Re: Have I told you how much I effin' love my Thunderverb 50?
So, how did the overall tone changed with that 'mod' ?
Never heard of a 6Ca7 before.
6CA7s can be used in EL34 amps and aren't the same, structurally speaking, as EL34s (tetrode instead of pentode). They have more of a 6L6 feel than regular EL34s. As far as I can tell, the most common nowadays are
Electro Harmonix and
JJ. Based on the
Tubestore the JJs aren't really reminiscent of real 6CA7s (but I'm just paraphrasing here, don't take my word for it).
I loved the EH 6CA7s in my Rocker 30, they kinda gave the bass a bit more thump but not woofiness and made the high-end clearer. However, I never felt they took away much midrange.
In the TV, the major thing they fixed was channel B. I don't like the tone with the shape much higher than noon, I need those mids. However, around 10-11 there isn't enough highs left to make the amp cut through. Switching to 6CA7s allowed me to use it pretty much there (10-11 o'clock) so get all those mids but retain more (I'd say a lot but that's just my ears so...) highs and lows there, keeping the amp quite present when I dial in the right amount of mids.
It's not just the tubes though (I assume), as I said, I also biased the amp quite a bit hotter than it was originally. Based on plate voltage, the amp would've needed to be biased at 43mA to attain the "benchmark" 70% plate dissipation. It was biased quite cool at 34mA. I thought there might be a good reason for that cool bias but still tried it at 40mA and, well, it works quite well for me. I don't think the cleans suffered much (they might be breaking up a bit sooner). The amp just sounds a bit livelier and more responsive (to ME)....
To expensive for my taste lol but lucky you! it must sound great.
It is quite expensive, I just got lucky and scored one for a song... They aren't cheap new but they are not that popular so they show up cheap used once in a while...