Tblues1
19 posts
Sep 06, 2012
4:48 AM
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I may be coming into a Fender Twin Reverb 2x12 for next to nothing. Any thoughts on making it a viable harp amp?
Anything besides maybe tube swaps?
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5F6H
1344 posts
Sep 06, 2012
5:16 AM
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Before the Bassman reissue came on the scene, the Twin Reverb (along with the Super Reverb) was a very popular amp for harp, still has its devotees.
Keep the bias to the cool side if you can (~15mA per tube, some brands might need more like 20mA-ish), speaker choices can be critical (you might even try a high wattage 10" with a converter ring?), you might not need or benefit from a particularly hot mic &/or maybe consider using the #2 inputs to make life easier regarding feedback. Great amp for big stages, can be a handful for small, cramped stages...but still a good amp, even if you had to pay "something" for it ;-)
Biggest downside is really the weight.
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Tblues1
20 posts
Sep 06, 2012
1:01 PM
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5F6H,
Thanks for the info.
Not sure I'm going to do it, but I'm trying get some info to see if it's worth messing with.
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The Iceman
454 posts
Sep 06, 2012
2:28 PM
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It can get loud - that's for sure.
I think Charlie Musselwhite used one for many years.
ditto on the weight!
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The Iceman
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bonedog569
618 posts
Sep 07, 2012
1:17 AM
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I've got a silverface twin , early master volume style , originally packaged with six tens and sold as the Super Six. Same 100 watt twin circuit though. I got it as a naked chassi at a garage sale for next to nothing and put it in a twin cab with one 12 and one 10" .
I lowered the voltage to the first preamp tube with a higher value dropping resistor, boosted the bypass cap values in the preamp for more bass response, then swapped in lower gain pre- amp tubes. It is a great amp. I recently revived it (minor problem I procrastinated trouble shooting) and its my current favorite amp - and I've got a bunch.
You can feel the power - even at less than deafening volumes. The bass cajones it's got are rediculous. It doesn't 'crunch' as easily as.other amps- but I haven't tried cold- biasing yet - and will as Mark suggests- when I next put it on the bench.
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Last Edited by on Sep 07, 2012 1:18 AM
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JTThirty
177 posts
Sep 07, 2012
8:53 AM
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Musselwhite used what's known as the "Red Knobbed" twin, as did Magic Dick, and yeah, for years.
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Ricky B
http://www.bushdogblues.blogspot.com
RIVER BOTTOM BLUES--crime novel for blues fans available at Amazon/B&N and my blog
THE DEVIL'S BLUES--coming Fall of 2012
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barbequebob
2020 posts
Sep 07, 2012
9:54 AM
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I used to own a real pre-CBS black face Twin Reverb back in the 70's, and along with the 4-10 Bassman, the 4-10 tan Concert, and the black faced Super Reverb, they were the most common amps being used by harp players in the 70's.
They certainly were loud, but they were one heavy SOB to lug around and the one I had had Electro Voice SRO speakers in them and the magnets on each of those speakers weighed 15 lbs. apiece, and the guy who I bought it from had to have a new baffle board put in because the stock one couldn't handle the weight.
For sheer volume, IMO, the earlier white Twins were louder, but after lugging it around, it killed my back so I wound up selling it to a country guitar player who absolutely was drooling the minute he hit the first note thru it on his old Telecaster guitar.
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Sincerely,
Barbeque Bob Maglinte
Boston, MA
http://www.barbequebob.com
CD available at http://www.cdbaby.com/cd/bbmaglinte
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jimr
34 posts
Sep 08, 2012
1:45 AM
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I have worked with a Vibrosonic Reverb which is a Twin Reverb with a single 15 in speaker, discussed at the site below.
https://sites.google.com/site/jimdramps/home/harness-the-beast
Jim R
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colman
195 posts
Sep 08, 2012
4:31 AM
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i have a fender twin 1968 with a AB763 INsides same as black panel also the dude i got it from did some work on it and i can flip a switch and it turns into the same as a marshall twin twelve it cooks for harp and screames with a guitar !!! also i saw butterfield play thru one in 1970...
