Lowering my 50W Plexi clone efficiency

[olddawg]

Spend $100 and get an Epiphone VJ head. Don't waste your time screwing up a perfectly good amp that is working as designed.

[MWJB]

Olddawg, how is a switch that goes from low power back to bone stock "screwing up" anything? Why by a horrid sounding Chinese import, when you can get more flexibility out of something you already own & love? A decent DPDT/3PDT and a 10W resistor cost a lot less than a whole amp, even an Epi VJ.

[Hardtailed]

Olddawg, how is a switch that goes from low power back to bone stock "screwing up" anything? Why by a horrid sounding Chinese import, when you can get more flexibility out of something you already own & love? A decent DPDT/3PDT and a 10W resistor cost a lot less than a whole amp, even an Epi VJ.

Not to mention it's already pretty far from an actual Marshall 1987 circuit
(What's the point of building if you're not going to experiment with it )

[EFK]

I should mention that I keep a couple of 'project' amps (chassis only) around just for things like this - they're frankensteins, covered in rosin splatter and look horrible, but fun to try out things upon rather than the "real" amps.

[EFK]

Well whad'dya know, I just found a patent covering this,filed by - you guessed it!

[MWJB]

I think I can guess...hell, looks like they give out patents in boxes of cereal these days!

Let's hope the party concerned doesnt try to patent breathing, sleeping & eating next.

[olddawg]

Olddawg, how is a switch that goes from low power back to bone stock "screwing up" anything? Why by a horrid sounding Chinese import, when you can get more flexibility out of something you already own & love? A decent DPDT/3PDT and a 10W resistor cost a lot less than a whole amp, even an Epi VJ.

Because, I have never found a 1/2 power switch, power scaling circuit, VVR, power soak, or other "magic" solution that doesn't sound and behave worse than a VJ at low volume and I'm not a cork sniffing gear snob. If you only need 5 watts, use a 5 watt amp. I have lots of vintage amps of various output power ratings. With a tube change (and it's actually ok with the original tubes) my "horrid" little Chinese import sounds great for the correct application. Many times I show up at a session with it. There are guys there with $10K worth of amps and guitars. I have my VJ, an old Tremolux 2X10 cab, (pedalboard) and my old '83 Squier Strat. Guess who sounds better. Choose the amp for the venue. Use your ears and not your ego. When you need 5 watts use a 5 watt amp. When you need 20, use a 20 watt amp, etc.

[MWJB]

Then try some of the switches I suggest. I have amps switchable from 70W to 7W...often sound better on the lower settings & sound better than any Epi Vr out of the box...even with a pedal board & another cab;-).

Hmmm...I know guys who have 10K, or more's worth of amps...I don't personally know any with 10K invested in one amp (you typically still have to buy 2 Clarks, Victorias, or Kendricks to get into that territory...I haven't seen much about the 10K+ Veros in a while...? ). You still need a guitar/instrument to play a Epi V Jr....it can still be 10Ks worth with the right guitar. I wonder how many "guys" really turn up at your jam with 10K amps? In short, your logic kind of eludes me. I'd play every gig with the amp that sounds best (1/8th W to 7W in my case), irrespective of venue, a strong drummer with sticks & bass rig are usually the lowest common denominators (given that everyone will be mic'd up in a big venue anyway).

[olddawg]

Then try some of the switches I suggest. I have amps switchable from 70W to 7W...often sound better on the lower settings & sound better than any Epi Vr out of the box...even with a pedal board & another cab;-).

Hmmm...I know guys who have 10K, or more's worth of amps...I don't personally know any with 10K invested in one amp (you typically still have to buy 2 Clarks, Victorias, or Kendricks to get into that territory...I haven't seen much about the 10K+ Veros in a while...? ). You still need a guitar/instrument to play a Epi V Jr....it can still be 10Ks worth with the right guitar. I wonder how many "guys" really turn up at your jam with 10K amps? In short, your logic kind of eludes me. I'd play every gig with the amp that sounds best (1/8th W to 7W in my case), irrespective of venue, a strong drummer with sticks & bass rig are usually the lowest common denominators (given that everyone will be mic'd up in a big venue anyway).

