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Post by bustertheboy on Jun 3, 2009 1:22:44 GMT -7
Given that the preamp design is so similar for the Z28 and Route 66, can you substitute a 12AX7 for the 5751 phase inverter and enjoy that extra drive the Route 66 has? I'd assume so because the tubes don't appear to operated that differently. I'm guessing the Z28 has the 5751 because, being a lower wattage amp, you usually would want the option of more headroom. The 12AX7 might also allow for more of that ability to introduce added drive at lower volumes using the tone controls in the way you can with the Route 66. I tried a 12Ax7 in pi and it was brighter, had more gain than the 5751.
Any thought? Brett
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Post by arniez on Jun 3, 2009 5:08:17 GMT -7
Brett, Lots of people use a 12ax7 in the 28 for the phase inverter. The tone is more aggressive and breaks up sooner, a little more gain available as well. I think the cleans are not as round and plump. If not mistaken I think the Greg Lockhart clip of the 28 on Dr Z's website uses a 12ax7 in the PI. The tone stack in the 28 doesn't change by changing the PI. The tone controls add gain past 12 o'clock regardless of the 5751 vs the 12ax7. Just depends on your application and what sounds good to you. ArnieZ
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Post by bustertheboy on Jun 3, 2009 13:53:22 GMT -7
Brett, Lots of people use a 12ax7 in the 28 for the phase inverter. The tone is more aggressive and breaks up sooner, a little more gain available as well. I think the cleans are not as round and plump. If not mistaken I think the Greg Lockhart clip of the 28 on Dr Z's website uses a 12ax7 in the PI. The tone stack in the 28 doesn't change by changing the PI. The tone controls add gain past 12 o'clock regardless of the 5751 vs the 12ax7. Just depends on your application and what sounds good to you. ArnieZ Hi Arnie thanks- no I didn't assume the tone stack would change as that's dependent on the original circuit, just that the slight extra gain would push the amp more into that flexibility of earlier breakup the 66 has- that legendary ability to tailor the distortion with the tone controls. The 28 already has that, but not quite to the same extent. I'd just noticed that relative to my Ghia, there's less gain on tap but maybe I have a tame tube in V1 Brett
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Post by arniez on Jun 3, 2009 17:02:15 GMT -7
Brett, Every NOS ef 86 has performed well for me with differences not that significant. The Russian ef86 that came stock in my amp was a pretty decent tube, but they were all screened by Dr Z. Currently I'm using an Amperex that is a relabeled Mullard. I thing the Valvo ef86, which is a relative bargain, is a great sounding tube with a little extra zing! ArnieZ
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Post by bustertheboy on Jun 3, 2009 23:23:41 GMT -7
I'd agree with the Valvo- that's what I'm using- significantly quieter than my Amperex Brett
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Post by blackice on Jun 5, 2009 23:25:25 GMT -7
Thanks for the info Gents.
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