And that’s why we listen to Justin when Justin says no no!
1 Like
Wow, just got a Mogwai rev2 and it’s blown me away. Question about tubes. If i use a 12au7, are there any considerations i need to be aware of regarding the reduction in gain compared to 5751 or 12ax7? Running with tung sol 6550’s and svetlana 5U3C. One of the headphones im powering is a hifiman HE6se, so i dont want to reduce watts too much. I need to do some studying up on amp design.
@urbanjanitor welcome to our forums!
The adequacy of gain depends a lot on the rest of your system. No doubt the Mogwai has plenty of power to drive your headphones, but it also has to do with your source output voltage. My opinion is that you should try tube rolling just to see; it’s so worth it for that amp where trying different tubes is so fun! And it’s pretty unlikely the 12AU7 won’t have enough gain… in fact, you might find that further cuts down on any background hiss/noise.
Keep us posted on what you find!
1 Like
Ramesh:
Welcome and congratulations on an amazing amp. The Mogwai really is a great all-around amplifier and one worthy of a final destination for many many people.
Not sure if you have done so, but I would definitely suggest playing around w/ some NOS rectifiers if able. It can make a major impact / upgrade on the sound. There are some mid-priced ones that are very very good. And then there are some super pricey ones that are the last 5% of the best (look at the Head-Fi Dubstep Girl thread). I used one for my Mogwai SE and it clearly transformed the amp.
Enjoy!
Nice, thanks for the info, ktc! I have a veritable stockpile of Russian tubes from the wonderful person I bought the amp from, but for rectifiers only some Svetlana 5U3C and TungSol 5AR4’s. I will need to look into some others for rolling purposes, because it seems like the rectifier makes a difference on this amp. Just found a great great deal on a Mullard 12au7 long plate from the 50’s, so hyped to get that in the Mogwai.
I’ll take a look at DubstepGirl’s recs, but will take with a grain of salt considering different amps were used. I have a WA6 first gen and have been comparing the amps and doing some rectifier testing since they use the samish rectifiers. I haven’t found the differences on one amp to necessarily correlate with similar differences on the other amp, but maybe a little more testing is needed hehe.
Update - Been doing quite a bit of tube rolling the past few weeks. I’m currently rolling with a Brimar cv717 rectifier, Tung-Sol NOS JAN-CTL 5881/6L6GWGB output tubes and a Mullard NOS 12AU7. This is the best I’ve heard, although still comparing a few rectifiers. Specifically, the Tung Sol 5881’s really bring a tube warmth and sweet mids to the amp. The Mullard 12AU7 gives a lot more play on pot while still providing plenty of gain. Overall, I’ve found rolling the output tubes a bit difficult because about 50% end up being quite noisy in this amp (NOS and Reissues). No problems rolling the driver and rectifier tubes though. Amp still sounds fantastic and I find myself excited to listen to it every day.
5 Likes