I was advised by an "expert" on another forum that it would be a good idea given JJ EL34s known propensity for thermal runaway. It didn't seem to affect the problem. Fair enough though i'd have got better valves and left it stock No visible carbon on the valve sockets. It aint often visible...often...

I ask as a lot of people who work on old oranges look under the hood, think....orange coloured marshall and fiddle away like its a superlead.. They then shrug their shoulders when it doesnt work. I'd suggest restoring it to stock, recapping everything including the bias caps then start fault finding...

How come you replaced the bias feed resistors? Thats going to effect stuff.

spam, spam...eggs and spam

Its difficult for me to relate but the Telefunken tends to give the overdrive tone a clarity and almost dynamic sparkle....it sounds like ridiculous audiophile stuff but i personally feel it makes a difference. The Mule you are using is good tube....i'd try the smooth plate and see what you think. I...

Always valves for the rocker series! They sound a lot better than transistors for the application we use - namely rock music Becareful though...that "rudimentary" circuit can fatally shock you!

i'm not sure what size fuse orange use these days but i would of thought radioshack would carry them. Failing that, check mouser.com. They stock EVERYTHING!

ffs

New stock tubes often fail out of the box. They arent as well made as they used to be back when tubes were in everything.

I'd expect a simple replacement of your tube compliment should solve your problems.

You've not got a loose thread on the chassis bolts or some such thats making the chassis a loose fit do you?

You could have someone recover your headbox and cab. That might be cheaper than buying another. Contact Orange USA. They might sell you one as you already have an amp.

I believe the Svetlana name was taken, not bought. The Winged C boys never trademarked the name so the EH lot just steamed in and took the name, copyrighted and screwed everyone over.

Sounds like a microphonic pre-amp tube to me. Take the top off the amp so you have access to the tubes and plug it all in as usuall. Crank both the MV and gain up. With no guitar/lead attached gently tap the pre-amp tubes with a wooden chopstick. I'll bet one of the tubes will ring like a bell throu...

As Chris has said, you want a power tube that can handle high plate voltage. Go with JJs or maybe the wing C tubes. I've heard they're not too bad. If you cn afford it though, grab a quad of NOS RFT EL34s. They sound good and can handle the volts. Also, consider a nice NOS preamp tube like a Tesla, ...

Those look like NOS (or very lightly used) RFT EL34s. Great tubes! I have many set myself. One caveat i will mention regarding tube testers is this: How well calibrated is the instrument? If the tester has been well maintained and calibrated once a year (and not the internal calibration....i mean ag...