Amps and guitars dude, truth. It isn't hard to rack up $10k in gear nowadays. Especially if they have custom and/or vintage stuff. That 59 LP Jr DC in my siggy is probably half that. My real point is why drag around some big beast if you don't need it. You are right about hard hitting drummers, but I rarely need more than 20 watts unless I'm outdoors or on a really big stage (and then sometimes only for looks) with anyone. If you want great rich low volume breakup, a single ended EL84 amp is always a good choice IMHO. VJ heads are super cheap (a lot cheaper than an attenuator) and (the late production ones at least) sound pretty damn good right out of the box. It's just another alternative, choice, and perspective. Use what you want and mod it however you like. However, if there was a magic bullet mod to make a big amp sound like a big amp cranked at low volume, every manufacturer would be doing it. The closest thing I've seen is modeling amps and I don't much care for those.

[Steve Conner]

If you have a job, you can say your time is worth whatever hourly rate the man pays you. I bet it's not that hard to have 10k worth of time invested in a homebrew, especially if you count all the research and failed prototypes you needed to get to where you wanted to be. If you just went to a store and bought a Valve Jr. none of that would be required. (But of course you would instantly feel an urge to mod it...)

Good tone at low volume is a kind of holy Grail. I don't think it is possible. Playing the electric guitar is all about loudness, aggression, and then you have all that Fletcher-Munson stuff. You might as well ask for a Harley that you can ride round your yard without waking up the neighbours.

I've had some success with inverse power scaling. You start by admitting that you are too old to rock any more, and your amp will mostly be played at modest volume. Then you design it to sound good like that (implying some sort of Champ or VJ type thing) and add a "Herzog" device for the occasions when you need to get louder, or cleaner.

[MWJB]

Some manufacturers are already selling stage powered amps with low powered capability, whether by switching in/out power tubes, PP to SE, on board attenuation etc...the main reason why the mass market guys aren't aiming at <5W amps, fixed bias octal outputs, with big amp features like reverb & efficient speakers is because there are only so many folks who will pay the price hike over a more cheaply built, entry level SE amp. Guys like Kendrick, Carr & Victoria have that covered, at 10x the price and up, over the Epi.

And yes, I agree that a fixed bias amp with 25W tubes, running around 500vdc, with over 300sq. inches of air pushed by the speaker is likely to be perceived as much louder than a single low efficiency speaker, cathode biased SE amp @ 3-400vdc on the plates and ultimately if any switching/low power mode negatively affects dynamics, the player will most likely just turn up...but like I said, I'm a tight wad, I only buy an amp on very rare occasions, if there is something I want to try then I build something to test the theory (OK, building costs more than buying a Chinese import, I'm shooting myelf in the foot here), but most of the time, with a bit of thought major "steps in the right direction" in power reduction are achievable...if not exactly a panacea. Though of course, an amp's loudness is measured in dB, not W...can be a degree of swings & roundabouts.

Steve, I like the theory about converting your day job hourly rate to be added to your amp "value"...a shame it isn't reflected in the market place...what happens when you see a hobbyist hedge fund manager trying to e-bay his home brew 5F1, that took him 3 weeks to eliminate hum hum & oscillations :-o I'll wait till the rush of bids dies down on that one ;-) My "amp work/building rate is 3-4 times what my day job hourly rate is....but then building is an ad-hoc exercise for most, rather than 40 odd guaranteed hours per week in the office PAYE. Again, if that amp building job guarantees you 40hrs a week, 48 weeks per year, you can bet market forces will just push that hourly rate back down again. Check out what Mojo charge for assembling you a 5F6A, or 5E8A...

