Lowering power output

[James_rc]

Hi everyone. I’m jumping back into the hobby after about a 10-12 year hiatus. I made a few Lightning clones and some D’Lites back then, but I have a board and chassis set on the way from Taylor, and I’m really looking forward to re-learning things and building a JM Sig or Joyful Noise with it.

It’s really meant to be a bedroom amp, and I’m really attracted to o half-power switches that let you go from 22 to 10 watts, or even just a 12 water like the Princeton, or 5 watt power section like the Milk Man Half Pint.

Is it too basic to think I can just make a low-powered version of these two amps like that?

I’d be so grateful if someone could point me in the right direction for getting started. Have there been any threads on wiring up half-power switches? And if anyone’s built a low-powered version in general, I’d love to know how you did it?

[alkuz1961]

I once built an amplifier (#183) with a power scaler from London Power. It really works well and you can get 1-2 watts from a 100 watt amplifier

[timrobertson100]

These are super clean amps which have a really good master volume. I’d recommend building one to the max power you need and then using the MV for home use.

The two I built were both 22W combos and serve quiet home use and band practice (for my friend) really well.

It wouldn’t hurt to add a triode switch as well, but I’m a fan of keeping things as simple as they can be.

My build thread: https://ampgarage.com/forum/viewtopic.php?p=441492

[James_rc]

These are super clean amps which have a really good master volume. I’d recommend building one to the max power you need and then using the MV for home use.

The two I built were both 22W combos and serve quiet home use and band practice (for my friend) really well.

It wouldn’t hurt to add a triode switch as well, but I’m a fan of keeping things as simple as they can be.

My build thread: https://ampgarage.com/forum/viewtopic.php?p=441492

Thanks! 22 watts would be ideal. I’m going to head over to your thread.

[rootz]

I'm with Tom on this one. Yes, 22 Watt is less loud than 100W. But still friggin' loud as hell! I choose my 100W #94 with reverb over my 20W #124 with reverb any day. Sure, different amps, but there is a certain depth and boldness to the 100 Watters that is just not there in smaller amps. Not a bad thing perse, but if money weren't an option, I'd go with a 100W amp.

[James_rc]

These are super clean amps which have a really good master volume. I’d recommend building one to the max power you need and then using the MV for home use.

. . . there is a certain depth and boldness to the 100 Watters that is just not there in smaller amps.

I've heard this before. The other thing building a full power version has going for it is that I'm not trying to reinvent the wheel, and that's never a bad idea. In the car audio world, doubling power results in higher headroom but negligible differences in output. I think it's an additional 3dB or something like that. I'm not sure if the same holds true here.

If you can still get great tone with the master set low, I agree, it's prob the way to go.

[rootz]

Yeah, same is true here.
But it is not really reinventing the wheel to do a 2x6V6 amp either. Bias network is the same, halve the power tubes and different transformers. But that's about it.
The big plus of smaller amps is a bit lower cost and they are much lighter. But for the sound, the oomph, go bigger. There is no replacement for disp... well you know.

[Johnny_Boy]

I'm with Tom on this one. Yes, 22 Watt is less loud than 100W. But still friggin' loud as hell! ... but there is a certain depth and boldness to the 100 Watters that is just not there in smaller amps.

My understanding is that 100 watt amp will roughly sound twice as loud as 10 watt amp, and 10 watt amp will sound twice as loud as 1 watt amp. So if you think 100 watt amp is really loud, 22watt amp will be still way too loud. I would love to get 1-2 watt guitar amp that sounds fantastic for bedroom level (you can still crank these for 85-95 dB depends on the speakers) but I haven't found them.

[xtian]

I would love to get 1-2 watt guitar amp that sounds fantastic for bedroom level (you can still crank these for 85-95 dB depends on the speakers) but I haven't found them.

