Maybe try Ruby EL34B HT or EHX 6CA7s. I've heard that both of these sound good in Marshalls. I have a DR Z SRZ65 (Hot Rod JCM800 inspired) and it has JJ KT77s in it and they sound pretty good also.
My TAD's didn't last long but were at the max bias point of my amp. Just received my new RUBY's which will sound like the TAD'S ,but hopefully bias better. I have a cheap quad of old/new stock Chinese EL34's in there now, I think Shuguang, that kick butt so the RUBY'S will be my backups . I have grown not to be picky about power tubes , I don't trust any of them.
For the price, the Svet's are a good choice. But being pleased with the tone and performance of these will depend on which amp circuit you are running them in.
These valves have a similar tone to the =C= but with a bit less bottom end. They have a good midrange crunchiness emphasis that I really dig. So basically, if you have an amp that is somewhat dark and punchy in the lows and low mids, these valves will shine big time. That is, if you want to add some mids and upper mids to the EQ spectrum. But as with most new production EL34's, running them with well over 450V on the screens is hard on them.
I picked up two new quads of these for under $90 including shipping last year. I have them loaded into my TSL100 and DSL100. They are working for me in those amps big time.
Shuguang are hands down the best cp. el 34 power tube I have tried. Hands down. Tung Sols where pretty good to maybe more in the lows which my setup doesn't need.