Tube power amp

Paul Sutherland · Post by **Paul Sutherland** » 27 Nov 2015 11:11 pm

What would be a tube power amp that could be used with the Sarno V8 preamp (and Black Box) that I already own and use? I want a single channel power amp (monoblock) that I could secure in the back of a speaker cabinet to make a powered cabinet. I would want 4 6L6 power tubes for about 100 watts, 4 ohm output, an on-off switch, and maybe a fan. Basically a Twin Reverb, but just the power stage--no preamp, no tone controls, no reverb or tremolo.

I don't want a complete amp like a Showman head. Any extra features would probably not be a benefit, but rather would be viewed as a negative. I'm thinking of following the line of thinking that went into the Sarno V8: a minimalistic signal path of the highest possible quality.

I've searched the internet and can't find anything this bare bones. I already have a very good Matrix solid state power amp, but I'd like to consider an all tube option.

Tom Gorr · Post by **Tom Gorr** » 28 Nov 2015 12:10 am

Nearly every major amp builder made a 6L6 power amp at one time.

Another way to go is a 6L6 amp head and run into the effects loop return. Bonus is that you get a Guitar preamp. Weight isn't much different.

George Seymour · Post by **George Seymour** » 28 Nov 2015 5:31 am

Paul Sutherland wrote:What would be a tube power amp that could be used with the Sarno V8 preamp (and Black Box) that I already own and use? I want a single channel power amp (monoblock) that I could secure in the back of a speaker cabinet to make a powered cabinet. I would want 4 6L6 power tubes for about 100 watts, 4 ohm output, an on-off switch, and maybe a fan. Basically a Twin Reverb, but just the power stage--no preamp, no tone controls, no reverb or tremolo.

I don't want a complete amp like a Showman head. Any extra features would probably not be a benefit, but rather would be viewed as a negative. I'm thinking of following the line of thinking that went into the Sarno V8: a minimalistic signal path of the highest possible quality.

I've searched the internet and can't find anything this bare bones. I already have a very good Matrix solid state power amp, but I'd like to consider an all tube option.

Custom builder, Dan Lurie. FYD Amps. Google and you'll find, built my custom FYD
Or: fydamps.com

Lane Gray · Post by **Lane Gray** » 28 Nov 2015 5:34 am

I also bet Tim Marcus would do it.

William Hughes · Post by **William Hughes** » 28 Nov 2015 5:52 am

Take a look at this.

http://www.carvinaudio.com/products/ts100

Patrick Ickes · Post by **Patrick Ickes** » 28 Nov 2015 9:03 am

Mesa Boogie also made several 2 rack space mount all tube power amps back in the nineties. I remeber seeing them used at Zone Music in Cotati. I think they were called the 50/100 and had a switch to cut out 2 of the 6L6 tubes. I'm pretty sure it had a fan built in.
Very similar to the Carvin link in William's post. The Mesa was very heavy.
I used an ADA microtube 200 that I really like.
Patrick

Len Amaral · Post by **Len Amaral** » 28 Nov 2015 11:07 am

Are you looking to run one speaker? If so, I believe you need a mono tube power amp if one exists as the tube power amps are usually two channel. Leaving one side of a tube power amp without a speaker or load can do some harm.

Feel free to correct me?

Tom Gorr · Post by **Tom Gorr** » 28 Nov 2015 11:13 am

Many of the power amps I investigated in the past could have the outputs bridged for mono output of twice the wattage. Each side of the stereo operation could also run independently so no harm as long as you turned the unused side down or off.

admin · Post by **b0b** » 28 Nov 2015 1:07 pm

I used to play through a Mesa 50/50, but found that the Mesa 20/20 was actually enough power and it sounded much sweeter. Lighter, too. Both of those are stereo amps, though. I sold the 50/50. I still use the 20/20 now and then.

Paul Sutherland · Post by **Paul Sutherland** » 28 Nov 2015 1:24 pm

A stereo (or two channel) amp is ok since I have two 8 ohm speakers in the cabinet.

