Marshall Amp Forum - View Single Post - Preamp Tubes?

RiverRatt · 06-05-2009, 10:13 AM

OK, I finally scored a couple of 12BZ7's from the Tube Depot. I got two RCA gray plates yesterday. These were not what I was expecting at all. I put one in V2 on my DSL50 and I'm really pleased with the tone. I was expecting something over-the-top, but these things SING. It really doesn't seem to have much effect until you crank up the gain. Nice, creamy sustain from the neck pickup of my LP, and more agressive on the bridge pickup with nice pinch harmonics. It seems to respond well to pick attack, too. Thanks for the tip - these are definitely a keeper.

I ended up with this setup: V1=RCA side-getter ECC83, V2=RCA gray plate 12BZ7, V3=Raytheon black plate 12AT7 (I don't have any way to measure the gain on this tube, but I can't hear much difference between it and a 12AX7 - it has VERY short plates), and a new Tung-Sol 12AX7 in V4.

On a side note, I noticed on one of the 12BZ7's and on one of my RCA clear tops that I pulled for the BZ7 that the spacers are askew. Will this affect the tube's performance?

06-05-2009, 10:13 AM	#402 (permalink)
RiverRatt Senior Member Join Date: May 2008 Location: Between Memphis and Nashville Posts: 1,309	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? OK, I finally scored a couple of 12BZ7's from the Tube Depot. I got two RCA gray plates yesterday. These were not what I was expecting at all. I put one in V2 on my DSL50 and I'm really pleased with the tone. I was expecting something over-the-top, but these things SING. It really doesn't seem to have much effect until you crank up the gain. Nice, creamy sustain from the neck pickup of my LP, and more agressive on the bridge pickup with nice pinch harmonics. It seems to respond well to pick attack, too. Thanks for the tip - these are definitely a keeper. I ended up with this setup: V1=RCA side-getter ECC83, V2=RCA gray plate 12BZ7, V3=Raytheon black plate 12AT7 (I don't have any way to measure the gain on this tube, but I can't hear much difference between it and a 12AX7 - it has VERY short plates), and a new Tung-Sol 12AX7 in V4. On a side note, I noticed on one of the 12BZ7's and on one of my RCA clear tops that I pulled for the BZ7 that the spacers are askew. Will this affect the tube's performance?