TH100h dirt channel

[Smeigel_12000]

Hi everybody,

I'm Michiel from Holland. I'm new to this forum but secretly allready have read a lot of information before registering.

Recently I bought myself a second hand TH100h with closed back ppc212. An awsome set and I'm very happy with this amp. I do have an issue though. For some reason I feel the dirt channel is to low in volume compared to the clean channel. In my band I run the clean channel around 25% while dirt channel is at 75% to equal volume. When I turn on my boost pedal on the dirt channel (fx-loop), that's where the dirt channel comes alive.

Do I have bad preamp tubes or is this just the design of this amp?

Cheers,
Michiel

[bclaire]

It's never a bad idea to retube preamp tubes when you buy a used amp... it could easily be just tubes.

[Jondog]

Maybe tubes, but you have to treat each channel like a seperate amp (because they actually kind of are. Different signal path until the power amp) and adjust accordingly.

[Smeigel_12000]

Thanks for the reply’s.

So retubing is a good plan anyway. Then my next question (and maybe a noob one), is it hard to change preamp tubes? If I’m right only power amp tube need a bias do they? Anyone knows of a clear manual? Sorry for all the questions .

Cheers

[Jondog]

TH100 will need to be biased for power tubes. Not preamp tubes. The aluminum shields come off with a slight twist, the preamp tubes just gently wiggle pulling up at the same time. Pay attention to the orientation of the pins when taking them out. Theres 9 and a wide space between two of them that needs to line up in the socket when installing presmp tubes.

[Smeigel_12000]

Anyone of you changed the preamptubes (12AX7) for 12AT7 tubes? If yes what were your findings?