New Loudness

[ThreeChordWonder]

Finished the Mpjotone JTM45 kit, finally, and with a few mods including a Post Phase Inverter Master Volume (PPIMV).

My decibel meter arrived yesterday.

Big digital display one like you see on the back wall in the Andertons vids, for example.

Not sure mine is exactly the same, nor that it's calibrated or anything, but.

I tried it out with the JTM45, my Line6 4x12, and my "Schenker" flying V knockoff with the Dean "Lights Out" humbuckers.

At 12 feet...

In my 20 ft x 20 ft x 20ft ceiling height open plan sitting room...

110 dB(A)

Whoo-hoo!!!

[beaubrummels]

Nice! Very nice! (I'm a custom build JTM45 user myself, though admittedly I didn't build mine)

[Inflames626]

There's probably a reason for this but it looks like the larger power amp (I'm guessing) tubes are slightly angled (especially the 4th and 6th tube going from left to right). I'm guessing the straight blue tubes are preamp tubes.

[Rex_Rocker]

There's probably a reason for this but it looks like the larger power amp (I'm guessing) tubes are slightly angled (especially the 4th and 6th tube going from left to right). I'm guessing the straight blue tubes are preamp tubes.

It's not uncommon to get new tubes that are crooked, LOL.

I mean, I can get along just fine with new production tubes, but there is a reason NOS tubes are well-regarded as being higher quality.

[GuitarStv]

Holy ****, those tubes are super cooked. That would bug me.

[ThreeChordWonder]

Holy ****, those tubes are super cooked. That would bug me.

So long as they work they're fine.

I think the sprung cap type tube retainers pulled them a bit wonky, that's all.

[ThreeChordWonder]

PS Strat owners are encouraged NOT to start a "how do different [trem] spring types affect my tone?" debate :-)

[JOLLY]

Nice!!

[jeremy]

looks good to me! once you put the back cover on, you wont see the crooked tubes anyway. as long as it works, who cares. i assume the mv is on the back of the amp? pic is a bit blurry but could be my ageing eyes.

[ThreeChordWonder]

Yeah. The MV is the knob on the left. It's a dual 500k pot wired between the 100 nF DC blocking caps and the 220k grid resistors between the output from the phase inverter ECC83 V3 and the power tubes.

The small red / black /black things are the EL34 bias testing probe points.

The rest you can figure out I'm sure.

[jeremy]

i figured those were bias points. enjoy the sweet new amp!

[JOLLY]

Every time I see this thread, I keep thinking the band Loudness has a new album out.