[Steve Conner]

the main reason why the mass market guys aren't aiming at <5W amps, fixed bias octal outputs, with big amp features like reverb & efficient speakers is because there are only so many folks who will pay the price hike over a more cheaply built, entry level SE amp.

This doesn't really make sense. If you sell a 5W amp, surely it's because bigger ones are too loud. So why go to all the trouble of designing a quiet amp only to make it too loud again with efficient speakers?

Steve, I like the theory about converting your day job hourly rate to be added to your amp "value"...a shame it isn't reflected in the market place...what happens when you see a hobbyist hedge fund manager trying to e-bay his home brew 5F1

Well, as any hedge fund manager knows, the value of an investment can go down as well as up!

I gave the example more as an "opportunity cost" to help in personal decision making, ie, if you used the time spent building the amp to raise money to buy one, would that get you better value for money? It should have been obvious to said hedge fund manager that just buying a half dozen amps with the profits from the morning's trading would have been a better use of his time.

Of course this doesn't take into account that he might actually want to build it as an educational experience.

[MWJB]

"This doesn't really make sense. If you sell a 5W amp, surely it's because bigger ones are too loud. So why go to all the trouble of designing a quiet amp only to make it too loud again with efficient speakers?" Efficient speakers will increase loudness to a point but they also help a low powered amp retain detail & dynamics at lower volume... a low powered amp with a low efficiency speaker may have to be driven harder to perform, or may simply never deliver on clarity. It's a fallacy that very low efficiency speakers make your amp easier to play at low volume. Also, a specific speaker's tone may not be easily replicated by a different model, irrespective of SPL, so if you've got something you like, it makes sense to stick with it.

Even if you do decide to build & market a 5W amp with fixed bias & efficient speaker, like the Carr Mercury, the lower dissipations at the OT secondary make attenutation a simpler/cheaper affair.

"I gave the example more as an "opportunity cost" to help in personal decision making, ie, if you used the time spent building the amp to raise money to buy one, would that get you better value for money?" Aaah, you are applying logic to a situation where none, or certainly very little exists :-) If any would be builder weighed up the costs of small scale amp building, including a realistic hourly rate, against purchasing even a mid priced hand built amp, then the head should say, "for the small percentage in difference, I should just buy the amp that comes with a waranty"...but when you've got an itch, you can't help but scratch...and as you say, the experience of building is the best way to educate yourself on the matter (both in terms of executing a design & in the economics of amp bullding). It's virtually never the most cost effective solution, but hell, can it be gratifying...:-)

[Chuck H]

Buying a well respected "production" amp and then adding a better speaker, known circuit mod, tubes, etc., may be the most cost effective way to get a good tone at any wattage. One of my customers was using a Peavey classic 50 (that I tweaked a bit and changed speakers in) before getting his new custom amp. Now the Peavey sits in the corner gathering dust. I was in his studio alone two days ago and just for curiosity I plugged into the Peavey and it sounded VERY good. Embarrassingly good considering the amp I built custom for him at four times the cost sounds only a little better.

But we don't build amps for the cost savings. We do it for the same reason some people cook at home. Buying expensive kitchen gadgets and gourmet ingredients that often render a meal more expensive than what you could have at a five star restaurant once you figure in your time for prep and cleaning up.

The above customer is a friend, so he did get the nice price. But after materials and my meager fee his cost for the amps and cabs I built was still only about $400 under what he would have paid for many well known "boutique" amps. But... It was a fun project and a custum order. I love to design new stuff and build one of a kind gear. I like the designing and tweaking best. The building part is fun too for custom fabricated stuff. And the basic loading and wiring is sort of like knitting or just doing a jigsaw puzzle. It's relaxing in that good way that requires your focus but isn't that hard to do. But the best part is how every time I build an amp I stand back at the end and think "Wow, look what I made." And then some really discriminating player might play through it and say "Wow, you made that?" And inside I'm thinking "Yeah, look what I made."

If I was only doing it for the money I wouldn't. I have a day job that pays much better.

[EFK]

Right on!