Dave Friedman mods to Concorde?

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Structo
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Re: Dave Friedman mods to Concorde?

Post by Structo »

M Fowler wrote:Thanks Dave, that Larry Mann (Distortions) does great work. I told Larry take your time and make a beautiful cabinet please, he did.
Holy crap Mark!

That cab is off the hook!

I would be afraid to take that anywhere.
Tom

Don't let that smoke out!
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M Fowler
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Re: Dave Friedman mods to Concorde?

Post by M Fowler »

Thanks Tom,

I wrapped a blanket around it and it sat in the back seat of my truck to and from the gigs. I only used it twice for a gig.

It now sits on display and I crank it up every now and then if I haven't stole the tubes out of it. :lol:

Mark
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Re: Dave Friedman mods to Concorde?

Post by Jackie Treehorn »

Colossal wrote:
Jackie Treehorn wrote:The third triode in the Concorde, will clip asymmetrically, too due to the dc coupled cathode follower. The cool (or frustrating) thing about DC coupling is you can change two things at once. If the third triode was biased colder like a K60 with a 10k bias resistor, then we can estimate that the plate of the triode would be at about 270 volts (I'm using express voltages, here actually) which would put the grid of the cathode follower at 270 volts which would pull the cathode of the cathode follower to something like 271 volts, which greatly exceeds the cathode to heater limit of the tube. By biasing that triode stage hotter, the plate voltage comes down on the triode gain stage and those voltages are more in line. The cathode follower is in a state of grid conduction, so it pulls down the plate voltage of the third triode, causing a colder bias and the clip to be asymetrical, during the positive portion of the signal. I suspect that's why the k60 and k50 sound similar, at least on Komet's website.
Excellent post as usual Jackie. I suspect they lowered the 3rd stage cathode resistor to 3k3 from 10k with the addition of the cathode follower in the K50 specifically because of the increased gain the CF would add to the 3rd stage. It would be a good idea to DC elevate the follower to bring down the grid-to-cathode voltage.
Jackie Treehorn wrote:I don't think there's any advantage to using the low impedance output to drive the phase inverter, though.
I love what cathode followers can bring to an amp and I'm guessing that there's a bit of added compression with it in the K50 although that could be really enhanced too if desired with some adjustments to the CF. I'm kind of a compression freak though (as long as it's not overdone), just a bit of added warmth and singing sustain.
Jackie Treehorn wrote:I do remember the thread on TGP with these mods. There were clips to compare. It sounded to me like the mods backed off the signal to the power amp, allowing more gain before losing the tightness, perhaps increasing the 220k in front of the PI. The amp had more of a hair metal sound with the mods.
Hmm interesting. So by "hair metal" would that be good or bad? :lol: I can get some really heavy but tight sound out of my modded JCM but I do not care for the buzzy, one-dimensional chain saw tone some of the over-modded JCMs can take on. Lifeless and boring, so that's kind of what I equate with some "hair metal". Pete Thorn's Concorde video demos sound great so I was thinking that the Dave Friedman's mods would certainly not make the amp worse off and Jim's description sounds like it only made the stock amp better.
Yes, the cathode follower does bring something to the tone. Maybe a bit of focus to the mids and a softer grind? I also agree with you about compression, when it's good it's very good! Most of the opinions on forums tend to present compression as a negative aspect of an amps performance, which is not always the case.

I think I meant "hair metal" in a good sense. It's been awhile since I listened, but my impression was a higher gain, tighter sound more conducive to distorted rhythm playing. Perhaps gained at a loss of some of the swagger and looseness of the stock amp which someone might like more for lead work. I can see why a really skilled, precise player like Pete Thorn would want the mods. They sounded great for what he was doing. A player like myself, with a little swing :wink: (slop?) to his sound may go for that looser, swirly sound. I don't think either way was right or wrong, but it was definitely interesting to hear the amp taken in a different direction; stuck out in my mind as being a pretty good thread.
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Re: Dave Friedman mods to Concorde?

