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kt77 in rocker 30?
Posted: Wed Mar 10, 2010 12:21 pm
by guitblues
Hi, any one tried it? Cathode bias so no problem with switching el 34's but im not sure about kt 77's. Would there be a bias problem?
Re: kt77 in rocker 30?
Posted: Wed Mar 10, 2010 12:59 pm
by Orphin
It shouldn't be a problem. The KT77 is a "kinkless" EL34. Plug 'em in a try. Make sure you have a matched pair though.
Run the amp in a dark room and check for red plating. If they do, you can always modify the cathode resistor to get the bias down.
(This is actually a modification that has to be done with a Marshall 2061X if you run the amp with any other tubes than JJ's)
Re: kt77 in rocker 30?
Posted: Wed Mar 10, 2010 4:57 pm
by guitblues
Thanks orphin, will give them a try.
Re: kt77 in rocker 30?
Posted: Sat Mar 27, 2010 7:42 am
by flea
I have some in my Rocker 30 right now as a back-up pair. I just got my new EL34's in and am going to put them in tomorrow. I prefer the EL34's honestly. Give it a try though.
Re: kt77 in rocker 30?
Posted: Sat Mar 27, 2010 5:42 pm
by LowWatt
flea wrote:I have some in my Rocker 30 right now as a back-up pair. I just got my new EL34's in and am going to put them in tomorrow. I prefer the EL34's honestly. Give it a try though.
How would you compare the tone between the 77s and the 34s? What are you using for 34s?
Re: kt77 in rocker 30?
Posted: Mon Mar 29, 2010 10:54 am
by boroman
a bit extended top
a bit extended bottom
way less compressed tone which seems like more headroom.
That was my observations changing thru EH EL34 to JJ KT77 in OR120.
Re: kt77 in rocker 30?
Posted: Tue Mar 30, 2010 1:50 am
by LowWatt
boroman wrote:a bit extended top
a bit extended bottom
way less compressed tone which seems like more headroom.
That was my observations changing thru EH EL34 to JJ KT77 in OR120.
Thanks for the review. The highs and lows are extended, but do the mids hold strong?
I'd like an extended top and bottom, and I know this may knock the mids back in the mix, but I don't want to lose the character of the mids that I get with the 34s. Low string single note riffs still need to sound massive.
Re: kt77 in rocker 30?
Posted: Tue Mar 30, 2010 3:20 am
by thenetsux
Can't comment about the KT77's in a Rocker, but in my AD140, I noticed a bit less mids with my previous eq settings, but was able to dial in more than enough to compensate. Huge is a good way to put the sound I try to get out of my amp, as well. The KT77 are "kinkless tetrode" version of the EL34 and they are more similar than dissimilar, I would say. I did have to play around with new combinations of preamp tubes before I was entirely happy, but I like them quite a bit.