Guthrie Govan Discussion

[alexkhan]

Suhr has just released the Custom Audio OD-100 which John Suhr designed for Custom Audio Electronics (the Bob Bradshaw company) back in the early-90's I believe. This amp has been making waves since its re-release less than a month ago with some impressed owners comparing it to some high-end PTP amps. Seems that has irked some PTP amp makers who insist that a PCB amp cannot possibly sound as lively or as good as a PTP amp. John Suhr advised me that I can quote him on this comment that he made regarding this PTP vs. PCB matter:

"There are good PCB amps and bad ones, it is all up to the designer just like any other amp.

It is interesting they (the PTP builders) don’t believe a PCB can sound as good but you have to remember my OD-100 is not all PCB.

It is Half and Half, Power tube section is point-to-point like an old Fender. All critical interconnecting wires are Teflon shielded cable and are not run on the PCB traces but are separate wires.

Also we use 3/32” PCB as opposed to 1/16” Double sided PCB 2oz copper instead of 1 oz.

With a PCB amp that is well-designed, you control the coupling of one part to the next, you can't do this on PTP, bundle wires have crosstalk and oscillations which we don’t.

We also have DC heaters on our preamp tubes which = no hum and make the tubes very forgiving on their quality.

Also consider that there would be no humanly possible way of building the features of this amp has in a PTP amp and still keep it reliable. There is way too much going on.

Man who said it could not be done shouldn’t interrupt man doing it!"

The OD-100 is the amp that is being used by Scott Henderson and Mike Landau. I got the first one in and shipped it to Steve Snider recently. Steve is a total amp freak and has owned and/or tried almost every boutique amp out there. I think it's an amazing amp, as does Steve. The buzz is fueling this PTP vs. PCB debate again and I thought it'd be an interesting fodder for the amp freaks in here.
_________________
Ed Yoon
Certified Guthrie Fan-atic
BOING Music LLC - Managing Partner
.strandberg* Guitars USA
Ed Yoon Consulting & Management
Guitar Center Inc.

[Donnie B.]

You know there is a lot of logic to using PTP for the power amp (high voltages) section and PCB for the pre-amp (low voltages) and EQ, switching, etc. sections.

The analogy I was given once was that using a PCB trace between componnent leads was like having a garden hose and flattening out a section - disrupts the flow in a way. Doesn't stop it but just alters it.
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What would we all do without guitars............. take up knitting?

[kirk95]

I can't wait to try one out! What's the difference between the the standard amp and Scott Henderson Mod?

Landau is playing this amp again? All the recent live pics I've seen lately he's playing his Dumble? But Suhr would know!

[alexkhan]

[alexkhan]

Randall Aiken of Aiken Amplification chimed in at the TM Forum regarding this matter with this quote:

"In my opinion, there is no difference in tone between a *properly* designed PCB amp and a PTP amp. That stuff about "tiny capacitances and coplanar traces robbing high frequencies" is complete bunk. I've designed PC boards that are used up in the GHz range for serial digital HD video products - it is certainly possible to lay out a fine PC board in the 20kHz and below range. As with any PC board, no matter what the frequency range, it all comes down to proper layout techniques. These same techniques and routing rules apply to PTP designs as well, just in a different manner.

What separates a good PC board from a bad PC board is things like board thickness and mounting (so it doesn't flex), use of a soldermask and a silkscreen for ease of component identification during repair, proper high-voltage clearances, and heavy copper weights.

You can make good and bad amps using both methods. The only inherent advantage PTP has is in ease of repair and modification (which can be a big advantage, however!).

Randall Aiken"
_________________
Ed Yoon
Certified Guthrie Fan-atic
BOING Music LLC - Managing Partner
.strandberg* Guitars USA
Ed Yoon Consulting & Management
Guitar Center Inc.

[kirk95]

This is from Mike's Baked Potato gig a couple weeks ago:

http://members.cox.net/rainmkr63/Jammin_15.jpg

[Donnie B.]

Here's an interesting article from Randall Smith of Mesa Boogie fame:

http://www.mesaboogie.com/US/Smith/point-to-point.html
_________________
What would we all do without guitars............. take up knitting?