5751 Preamp Tubes...

Re: 5751 Preamp Tubes...

Glad to hear the 5751's are working for you. I haven't noticed any need for break-in....seem to be the same from the start to my ear.
 
Re: 5751 Preamp Tubes...

I tried a lot of tubes in the v2 slot like 5751 from RCA, JAN Phillips and GE, same as 12at7 of different brands like telefunken, RCA, Mullard and Sylvania. My point is that amplication factor in these tubes is too low compared with a 12ax7, because both sections of the tubes are lower. Did anyone tried a 12dw7 in the V2 slot?
 
Re: 5751 Preamp Tubes...

I ordered a JJ 5751 just to try to tame the gain on my JCA50H overdrive channel after reading this thread, and it really didn't sound good at all. It was way too fizzy and hairy. In V2 in that amp, a 12AU7 is much more effective. Now I can run my gain at 3 or 4 instead of 1 and have it sound good.
 
Re: 5751 Preamp Tubes...

I tried a lot of tubes in the v2 slot like 5751 from RCA, JAN Phillips and GE, same as 12at7 of different brands like telefunken, RCA, Mullard and Sylvania. My point is that amplication factor in these tubes is too low compared with a 12ax7, because both sections of the tubes are lower. Did anyone tried a 12dw7 in the V2 slot?
I'd agree with all BUT that of the 5751.
 
Re: 5751 Preamp Tubes...

'Recently I acquired a new Deluxe Reverb Reissue! While I'm quite happy with the amplifier overall I'd like to try and tame it's inherent upper mid spike...' That's because Deluxe Reverbs are the only BF amp that Fender wired with a permanent bright cap. 47 pF right at the volume control. Clip it out and lose the excessive treble. You can change tubes all you want, but that really won't cure it.
 
Re: 5751 Preamp Tubes...

not a fan of the bright cap either, clip it. i dont care for the bright switches on bigger fenders either
 
Re: 5751 Preamp Tubes...

http://thetoneking.com/wp/the-king-of-tubes-peter-watson-and-pm-tubes-make-their-way-to-us-shores/

From what I understand they are a Chinese tube somehow PM selects a higher quality. The inner construction is different from a standard 12ax7b. It looks more like a short grey plate RCA or something. They don't have that metal band inside like the Chinese tubes do.
I have them in my Quickrod and was able to A/B them with the standard Chinese Sino 12ax7b. I found them to be smoother and have a rounder top end.
They made a definite difference to my ears anyway. I know the tube debate will go on and on. And to be honest, I've rolled a LOT of tubes in my Splawn from the new ones to NOS. Right now the PM are my favorite followed closely by the Chinese 12ax7b....
My .02 anyway.

Good to hear you had a good experience. I'm not sure they are sourcing from 1 manufacturer or just China only -they may be a little more opportunistic (like Groove tubes and Ruby etc) and purchasing from wherever the price and quality is meets there supply needs. The reason I say this is -the EL34 shown on on their website is almost DEFINITELY a Russia made Tung Sol brand EHX tube.

I guess I could be wrong if the Chinese are using the identical socket color and look -but I doubt it.
 
Re: 5751 Preamp Tubes...

I have an old RCA 5751 in V1 of my OR15. It still has way more gain than I'll ever use, it just comes in at a different setting on the gain knob. It did reduce some of the fizz on the top end.
 
Re: 5751 Preamp Tubes...

I like how Wampler has a 6 position rotary control with different bright caps. Seems like a good idea. Or at least like Friedman with 2 values and a bypass.
 
Re: 5751 Preamp Tubes...

Good to hear you had a good experience. I'm not sure they are sourcing from 1 manufacturer or just China only -they may be a little more opportunistic (like Groove tubes and Ruby etc) and purchasing from wherever the price and quality is meets there supply needs. The reason I say this is -the EL34 shown on on their website is almost DEFINITELY a Russia made Tung Sol brand EHX tube.

I guess I could be wrong if the Chinese are using the identical socket color and look -but I doubt it.

I’m pretty sure you’re right. They are basically a re-brander as you said, like GT etc.
 
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