Scrap parts 6G4 Super Build

[Esquirefreak]

Hi, everyone!

My first post here (possibly my first post at any forum that I can remember). And even though it's my first post, I've hung around and reading for some time, reading and learning A LOT on here.

If my post is off or wrong in some way, I appologize. Also, english is a second language for me, so spelling and so on might not always be the best.

However, I've been building some amps starting last fall, and finished the "amp part" of my 4th build roughly a week ago. And although I don't have a single degree in electronics, I've been building speakers, crossovers, guitars etc for pretty much all my life. Since the age of 5 or so (thanks dad, for making me a misfit among all the other kids  )

I'm using Hammond TRs for all my builds, since I've had good experience with those in a lot of other amps I've owned. For this build I'm using a 290DEX (EU PT), 1750M (2/4/8 - 4K) and a 194B choke.

I've tried to fabricate as much as possible myself, by hand. So the chassis, doghouse cover, eyelet boards are all hand made.

The amp sounds really nice. It might be the most sweet compressing cleans I've ever heard. Using a mix of Telefunkens and Siemens novals in the preamp, but with a GE 5751 in v1, because I really love the response of those. The tremolo is deep, lush and juuust a hint of thumping with the intensity maxed out. I'm fine with that, though.

So, speaking of the tremolo. I got this idea earlier today. If one would split the cathode of v4 in a 6G4, but with the alternative of switching to stock values (and common kR + kC), would this drawing suffice? I figure it would be interesting to bias the HP and LP filters with different value C/R to see what it does to the already kinda funky harm. tremolo.

Best regards from Sweden :)
/Max

PS. Sorry for a lot of info, but I felt I wanted to introduce myself. DS

[Esquirefreak]

Here's the schematic with a couple of changes I've made for personal preference.

I tried to upload a pic of the actual amp, but the files are apparently bigger than whats possible to publish.

[sluckey]

So, speaking of the tremolo. I got this idea earlier today. If one would split the cathode of v4 in a 6G4, but with the alternative of switching to stock values (and common kR + kC), would this drawing suffice? I figure it would be interesting to bias the HP and LP filters with different value C/R to see what it does to the already kinda funky harm. tremolo.

Your circuit will do that. The hi and lo channels would have different gains but I doubt that will be harmful to the guitar signal. But you're overlooking the LFO tremolo signal. The two out of phase LFO signals applied to the grids of V4 should cancel out when mixed together in the two 470K mixing resistors at the plates... that is, if they are equal amplitudes. But your mod will unbalance the gain of the two triodes so the LFO signals will be different amplitudes and will not completely cancel. This will leave some undesired LFO signal that gets passed on to the PI along with the desired guitar signal. Probably gonna hear even more thump thump in the speaker.

Easy to try and easy to undo. Let us know how this mod works for you. You can post big pics on one of the many file/image sharing sites and then just post a link in the forum. Many posters do that.

[Esquirefreak]

Thanks a bunch, Sluckey!

I'll try to get the mod done this weekend and get back here to tell you how it went 

[Latole]

Here's the schematic with a couple of changes I've made for personal preference.

I tried to upload a pic of the actual amp, but the files are apparently bigger than whats possible to publish.

Reduce the file in you PC and post it. I have to do often.

[PRR]

...I tried to upload a pic of the actual amp, but the files are apparently bigger than whats possible to publish.

https://el34world.com/Forum/index.php?topic=23286.0

[Esquirefreak]

Thanks, I'll give it a try next time I open my computer =)

[Esquirefreak]

Here are some pics of the actual amp I've built.

And although it's not pretty, I can at least say that I've built it myself.

/Max

[Esquirefreak]

/Max

[Esquirefreak]

/Max

[Esquirefreak]

/Max

[sluckey]

Looks very Fendery to me. How does it sound?

[Esquirefreak]

Well, since I've never played an actual brownface, let alone a brownface Super, I can't really compare it to those.

However, I really like the sound of it. With a 5751 in v1 it's a bit more polite and sweet, where as a 12ax7 in that position makes it a fair bit bolder, fatter and meaner! Clean, it sounds pretty swampy/Fogerty-ish. Hard to describe, but I hope you get the idea.

I have yet to turn it up past 9 o clock to hear it overdrive  . I'll do that as soon as I've built the cabs and I'm able to take it out of the apartment.

/Max

[Bieworm]

I would not trust the solder joints of the eyelets on the board. It's really thin. But then again, I'm a turret guy and have no experience with eyelets.  Though my vibro king has the eyelets soldered full

[Esquirefreak]

Before I flow any solder I make sure I have a hook/good mechanical connection. After I've soldered, I yank the leads with a reasonable amount of force to make sure none of them are at risk of coming loose. They're secured, firmly.

I have yet (after a lot of soldering the last 10 or so years) to have a lead/joint come loose.

/Max