Last Edited by on Sep 08, 2012 4:33 AM
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Rick Davis
653 posts
Sep 08, 2012
8:23 AM
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I had a silver face Twin Reverb with Altec speakers for several months. I restored it to new original condition and tried it for harp. The reverb was lush and the low-volume tone was nice, but there was just no way to avoid screaming feedback at 3 on the volume control.
As others have said, it is one heavy and awkward monster.
I decided to pass the amp on to a guitar player who would get more satisfaction out of it than I ever could. I traded it for PA gear.
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-Rick Davis
Last Edited by on Sep 08, 2012 8:28 AM
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kudzurunner
3487 posts
Sep 08, 2012
9:00 AM
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In general I think it's a pretty bad amp for harp. It's certainly not a good general-purpose or general-duty harp amp.
But there are certain applications where it might work. Rick's right about those SROs: If you've got those heavy-duty speakers, you've got bad speakers for amping harp.
Magic Dick used to use a Twin, I believe. If you're playing fairly big rooms with a rock band AND if you use a mic, like a Green Bullet, that can drive the input channel really hard, you might just be able to get a squalling sound. I saw one guy at the International Blues Challenge work that combination and he had a great sound.
It's a very loud guitar amp. That's really its best application. Again, if you're going to be in a context where you're playing outdoors--on the street, for example--with no sound reinforcement (i.e., no PA), you might be able to crank it up and allow it to breathe.
In most clubs, with most blues bands, and in most performance contexts, it won't serve a harp player well. But it might be worth having for specialized applications, which occasionally come up.
Personally, I'd run in the other direction. But Magic Dick used one.
Actually, the first time I saw Butterfield at the old Tramps in NYC, he was playing through TWO Twins. So never say never. And yes, he was loud as hell. But he was Butterfield.
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colman
197 posts
Sep 08, 2012
9:51 AM
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talking about the fender twin i`ve had about 30 yrs.
most of that time i`ve used it with two power tubes pulled out of it,the dude that sold it to me told me about pulling 2 of 4 power tubes ,it cuts the power in half and less feedback i can crank it up to 7 before it feeds back .check into pulling power tubes it works on most big amps...
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5F6H
1347 posts
Sep 08, 2012
10:28 AM
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I run my "SF Twin" (well it was that when it rolled out the factory, preamp is wired like an early brown/blonde amp...no reverb or trem anymore) with only 2 power tubes, which is perfectly feasible with the stock Twin transformers. Seeing as I have bunch of speakers, I also corrected the speaker impedance too (2x 6L6 would ideally like to see 8ohms total load...but are happy with anything from 4ohms to 16ohms as far as the Twin is concerned)& use 2x 12" to 10" converter rings (sometimes just 1x10" & 1x12").
12" Eminence Alphas are a cheap & reasonable replacement for overly heavy/bright speakers.
In fact if I ever wanted more volume I'd switch the 2x6L6 for more powerful tubes (biased accordingly)...but it's plenty loud as it is.
I'm pretty feeble, but the Twin with casters is a lot more manageable...fit some tube spring retainers (ones that fit around the ends of the tubes, not the stock "bear traps") if using casters...just so you can be sure it still has the required amount of tubes in it, when you have finished wheeling it around! ;-)
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Last Edited by on Sep 08, 2012 10:29 AM
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kudzurunner
3488 posts
Sep 08, 2012
11:10 AM
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I'm intrigued by the pull-two-power-tubes idea, but man: you better make sure you understand what you're doing when you do this! 5F, you seem to really know your way around this stuff. Is it feasable to pull two power tubes out of a stock silverface or blackface Twin, without making any other modifications?
