Has anyone any experience with Burman amps?

[CraigGa]

Thanks Tony,

No I don't have the screening cans on, but I'll try that tomorrow.

The tubes are a mixture,
New Genelec KT77's because the old ones were duff.
Preamp tubes, there's a couple of the original mazda's in there,
V2 I think is a Golden Dragon, I can't find any info on those but they must have been in there a long time and there's a JJ and a Mesa boogie.
I've also got a couple of ICL CV492 nos from the 80's and I can't find any info on those either.

I do have a USB Picoscope and I just checked and it's rated to 600V DC when AC coupled mode so I guess I could use that to look for ripple on the supplies.

There is no real hum on it though, it's much quieter than before I changed the filter caps.

Back in the day, my only guitar was a Music Man Sabre with an active preamp that could kick out 2V so I used to go through V2 tubes pretty quick.

Craig

[tony hunt]

CV492 was a military grade ECC83 selected for low microphonics and mechanical stability. May be good, may be a wet blanket, may be so strong that it opens a new can of worms.
Put one of your original Mazdas in V2, even if it is tired. That would be my first move.
I understand you liked the compressed sound of Gain 2 pushed way up. That is putting all the action in the first stage and what ever tube is in there is even more critical than usual.

I offer you my starter for ten approach with these amps:
all gains at three with the 2x KT77 model, all at five with the quad KT77 models.
Bass no more than at 3 and everything else noon.
Roll you guitar (non-active) volume back about 10-15%.
You should get glorious touch sensitivity. Let the right hand and amp do the work. Make music.

[CraigGa]

So I've put the Mazda tube in V2 and put the cans back on and tried your settings (although with G3 less than 3 because my wife is in) and it does sound pretty good.

I've also attached a couple of clips
Burman 1 is with your settings

Burman 1.mp3

and Burman 2 is with gain 3 being turned up.

Burman 2.mp3

I'll pull the chassis out tomorrow and check the lead dressing but I don't think anything has been moved.

Craig

[tony hunt]

Sounds right to me.
I couldn't hear any issues with the bass on either clip.
Leave the chassis in for now and play it some. Report back if it gets funky.
tony

[CraigGa]

Ok will do, maybe I've been spoilt by the more modern amps that I've been playing.

Thanks for your help.

Craig

[parker_knoll]

Great to read this thread - and not so old!

I have a Pro 2000 quad KT77 model I'm about to restore to greatness. Currently working okay on the clean channel (which is great), but is a bit hummy and gets very hot, despite some tube swapping. I understand the getting hot thing can be part and parcel with these amps.

I note with interest the danger of wear on the bias pot and will look into modernising that. Otherwise, great amp and in no way obsolete in my view.

[CraigGa]

Good luck with restoring it, the 4xKT77 versions must be monsters.
I got mine working pretty well except turning gain 2 up causes a fuzzy overdrive from V2B which I'm sure it didn't used to do.

I'll get back to it someday.