A Little Green Wonder Box - Part 2

[mrpicard]

Well, I thought I would show something that could rival the wonderful Elpico amp presented by Graham. The Elpico AC52 is a classic from the past but this could be a classic from the future. Quick details are:

1. Built by two of Europe's top amp designers.
2. Hybrid solid-state preamp; there are no opamps.
3. Single end power stage using a NOS ECL82/6BM8 tube (the ECL82 is triode plus pentode).
4. Goes from NEAT to OTR (On the Rocks); activated via a footswitch. I am pretty sure that this is a built-in-fuzz using a NPN transistor.
5. Three knobs (a) "Louder" knob controls the volume (b) "&" knob smoothes or roughs the "rocks", only active in OTR mode and (c) "More" knob is the real innovation. The operating mode of the power tube is continuously variable between triode and pentode with varying degrees of Ultralinear (UL) mode in between. So, the "More" knob reduces the available output power in the triode mode it also provides some presence/edge boost as the knob is turned more towards UL/pentode modes.
6. Output power in pentode mode is ca 3W, in triode mode drops to about 1W.
7. 12" 8 Ohm Eminence Red Fang speaker.
8. Red powder-coat chassis.
9. Seven vertical slits in the front baffle that work as sort of acoustic Fresnell lens and provide some treble dispersion in horizontal plane.

The inspiration for the tone was "a Chicago tape recorder with a diode input". It is the kind of tone I have heard lots of people from the '50s, '60s and early '70s say was the best thing they ever heard. Evidently this amp is very loud!! Anyway, I have no financial involvement at all but I though that this little guy just seems to capture that little amps of the past and it sounds pretty amazing. It is nice to see new amps made with the spirit of the past.

Here are some demos of the prototype:

http://www.youtube.com/watch?v=8ljVltgU ... re=related
http://www.youtube.com/watch?v=hcN3bZBz ... re=related
http://www.youtube.com/watch?v=v5l4QdaQ ... re=related
http://www.youtube.com/watch?v=kfJrqdmC ... re=related
http://www.youtube.com/watch?v=Qq1gAMs4a_4
http://www.youtube.com/watch?v=bGqe17V49pY

There are other related videos in the same area.

I understand that the amps are not fully finished yet so these photos of the amps don't have the logos, the labels on the chassis etc, etc so I think there is more to do. Interesting though.

[psycho*daisies]

wow, cool little (big) amp!

Not sure about Graham's, but my Elpico is nothing like that though...

That little thing sounds very harmonically rich and "tweaked" by an amp designer...
...even though it's a 3 watt amp, in a way it sounds a bit hi-fi in it's construction....
a modern, efficient speaker, etc. Hot, punchy, creamy...sounds great...
very boutique-esque. Maybe a little too much so, for my tastes...
I mean, it's almost a little too sweet sounding,
if you get me. Kinda like Mesa Boogie amps.
I like a shittier sound, personally.

Similar to a smooth, soupy fuzz tone with endless sustain...I'd prefer a spitty, gnarly one instead.

The Elpico is much more ratty, inefficient and old school sounding and probably not as loud.
It's got a great overdrive sound, but not as rich in bass or harmonic texture, I'm quite sure...

but i love it just the same....now, just gotta get it working again! (Major caveat of buying a 46 year old amp)

[Graham]

That amp looks nice and it sounds to have a few interesting twists tone wise although there isn't that much new under the sun when it comes to valve amps ---but I have come round to understanding that "big is beautiful" isn't always the best model when it comes to chasing the dragon of tone - I mean the kind of overdriven tones I as a fully fledged fuzz fiend like the most. Sure it's cool to stand in front of a towering stack and "ride" the wave of air they can throw out - everybody ought to have the chance at least once in their lives of strapping on a nice Les Paul and plugging into a 100watts of hot glass atop eight or ten nice speakers (12 even if you can reach the controls and dont mind the risk of it all toppling down on to[ of you -not to mention the impedance trickiness of 3 cab stacks!) No doubt about it at all - feels like the best thing in the whole wide world to get a 100w Marshall feeding back without a pedal! Visceral - (means in the guts!)!!

