Jazz specific (tube) amp circuit - Have you one ?

[kagliostro]

Have you a preferred schematic (or commercial amp) for Jazz ?

K

[eleventeen]

For me, it's simply a Fender blackface with reverb and 12" speaker. Clean, 6L6 power. Little dirtier, 6V6 power. End of story.


It is so ironic and odd that before the 80's Fender never made a 35-40 watt single 12" combo amp. Why not?


With 35-40 watts of power you could get 2-10" (vibroverb/vibrolux/tremolux) 2-12" (bandmaster/bassman/Pro) 4-10" (Concert/Super)


And of course you could get 85 watts driving 2-12" in a Showman or a Twin or 1-15" in a Showman or a Twin but you could not chainsaw such an amp in half and have 35-40 watts driving a single 12".


And this was in an era where, across a product line, usually the differences from model to model going up the line were very very small. The best example would be a Martin O-18, O-18, OOO-18. Go look at a 1964 price list for those guitars, I believe a D-18 was $265 and the others were $10 less, each.  Maybe $15. That was actual money back then, I know. $30 might have been a week and half's work. (I have two brothers, one bot a D-18 and one bot an O-18, both in 1961) Back then, if you bought the top of the line you were thought of as a flaming egotist!


Mysteries of the universe.

I should also add, I continue to be very impressed with and regularly use my $190 used Peavey Valveking. This is an incredible value in an amp, there is no way on earth I or anyone else could build the thing for $200. even if I deleted the 2nd channel (with its full set of tone controls) You MUST replace the stock speaker which sounds terrible and is unusable except for test-bench purposes. Add some better quality tubes for the Chinese ones it comes with, esp the 6L6's, and it's a great sounding amp, very ruggedly built, and very cheap. They are available clean-used for $250 all day long. Nice sounding amp (again, the speaker replacement is an absolute requirement)  that can definitely get loud if needed.

[shooter]

The last custom build I did was a very clean amp that 2 players said, "this would be a great jazz amp".  It's a hybrid, sudo kit build, I used a Marantz clone pre-amp, (M7PP), matted to a 70Wrms SS PA amp (MV100) and tweaked so it wouldn't overdrive the SS amp till like 9 on the volume. FWIW

[HotBluePlates]

You have to ask, "What flavor of jazz?" Because some players are very clean, others very distorted.

If clean jazz, then why not just get a solid-state amp? But assuming you want very clean, and you want tube, I wouldn't do a Fender blackface. They are a slightly-fuzzy clean. For a pristine clean, you want to start with a 12AX7 1st gain stage, then a 12AT7 gain stage, then a 12AU7 phase inverter to however big an output stage you need.

Doing this, each gain stage has a successively bigger allowable input signal before overload. That keeps each stage running as clean as possible, for the cleanest possible output.

[DummyLoad]

http://el34world.com/Forum/index.php?topic=17282.0

[terminalgs]

Have you a preferred schematic (or commercial amp) for Jazz ?

various photographs of Rudy Van Gelder's studio show an Ampeg Gemini I, a Standel, and was known to have a Fender Tweed as a studio am (Deluxe, I think). the RVG recordings of kenny burrell and grant green seem to be generally credited to the tweed.

Wes Montgomery played Fenders live,, early on,  maybe a bandmaster or twin, later a super reverb.  At some point he played  a Standel, and then later a Twin Reverb.  He was very finicky about speakers.  I think there is a GP interview with Wes where is talks about this.  Joe Pass, Herb Ellis, George Benson, Jim Hall all switched to Polytones when they came out.. weight of the amp certainly having something to do with it.  tone stack's frequency curves might have been more pleasing to them as well? (guess)..


A lot of the sound comes from playing style, pick style, etc.  You'll find some people will say one guy turned treble and bass controls all the way down, and another guy turned them all the way up. Any Fender or Ampeg 12-45W amp can be super clean at the right volume setting, so it comes down to how loud does the amp need to be?

[6G6]

Assuming you want clean, a Silverface Fender Twin Reverb should do the trick nicely.
Sure, they can distort, but by the time you turn up enough to do that, you are risking ear bleed.

