How much do power amps affect tone?

George Kimery · Post by **George Kimery** » 21 Mar 2020 9:36 am

I've had different power amps over the years and never really thought much about how they affect tone.I always thought that the tone was all in the pre-amp section. I have my Evans stereo pre-amp run through the RCA tape inputs on my Stereo Steel power amp section. Sounds good to me. If I had a separate, dedicated power amp would there be a noticeable difference in tone?.

Larry Dering · Post by **Larry Dering** » 21 Mar 2020 9:57 am

George, just from my own experience, it does matter. I tried a Peavey DPC 750 using the Profex II and a Peavey tube preamp and it sounded sterile. I subbed in a couple other stereo power amps and the same results. However the Stewart world power amp sounds good to my ears. Not very scientific but using what I had and same speaker cabinets, both 115E Peavey.

Earnest Bovine · Post by **Earnest Bovine** » 21 Mar 2020 10:06 am

For my steel, the Mosvalve power amps sound better than the others I've tried.

Donny Hinson · Post by **Donny Hinson** » 21 Mar 2020 10:54 am

Most power amps are designed to have a relatively flat response curve. They do have tonal differences, naturally, due to design quality and the components used. But those differences are likely far less than the differences made by preamps (and their settings), speakers, and the speaker enclosures themselves.

It's also good to keep in mind that musical instrument amplifiers are pretty far from being "high-fidelity devices", due to their design and market constraints.

Jerry Overstreet · Post by **Jerry Overstreet** » 21 Mar 2020 11:04 am

Earnest Bovine wrote:For my steel, the Mosvalve power amps sound better than the others I've tried.

Me too. The BK Butler propaganda states the MosValve amps are built to produce sound vs. reproduce sound.

I take that to mean instead of the traditional neutral and flat approach he intentionally colored the sound. Actually tailored the amp to deliver what he wanted and liked.

They seem to credit part of it to the type of output devices that they call mosfets. [metal oxide semiconductor field effect transistors.]

There's probably a technical bulletin somewhere where he talks about how it was designed to be musical in nature, how the devices behave in a push pull manner similar to output tubes, etc.

I don't really know about all of that, but I do know I like the sound of the 2 that I've used for years.

So yes, I think the power amp affects the sound.

Steve Lipsey · Post by **Steve Lipsey** » 21 Mar 2020 11:59 am

Uh....tubes!
Preamp tube response warms things up (like a Sarno Black Box) but final amp tube response is a treat...I learned that from standing in front of a Marshall stack - once the master volume got past 8 or so it had a magical effect on tone.

And I loved my Milkman Pedal Steel Mini (40 watts) even more than my full-size Pedal Steel amp (85 watts)..with fairly frequent chances to play it dimed it really sang...not the totally clean tone some seek, but a rich, warm sustain...

That's why folks are using smaller tube amps for so many things now...finally learned to make them sing at reasonable volume...

I'm not sure that is what you are asking about, but that's where I'm at. Now using a Milkman "The Amp" and sort of missing the "goes to 11" tone, but fitting it on my pedal board has gotten more important as the years progress..

Brett Lanier · Post by **Brett Lanier** » 21 Mar 2020 1:17 pm

I used to have a McIntosh mc50 that sounded great. It's the smallest mono version of McIntosh's early transistor amps, but still very loud. I did some comparing with other amps and it was always the winner for steel... I was able to compare it to the power amp in my twin by taking a line out, into the McIntosh, then back into the 15" speaker in the combo. Even at 50 watts it was louder and more robust sounding than the power section of the twin. At home I would often play straight into the McIntosh power amp with no preamp. It wasn't very loud but it was a completely quite signal with a very well balanced eq.

Jack Stoner · Post by **Jack Stoner** » 21 Mar 2020 2:23 pm

Back when I was into "Stereo" for steel I tried several power amps including Peavey DPC 750 and 1000 and several other "PA" type amps and they all seemed "sterile". Very flat and "Hi Fi". I got a MosValve 500 power amp and there was the tone.

Gabriel Edell · Post by **Gabriel Edell** » 21 Mar 2020 5:17 pm

Jack Stoner wrote:Back when I was into "Stereo" for steel I tried several power amps including Peavey DPC 750 and 1000 and several other "PA" type amps and they all seemed "sterile". Very flat and "Hi Fi". I got a MosValve 500 power amp and there was the tone.

Which makes sense as the MosValves were designed to emulate the sound of an overdriven tube power section, which they do pretty well. They colour the sound - in a good way.

David Spires · Post by **David Spires** » 21 Mar 2020 7:51 pm

Everything affects everything...

But, I've heard Paul Franklin though Nashville 400s, a Walker Stereo Steel, Little Walter, and (although noticably not HIS sound) a Line 6 POD 2.0, and...

Paul always sounded like Paul.

The ideas, musicality, and execution win every time.

(as I try different gear today, looking for the elusive magic, not listening to my own advice...)

Sincerely,

David Spires

Steve Hinson · Post by **Steve Hinson** » 21 Mar 2020 8:19 pm

+1 for the Mosvalve!

I use the Mosvalve with either the Mesa Boogie Studio Preamp or the Evans single space preamp bout every day...
closest thing I've found to a Twin...with extra headroom...

SH

Sandy Inglis · Post by **Sandy Inglis** » 22 Mar 2020 12:41 am

Hi George, Be aware that some RCA Tape inputs can be tone compensated to roll of the pre-emphasis of the old tape players. I'm not sure that that will be the case now but it's something to think about. You are better going into a line input if you can.
( I used to work in Radio & TV a long time ago).
Sandy

Godfrey Arthur · Post by **Godfrey Arthur** » 22 Mar 2020 12:43 am

Even if you used the exact same model of power amp for your extension, there would be a tonal difference just because that's the nature of things. Not unless you went through 2 dozen of the same model to match the tone of the 1st amp would you get something "ballpark."