Since posting the thread I've come across the following options:

Mesa Boogie 50/50: far too heavy and won't fit in the back of the speaker cabinet.

Peavey Classic Series 120 Tube Power Amp: too heavy and won't fit in the back of the speaker cabinet.

The Carvin mentioned above: looks pretty good on the power and price, but it won't fit in the cabinet.

Engle E840/50: It might fit and has the right power (50 watts per side), but it's far too expensive ($1525), and too heavy (26.5 pounds).

Engle E810/20: It might fit and is lighter and somewhat cheaper, but it's not enough power (20 watts per side). I'm also not sure I would like EL84 power tubes for pedal steel.

Then I came across this: Oddwatt Oddblock Series 1. I can't find the physical dimensions anywhere, but it's 45 watts using two KT120 power tubes. I can't find the weight for this specific model, but it's lower powered brother, the Series 2 that puts out 25 watts using two KT88s, only weighs 14 pounds. I would expect the Series 1 to weigh a bit more as the transforms are probably larger. 45 watts is not really as much power as I want, and the Series 1 costs about $1050, which is more than I can pay. And then there is the fact that the Oddwatt Oddblock is a kit!!! I'm not at all sure I want to try to build a power amp. I can barely solder instrument cables. This is the kind of amp I had in mind, but with more power and cheaper. I'm also not sure what a KT120 powered amp would sound like.

Still looking.

Paul Sutherland · Post by **Paul Sutherland** » 28 Nov 2015 2:01 pm

As a follow-up question: Can anybody post a schematic of a Twin Reverb style power stage; only show the power amp; specifically leave off the preamp, reverb and tremolo wiring. I'd like to see how simple or complex it would be. Maybe I could show it around and have someone build just that.

Rick Abbott · Post by **Rick Abbott** » 28 Nov 2015 3:29 pm

TubeWorks Provalve? 4-6L6 in a dual-mono setup. Can be ran mono at roughly 100 watts (probably 85)

I'd sell mine. Butler designed. Looks like it would be cheaper to get a wider cabinet than to spend 1K + on an amp.

Stephen Cowell · Post by **Stephen Cowell** » 28 Nov 2015 3:55 pm

Paul Sutherland wrote:As a follow-up question: Can anybody post a schematic of a Twin Reverb style power stage; only show the power amp; specifically leave off the preamp, reverb and tremolo wiring. I'd like to see how simple or complex it would be. Maybe I could show it around and have someone build just that.

The easiest way to go that route would be to install a power amp in jack on a Twin, Showman etc. This is easy to do, folks usually sacrifice the external speaker jack on a Twin for this. When you plug in, it disconnects the preamp with a switching contact. Having someone build you a 4x6L6 power section will not be cheap... might as well build a Twin kit and put the PAI jack on it.

Back in the day companies made 'slave' cabinets, basically what you're looking for. Gibson, Fender, others made them... they should be cheap, since most folks won't have a separate preamp anyway.

Or you can go the hi-fi route... there's old Heathkits and Dynacos out there too. I used to have one with 4xEL34's, a real beast... stereo, 40w per channel.

Len Amaral · Post by **Len Amaral** » 28 Nov 2015 6:05 pm

See if you can get a Fender PA-100 or PA-135 that has he same four 6L6 and preamp section as a Fender Twin. These go for around $300 and would be a nice power unit with the mentioned mod for an input for your preamp.

Tim Marcus · Post by **Tim Marcus** » 28 Nov 2015 7:17 pm

Easily done. I could fit that into a very small package

Mesa and VHT made these exact amps years ago. Also, you can find old tube PA systems.

A modern version will probably sound better than a repurposed vintage one, but if you can find an old Mcintosh amp you'll be in very good shape

Brett Lanier · Post by **Brett Lanier** » 28 Nov 2015 8:50 pm

You could probably fit a McIntosh mc50 or Leslie power amp in a cab if you had the cab designed around those dimensions. The only thing I know of that will fit in a normal 1 x 15" steel cab would be a small class D amp like the amp in a TC Furlong Split cab or this http://bb.steelguitarforum.com/viewtopic.php?t=282246 .
I have an MC50 and it's awesome for steel. A lot better than the power amp in a twin in my opinion, I've compared them using the twin preamp for both. It doesn't fit in a Rick Johnson cab though, you'd need another inch or two in the bottom of the cab.

