The 6550 Experience

[shakti]

Since we're all waiting for exciting new fuzz clips, I threw this one together to tide us over.
Same '69 SL spec amp, but with shared cathode, 6550s in class B. But this time running mismatched (8 ohm setting into 16 ohm load), and also with the .68uF V2 bypass cap in place, as well as the 5n volume bright cap. There's a little less output when mismatching, but that's only a good thing, as I was able to attenuate less. Can't remember if this was -6 or -9dB.
Amp settings were presence 5, bass 0, mids 6, treble 4, volume one 7.

The fuzz is an Analog Man NKT275 Sunface, with the input trimmer turned up quite a bit. Volume on full, fuzz turned just slightly up.

Again, the playing sucks, and the recorded sound sucks, so you may or may not be able to hear any differences. The fuzz is set for a clean fuzz boost a la Xplorer, and I am turning it on and off, playing the same passages. I am beginning to believe in the "fuzz theory", but then again the difference is rather subtle. It's more in the nuances of how it cleans up and the dynamics, as the base sound is very close even with no fuzz.

[neikeel]

Sounds lile great fun noodling. The base tone is very nice and the very little extra that your pedal adds a little spice and interest to my relatively untuned ears have a very BOG flavour. I don't think the playing sucks either . The recording craps out a little here and there but I like it.

[Xplorer]

Interesting !

it also sounds like a few other concerts when you do "them changes" but i don't remember which.

that would be great if you could record the exact same setup , but with the univibe preamp added : volume at maximum, intensity to zero. the conjunction of this clean fuzz setup and the univibe preamp makes an interesting difference as you know.

the saturation of the amp is recognizable on some later Hendrix tracks, like at 5:05 , quite bog, yes, but quite right for some other Hendrix stuffs too. but at 4:18 it isn't spot on imo, too aggressive or something, to be bog.
you get some very nice bog accents and phrases anyway.

the stepping stone you're doing, definitely sounds Hendrix, as well as quite a few other stuffs.
imo it's on the way for sure, there's still a bit of research to do though, not sure of which direction.

one funny thing , i first listened to your clip on my iPhone, and there i could hear your voice saying "fuzz on, fuzz off" . but now on my bang & olufsen and 4 x speakers, i don't hear it anymore ! ( or i'd have to push the volume too high to hear it, and the guitar would be super high volume in my room ) and it sounds closer to bog than on my iPhone.

if i had to do a cover concert of the band of gypsys, i'd certainly mix my 45/100 with the west coast superlead , this would certainly blend very well , and deliver all the accents we're looking for. and along with the promising Hendrix fuzz mod by Dave , i would certainly have fun.

listening again to my clips, i realise that the clean fuzz blend is a bit too much, a tad muddy and i should use the input bias a hair more than that and record on my real speakers. the saturation on this setup is more rough and fine for me for bog.

[peter25]

Sounds good Shakti.
Btw who's making the 3 transistor fuzz? Can't wait to hear some clips...

[Tek465b]

Sounds good Shakti.
Btw who's making the 3 transistor fuzz? Can't wait to hear some clips...

Am waiting for the germanium transistor to arrive from russia, should be 7-14 day :O.

[shakti]

Thanks for the positive comments, guys. I do think it's probably the closest I've come yet. And that's with a fuzz which probably does not sound/react quite like the BOG fuzz (whatever that pedal really is). IMO, the BOG sound has quite a fair bit of gain, but it's still fairly clean sounding. Getting a cleaner/tidier sort of overdrive is what I am hearing with the mismatch. Also, concentrating the drive around the right frequencies adds sustain without too much messy saturation, and cutting the bass back definitely does that. Then there's the fuzz itself which adds its own kind of "warm brittleness" which does have BOG flavor, even if it is not the exact fuzz.
I can only imagine that old stock Tung-Sol 6550s would sound even better and "tidier".

The recording and room adds a certain hard sound and some added harshness/distortion, so you'll just have to take my word for it that it sounds a little closer still in person.

Xplorer; about the sound at 4:18, it is too aggressive, but that could be remedied very easily with a slight twist of the guitar volume knob.

In this setting, I think the sound of the bridge pickup with the fuzz boost on is almost exactly spot on, like the opening to Stop. Can't wait to try this setup with a three transistor "always on" fuzz!

BTW, the Uni-Vibe preamp was still in the chain, but I don't have it all the ay up, only at about unity gain or a very slight boost. According to Stuart Castledine, the Supra-Vibe has more output available than a genuine Uni-Vibe, so I keep the output knob at 1-2 o'clock. Maximum on an old Uni-Vibe would correspond to about 3 o'clock according to Stu.
Has anyone seen a shot showing the output level of Hendrix' Uni-Vibe?

[daveweyer]

Probably the most constant thing you can find in BOG is the 6550 based amps. I think I can offer with some certainty that the FF units were not the same from gig to gig. Jimi liked the modded units, and there were several varieties of those. Most of the ones were likely Roger's, but there were three or more varieties of West Coast mods in the box too.
Roger also had different ideas he tried in those Arbiter shells; I either repaired or added mods of my own to those if they came in to West Coast not working, including adding white or metal knobs, pots, etc.
The "always-on" 3 transistor FF unit from West Coast is one thing you can try, if it brings you closer to the tone you seek, then you may deduce forensically the probability Jimi used it on a particular gig.
But the trail; doesn't end here; there are other FF mods to try too.

The playing samples are just great though, no matter what.

[spaceace76]

Just put an order in, going to try my hand at the 6550's, and some of the changes Dave mentioned he tried.

My results may end up a bit odd, my amp is a 50w frankenstein of different marshall circuits and mods. It has a 50w OT with a JTM45 PT (around 440-450vdc B+ at idle), and currently uses a SS plugin for the rectifier. It has a few options for V1's cathode R/C combos, If I record anything I'll be sure to note what was used.

I've stated before that I already run a 12AT7 in the PI, and have been very happy with the change. Very interested to see how the 22k in the PI will affect things.

I'm not sure how I can record a clip, probably have the means but I doubt it would sound all too great with the space I have. Also don't have quite the right speakers for the job, G12C65's, in a peavey cabinet. Sue me, it was free and had metal handles

[daveweyer]

Bill Bokey, haven't seen you around lately. Are you just waiting to spring a killer amp sound on all of us based on a newly constructed 6550 modded SL?

[neikeel]

Thorlief did you use 220k grids on the output or go to 150k or 82k?

I have a late 69 (metal panel SB) that I am restoring (slowly) and am tempted to use the 6550s I bought for the AFD amp but never used.

[shakti]

I stuck with 220k. According to Dave that should be fine until the tubes are very worn.

[shakti]

BTW, I am waiting for more user feedback on the three-transistor "always on" fuzz.

[Xplorer]

Hi ! i'm deeply sorry for this long delay and no feedbacks on the fuzz. been very busy lately, but i'll do some clip and talk about it.
it seems that the forum slowed down these last weeks but it's as usual, like with cycles, can't explain.

[daveweyer]

I think we ought to find a way to get Shakti one of the three transistor fuzz units.

[shakti]

I think we ought to find a way to get Shakti one of the three transistor fuzz units.

Shakti thinks that sounds like a veeerry good idea!
I plugged in again today - the setup sounds very close, but an always on fuzz could be just the last ingredient. I would be sure to make clips, of course.