Valve power amps

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digitalscreamdigitalscream Frets: 26457
I find myself desiring a mono 40W+ valve power amp, preferably 1U and not too heavy (or pricey). Does such a thing exist?

I know there's the Marshall 20/20, but it's stereo. I can live with that if need be, but I'd much rather have a straight mono amp (the 20/20 can't be bridged). The Deep switch is a definite bonus, mind.

There's also the R&R SOLO (of which I believe there's one in the country which used to be mine), but that fails on the price front mainly because it's a full-on two-channel amp.

Anything else?
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Comments

  • Danny1969Danny1969 Frets: 10357
    edited April 2014

    I used to use the 20/20 ... it's a sweet little amp but has some problems. Air intake is from the side and in a regular rack it can overheat. At least mine did till I modded the rack. It's also not the loudest of amps either, it was enough for me but you could run into problems in certain situations

    Almost all the rack power amps are stereo because their designed for stereo effects, I've never seen a mono one. I use the EL34 100/100 now and enjoy the duel mono block redundancy. Only last month a valve went at a gig, so I just turned that side off and used the other. Downside is weight, it's stupidly heavy so lives in a rack on wheels. 

    What about tearing the guts out of a 40 watt combo, junking the pre stages and just keep the power section. You could get a 2U rack case and make it quite easy using turret strips and bolting the mains and speaker transformers to the rack chassis. That would be a nice little project :)
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  • octatonicoctatonic Frets: 33725
    You will struggle to find a low wattage monobloc.

    Fryette have been threatening to release the LXII which could be 40w stereo or 80w mono but it never happened.
    Really you should look for a stereo amp that has independent standby for each channel and run one side at a time.

    I did this with the VHT2:50:2 before I went for the Matrix and it worked fine.
    I would avoid the Marshall 20/20 for the reasons Danny states.

    I find pretty much all the 20watter power amps to be underpowered in terms of clean headroom.
    Any of the 50 watt ones should be fine- the VHT/Fryette is really terrific.
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  • digitalscreamdigitalscream Frets: 26457
    Danny1969 said:

    I used to use the 20/20 ... it's a sweet little amp but has some problems. Air intake is from the side and in a regular rack it can overheat. At least mine did till I modded the rack. It's also not the loudest of amps either, it was enough for me but you could run into problems in certain situations

    Almost all the rack power amps are stereo because their designed for stereo effects, I've never seen a mono one. I use the EL34 100/100 now and enjoy the duel mono block redundancy. Only last month a valve went at a gig, so I just turned that side off and used the other. Downside is weight, it's stupidly heavy so lives in a rack on wheels. 

    What about tearing the guts out of a 40 watt combo, junking the pre stages and just keep the power section. You could get a 2U rack case and make it quite easy using turret strips and bolting the mains and speaker transformers to the rack chassis. That would be a nice little project :)
    Yeah...I figured the 20/20 would be fine using it stereo (with a mono input), because it's basically a 40W amp (I play with a 50 watter which, with its current valves, only puts out about 42W anyway). Wasn't aware of the intake issue, though...that's a bit of PITA.

    You're right that it'd make a nice little DIY project to convert a head or combo into a power amp, but I'm not sure I'm technically up to the job.

    I might just go for an ART SLA-1...I just love the idea of the Deep switch on the Marshall. Reliability and (lack of) weight of a solid state amp would be nice, mind.

    There's also the 2U Peavey Classic 50/50. It isn't dual monobloc, but it can run mono (100W) and has resonance controls on each channel. The only downside is weight - 13kg, twice the Marshall. I did have a 60/60 once, and it was bloody brilliant...even heavier, though, and 3U.

    octatonic said:
    You will struggle to find a low wattage monobloc.

    Fryette have been threatening to release the LXII which could be 40w stereo or 80w mono but it never happened.
    Really you should look for a stereo amp that has independent standby for each channel and run one side at a time.

    I did this with the VHT2:50:2 before I went for the Matrix and it worked fine.
    I would avoid the Marshall 20/20 for the reasons Danny states.

    I find pretty much all the 20watter power amps to be underpowered in terms of clean headroom.
    Any of the 50 watt ones should be fine- the VHT/Fryette is really terrific.
    Yeah, I've been looking at those...price is a bit out of my range, though. £300 is essentially the top end of what I can reasonably spend.
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  • ecc83ecc83 Frets: 1589

    Y'know, I tried to to tell 'em a couple of times that a rack mount amp would sell!

    You can connect two stereo amp channels in parallel and get twice the power into 1/2 the Z . Quad lls were often used this way for "HI-Fi" PA work.

    Dave.

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  • octatonicoctatonic Frets: 33725
    If you're looking at the ART why not consider the Matrix?
    It is much, much better.

    £300 is a tricky price point.
    You could get a Mesa 5050 for a bit more than that but if you are prepared to spend extra for the Mesa 5050 then you might as well go the whole hog for the VHT/Fryette.

    The Peavey is good for the money.
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  • digitalscreamdigitalscream Frets: 26457
    ecc83 said:

    Y'know, I tried to to tell 'em a couple of times that a rack mount amp would sell!

    You can connect two stereo amp channels in parallel and get twice the power into 1/2 the Z . Quad lls were often used this way for "HI-Fi" PA work.

    Dave.

    Funnily enough, a rack amp is consistently the most popular request for the Jet City boys. They're convinced that they won't sell.

    I'm a bit squicky about connecting power outputs together, for some reason...
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  • digitalscreamdigitalscream Frets: 26457
    octatonic said:
    If you're looking at the ART why not consider the Matrix?
    It is much, much better.

    £300 is a tricky price point.
    You could get a Mesa 5050 for a bit more than that but if you are prepared to spend extra for the Mesa 5050 then you might as well go the whole hog for the VHT/Fryette.