Patrick Ickes · Post by **Patrick Ickes** » 28 Nov 2015 9:55 pm

Skip Simmons in Dixon is pretty famous for redoing the old Tube PA systems. He's mostly loved by harp and blues guitar players, but he'd be a good resource if that's where you're heading. Might be a bit low powered and gritty for what you want, but another resource to check out.
Patrick

Les Cargill · Post by **Les Cargill** » 28 Nov 2015 9:57 pm

I can't help but think that a quilter Toneblock would be pretty sweet for this application. Small, light, inexpensive and available.

admin · Post by **b0b** » 29 Nov 2015 6:41 am

I think the Mesa 20/20 would be perfect for you. It's louder than you think it would be. I've used it in a dance band with two 8-ohm speakers and felt no lack of headroom. One rack space.

Paul Sutherland · Post by **Paul Sutherland** » 31 Jan 2016 11:54 pm

To follow up on an old thread: I bought a Peavey Classic Series 60 tube power amp off Ebay. It has 2 6L6 power tubes and 2 12AX7 tubes that I assume are driver and phase inverter. Supposedly 60 watts, but that's probably optimistic.

It was cheap, about $150 shipped. One power tube was broken and the power tubes didn't match. I replaced all tubes and have been playing the setup today. Using the Sarno gear mentioned before, a Wet Reverb pedal, and various JBL speakers, this setup really sounds good. I think the tube power amp brings out the best of the Sarno gear. I can't wait to try it at a gig. I think this might be great for recording as it's really quiet at idle.

It's a three piece rig, but each piece is much lighter and easier to move than a Twin. The Peavey power amp is listed at 21 pounds, not in a rack case.

Robert Parent · Post by **Robert Parent** » 1 Feb 2016 4:36 am

Hi,

There many places to get a Twin Reverb schematic, just search.... Here is the first one I came to:

http://support.fender.com/schematics/gu ... ematic.pdf

Robert

Ken Fox · Post by **Ken Fox** » 1 Feb 2016 6:12 am

I use an earlier model of the Carvin amp above for my church rig with a Transtubefex. I run it in bridge (mono) mode. Does a terrific job. The newer one mentioned above works the same and made in USA:

- All tube design, 4 12AX7, 4 EL34
- Internal bias selection switches for each channel (EL34 or 6L6/5881)
- Front panel volume and presence controls
- Front panel power and stand by switches
- Rear panel impedance, bridge, parallel, and ground lift switches
- Premium construction features metal bushings and shafts
- 19" 2U all steel chassis with Chrome front panel and knobs
- Dimensions: 3.5" high x 19" wide x 10.5" deep
- Weight: 25 lbs
- Made in San Diego, California

James Quackenbush · Post by **James Quackenbush** » 1 Feb 2016 8:19 am

As mentioned , some of your older tube power amps that were used for stereo , when it use to sound good !!...

Dynaco made a nice 60 watt mono amp that you could use in each cabinet ... Not 100 watts but plenty of power ....and it sounded GREAT !!.....Jim

Mark Wayne · Post by **Mark Wayne** » 28 May 2016 12:14 am

I'm new to the tones of a tube amp. What are some adjectives in general used to describe the tone in comparison to the solid state, Nashville 400's? Warmer? Thicker? More shrill? Peakier? Woofie? Etc.

James Quackenbush · Post by **James Quackenbush** » 28 May 2016 3:02 am

I know a lot of you guys are concerned with the weight of your gear since we're not getting any younger ...You could always go with a tube preamp, and a solid state power amp ....This combination would save weight , and still give you a decent tube tone ...The solid state power amps today are light in weight , and can give you a LOT of power for the $$ ....Jim

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