The 6550 Experience

[revolver1]

Thanks Dave great info.

[daveweyer]

Try a 12AZ7 in V-2 slot. It gives more drive for the tone stack among other things. Another Jimi secret most folks are unaware of.

[revolver1]

That's interesting, could be worth a go. Don't think I've ever come accross that valve before.

I've ordered some caps they should be here soon so I'll have some mustard repro caps some tropical fish and some tantulum in 1uf, 1.5uf and 2.2uf to try out.

[revolver1]

O.K so that was pretty interesting. Only some of the caps have turned up so I just tried out what I had.

I started with the 1uf Tantulum but 1uf is too bright so I jumped to the 3.3uf wich was a bit better but I think Tantulum is just too aggressive for this application. I could see it working on V1 but not for this.

I then tried a 2.2uf Tropical fish which straight away was much warmer it was actually quite good but not quite there, I think the Tropical fish type cap kinda thinned it out a bit which isn't really the way I want to go. The bottom end wasn't loose enough.

Based on what I'm hearing there I want to try a 3uf on the V2 cathode with the .0047uf and then try a .0056uf and then .0068uf with the 2.2uf on the cathode.

I think the .0047uf might work better with a little less boost in the highs or the 2.2uf on th cathode may work better with a little less shelving of the bottom end from the coupling cap.

At the end of my little session I put it back to just the .0047uf with no cathode cap and I gotta say it did sound really good. I think if these two experiments don't get better results I'd be very happy with this set up. It really is splitting hairs now and just slightly different flavours on the same theme.

Just gotta wait for the caps to turn up.....

[Frank1969]

Hi everyone I have been following this very interesting forum for a long time. Regarding the BOG sound I invite you to listen to this version of Who Knows that I recorded with a super lead from 1969.
what do you think…

here is the link
https://drive.google.com/file/d/11tOu5J ... sp=sharing

[revolver1]

Very nice..... well done.

[Frank1969]

Thank you! I state that this head is my build, I would like to hear the Opinion of Dave and of course also of others ... how close does this sound come to the famous BOG sound?

[revolver1]

So, any info on the recording process and equipment set up?

[revolver1]

I think it comes very, very close, at first I thought you just posted a clip of the Filmore recording! A couple of the phrases were slightly different wich gave it away. Your playing is also very good.

Great to know it's your own build, when you said it's a 69 Superlead I assumed it was an original. So is it stock or modded?

[Frank1969]

So, any info on the recording process and equipment set up?

I recorded with an H4N zoom
amp settings:
presence: 5/4,5
Bass: 8
middle: 4
treble 4
vol: 8
zoom distance 1.5 m

[Frank1969]

I think it comes very, very close, at first I thought you just posted a clip of the Filmore recording! A couple of the phrases were slightly different wich gave it away. Your playing is also very good.

Great to know it's your own build, when you said it's a 69 Superlead I assumed it was an original. So is it stock or modded?

I created a super lead identical to the circuit layout of the March 1969 super lead models used by Jimi, with bridge rectifier to be clear

[Tazin]

Nice playing. Did you incorporate any West Coast modifications on the amp?

[Frank1969]

thank you!
no but I built another super lead I would like to try to modify this last one, but I am not an expert as refined as you, so if any of you post the layout of the 6550 circuit I could try to insert the changes and see what happens
how about ...

[daveweyer]

Wow, glad I checked in!
Frank, hey thanks for joining up, and thanks for lighting a fire here. It always enlivens things to hear the efforts of an impassioned Jimi amp builder. Loved the clip by the way, it really had a good Jimi quality to it. Should be an inspiration to other Forum members.

But please enlighten us more about your build. Am I to assume it was the stock 1959 circuit, with no shared cathode and V2 cathode bypassed, 12AX7s throughout?
And was it built with modern components like Heyboer transformers and such?

Do keep up the good work.

[Frank1969]

Wow, glad I checked in!
Frank, hey thanks for joining up, and thanks for lighting a fire here. It always enlivens things to hear the efforts of an impassioned Jimi amp builder. Loved the clip by the way, it really had a good Jimi quality to it. Should be an inspiration to other Forum members.

But please enlighten us more about your build. Am I to assume it was the stock 1959 circuit, with no shared cathode and V2 cathode bypassed, 12AX7s throughout?
And was it built with modern components like Heyboer transformers and such?

Do keep up the good work.

Yes exactly! except the capacitors which are the old mullards and resistors nos Allen-Bradley resistors