| Author |
Message |
    
Phil G
| | Posted on Thursday, April 08, 2004 - 09:17 am: | |
On my MM 410 65 & 212 130 there is no volume (set to 5 master and main on both channels) until I turn up any one of the tone controls. Both amps have new tubes with correct bias settings including new 12AX7 phase splitter. My other 2 MM 212 130 & MM 112 100 work fine (no 12ax7 in those).
Is this a normal condition for amps with 12AX7 phase splitters? Or is there a component issue (CAPS ETC). I just purchased the amps in question and I’m not too familiar with the older MM 12AX7 phase splitter type. Any help is appreciated.
Thanks,
Phil
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Langley
| | Posted on Thursday, April 08, 2004 - 04:30 pm: | |
My 210-65 with solid state driver has no output
when the tone controls are zero'ed. It's been that way since day 1.
Without doing any real time testing, and the fact that my arse may resemble my elbow, looks to me like IC1's output gets 'isolated' from the circuit when the tone controls are zero'ed.
IC1's output may not be sufficient to overcome
the zero'ed tonestack's impedance. (My Blues Jr
does not have this issue. it's tone stack positioned post gain stage 2, and I think that
12AX7's have a bit more oomph than an LM307.)
From a logical point of view, by setting the tone stack to zero, one is telling the amp "hey, no tone please". In this light, getting nothing out of the amp does make sense.
IMHO, It looks like all is well.
Enjoy.
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John Drexler
| | Posted on Tuesday, November 02, 2004 - 12:21 pm: | |
I agree. They are apparently "linear" tone pots, meaning 0=no sound. Both my amps are the same way, one with and one without the 12AX7 driver. Dark is the absence of light, silence is the absence of all tone...? |
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