i second that, my bedroom fender m-80 had a subtle reverb until i discovered that one of the spring's end was not attached to the pickup. Its weight was damping the overall reverb capabilities of the tank. fix that and you'll have a great reverb! probably the tank on your fm65 is similar to mine: accutronic short tank with three springs (it's a medium reverb lenght model.)

if you look at high-end hi-fi power amps there's only a volume knob.  But we're speaking of power amp. A preamp HAS has a tone on it's own.

Concerning the small parts count i don't know. I suppose that for preamp simple is better but too simple probably it's not enough. Talking about bass you need a little bit of compression, clarity, and probably more than two gain stages.

Too much gain for one stage = distorsion
a lot of distorsion from only one stage = probably sounds ugly
a bit of distorsion from a lot of stages = probably more ear pleasing

That's just my 2 cent and i' no electronic expert.

thank you very much Joe.

if i think about fet and bass preamp i think about this one

http://www.albertkreuzer.com/pics/el/pre/schem/preamp_sch21.gif
http://www.albertkreuzer.com/pics/el/pre/schem/preamp_pcb21.gif
http://www.albertkreuzer.com/pics/el/pre/schem/preamp_comp21.gif
http://www.albertkreuzer.com/psu01.htm

keep in mind that this preamp is made by a bass player, not just
an amp emu. It's made to work at +-15v. So you'll have all the clean sound and power you want.

i would be interested! But i live in italy how much would be the surface parcel shipping?

Marco
marco_andreettaATyahoo.it

yes but look at the schematic!

it's a really simple two stage preamp. now look at the fetzer of runoffgroove, the sixteen overdrive
http://diy.erikhansen.net/schematics/misc/sixteenoverdrive.gif

as you see it would be really simple to tweak this one. changing the caps would change the general tone
and if you keep in mind biasing you can change almost everything keeping the layout!

i think that this pedal/preamp will be my next build.

no i don't.

Now i have a fender stereo setup
fender twin with all the modulation pedals and the other channel is a fender m80 transistors with
meazzi echomatic tape delay.

But you should consider building a tube preamp. or maybe a tube stompbox in front af a solid state pre
like the tube driver or the real mctube on tonepad (i've heard great comments on the real mctube, and it seems
very easy too)

i used for some months a mesa v-twin stompbox into a 20W mesa power amp.
it was really a great pre, used also into a mixer with
runoffgroove cabinet simulator.

i'll post it as soon as i can. there are some interesting things: the reverb circuit is great and can be reused. for the gain it can be calculated and modified.

i received yesterday the schematics of my solid state amp from the italian distributor. it's a fender m80 amplifier with tl072 based pre and darlington final. i do think that fender eq sounds better on ss amps than marshall eq. i can scan and post the schematic if you want. it's a clean pre (it's easy to get rid of second channel) with reverb circuit.

i would prefer instead using jfet a la runoffgroove: fet are not like tubes but they break up (their non linear region response) is softer and very beautiful sounding.
i would probably mix the design of opamp and fet: maybe two or three fet stages with simple eq (like the big muff eq) and a simple low pass fixed filter in the end to get rid of the ear piercing frequencies.

even simpler: a mosfet stage>> simple big muff eq >>  fet stage for warming up the signal and simulating a little bit of power amp break up and maybe in the end a simple fixed low pass filter.

i hope not to be confusing, my poor english doesn't help me

the program is very easy to learn. I wish it had Pspice capabilities for simulation...

Since you are building a new pre i would try to add a fet buffer in front of the ic. It's not
very good to have the guitar signal directly hitting the opamp.

You can fet buffer and boosters everywhere. Look for the "fetzer valve" in the Runoffgroove webpage.
www.runoffgroove.com

Try a fet buffer before your  Dean Markley exisisting amp.

you should learn to use the free pcb-cad program EAGLE and etch your own pcb at home :tu:
it's really a rewarding experience and gives better understanding on what you're working on.

look what i've found...
http://guitargeek.com/gearview/1134/
http://guitargeek.com/gearview/418/

I think that roland jazz chorus where used a lot by pro. i think it was the Roland JC-120 Jazz Chorus.

It was used for sure by Slowdive.

One of the Radiohead guitarist uses a fender SS amp in stereo with a vox ac 30.