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5F6H
1348 posts
Sep 08, 2012
11:58 AM
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Hi Kudzurunner,
With a BF/SF twin, you can pull two power tubes without fear of damaging anything, or necessarily having to rebias (if the amp worked fine with 4 tubes, it will even run a shade cooler with just 2...but probably not enough to detect by ear).
It doesn't cause any more stress to the amp or tubes than using the Ext Speaker jack (4ohm ext cab) with all 4 tubes (NEVER use the Ext jack though, if running just 2 power tubes & the stock speaker set up, it will pull the impedances down to dangerous levels for the amp).
Ideally, you would pull tubes to allow at least one tube to remain at either end of the OT primary, so if looking at the back of the amp, you might pull the 2 outer power tubes (#1 & #4), or the 2 inner power tubes (#2 & #3). I am not including any preamp tubes in the numbering sequence.
If you pulled #1 & #2, or #3 & #4 the amp will make a lot less power and be very distorted (for a twin at least) because it is now running "single ended" like a big champ. This is the equivalent of pulling one power tube on a bassman or super reverb.
The above relates to 60's, 70's, 80's classic & "RI 65" Twin Reverbs...it does not relate to the PCB Pro Tube "Twin Amps", not because it would be risky, but because they don't have all 4 tubes in a line, so it's not obvious how many would be at each end of the output transformer primary winding. The Pro Tube Twin has a 25W switch anyway, without pulling things out.
The above advice above does NOT apply to Marshalls, nor to any other brand of amp, like old 4 power tube Danos. Fender picked 'middle of the road' transformer impedances to allow this to work, other manufacturers were not so circumspect.
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Tblues1
21 posts
Sep 08, 2012
3:21 PM
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Thanks everyone for the input. I think I'm going to pass on the project. I just don't have the time to mess with it. The amp is part of an estate liquidation and there is guitar player relative that is interested. I just had first call. It's a bit sensitive anyway.
Adam, talking about heavy duty speakers though.
I have a 50 watt Mission Harp Amp with a single 15 inch Weber, 80 watt speaker/60 OZ. magnet tha works quite well.
It did, however take some tweaking to get feedback under control.
I run TAD 6L6 WGC-STR's biased at 19ma, and a 5751/12AT7 combo with a 5U4 rectifier.
Also if anyone may be interested I'm thinking of selling my Fat Dog model 1A. Probably one of last ones built by Robbie before he got rid of the business.
I'm not sure yet. I'll put it on the for sale page when I make up my mind.
It has an Emminence Cannibis Rex in it, but I will also include the Jensen that came in it, also a Tuki cover. It would be interesting to see if there is any interest. I just don't use it.
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bonedog569
624 posts
Sep 08, 2012
3:49 PM
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One of the reasons I enjoy playing through a larger amp (when I do) is the feeling of power. Bass you feel in your gut - notes and chords in you chest.
I am not sure why - maybe its in my head, but the 100 watt twin as I'm running it just feels and sounds more powerful than my BMRI at the same volumes. That may change if I up-value the bypass caps in the Bassman - but my guess is , that while I'll get deeper bass, there will still be a difference in that feel .
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Last Edited by on Sep 08, 2012 4:11 PM
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5F6H
1349 posts
Sep 08, 2012
5:58 PM
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@ Bonedog "I am not sure why - maybe its in my head, but the 100 watt twin as I'm running it just feels and sounds more powerful than my BMRI at the same volumes."
It's not in your head, it's in the lower resistance (thicker wire in the PT, no rectifier tube), higher current handling power supply! ;-) I've got an upgrade 160W power transformer in mine...even with just 2x6L6 you feel the difference in transient response general "thump". Think of it as being like torque in an engine as opposed to simply BHP?
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bonedog569
627 posts
Sep 09, 2012
12:16 PM
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There ya go- I'm only half crazy after all - thanks.
I did a lot of experimentation on this amp before taking it back closer to stock. I think I'll make another thread of the saga when I get a few minutes.
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