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Topic: Blackface Twin, Preamp Tubes and Bias settings for steel. |
Cody Stewart
From:
Traverse City Michigan, USA
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Posted 21 Jul 2020 4:48 am |
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What configuration of preamp tubes and output tube bias are you guys using to get the smoothest tone out of your twins?
Thanks,
CS
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Bolt On’s: Red Belly, Brown Belly, 73 Sho~Bud Pro~II, Fender’s/Peavey’s. If it doesn't sound like 1968, then I probably won’t like it. |
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Craig A Davidson
From:
Wisconsin Rapids, Wisconsin USA
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Posted 21 Jul 2020 7:10 am
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| The tubes in my Twin are just like the diagram on the inside back of my Twin shows. I use Electro-Harmonix tubes installed by the amp-tech at Dave's Guitars in LaCrosse Wisconsin. Todd works on a lot of tube amps and knows his stuff. He just sets the bias for clean as possible. |
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Tim Whitlock
From:
Colorado, USA
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Posted 21 Jul 2020 7:36 am
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I too am happy with the stock configuration of tubes and not picky about the brand or about using expensive vintage tubes. My tech installed some NOS JAN Phillips 6L6s in my Twin and to be honest I didn't hear much difference to the Rubys I had been using. Maybe I just don't have an ear for what I should be hearing. I forget the bias voltage my tech uses, but the amp sounds very clean and warm.
That being said, I have tried out at least a dozen 2x12 and 1x15 speakers in my Twin Reverb. To my ears the right speakers can really make a huge difference - much more so than tube choice. |
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Michael Butler
From:
California, USA
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Mike Marsh
From:
Florida, USA
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Posted 22 Jul 2020 6:50 am Biasing a Twin Reverb
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Generally the Twin has plenty Head room for steel, so the Common Biasing of modern 6L6GCs or 5881's can perform well in the range of 30-32ma per tube. Typically -50VDC to -51.5VDC should get you there.
Mike
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Williams Series 700 4X5 |
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Marty Holmes
From:
Magnolia ,TX USA
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Posted 23 Jul 2020 6:53 pm Tubes
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| Nos tungsol 5751 and 7025 and sylvania backplate 12ax7's.Nos power tubes are VERY EXPENSIVE so i tend to use preffered series 6l6gc or tungsol 7581a. Power tubes.Marty |
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Don Griffiths
From:
Steelville, MO
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Posted 29 Jul 2020 1:51 pm Tubes and speakers
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What speakers did you finally settle on Tim Whitlock?
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Shobud Pro1,BMI U12, Santa Cruz F, PRS Standard, Fender Twin Reverb, ‘53 000-28 |
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Tim Whitlock
From:
Colorado, USA
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Posted 3 Aug 2020 8:36 am Re: Tubes and speakers
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| Don Griffiths wrote: |
| What speakers did you finally settle on Tim Whitlock? |
I have had an Altec 418b in it for about 8 years. The Altec is magic. I thought about trying a Telonics or Eminence neo to lessen the weight but I didn't want to compromise on tone. The Twin Reverb is now retired to the basement so the Altec will stay. |
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Dave Grafe
From:
Hudson River Valley NY
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Posted 8 Aug 2020 8:45 am
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In my JBL-loaded 1964 TR I am using Tube Amp Doctor power tubes biased at 31-32 ma, to my ear they are as close to the GE and Sylvania 6L6GC tubes that are in my Vibroverb and Super reverb, and seem to be fairly interchangeable bias-wise. I have tried JJ, Ruby, Sovtek, and Electro Harmonix, all have a distinct character all their own, the TAD pre and power tubes have the smoothest, cleanest response to my ears, although they also seem to be among the most fragile, but since I always carry a full set of spares this has not been a problem for me so far.
If I get a call to play more of a rock sound I may switch out the TAD's for JJ's, which have have a smooth wail that is very distinct, and I usually have a JJ 12AX7 in the first position to give the normal channel more if a edgy sound. The Electro-Harmonix pre tubes I am not a fan of except in the vibrato driver as they tend to be a fairly hot, generating more of a harsh distortion, not a pleasant sound for pedal steel IMHO.
In a Fender amp it doesn't much matter which brand of 12AX7 one uses for a vibrato driver - tube #5 counting right to left - as it does not affect the audio signal, only the oscillator. The first 7025/12AX7 pre tube in each channel - positions # 1 for the normal and #2 the vibrato channel - makes the most difference, followed by the reverb recovery 7025 - #4 from the right, the phase inverter 12AT7 - #6 - and finally the reverb driver 12AT7 - tube #3.
Everybody has their own idea of what sweetness sounds like, I suggest you try as many combinations as you can to get an idea of the range of possibilities. |
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