trinityamps.com

oh yes and its the auto transformer, not the l-pad.

I've read that in other threads that it sucks after 8

At the last few clicks, whre it's really cranked down, I'd probably agree. But there ar ethe speakers to conider at that volume to.
I'm using the 50 watt version to but at 8 ohms.

Does it suck after 8 or is the stereo version better. I have the mono version

They all work the same, and they're a pretty darn clever little design. The last couple of clicks make the amp sound pretty fuzzy, but above that they're very usable. Both the mono and stereo versions are only for 8 ohms usage, but with the stereo version you can parallel both channels together for 4 ohms, or bridge wire them for 16 ohms.

yea thats it, its real fuzzy at the last few clicks. the sound is not at all natural, so i don't go down that far with it.

so even if you get the stereo version and bridge for 4 or 16, the last few clicks are still useless?
If that's the case I'll stick with the mono, as , of course it's cheaper.

Why do you think it's like that? Is it the amp or attenuator that's going fuzzy?

Really should scope this out as there may be a cool way to get around that.

Interesting mod! Could this be used in larger wattage amps too? For instance a JTM 45? Would there have to be any change to the resisotrs used?

I like it, but it's not perfect. The more extreme settings (more attenuation) tend to be overly distorted and compressed and a little bright. I like the second or third position in conjunction with the rRadio Shack attenuator on the 2nd or 3rd click.
It is a very cheap and reversable mod. Try it.
I've lost the links to the original thread that got me going. I believe that it was on the Gear Page. I'll hunt for it. It is on a Mohave amp.


It was originally on a 50 watt Plexi-ish amp. It used a 50ohm reverse taper pot wired as a reostat. I used the resistors because I couldn't find a pot locally that had the control that I needed.

It basically "starves" the PI (phase inverter).


LeeMo

Oh yeah, that was the Mojave power dampening system? I checked out some of the ax84 thread. Might be worth trying in my JTM 45 clone. Cheers!

I use one side of the 50W stereo version. It really brings the volume down transparently for the first 4-5 clicks. After that the tone becomes fuzzy and phasy. I also notice my EL84's dont like it below 5 clicks as they start to glow in relation to how hard I hit the strings.

So - In my case I think it is something to do with the attenuator AC impedance somehow changing at higher attenuation values. IIRC the DC impedance doesnt change "significantly" throughout the range of the unit.
I usually run with the amp 3/4 up fill into an 8Ohm speaker. The tubes are JJ's.


I might have to try the PI attenuation method. Thanks for sharing that Leemo.

Paul

Well, i've tried the mod on my Loverocker 18 watter and i like it!

I can now crank the amp ful tilt and just above red-room level is all i get! It does get somewhat fuzzy and it sounds very muffled...especially the low end. It is however perfect for practise. I can now play without worrying about deafening the neihbours. All thanks to the "Leemo mod" (the six position rotary switch).

Now i'm going to mod the amp for EF86s and see what other fun i can have

i'm having a hard time making this useful. the more resistance i apply to the PI using this switch setup, the less drive i have. so to get the drive back i have to turn the amp volume up more, and i'm back where i started volume wise. this most definitely does make the amp quiter at the cost of overdrive, and also judging from my wife-ometer, its not doing the trick. just my experience so far with it. is it possible i'm doing something wrong?

EF86 thread:

viewtopic.php?t=682

It does cut out overdrive a bit but not majorly so in my experience. I dont like too much anyway so it works out great for me. For me though the amp lost a little something. The sparkle had gone and its whole 3d presence vanished the more i wound up the attenutation. Still, it goes back to normal when the attenutaor is on the bypass mode so alls good. It'll do for my day time practises

I also want to try the modified Ken Fischer PPIMV mod at some point but i need a dual ganged 250K pot.

Cheers! I have worked out a simple way of modding the existing layout i have for my Ampmaker 18 watt lite to upgrade it to the ef86 lite i got off the 18watt.com archives. That diagram with interchangable values is going to be even more fun to play with!

maybe it has something to do with my running a 5751 in the PI. thats already lower gain, so maybe i'll try a 12ax7 in its place.

Good point! I've got a cv4024 in my PI...lets see what a TFK smooth plate does....

i tried a 12ax7 and i'm still getting similar results. it is getting the amp quiter, but the tone stinks IMO. at least in my configuration.