JH100 break up question

[sixty2strat]

Tried the head out the other day. They have a nos for 1999. I bought the B cab last year so tried the head out. The best the had was a mesa with V 30's. I got up to 9 with a strat and the amp would not break up. my old 1987 will warm up between 5-7 depending on the guitar and how hard you dig in the after 7 it's 60's uk guitar god. I would have thought even with cab rated at 240 watt a 100 wat plexi would get some destortion. The clean was amazing fat round powerful yet not brittle. I never used a 100 marshall in 30 years of plying Always 50's is that the effect of the 100 or is it the nature of the JH100 kt 66 and PT. I know the older circuts ar cleaner, is this th amp or the effect of the cab?

[Sigi M]

Welcome to the Roadhouse!
Which Input did you use, did you "Jump" the Channels?

Sigi

[jboyjams]

I have 2 Super 100JH heads and a 1987x. One of my JH heads has a little more headroom than the other, and Steve D said this would be due to the power tubes. Both heads would have a lot of distortion (somewhat fuzzy) when set at 9 on either channel - even if the eq was not cranked - using a 62 reissue strat and either a Greenback cab or a 1960AV.

I find the JH to be beautiful clean and fat up until around 7 on the dial. For vintage Cream tones, I'd use Channel 2 upper input and dime everything and work the controls on my Les Paul.

The JH was cleaner than expected, but defintely has a lot of distortion and fuzz when pushed hard. If using a strat into the upper left input with the eq at noon and Volume at 6 it's still more like Little Wing. However ,increasing the Volume I a click or two starts to introduce the gain - and the EQ on these amps affect the gain a lot. Increasing the Mids adds gain as does the Treble.

I too wondeer which input was used...

[Steve Snider]

I had one of the stacks when they first came out and by mistake I sold the head but kept the cabs which are the best sounding cabs I own. I like them better than my HW cab or Bogner cabs. They do break up nicely and are part of the sound. As others say it stays clean up to 6-7 depending on eq settings.

I just snagged another complete rig - head and two cabs and will pick it up in a week or two. The head is a great platform for pedals and the versatility between jumping the channels and the eqs and volume settings works for me.

No the gain level is not as high as SLPs or others it has its own thing going on and the tones and response are great to me.

[sixty2strat]

Thanks guys, I was running it into the upper left hand input. Seems as sweet as it sounds and with the adjustments running it with 1 cab at a gig would be pushing volume and frying the cab. Still might give it a go again.

[Steve Snider]

Thanks guys, I was running it into the upper left hand input. Seems as sweet as it sounds and with the adjustments running it with 1 cab at a gig would be pushing volume and frying the cab. Still might give it a go again.

You would not fry the cab. I used mine cranked up through one of the cabs with no issues. I am a big fan of the new Celestion creambacks and a good gigging half stack would be the top cab with a pair of creambacks loaded at bottom with G12Cs.

[sixty2strat]

How much a role to the KT66 play in the amps tone?

[surfnorthwest]

No more or less then any other power tube. But yes, KT66 tubes ha ve their own sound that is noticably different then any other tubes in a good way. So they play a significant part to the tone of the amp.

[jboyjams]

Just switching from Shuguang KT66 to Gold Lion KT66 made a noticeable difference in the amp. Gold Lions are a little thicker sounding and the Shuguang are a little clearer sounding.
Also, the preamp tubes make a big difference - especially in V1. I'm using a Tung-Sol reissue in V1 and Mullard reissues in V2 and V3.

[aristotle]

I can't speak directly the the JH100, but I have the 45/100, which was essentially NOS when I got it about a year and a half ago (Chuck Levins bought the entire Marshall stock at NAMM the year that it was introduced...2004 I think...and it sat in the box in their wharehouse for 6 years) In any case, the amp was biased waaay cold when I got it. Not sure why, but biased up, it's nice and warm and crunchy now.