Tube Amp Archive

Thanks all, Sorted the problem out this morning. I had it wired correctly but had a leaky F&T 220uf. I measure/check all my resistors before but figured/counted on brand new caps were working. Swapped it out for a used one I had just to confirm and sure enough voltages up to 480 OT CT and 450 plates...

I went ahead and replaced the bias pot and was able to bring bias up to 35Ma on each tube. This dropped the plate voltage to 299v so I’m going to go through the boards once more and do some more tracing over the next few days and try to figure out why I have an audio signal without a reverb tank plu...

Good eye Richard!! Thanks for that and I had to double check again. I’m not running the amp for longer then 30 second intervals as the bias is so low. Fluctuating wall voltage can be frustrating here so that chart was made over 10 minutes. I measured it again to see if I was off and it is actually p...

Thanks for the quick reply guys. I tried to my hand at some rosewood boards but getting the turrets in there was a huge pain!! 1. Planning on getting some rubber bushings when my local stores open back up (lockdown due to Covid and I can’t deal with the cut side pickup thing). There is a jumper wire...

Hello all, It’s been awhile since I posted here but was wondering if anybody could offer a fresh set of eyes or help me out with diagnostics. I followed Taylor’s layout and all my preamp tubes are working fine. I should add that I’m using a brand new matched 6L6 quad from antique electronic supply. ...

http://www.gbase.com/gear/trainwreck-rocket-1993

With all the resurgence of Rocket builds as of late I thought I'd post it for those of you with DEEP pockets.

As far as I can tell looks like a Stancor OT but does anyone have any info on 'Joni' ?

Andrew

Zippy, I posted my Voltages of the stancor on the first page of the thread but it ended up at about 325 on the plates. Either way I think it sounds a whole lot better now with the lower voltage. Next up I need to order a 250-0-250 and hear how that sounds to really make my mind up on these Rocket PT...

Had a bit of extra time today so I swapped my Stancor 8356 out of my Rocket and installed a MM TW-PT in there to compare voltages. My wall voltage was a little high today at 122v. I ended up using the 260v taps on the PT and was happy with the voltages it produced. I reverted back to the 50 ohm bias...

RJ, Your quest for TW knowledge and inisight is truly admirable. I have just finished up my Rocket build and used a Stancor 8356 PT. My voltages were a little higher than I expected and I had to adjust my bias to bring it back into spec. I used a MM Dynaco OT as well as the reccomended Hammond 158L ...

I scored a NOS 8356 several months ago on EBay. Once I fired up my Rocket and started checking voltages I realized I was getting about 340v on the plates. I actually tried a daisy chain of five 5w 10v Zeners in series to drop the B+ down to 290. Problem was that this got so hot (within minutes) the ...

I'm confused here as Mercury specs for the their TW PT and OT are posted on their webpage??? If you click on the trainwreck logo and it's all there. I don't believe they are trying to hold specs back on this iron at all. It is definitely not a clone of a stancor or pacific but it's what they feel wo...

Rooster No prob. The MM KF-OT is equipped with both 6k6 and 5k2 primaries. I used the 6k6 in my express and compared it to RJ's express iron and I also used the 5k2 primaries and compared it to RJ's Liverpool iron as well. The primary specs are posted on their webpage for this particular OT. In spea...

Cap217, I have used both the MM-KF-OT and the MM Woden OT. These are both excellent pieces of iron and I don't think you can go wrong with either. The MM Woden OT is one of my favorite OT's and I have used it in a Stangray, DC-30 and a Z wreck with great results. That being said, I have now replaced...

Rooster, Tying my best to be helpful.:) these are tough questions " You didn't talk about saturation. Can you hear/feel/ sense a saturation difference between the Pacific and the MM?" Saturation... The MM to my ears sounded a bit high fi-ish if that makes sense. The saturation was more abrupt and ha...

Afternoon, Well.... This thread inspired me to do an OT swap in my Express this afternoon. I had the Mercury Magnetics TW-OT (using the 6k6 primary)in there for about the past year and today I swapped it out with RJ's Pacific iron P#25525. I realize that there is a bit of conversation going around w...