BUT most of us live in the real world where a full blown 100 watter (or a fifty for that matter) would be just too much - you try setting up a 100w head and a pair of 4x12's in your local boozer and see if the landlord will mind you going above 2 or 3 on the volume!! Lord knows I been there often enough! And somehow (says he with several nice plexis still in the den downstairs) using an attenuator is like having sex with a double thickness condom or getting your hands on a nice 150mph motorbike but living within a 30mph limit...with roads full of full of speed humps

No like I said the bigger the better is no longer my mantra - I enjoy hearing my hot glass at meltdown level and then giving it a little bit of a kick with some transistorised condiment - a decent size for me these days is definitely down around five (true) watts - particularly through an appropriate speaker when indoors - (but ten or fifteen is better if playing out in a smallish setup) but surprisingly a well built tube amp of even ONE watt can be easily loud enough to uspset people in the room next door......

Enough - almost into "rant" mode - back to the post:

When I apply myself to working out how to do the pics here I'll dig out some seriously old amp porn - I have a few from the earliest days of "portable amplification" temperamental beasts that are prone to give you the odd little "tickle" through the strings just to remind you who's in charge and what they are tunning on.....

I stuck up some pics on the old forum of a nice '55 Tweed Gretsch Electromatic but I have some from the forties and several more from the early fifties - A favourite is a lovely big old Epiphone with a sloping topped wooden case (nice figured maple) and a cool art deco fretwork epi E over the ancient 12in Rola speaker - like the old jazz or big bands used also a small tweed "Serenader" a beautiful little gem of a thing - Also got a nice old Kay - again in a flame maple art deco case and a nice cool blues amp with a big old field coil Rola giving it the same compressed/overdriven sound you hear on those old Elmore James tracks --some of those pretty little lap steel amps in their "Mother of Toilet Seat" material are also worth looking into - sure they are not so loud but give a surprisingly pleasing tone when running on decent tubes and have had any dried out caps replaced - a wonderful thing a little magnatone on song! - I could go on but suppose I ought to stick up some pictures..

G

[mrpicard]

... I have come round to understanding that "big is beautiful" isn't always the best model when it comes to chasing the dragon of tone...

Definitely agree with that. History is littered with people getting "big" sounds from small amps. Putting your ear 2 inches away from a 3W is way louder and more powerful than listening to a bank of 100W amps from 200 feet away :-)

[mrpicard]

...although there isn't that much new under the sun when it comes to valve amps...

Graham, have you seen a tube amp that is continuously variable between triode and pentode with some ultrlinear in between? This is sometime I have not seen before and I can't find anyone else doing it. I have heard that the basic idea was published in 1972 in a Czech electronics magazine but it never made it to a final product. I was wondering if anyone else had tried it...

[jimi_dylan]

using an attenuator is like having sex with a double thickness condom

[Doctor X]

...although there isn't that much new under the sun when it comes to valve amps...

Graham, have you seen a tube amp that is continuously variable between triode and pentode with some ultrlinear in between? This is sometime I have not seen before and I can't find anyone else doing it. I have heard that the basic idea was published in 1972 in a Czech electronics magazine but it never made it to a final product. I was wondering if anyone else had tried it...

Hi! I'm a newcomer here and thought I'd mention that this sounds a bit similar to an amp of mine that goes from 3 to 1 watt's with the turn of a dial. Sorry, but I don't know anything about amp mechanics or how my amp does what it does. It's one of these: http://www.sheldonamps.com/truetone/tt3.htm

[mrpicard]

That Sheldon TT3 looks like a very interesting amp. Instead of using a variable triode/pentode approach it gives you a lot of control over the tube bias, thus giving you different tube-based textures. I love these little amps. These amps are kind of a half-way point between foot pedals and "big" amps. If you have all the foot pedals you want then move onto small amps and collect all them...

[mrpicard]

Hey, it comes as just a head as well.