[Willabe]

Wes Montgomery played a SS Standel.


                 Brad   

[kagliostro]

Many thanks to ALL you friends

and ... I was thinking to something among the Fender amps and also the Standel 25L15

Many Many Thanks Again

Franco

[SoundmasterG]

Check out the Vox AC100 preamp also. Those are very clean amps and fully up one of those will sound like the Beatles I Feel Fine, but that is as gritty as they get. Quieter down they are very full and warm....one of the best cleans I've ever heard and played.


Greg

[jojokeo]

The Roland JC120 is about THE standard to which most a measured by and played. A very long time ago when I was sneaking into jazz bars with my dad there was a guy that played a Polytone that I can still remember hearing in the back of my mind to this day which had a particular bark & tone to it that was off the charts. I know a lot of it was the guy playing it but...

[kagliostro]

Many Thanks also to you Friends

Franco

[HotBluePlates]

and ... I was thinking to something among the Fender amps and also the Standel 25L15

If you do the 25L15, the JBL D130 is a big part of the frequency range and volume output.

[kagliostro]

Ciao HotBluePlates

I know the D130 is an important part of the sound of the 25L15

but if I don't want an exact replica of the original (Pete promised me a layout for his version of the 25L15 http://el34world.com/Forum/index.php?action=dlattach;topic=17282.0;attach=44133), which can be an alternative to the D130 ?

Thanks

Franco

[HotBluePlates]

but if I don't want an exact replica of the original ..., which can be an alternative to the D130 ?

I only tried an original D130. I know Weber makes the "California" to mimic the D130.

My point is the D130 is 30-17kHz, and 100+dB efficient (old JBL spec sheets don't say exactly) which puts a lot of volume in a room for 25w. But if you already have a favorite speaker for jazz, use it. However, I don't imagine there are many speakers out there which will be as clean, articulate and loud for the applied power as a D130.

[kagliostro]

Grazie

Franco

[darkbluemurder]

Maybe this one: http://roehrenfibel.files.wordpress.com/2009/03/jazzboy-baumappe-409.pdf


The narrative is in German, unfortunately, but the schematic and parts list are in there.


Cheers Stephan

[kagliostro]

Molte Grazie Darkbluemurder

I'm not confident with german language, but the project seems interesting and full of documentation

there is the schematic and a layout, and this, despite the language, are international 

Franco

[darkbluemurder]

I have not built it as I don't play anything remotely jazz. The special points about this amp are:


- triode push-pull power amp to get the maximum damping factor to control speaker inertia
- direct coupled concertina phase inverter using a 12AU7/ECC82 tube to get a soft compression rather than clipping
- variable global negative feedback to control damping factor
- tone controls by which you can only decrease bass and highs but leave the mids unaltered
- pentode 1st gain stage


Cheers Stephan

[6G6]

The EVM12L could be an alternative to the JBL.
They are a little flatter, even more 'hifi.
I think the JBL has a peak around 1-2K.
Both give you a lot of Dbs/watt, which is part of the recipe.
Anything that lets you get the output you want without having to turn the amp up will help it be cleaner.

[DummyLoad]

EVM15-L is the 15" EV equivalent to the JBL D-130. nice sounding speaker.


--pete

[PRR]

> EVM15-L is the 15" EV equivalent to the JBL D-130

In days when I could get either, I preferred the -130. The Lansing company really had it together, E-V just missed.

I do not find the EVM-15 in E-V current website?

The EVM12 is *clearly* the present "equivalent" of the old JBL D-120 types. The nominal efficiency, 5.9%, is well ahead of any other guitar speaker, and right up there where a "wide range" speaker should not go (Lansing picked the range wideness wisely, and E-V got to a similar place with different design).

Hmmmm.... the formal specs give 4.3% eff. Which is in-line with what I remember (and still huge for a Twelve). Wonder how the "5.9%" number is derived?

I'll be dinged. The 1828/1829 and CDP-828 are *still* offered. I made some money with those ear-rippers. The 828 is seen in M*A*S*H, and I believe it is semi-correct for the early 1950s.