Author Topic: Darker tubes for JCM800? (Read 5067 times)

Woogie · « **on:** July 26, 2007, 12:13:55 PM »

Which EL34's will tame the brightness of the JCM800?

It has Electro Harmonix tubes at the moment.

TwilightOdyssey · « **Reply #1 on:** July 26, 2007, 01:50:27 PM »

Mullard

Twinfan · « **Reply #2 on:** July 26, 2007, 02:13:14 PM »

Ha ha - at a price!!!

Try JJs ;)

gwEm · « **Reply #3 on:** July 26, 2007, 02:14:40 PM »

real mullard or new sensor mullard?

TwilightOdyssey · « **Reply #4 on:** July 26, 2007, 02:15:16 PM »

New Sensor

gwEm · « **Reply #5 on:** July 26, 2007, 02:33:28 PM »

Quote from: TwilightOdyssey

New Sensor

cool. i brought a pair from rudy's when i was in new york. the fool didn't bother to give a matched pair - in fact the opposite - one grid current is like twice the other :/ obviously i couldn't use them... maybe i'll try again.

TwilightOdyssey · « **Reply #6 on:** July 26, 2007, 02:39:02 PM »

Can't say you weren't warned about Rudy's!!! PDT_008

gwEm · « **Reply #7 on:** July 26, 2007, 02:43:51 PM »

Quote from: TwilightOdyssey

Can't say you weren't warned about Rudy's!!! PDT_008

you were right mate :) the guys are dicks, they can kiss my arse before i'll leave any more money in there!

Mr Ed · « **Reply #8 on:** July 27, 2007, 11:46:58 AM »

JJ's rule.

robbo · « **Reply #9 on:** July 27, 2007, 11:54:04 AM »

Snip the bright cap before trying anything, made enough difference for me.

HTH AMPS · « **Reply #10 on:** July 27, 2007, 11:56:09 AM »

different valves will tame the brightness to a degree, but to get rid of the extreme treble you'll need to mod the amp (done lots of these mods on JCM800s). also, are you running the amp at low (bedroom) volumes? - if so you have your answer right there, these are stage amps and only sound good at decent volumes.

Try some JJ ECC83s for a darker preamp valve. For EL34s I'd say that EH 6CA7s are your best bet, they're quite dark too (6CA7s are an American equivalent of EL34s - EVH used 'em in his Marshalls).

What speakers are you using btw? - G12T-75s would perhaps be the worst possible choice for this amp. G12Hs are a perfect match and I've had good results with the G12-65s too.

What pickups are in your guitar - those JCM800s tend to like something a bit hotter to counter the treble in the amp.

:twisted:

Woogie · « **Reply #11 on:** July 27, 2007, 12:51:01 PM »

Quote from: HEAVIER THAN HELL

different valves will tame the brightness to a degree, but to get rid of the extreme treble you'll need to mod the amp (done lots of these mods on JCM800s). also, are you running the amp at low (bedroom) volumes? - if so you have your answer right there, these are stage amps and only sound good at decent volumes.

Try some JJ ECC83s for a darker preamp valve. For EL34s I'd say that EH 6CA7s are your best bet, they're quite dark too (6CA7s are an American equivalent of EL34s - EVH used 'em in his Marshalls).

What speakers are you using btw? - G12T-75s would perhaps be the worst possible choice for this amp. G12Hs are a perfect match and I've had good results with the G12-65s too.

What pickups are in your guitar - those JCM800s tend to like something a bit hotter to counter the treble in the amp.

:twisted:

Master on 5/6. Goldback speakers and I shall be running Holydiver and 2 x slowhands in the next couple of days!!

Maybe I should get the bright cap changed?

HTH AMPS · « **Reply #12 on:** July 27, 2007, 01:13:21 PM »

master on 5/6 and Holydivers - should be thicker than a whale omelette. not sure what those speakers are so cant say whether they're the cause of your brightness problem.

Are you plugging directly into the amp or using other pedals?

Where do you have the gain set?

If the gain is on full then changing the bright cap won't do a thing. If you like to set the gain low then I'd certainly advise changing the bright cap to a smaller value (100pF is best imo).

:twisted:

Woogie · « **Reply #13 on:** July 27, 2007, 01:16:03 PM »

Gain at 6, channel volume at about 5. Boosted with MXR Zakk Wylde OD, MXR Distortion+, Boss OD-1 or Tubescreamer, all with level on full and gain on 1/10. I like adding different flavours depending on the mood!!

I guess its just a trebly amp by nature.

Alex · « **Reply #14 on:** July 27, 2007, 01:58:02 PM »

I think speakers work better for "finetuning" an amp than tube swaps. On many tube amps A/B-class with modern preamps there's not soooo much difference - and I would count a JCM800 to them.

Try some different speakers. My fav for rounding out the bottom end is the Eminence Cannabis Rex. Put two in the lower positions on your 4x12" and you'll be in heaven!