2 watts! Check out my Black Butte builds. Exactly that. Crank it up and enjoy!

https://www.maharsvintageguitars.com/pr ... 2022-black

[10thTx]

Over the years of amp building, I've become quite fond of the 6BM8 tube. The amp I play the most at home and at open mics is the 6BM8 "The Minimalist amp". The solo on this was played on The Minimalist. https://soundclick.com/share.cfm?id=14391017

Sometime back, I drew up the Tweed BluezMeister idea of using 6BM8 tubes. I have NOT built the amp so this is simply a DRAFT idea for someone who might be interested in coloring outside the lines and experimenting.

It obviously borrows from Dumble ideas ........ but I would NOT expect this to sound like a Dumble clone at all. (compare the schematic with layout & if there is a discrepancy go with the schematic. Check for errors!)

However, I think one could have a great sounding amp using this idea & have it be a small combo amp with a 10" speaker and use it as a home practice amp. I ran my Tweed BlueMeister preamp into the Minimalist power amp and thought it sounded good. No, it did not sound like a Dumble amp.

So IF one's goal was a portable grab and go 7-9 watt in a small combo cabinet, this might be a consideration?

Dumble came up with a great amp coloring outside the lines obviously.

We've had numerous members here use Dumble topology to come up with some pretty cool stuff. An example is Mat's "mini-HRM" (also his 86 Special) which is a single ended Dumble influenced amp that has superb tone, IMO. It sounds more Dumble like than some of the Dumble clone YouTubes I've heard.

https://soundcloud.com/ef86special/sets/seel84hrm His solo is later in the soundclip.

I am not suggesting you "should" build this amp. Just tossing the idea out in the mix for discussion and consideration.

Respectfully, 10thtx

[JM-1]

I was wondering about grafting a Dumble preamp with a Rob Robinette Blackvibe Micro which to my understanding, involves one 12AU7 output Tube in push-pull for 1W.

The only problem is to fit 8 potentiometers, 3 toggle switches and input socket on the front panel, the amplifier will need to be full size.

[sergio]

power scaler is the best solution! IMHO.

[JD0x0]

Since the power amp is mainly clean anyway... how about a *gasp* Class D output section with a tube preamp? I routinely work on 500W~700W bass amps and with the master volumes, can easily be tamed down to 3:00 A.M. bedroom levels.

Power scaling on tubes is cool and can definitely be useful, but I find it changes the tone a lot, as you are basically turning down the B+ voltage to the power tubes, so the sound gets more compressed and distorted as you starve the voltages. Could be a desirable trait on a Marshally or a Tweedle Dee circuit, but with the ODS amps having such clean power amps, I think it may be slightly less than ideal for the ODS circuits.

[rogb]

Since the power amp is mainly clean anyway... how about a *gasp* Class D output section with a tube preamp? I routinely work on 500W~700W bass amps and with the master volumes, can easily be tamed down to 3:00 A.M. bedroom levels.

Power scaling on tubes is cool and can definitely be useful, but I find it changes the tone a lot, as you are basically turning down the B+ voltage to the power tubes, so the sound gets more compressed and distorted as you starve the voltages. Could be a desirable trait on a Marshally or a Tweedle Dee circuit, but with the ODS amps having such clean power amps, I think it may be slightly less than ideal for the ODS circuits.

Well, *gasp*, I just did this, #183 preamp into Dumbleator into powerful Class D stereo amp. I convert the mono output into stereo via TC Hall Of Fame and Flashback pedals. I also have a Suhr MiniMix and TC G Major 2 rack FX should I feel like going with parallel loop.

I'm overseas at the moment so I only briefly tried the rig through a Marshall 2x12 and it sounded huge. I'll admit that #183 sounded better through a Marshall 9000 50+50w power amp but really unless you A/B them it's hard to tell the power amp is Class D.
I found it's best to turn the power amp up a bit, then control volume through the Master and the Dumbleator. You can play very quietly with this, of course.

I've just built a very lightweight 2x10 cab for stereo or mono, and in fact, just picked all my cab accessories at a store called Uraltone here in Helsinki, I must give a shout out to them, a great European source of parts, I got Vox cloth, Tolex, corners, handle etc.

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