Yamaha 1280 solid state guitar amp with tube pre section ...Help me, i need schematic diagram or manual service.
:dbtu:
Thanks
Mystery amp, not even Yamaha mentions it in its own page.
What kind of problem do you have with it?
QuoteMystery amp, not even Yamaha mentions it in its own page.
Yamaha has plenty of mystery amps in their sleeve.
Evidently they made a whole series of these hybrid amps in Italy.
Thanks for answers.
I would like to make changes to the preamp to get a warmer sound.
In origin it is very harsh and metallic. (the tube is ok)
I tested an external preamplifier and the sound improves. direct entry into the "return"
http://en.audiofanzine.com/guitar-combo-amplifier/yamaha/1280r-tube-80w/medias/pictures/a.play,m.716654.html
http://en.audiofanzine.com/guitar-combo-amplifier/yamaha/1280r-tube-80w/medias/pictures/a.play,m.641318.html
Hi Giulio, welcome.
What is the valve/tube type in the preamp?
If it's a 12AX7 then there are several other twin triodes which are plug in substitutes with less gain that may make it sound less harsh, 12AT7, 12AY7, and the lowest 12AU7. YMMV.
Hi Roly, Thank you!
Original is a 12ax7w I tried with different types of valve-tube.
noticed a change in volume, but the sound as transistors poor cheapest. :-\
This amp model TU1280r has been proposed to the European market, probably in the U.S. is a different model code
Maybe the best bet is to build an external preamp, Tube or SS, either inside a rack type cabinet or housed in a "big pedal" enclosure.
*There are* "pedals" which are actually preamps, such as MB VTwin and even Marshall Guv'nor/ShredMaster/Jackhammer "Distortion Pedals" which are actually a full preamp (some even have their own effects loop, go figure)
Yes, at the moment the best thing is to use an external preamp, but it is not convenient :-\
Well, then you'll have to grab pencil, paper, a good light, and start drawing the schematic yourself :(
That's how all those "mystery amp/pedal" schematics eventually appear on Internet.
And of course an obvious question is: has Yamaha been contacted yet?
If they are not willing to share shcematics then it's pencil and paper time.
Yamaha has advised me to contact the service center. :trouble
But in fact it is not a fault but a natural characteristic of this amplifier.
A design schematic ? (the only pre-amp) .... I'll see you next year :cheesy:
Keep plugging at them until you get it. :trouble :dbtu:
FWIW I don't think there's much room for "improvement" there, if any at all.
Yamaha are not fools or beginners, I bet they *already* got the best sound they could .... for that configuration anyway.
But it's probably, from what can be seen, a "Marshall Valvestate type" amplifier, a full SS amplifier with , at best, a lonely small tube thrown in for distortion ... and that's not enough for what I guess you want.
Don't expect miracles :(
Usually most what can be done is to, say, add a small capacitor, killing some highs to make it *somewhat* less harsh ... usually making sound dull in the process .... or cutting some lows before distortion so it's less farty, or finding some stage where there's a little extra gain still unused, to give it a little more sustain (this alone opens a new can of worms).
All small tweaks, but which won't radically turn it into something else.
I repeat, Yamaha know their stuff, I bet it already sounds as good as it can, or very close to it.
And by the way, I don't think it sounds *that* bad, play it loud and most of the little problems disappear.
Now, at lower volume in a bedroom or something, yes, most amps (even a few good ones), sound buzzy and harsh.
Hey !!! Just found this:
http://youtu.be/zBjsitYZGG4
It sounds VERY good !!!!!!! (as I suspected).
You just need a good distortion pedal (your choice) .
To be or not to be this is problem,
the sound is :duh "acid" in clean channel... in lead channel, the "distortion" is without bass tone, 4-5-6th strings is same "sounding" of 1-2-3th-strings :'(
The sound you describe is so much like what a Valvestate 8080 would sound like, that I fear it's just a straight clone, or at least *very* close.
Given that your amp works, the problem is one of taste, and it's practically impossible somebody can mod it to your liking, doubly so without schematic and not being able to hear it.
As of the lack of bass you notice, it's a normal design decision to minimize farting and very dirty and muddy distortion.
So in a nutshell:
1) if it were burnt/shorted, maybe we could help you detect and replace shorted power transistors, open emitter resistors, blown rectifiers, etc., which is what you'd probably find there ... but , best case, it would sound exactly as before.
2) if you don't like its sound, well, if neither Yamaha nor Marshall could make them sound the way you like, what can *we* do?
3) I insist on you making an external preamp is the only practical solution.
Name an 80W , 1 x 12"Celestion speaker SS amp you like and *maybe* we can help you clone its preamp.