Bassman - How do the way the 2 Drive controls interact

FractalAudio said:
I'm working on a '59 Reissue model. There are quite a few differences between a 5F6-A and the reissue:
1. 12AX7A vs. 12AY7 input tube.
2. Different tone stack (this is a big one).
3. Different presence network.
4. Different B+ voltage.
5. 6L6s vs 5881s (minimal difference).
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I am curious about the 5881 in the power tubes list. Is that a vintage USA 5881 (and what brand was it?) or a Sovtek "5881" that was really a relabeled Russian military tube?

I matched a lot of the Sovtek ones when I worked at AES in '94. They were a rugged tube, and very consistent - to the point that I had to tighten the specs on the match a lot to leave singles for the folks that didn't want matched sets. They sound really good for guitar at about 6k6 plate-to-plate load, through Hammond 1620s. They got a bum rap for unreliability because the bear claw tube retainers typically found on old Fenders would scratch the base of the bottle above the wafer base, which would then crack after a bunch of thermal cycles. They also don't sound much like 6L6GCs at the typical low-load spec Fender used for its OTs.

I also had a pair of Sylvania 5881/6L6WGB in a Bassman Ten for years that sounded great, with a nice, fat, present midrange and clarity....
 
Joe Bfstplk said:
I am curious about the 5881 in the power tubes list. Is that a vintage USA 5881 (and what brand was it?) or a Sovtek "5881" that was really a relabeled Russian military tube?

I matched a lot of the Sovtek ones when I worked at AES in '94. They were a rugged tube, and very consistent - to the point that I had to tighten the specs on the match a lot to leave singles for the folks that didn't want matched sets. They sound really good for guitar at about 6k6 plate-to-plate load, through Hammond 1620s. They got a bum rap for unreliability because the bear claw tube retainers typically found on old Fenders would scratch the base of the bottle above the wafer base, which would then crack after a bunch of thermal cycles. They also don't sound much like 6L6GCs at the typical low-load spec Fender used for its OTs.

I also had a pair of Sylvania 5881/6L6WGB in a Bassman Ten for years that sounded great, with a nice, fat, present midrange and clarity....
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It's an original American-made Tung-Sol.
 
FractalAudio said:
It's an original American-made Tung-Sol.
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Nice! Made in New Jersey! I have a handful of nice JAN Tung Sol preamp tubes in my stash, as well as a number of other brands.

The Sovtek "5881" would be a nice addition, as IIRC, those were the stock tube in Soldanos at one time, if not still....
 
GreatGreen said:
I've never understood this. Why would they call it a "reissue" if it's so categorically different from the original?
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A lot has changed in electronics in 60 years. Some changes are for safety, reliability, and convenience. For example, the original had a non-adjustable bias for the power tubes, while the LTD reissue has an adjustable bias. Back in the 50's and 60's tubes were higher quality and more consistent compared to what we have available today. Having a range of adjustment is more necessary these days. Mains power is generally a bit higher voltage today as well. Back in 1959 it would have likely been in the 110 to 115 range. These days 120 is the standard here in the US. Amps back then almost never had a proper grounded chassis and used 2 conductor power cords. If a tube failed and B+ somehow shorted, you became the path to ground through your guitar. Not good.
 
mr_fender said:
A lot has changed in electronics in 60 years. Some changes are for safety, reliability, and convenience. For example, the original had a non-adjustable bias for the power tubes, while the LTD reissue has an adjustable bias. Back in the 50's and 60's tubes were higher quality and more consistent compared to what we have available today. Having a range of adjustment is more necessary these days. Mains power is generally a bit higher voltage today as well. Back in 1959 it would have likely been in the 110 to 115 range. These days 120 is the standard here in the US. Amps back then almost never had a proper grounded chassis and used 2 conductor power cords. If a tube failed and B+ somehow shorted, you became the path to ground through your guitar. Not good.
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Given that these are all well-known factors, F* could have spec'ed a PT that gave something close to the vintage 432VDC per the originals, but chose not to. To get 490V, they had to spec a slightly higher turns ratio than vintage, rather than the slightly lower ratio that would make the higher wall voltage deliver something in the vintage-correct range. Adjustable bias is a good addition. Tubes these days are nowhere near as consistent as in their heyday. The tone stack and any other circuit changes? Who knows what they are thinking? Maybe someone should send them a copy of the schematic? :D
 
I feel like they also know that the overwhelming majority of players will have no direct frame of reference for the original either. That frees them up for a little "artistic license" in trying to better appeal to today's players.

Even if a reissue is 100% dead nuts accurate, you're still comparing a brand new amp full of brand new components to an over 60 year old amp that will have no doubt drifted (sometimes significantly) with age and likely have had multiple servicings, recaps, and/or retubes over it's lifespan.
 
mr_fender said:
I feel like they also know that the overwhelming majority of players will have no direct frame of reference for the original either. That frees them up for a little "artistic license" in trying to better appeal to today's players.

Even if a reissue is 100% dead nuts accurate, you're still comparing a brand new amp full of brand new components to an over 60 year old amp that will have no doubt drifted (sometimes significantly) with age and likely have had multiple servicings, recaps, and/or retubes over it's lifespan.
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The Reissues sound good, but not at all like an old one. I wonder if changing a few resistors/capacitors and fitting a proper PT would be all that's needed, or if the speakers are also different enough to need replacement as well. By that point, might as well get a Weber kit and build it right from the start, though....
 
Joe Bfstplk said:
The Reissues sound good, but not at all like an old one. I wonder if changing a few resistors/capacitors and fitting a proper PT would be all that's needed, or if the speakers are also different enough to need replacement as well. By that point, might as well get a Weber kit and build it right from the start, though....
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Depends on the version too. I believe the previous reissue had a plywood cab and Eminence Alnico blue speakers. The LTD has a solid pine cab and Jensens like the original.
 
WOW! There's a lot of info to be found here.

For a novice tone nerd like me, I feel a bit overwhelmed. I'm glad to know there are people with great, in-depth knowledge of these things.
 
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