Metropoulos Forum

Discussion on this topic over at PP board
http://vintageamps.com/PlexiPalaceUBBcg ... 1;t=010573

with Randall Smith's input over here
http://www.mesaboogie.com/US/Smith/point-to-point.html

I still think that Jon's solution to this is the most viable argument towards this topic in that you need two boards, one set of componants and do a physical swapout of all parts on the board to truly figure this out.

Well, I have had both George's PTP board (with SoZo's) and the original PCB converted to Lead spec w/SoZo's in my '78. No the resistors were not the same parts transferred from board to board, but many of the SoZo caps went from one to the other.
Both sounded equally as good to my ears. If you want just to improve the sound of your amp, reworking the PCB with better caps is fine on older Marshalls.
If you want to experiment with other component values, you NEED the PTP to do it.
I firmly believe this line of thinking only applies to simple, one-layer PCB's however. If someone came up with PTP boards for the more complex JCM900's and JCM2000's (if it's even possible to cram that much crap on one!!) I think you would see a marked improvement in tone.
The original PCB is still in my '78 right now. It wasn't worth swapping the boards back around -- I wasn't gaining anything with quality components on both.

I tell everyone who calls or emails that the cheapest upgrade they can do is to change all of the signal caps on their existing board. That $20 is money well spent. Oddly though, most people prefer to swap the entire board. Even after I've told them that the board itself doesn't make any improvement in tone. At least above the quantum level.

If fact, a well designed circuit board can help prevent extraneous noise and be condusive to great tone. I don't see those things happening in the modern Marshall boards, but it can be done. Don't even get me started on high voltages and ribbon cables.......

I also find it hard to believe that the designers at Mesa calculated for, and actually utilized the capacitance happening between traces. It's just too far fetched for me. It reaks of marketing. I may be wrong, but are you saying they crammed all of those components into a given space, found a way to connect them properly, and then made measurements of what was happening between traces? Upon which, they went back and changed the layout? To utilize the natural capacitance? C'mon.
And 2 sided boards. Those through holes are terrible. Practically unservicable.

Let me now superceed my own previous points: every Mesa I've been inside has had caps across the plate resistors in most gain stages. Typically between 10 and 100pf. The purpose of these caps? To roll off high frequencies making the stage stable. Think about that..........

If you have stray capacitance on the board in a particular stage, it's likely less than 10pf. If not, you need to go back to the drawing board.
Why would that stray capacitance even be a concern if you've already shunted all of the frequencies that might possible be affected?
And.......how can you claim to be using the interaction of those traces to your advantage?

I don't mean to pick on Mesa Boogie, it was just the topic at hand. Anyone making large quantities of amps these days has to automate things to compete. Fair enough. But please don't spread bad info in an attempt to validate your construction techniques.

The other side of the coin is the implied superiority of PTP boards. This just isn't true either. I wish it was, I sell PTP boards! But it's not. It's the components. At least in the classic designs. That's the new mantra, say it with me now: "it's the components".

Now everyone go buy some of John's Sozo caps. At http://www.sozoamplification.com

More on that later...................

George

I originally posted this with the hope that I would get answers like both of you have given. I tend to agree with both of you on this. I have never seen the inside of a Mesa in person but if they are using multi-layered PCB's then there is a fair room for problems to occur and could be quite catastrophic if one went in there and tried to mod it and nicked an internal trace.
George I know exactly what you are saying about ribbon cable and heat. I fried a preamp that I had with a ribbon cable attaching the tube board in it to the main board when I modded some of the tube board section which I needed to reroute the ribbon cable which made it too close to one of the tubes.
I am also glad I took your advice when I did my cap swap with the ones on my board. Night and fucking day difference. I did have mind to change to a PTP but since I do not want to drill holes in my chassis to change out the boards, changing componants is the way to go. The only change I am looking at now is doing a resistor swap on my board. I am thinking about going from the 5%+/- resistors that are on the board to 1%+/-. I will probably do this change when I retube my amp.

I say to each his own but I just prefer PTP over PCB construction for the ease of serviceability, I love the look of a well constructed PTP board as opposed to a mass produced PCB.

What I get out of those articles amounts to "pikin the pepper out of the turd"! and sounds like a marketing ploy to me.

As far tone is concerned....My SLP R/I had a very good tone with the PCB but it WAS NOT what I call and know as THE Marshall sound that I grew up hearing in the late 60s.

I put George's 68 board in it and it is a COMPLETLEY different amp now and has the stock PCB beat hands down.

Is it the PTP construction? Maybe. Is it the grade of components? You betcha.

Point being....I know what I like to hear and what will achive that for me and I stick with what works.

If it ain't broke don't fix it.

If it's a PCB ( or a PTP for that matter) with crappy components...fix it ASAP with a Metro board, screw all of the marketing hype and get on with the task at hand....PLAYING

Peace

I agree with George on his statement's on Mesa. I've seen the insides of a Mesa and i'm terrified. Having a glance in a triple recto is even more intimidating... screw that shit.

white room wrote:I say to each his own but I just prefer PTP over PCB construction for the ease of serviceability, I love the look of a well constructed PTP board as opposed to a mass produced PCB.

