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Dave Friedman mods to Concorde?
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RobBozic



Joined: 04 May 2007
Posts: 20
Location: Sydney

PostPosted: Thu Oct 21, 2010 4:01 am    Post subject: Dave Friedman mods to Concorde? Reply with quote

Hi guys,

I came across a thread on TGP by Pete Thorn where he had Dave Friedman mod his Concorde to get more usable gain from the amp.

Does anyone know what the mod is?

Thanks
Rob
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JamesHealey



Joined: 28 Aug 2008
Posts: 477
Location: Leeds, UK

PostPosted: Thu Oct 21, 2010 6:46 am    Post subject: Reply with quote

Why mod a concorde?
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paulster



Joined: 10 Oct 2006
Posts: 1299
Location: Los Angeles & London

PostPosted: Thu Oct 21, 2010 9:46 am    Post subject: Reply with quote

It was only a very, very minor mod so it could easily be something as simple as changing the tap for the NFB to tighten things up or just a resistor value.

You could always ask him. He's a lot more responsive to questions about mods than people might assume.
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RobBozic



Joined: 04 May 2007
Posts: 20
Location: Sydney

PostPosted: Thu Oct 21, 2010 10:37 am    Post subject: Reply with quote

Quote:
Why mod a concorde?


Why don't you ask Pete Thorn.

I'm thinking of building one & from the clips I've heard on Youtube from Pete Thorn & from what I've read on this forum about the Concorde is that it has a lot of gain, therefore why not mod it too get more usable gain from the entire volume knob.

Quote:
It was only a very, very minor mod so it could easily be something as simple as changing the tap for the NFB to tighten things up or just a resistor value.

You could always ask him. He's a lot more responsive to questions about mods than people might assume.


Thanks for your response, I actually will ask Dave.
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Southbay Ampworks



Joined: 14 Nov 2006
Posts: 445

PostPosted: Thu Oct 21, 2010 11:29 am    Post subject: Reply with quote

I got Allyn and Dave hooked up a year ago over this, so Allyn knows, Dave knows, and I believe Hogy & Mike @ Komet are doing it as well.

There are a couple of mods, one is a change of the bass cap, the other I can't remember....sorry.

Contact one of the above mentioned amp gurus.

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JamesHealey



Joined: 28 Aug 2008
Posts: 477
Location: Leeds, UK

PostPosted: Thu Oct 21, 2010 11:50 am    Post subject: Reply with quote

Must admit Dave Friedman is pretty awesome with his information he gave me a full break down of George Lynch's 68 Plexi, including a few of the small circuit tweaks he'd done.

I should build a plexi to these specs at some point
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M Fowler



Joined: 16 Jan 2008
Posts: 10816
Location: MN

PostPosted: Thu Oct 21, 2010 1:15 pm    Post subject: Reply with quote

I think those mods are noted in an old thread under Trainwreck discussion but I may have it saved.
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paulster



Joined: 10 Oct 2006
Posts: 1299
Location: Los Angeles & London

PostPosted: Thu Oct 21, 2010 5:31 pm    Post subject: Reply with quote

M Fowler wrote:
I think those mods are noted in an old thread under Trainwreck discussion but I may have it saved.

That's likely the Mark Knopfler mod you're thinking of, which is to optimise a K60 for 5881s. I don't think this particular mod has been discussed yet, although I could have missed it.

Dave is a great guy though and if this isn't one of his bread-and-butter mods then he may be happy to share the details.
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Southbay Ampworks



Joined: 14 Nov 2006
Posts: 445

PostPosted: Thu Oct 21, 2010 6:40 pm    Post subject: Reply with quote

paulster wrote:
M Fowler wrote:
I think those mods are noted in an old thread under Trainwreck discussion but I may have it saved.

That's likely the Mark Knopfler mod you're thinking of, which is to optimise a K60 for 5881s. I don't think this particular mod has been discussed yet, although I could have missed it.

Dave is a great guy though and if this isn't one of his bread-and-butter mods then he may be happy to share the details.


When you find time to come over to see the new demo room, I'll pull out my Koncorde that has all those mods and you can try it out. Pretty sure they're not the same as the K60 mods.

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Colossal



Joined: 20 Oct 2007
Posts: 2627
Location: In and around the lake

PostPosted: Thu Oct 21, 2010 6:52 pm    Post subject: Reply with quote

While the Concorde (K50) is enjoying some attention, I wanted to ask those owners/cloners how they would characterize the amp's tone as compared to a Trainwreck and a Marshall Plexi. The Concorde has DNA from both and I have watched Pete Thorn's videos many times. I have heard the Concorde described as a "Marshall-on-steroids". I am not looking to make some kind of judgement for one versus the other, but merely to compare the tone. There is no right or wrong and I do not want to debate the merits of one over the other, just to understand what a Concorde might share in common with a Plexi and/or Express.

Thanks for any comments.
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M Fowler



Joined: 16 Jan 2008
Posts: 10816
Location: MN

PostPosted: Thu Oct 21, 2010 7:13 pm    Post subject: Reply with quote

After I built my K60 I was thinking of building the K50 and was told why if you have the K60 why build the K50.

They are different animals based on the schematics.
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Colossal



Joined: 20 Oct 2007
Posts: 2627
Location: In and around the lake

PostPosted: Thu Oct 21, 2010 8:59 pm    Post subject: Reply with quote

Mark,

Yes, I always wondered why that K60=K50 comparison was made as an analysis of the schematics shows they are different beasts. One other comparison I have heard made is that the K50 has a lot more low end than a Wreck, but with all of the touch sensitivity and harmonic content. In gradual mode, to me it sounds very much like a really punchy Plexi but you can definitely hear the Wreck (added compression) in it. In Fast mode it sounds pretty over the top. I wonder if the mods being discussed are to tame some of this over-the-topness? Maybe a change to the split load ratio on the second stage?

As an aside, my wife (plays drums) has an excellent ear and meter (and I think very, very good pitch) and I use her as my unbiased estimator from time to time. I played her the Pete Thorn video and said "what do you think?" She said, "I like the [50W] Plexi you just built better. The [Plexi] sounds more like Tool to me". Now that is not a slight against the K50 (and I love that K50!) but it's just an interesting point about the difference in the K50's presentation. She noted that my my 2x6V6 JCM800 sounds a lot like the K50. Of course the 50W K50 has way more punch, but interesting to note.

I still would like to hear what people who have or built a K50 think about the low end, its Wreck-like qualities, comparison to a Plexi, etc. That K50 is one bad@$$ amp.

Dave
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M Fowler



Joined: 16 Jan 2008
Posts: 10816
Location: MN

PostPosted: Thu Oct 21, 2010 9:10 pm    Post subject: Reply with quote

The K50 uses a lower primary OT then the K60.

The main filter caps are increased 220uf on K50 verses 80uf on K60.

The K50 is solid state rectified verses k60 GZ34.

The 220k resistor is removed at the entrance of V2B ? voltage divider 220k/330k tied after the 0.1 cap on the touch switch.

Mark
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paulster



Joined: 10 Oct 2006
Posts: 1299
Location: Los Angeles & London

PostPosted: Thu Oct 21, 2010 10:13 pm    Post subject: Reply with quote

And the K50 has a cathode follower too.
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Colossal



Joined: 20 Oct 2007
Posts: 2627
Location: In and around the lake

PostPosted: Fri Oct 22, 2010 1:24 am    Post subject: Reply with quote

The clipping stage on a K50 is 3k3 and the K60 is 10k.
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