Forgot about that fetzer article. Sorry for the noob question, but what do those acronyms mean?I’d start with a good HV primer. Working with a SMPS can go around 350V. I’m currently working on a 12AX7 (dual triode) preamp. It’s a common tube with a lot of circuits drawn around it. But I’m no expert.
You’ve probably read “A closer look at the Fetzer valve”, but it may be worth a 2nd glance.
forum.pedalpcb.com
forum.pedalpcb.com
I may just have to read those again. So much great knowledge in there.Tubes 101 - Intro to Tube Preamp Design
Hi there! I had a couple requests to talk about my design process for tube preamps, so figured I would write up a super boring guide with way too many words and way too many pictures. I’m going to be using a lot of resources from https://www.ampbooks.com/mobile/amplifier-calculators/ which has...Tubes 102 - Intro to Power Supplies for Tube Circuits
I had planned to add this post on to the previous post about tube preamp design, but as I was writing it I found it getting way longer than I had planned, so I figured I would make it a separate topic. So how do I power these tubes? Well let’s start with the heater, without that you won’t be...
Thanks for pulling those links so I didn't have toTubes 101 - Intro to Tube Preamp Design
Hi there! I had a couple requests to talk about my design process for tube preamps, so figured I would write up a super boring guide with way too many words and way too many pictures. I’m going to be using a lot of resources from https://www.ampbooks.com/mobile/amplifier-calculators/ which has...Tubes 102 - Intro to Power Supplies for Tube Circuits
I had planned to add this post on to the previous post about tube preamp design, but as I was writing it I found it getting way longer than I had planned, so I figured I would make it a separate topic. So how do I power these tubes? Well let’s start with the heater, without that you won’t be...
happy to help answer any questions you have if they aren't covered already. I don't think I'm old enough to be considered a tube expert, but I've built a good handful of tube circuits including a fair number of original designs and have a reasonable understanding of their general goings on.
producerhive.com
Guitar preamps are designed differently than hi-fi preamps, we don't use 6DJ8 mostly because they don't have enough gain. 12AX7, every amp-builder's dual triode of choice, has a mu (amplification factor) of 100, whereas 6DJ8 has a mu of 33, putting it just above a 12AU7. Typically for guitar amps you want something in the 70-100 range, so things like 5751 and 6SL7 on the lower gain side and 12AX7 on the higher gain side. We play tube amps because we want tube dirt.
I saw that video a few days ago. How do you think it would transfer over to the Black Eye?
Good reading on the tube differences. In my case, it turned out that a 12AX7 wasn't the best choice for my BK Butler clone. They have the highest gain, which makes total sense. A 12AT7 type tube still felt a bit too high. 12AU7 was the magic one. A lower gain tube made all the difference in this circuit. Might consider one of each just to test things out with.Check out The Tube Store, I got a great deal on some JAN 12AX7 there.
While I'm not as tube savvy as HamishR and Vigilante398 (I've bought a drop compared to the buckets of tubes they've bought), The Tube Store has been the best I've found for sourcing tubes.
Yeeps! I just checked the JAN GE prices and they've gone wayyyyheyyyy up. So maybe not mil-spec JANs then...
Still, I got great customer service from The Tube Store, and very good CS from Amplified Parts, too.
For some circuits, and/or for bass, you may want to check out getting some 12AU7 tubes, a little less gain than the Xes which may have Xcessive harsher distortion when you're looking for just some smooth grit.
Haven't read this, it was the first hit to find some info for you about 12A?7 series tubes:
12AX7 vs 12AT7 vs 12AU7 Tube Shootout (Differences, Which To Buy)
Swapping tubes is a cheap and easy modification that can have great results. But not all tubes are equal! We put three common types to the test.
I think it would carry over reasonably well, it gives you an idea of how much the tubes themselves will overdrive. As for mixing and matching in different positions it's absolutely something you could do. A single tube stage by itself doesn't distort really, it's only when you feed it too hot of an input signal that it gets into overdrive. So running a 12AX7 as V1 would give it more gain in the earlier stages, which would push the later stages harder, whereas a lower gain tube like 12AU7 in V1 wouldn't push very much and you would get much less distortion, even with a 12AX7 in V2. I wouldn't go out of your way to source a bunch of tubes to try it, but if you already have a couple different types on hand I would definitely say it's a worthwhile experiment.
Yeah on lower voltage circuits like Valvecaster and Tube Driver the rules change a bit. 12AX7 doesn't like being starved and sounds harsh and brittle when plate voltage is less than 150V or so. 12AU7 doesn't mind a low plate voltage and runs quite well starved.Good reading on the tube differences. In my case, it turned out that a 12AX7 wasn't the best choice for my BK Butler clone. They have the highest gain, which makes total sense. A 12AT7 type tube still felt a bit too high. 12AU7 was the magic one. A lower gain tube made all the difference in this circuit. Might consider one of each just to test things out with.