What I get out of those articles amounts to "pikin the pepper out of the turd"! and sounds like a marketing ploy to me.

As far tone is concerned....My SLP R/I had a very good tone with the PCB but it WAS NOT what I call and know as THE Marshall sound that I grew up hearing in the late 60s.

I put George's 68 board in it and it is a COMPLETLEY different amp now and has the stock PCB beat hands down.

Is it the PTP construction? Maybe. Is it the grade of components? You betcha.

Point being....I know what I like to hear and what will achive that for me and I stick with what works.

If it ain't broke don't fix it.

If it's a PCB ( or a PTP for that matter) with crappy components...fix it ASAP with a Metro board, screw all of the marketing hype and get on with the task at hand....PLAYING

Peace

I agree with you, but I think you misunderstood my question.

You had an SLP and put in a 68 board. Though the circuit is similar there are minor changes to it from 68 to the SLP.

My argument to the whole thing is Would your SLP sound the same with upgraded caps and resistors using the stock board vs. using a PTP board of the SLP circuit using the same exact parts removed from the stock board.

With that in mind, you like the Marshall sound you grew up with from the late 60's. The board you installed in your amp being PTP. If you were to get a PCB board of that same circuit and use the componants off your PTP board could you tell the difference?

This is the only way that I think one can really tell if the tone is actually different. In doing this though you would have to do a blind test with you as the owner not knowing which board you were playing through.

George relates it all back to componants. I think he is right. The circuit is the same. The electricity is flowing through the circuit the same way from componant to componant, if that signal is going through crappy stock parts it will not sound as good as running through good parts. I also believe that this argument between PTP and PCB for the majority of those who argue this boils down to elitism and aesthetics where tone sometimes takes a backseat.

I play a JCM800 1959. I would love to check out a PTP board if nothing else but for maintenance. But I do not want to drill holes in the chassis for mounting studs for the board. I am left to only upgrade the componants on the PCB.

Necrovore wrote:

white room wrote:I say to each his own but I just prefer PTP over PCB construction for the ease of serviceability, I love the look of a well constructed PTP board as opposed to a mass produced PCB.

What I get out of those articles amounts to "pikin the pepper out of the turd"! and sounds like a marketing ploy to me.

As far tone is concerned....My SLP R/I had a very good tone with the PCB but it WAS NOT what I call and know as THE Marshall sound that I grew up hearing in the late 60s.

I put George's 68 board in it and it is a COMPLETLEY different amp now and has the stock PCB beat hands down.

Is it the PTP construction? Maybe. Is it the grade of components? You betcha.


I had thought about changing just the caps on my PCB but I thought it would be cool to go all the way and just build a board.

Point being....I know what I like to hear and what will achive that for me and I stick with what works.

If it ain't broke don't fix it.

If it's a PCB ( or a PTP for that matter) with crappy components...fix it ASAP with a Metro board, screw all of the marketing hype and get on with the task at hand....PLAYING

Peace

I agree with you, but I think you misunderstood my question.

You had an SLP and put in a 68 board. Though the circuit is similar there are minor changes to it from 68 to the SLP.

My argument to the whole thing is Would your SLP sound the same with upgraded caps and resistors using the stock board vs. using a PTP board of the SLP circuit using the same exact parts removed from the stock board.

With that in mind, you like the Marshall sound you grew up with from the late 60's. The board you installed in your amp being PTP. If you were to get a PCB board of that same circuit and use the componants off your PTP board could you tell the difference?

This is the only way that I think one can really tell if the tone is actually different. In doing this though you would have to do a blind test with you as the owner not knowing which board you were playing through.

George relates it all back to componants. I think he is right. The circuit is the same. The electricity is flowing through the circuit the same way from componant to componant, if that signal is going through crappy stock parts it will not sound as good as running through good parts. I also believe that this argument between PTP and PCB for the majority of those who argue this boils down to elitism and aesthetics where tone sometimes takes a backseat.

I play a JCM800 1959. I would love to check out a PTP board if nothing else but for maintenance. But I do not want to drill holes in the chassis for mounting studs for the board. I am left to only upgrade the componants on the PCB.

I wasn't responding to your post, just giving my thoughts on the topic as a whole. Sorry, didn't mean for it to come across that way

Actually, I thought what you said made perfect sense.

I had thought about changing just the caps on my PCB but I thought it would be fun to go all the way and just build a board.

I personally don't think that there would be much difference ( in any) between PTP and PCBs. I think it all comes down the grade of components used. As I say, my PCB sounded really good but it was not the sound I wanted and I attributed that to the components.

I like PTP, if for no other reason, because it is much easier to swap out components.

I think my amp would sound the same as it does now if the Sozo caps, MO and CF resistors where mounted on a PCB but I think it would be good to be able to do a blind test just for the sake of being able to settle my curiosities.

As for Mesa amps, FWIW A amp tech I know, told me a few years back that he has more Mesa's come across his bench than anything else because they seem to be geared to run hot.