But as others chimed, using McIntosh amps, the power amp depending on build will all sound different.

Not only does the amp make a difference, the transformers in them make a difference in tone which is why you have companies like Mercury Magnetics making alternatives.

Bass players back in the 70's used to use a Phase Linear power amp because there was a circuit in one of those models that pulled the speaker back to "0" to get ready for the next note making for a tighter less muddy response because the speaker's cone was electronically pulled back rather than wait for it to spring back on its own... just to give an example of how design is varied. Imagine using such an amp for steel with the complexities of chord clusters and attack variations, if this type amp would work well for steel.

Ian Rae · Post by **Ian Rae** » 22 Mar 2020 4:02 am

No amplifier is inherently flat - it has to be engineered that way. For hi-fi it's a no-brainer, but for musical instruments (including the voice) it makes sense to tailor the response to its end use.

Having said that, the Telonics power amp I use does claim a flat response from 20Hz to 20kHz just like a typical hi-fi.

Erv Niehaus · Post by **Erv Niehaus** » 22 Mar 2020 7:54 am

I have a MosValve amp in my rack. Along with a couple of other TubeWorks units: a 12 spring reverb and a Blue Tube preamp.

Erv

Bob Hoffnar · Post by **Bob Hoffnar** » 22 Mar 2020 9:48 am

When I was into separate power amps I found the difference to be significant. The VHT 2/50/2 was my favorite. Really amazing sounding. I just got tired of hauling around all that stuff and moved on to different amp set ups.

There seems to be a difference in the class D amps I hear in different powered speakers and amps too. Some sound pixelated or maybe like florescent lights compared to incandescent to me. Others sound even and smooth. Those differences are pretty subtle though.

George Kimery · Post by **George Kimery** » 22 Mar 2020 11:15 am

When I got the Evans pre-amp, I had to have a power amp. I bought a Stewart 2.0 from a local steel player that he wasn't using any more. It was very heavy and wouldn't fit into my rack case. I had my Stereo Steel system at the time and during an unrelated conversation with GD Walker, I mentioned the Stewart. He said I could use the RCA inputs on the Stereo Steel as my power amp. So I made up two short adapter cords with RCA plugs on one end and 1/4" mono plugs on the other ends. The Stereo Steel combo amp was never designed to be a power amp so there are no 1/4" direct in jacks, only the RCA jacks which are convience jacks for hooking up a tape player.
I sold the Stewart so I don't have it to compare to the Stereo Steel. I have never noticed any problem with the sound I'm getting with the Stereo Steel.

I'm mostly using my SE 200 combo amp on gigs now.
Should I decide to sell my Stereo Steel, then I would need a power amp. From the feedback, it looks like MosValve would be a good way to go.

As always, thanks to all of you that have responded. You have been very helpful.

Jerry Overstreet · Post by **Jerry Overstreet** » 22 Mar 2020 11:54 am

I have stereo MosValves 962 and a 942. The biggest issue with TubeWorks/MosValve products is the control pots. They get noisy and sometimes cut out altogether. Just FYI.

Otherwise, they are heavy. The 500 watter weighs in at about 32#. The 2 sp. 160 watt a little bit less, but bulky. They also made one of these in a one sp. rack size.

They sold out to Genz-Benz and labeled them TubeWorks instead of MosValve. The 500 watt amp is a model 1500 in the GB line.

George Kimery · Post by **George Kimery** » 22 Mar 2020 8:16 pm

Jerry, I had one of those heavy TubeWorks power amps. I thought from the name, I had a tube power amp but I remember being corrected on the forum. I had a pre-amp like Herby Wallace was using. I am think it was a MosValve, but I'm not sure, it was a long time ago. I had forgotten about the weight of that TubeWorks power amp. Thanks for reminding me. I will just keep what I have. The combination of the Evans and Stereo Steel is a sweet set-up and I can go from one to the other by just moving the guitar cord.

Larry Dering · Post by **Larry Dering** » 23 Mar 2020 2:59 am

Jerry is right on the pots. Plus they have extra long connection legs wich are uncommon and hard to source. I spoke to one of the Tube Works engineers who had the pots but they were pricy.

Erv Niehaus · Post by **Erv Niehaus** » 23 Mar 2020 7:05 am

If I remember, the TubeWorks pots were smaller than standard in size.
I haven't dealt with them of late but Genz Benz were good to get parts through for the TubeWorks stuff.
I bought my original TubWorks stuff through Emmons, they sold them.
The Blue Tube pre-amp is hard to beat.

Erv

Jerry Overstreet · Post by **Jerry Overstreet** » 23 Mar 2020 3:47 pm

TubeWorks/Mosvalve pots are dime sized 16mm long leg vertical PC mount type. I did not go to GB because I wanted enough to do all of my units.
smallbear-electronics.mybigcommerce.com/ is where I got mine, but I had to cut down the legs on all of them to fit these amps and units.

I ordered about 30 of them from this co. They were just over a buck apiece and he has them in all both types.

I used a dremel to narrow the legs to go far enough down in the board.

Kenneth Kotsay · Post by **Kenneth Kotsay** » 24 Mar 2020 9:07 am

I have the Peavey DPC 1000 and a Mackie FR Series 1400i power amp, both satisfy my needs, I find no problems with both, tone sounds awesome.

George Redmon · Post by **George Redmon** » 24 Mar 2020 11:27 am

Every single word that Steve Lipsey said!

There's something about sitting in front of a 68 Plexi, through a Marshall stack, with just the right amount of compression, and an old Goodrich pot pedal, and the steel of your choice, to make you feel all warm inside and giggly like a school girl.