Post by Scumback Speakers »

Colossal wrote:I have a number of ideas of my own but, out of academic curiosity, I would be very interested to know what was modded on Jim's amp to improve touch sensitivity etc. I'm sure it sounds killer.
I can't tell you all of it, as I said before, you'd have to ask Dave. Billy Yates put in the footswitch mod (Allyn supplied the parts). We found the amp had a couple of bad solder joints (part of the PPIMV mod, I think, since removed), then Dave did the bass control cap mode (required two due to the footswitch mod), past that I can't tell you.

I know there were players who had one of Allyn's amps without the Friedman mods and they freaked. I went over the glass with them, one of them had done that mix of Tele/Amperex/Mules as well as the XF2 Mullards, and he said his amp still didn't sound as good as mine.

So the only thing I can say is talk to Allyn or Dave, I think they cross pollinated some info.
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Re: Dave Friedman mods to Concorde?

Post by Colossal »

Southbay Ampworks wrote:I can't tell you all of it, as I said before, you'd have to ask Dave. Billy Yates put in the footswitch mod (Allyn supplied the parts)...then Dave did the bass control cap mode (required two due to the footswitch mod), past that I can't tell you.

I know there were players who had one of Allyn's amps without the Friedman mods and they freaked. I went over the glass with them, one of them had done that mix of Tele/Amperex/Mules as well as the XF2 Mullards, and he said his amp still didn't sound as good as mine.

So the only thing I can say is talk to Allyn or Dave, I think they cross pollinated some info.
Jim, thanks alot for the comments, no worries about the specifics. Maybe Allyn will weigh in and throw us a bone - wink, wink, nudge, nudge say n'more! At Jackie's behest I googled the Gear Page and found what I think is the thread discussing the mod. Quoting Peter Thorn's from that thread:

"Here's a simple mod (1 part) you can do that fixes all that ['that' meaning the added noise and looser bass] - the bass is the reason for the compression. Lean out the front end. I've learned that if you try and push too much bass through the preamp circuit on any Marshall type amp, it starts to compress and collapse as you turn it up. lean out the bass and lo and behold, you can crank it to 10 and it'll stay tight and it sounds just awesome. I did this to both my Concordes."

Pete posted this clip of the modded amp:

http://dl.mp3lizard.com/peterthorn/Komet%5Fmodded%2Emp3

Since there is no coupling cap on V1 given the tone stack is plated loaded, I'm guessing reducing the 0.022uF bass cap or the coupling cap further downstream did the trick, less chance for blocking distortion and I'm sure with the high voltage and OT impedance mismatch that the low end is huge and pretty tight with the stock amp anyway. To squeeze more gain out of the preamp, the coupling caps need to stay small. The amp is fairly scooped in the mids compared with a traditional Marshall right?
Last edited by Colossal on Sat Oct 23, 2010 1:11 am, edited 1 time in total.
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Re: Dave Friedman mods to Concorde?

Post by Scumback Speakers »

I don't find mine to have scooped mids. In the gradual mode it actually sounds bigger in the mids than my Marshalls (71 JMP 50w, 71 SL, 100w Metro clone w/Friedman Kitchen sink/simple clean channel mods).

When I go to the fast mode, it's got Concorde tone to it, but with a bit more zing and presence. Hard to describe, you just have to hear it, I guess.
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Re: Dave Friedman mods to Concorde?

Post by Colossal »

Southbay Ampworks wrote:I don't find mine to have scooped mids. In the gradual mode it actually sounds bigger in the mids than my Marshalls (71 JMP 50w, 71 SL, 100w Metro clone w/Friedman Kitchen sink/simple clean channel mods).
Ah, ok Jim, thanks for clarifying! Very interesting. It sounds very tight and harmonically rich from all the clips I've heard (as well as Pete's modded K50) but I thought maybe a little less mids than some of the Marshalls I've heard/played in person, but that's probably the BoobTube clips giving that impression. Well whatever, it sounds massive to me. I love the tight "push" kind of sound you can hear when you palm mute...that fast, tight attack. Kind of that whoosh as the speakers release. Love it! Definitely Marshall-on-roids!
Southbay Ampworks wrote:When I go to the fast mode, it's got Concorde tone to it, but with a bit more zing and presence. Hard to describe, you just have to hear it, I guess.
Yeah, I hear ya, tone is hard to describe for sure. Well, I couldn't help myself and ordered some iron, so hope to find out for myself firsthand in the not too distant future :D 8)
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