smooth out the tone and it doesn't sound scooped at all.

[ChorusCrackpot]

I am wondering too what speakers to try with my JCM 800. Currently I am running an EV 12S 200 watter and a Celestion V30 (mesa/boogie style), as a series pair. The V30 is annoying me, so I need something to replace it with. Any ideas?

[stratburst]

'70's- 80's G12-65 kills with this amp.

[wizard333]

I remove the "bright cap" from pretty much everything.

[ChorusCrackpot]

'70's- 80's G12-65 kills with this amp.

Thanks for the recommendation.

Do I have to get a second one from the 70s? Or is the same when bought new?