Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: bakerlite on March 20, 2012, 08:24:14 am
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hey folks - would anyone mind throwing their eye over these voltages?
http://www.el34world.com/charts/valve/ValveData.php?e=view&f=12884 (http://www.el34world.com/charts/valve/ValveData.php?e=view&f=12884)
amp seems more distorted tha i remember - there seems to be little to no clean tone if i am honest the break up doesnt sound to bad but it shouldnt be there so early.
Does anything jump out at you?
- Valve Pin 1 Pin 2 Pin 3 Pin 4 Pin 5 Pin 6 Pin 7 Pin 8 Pin 9
V1 12AX7 213 0 1.42 * * 225 0 1.60 *
V2 12AX7 198 0 1.62 * * 201 0 1.61 *
V3 12AT7 393 1.2 4.6 * * 393 1.2 4.6 *
V4 12AX7 212 0 1.9 * * 161 0.76 1.9 *
V5 12AX7 331 -9.9 -003 * * 325 -.01 .1 *
V6 12AT7 260 56.2 111 * * 269 59.6 110 *
V7 6L6 * * 407 407 -39 * * 410 *
V8 6L6 * * 410 409 -37 * * 409 *
V9 GZ34 * 414 * 333 * 333 * 414 *
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V3-2&7... you show 1.2v but I'd expect 0
V3-3&8... you show 4.6v but I'd expect approx 8V
V4-7 ... you show .76v but I'd expect 0v
V7-8 ... you show 410v but I'd expect 0v. (got to be a reading/writing error)
V8-8 ... you show 410v but I'd expect 0v. (got to be a reading/writing error)
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cheers sluckey
It turns out the tubes (which were ummarked) were incorrect - on placing 'known' 12at7's in the correct sockets most was remedied.
And that way a typo for the 410 sorry!
what a tryeuly stunning amp these are had never had the pleasure of hearing a vibrolux reverb and this one despite tired caps sounds just amazing.
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AA964 is a Princeton?
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well spacelabstudio you could be right but I am pretty sure i had the rights schems and layouts:
(http://vintageampguide.com/schematics/vibrolux_reverb_aa964_layout.gif)