    The Peavey is good for the money.
    It's all about the price, really. Can't find any Matrix amps for that money (not even the old XT500). The ART is about £230 new, which helps...
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  • digitalscreamdigitalscream Frets: 26457
    edited April 2014
    Hang on a sec...am I thinking about this completely wrong? What about a bass amp, like the Peavey Tour 450? Built-in EQ, plenty of headroom and designed to be clean all the way to the top. The only worry is that the top end might be lacking.
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  • octatonicoctatonic Frets: 33725
    edited April 2014
    Hang on a sec...am I thinking about this completely wrong? What about a bass amp, like the Peavey Tour 450? Built-in EQ, plenty of headroom and designed to be clean all the way to the top. The only worry is that the top end might be lacking.
    Plenty of bands have used bass amps as guitar amps.
    Yes you will have some EQ correction to do.
    What preamp will you be using?
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  • vizviz Frets: 10645
    Carvin do a whole range of 2u amps - not sure if they have one stepped to 240 though.
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  • citizen68citizen68 Frets: 172
    Maybe a silly question but why are the valve power amps seemingly much more expensive than for example a decent valve guitar amp?
    Seemed like a good idea.....

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  • Phil_aka_PipPhil_aka_Pip Frets: 9794
    May I suggest its because it takes more design effort and better quality components to get one to run clean at the rated o/p, whereas a guitar amp can distort like hell and have a narrow bandwidth?
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  • octatonicoctatonic Frets: 33725
    citizen68 said:
    Maybe a silly question but why are the valve power amps seemingly much more expensive than for example a decent valve guitar amp?
    There isn't a huge difference if you compare like for like.
    If you compare a stereo power amp to the price of a professional high end amplifier then they are roughly equivalent.
    Power amps are generally built to a high spec, have two output transformers, one per channel, too.
    They are sold in much smaller numbers, which must account for some of the difference.
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  • fretmeisterfretmeister Frets: 23943
    Hang on a sec...am I thinking about this completely wrong? What about a bass amp, like the Peavey Tour 450? Built-in EQ, plenty of headroom and designed to be clean all the way to the top. The only worry is that the top end might be lacking.

    So use a PA amp. Most big bass power amps are really PA amps anyway.

    I used a Yamaha P5000S for ages and it was brilliant - both with bass preamps and a Line 6 Pod Pro.
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  • Danny1969Danny1969 Frets: 10357

    In terms of design you don't need any great bandwidth for guitar, there's very little going on under 80hz or so and not much above 6K . The cost of stereo power amps is a lot because of the increased component count, basically it's 2 amps in one box even if it's not a duel monoblock design and they are made in much smaller numbers. 

    I always felt gigging a modeller into solid state amps was a bit harsh. I used a Rotel amp, a Marshall Valvestate and a homebrew amp I built. I wasn't happy until I spent the money on a valve power amp ..... there's something about the ouput transformer in a valve design that filters off the nasties and harshness. I've often wondered if an SS amp might benefit from a transformer on the output stage even though it doesn't need one. A simple 1:10 and 10:1 back again, not to change any transfer impendence but to benifit from the effects of passing an audio signal through a transformer. That's where some of the mojo is in my opinion, it's not just the valves but the transformers. 
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  • ecc83ecc83 Frets: 1589
    edited April 2014
    Once you have the power and output transformers and a chassis to take them there is not a great deal left in a guitar amplifier. Ok! Yes SOME are very complex but even so most of the cost is in the mass.

    A valve power amp would typically consist of a pair of OP valves, a PI and maybe another double triode input amp. However there is unlikely to be much of a market for a GUITAR specc' power amp with its low quality (in "hi-fi" terms) output traff, high output impedance, soggy PSU and high distortion (again, ref say a Quad or Radford) .

    No, I would like to see a rack version of the HT-5 for studio use. The ID series are of course naturals for racking...But nobody listens to me!

    Danny. Don't get TOO hung up on transformers. Valves, especially pre amp valves have a far bigger tonal effect. In any case, by definition, traffs only make a difference if you drive the bllx off them and most often you can't for social reasons (in fact it is virtually impossible to "saturate" a guitar amp OPT)
    Dave.
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  • digitalscreamdigitalscream Frets: 26457
    So use a PA amp. Most big bass power amps are really PA amps anyway.

    I used a Yamaha P5000S for ages and it was brilliant - both with bass preamps and a Line 6 Pod Pro.
    That's part of my logic, actually - the difference is that a bass amp like the Peavey Tour 450 also has some tone-shaping capability (resonance and a 9-band EQ) which could come in handy.
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  • siraxemansiraxeman Frets: 1935
    i'm a simpleton i'd just have a rack with preamp n fx and get a nice head and feed all that into the loop..i see many pro players with 2 or 3 heads racked up like that i guess thats what they are doing also??
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  • digitalscreamdigitalscream Frets: 26457
    siraxeman said:
    i'm a simpleton i'd just have a rack with preamp n fx and get a nice head and feed all that into the loop..i see many pro players with 2 or 3 heads racked up like that i guess thats what they are doing also??
    Yup - I can attest to the fact that the Eleven sounds awesome into the loop of my Jet City 50W (probably helped by the fact that the loop is in front of the tone stack). Thing is, I don't particularly want my rig to get bigger and heavier...smaller and lighter is the order of the day ;)
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  • ChrisMusicChrisMusic Frets: 1133
    Just to turn the thumb screws up a bit ~ this is available second hand at Coda in Stevenage ~ right now
    I know it is over budget, but as they say where there is a will there is a way, so here goes...

    Mesa Boogie 5050 Power Amp £599


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