[Kevin Haskins]

If you can hear the dielectric effects over all that extra noise then I'll lick your boots.

Size 9.5 / Medium width, Kevin.....and I've always been partial to the real Cowboy ones with spurs. Ouch - not a pleasant tongue-tingling experience  

I should mention I've had to lick a few boots in my time.  

[Roger A. Modjeski]

One thing that is not being addressed here is boards as they age. As the mateial ages it can become "leaky". Furthermore,anyone who uses PCB sockets for power tubes is asking for trouble, the heat coming down the pins fractures the solder over time (heating and cooling cycles). It even does this to some extent on driver tubes, though it takes longer.

Point to point is far better sounding and will last forever. Ever look at a 25 year old PCB in a tube unit, it doesn't look too good?

With a well designed circuit consistancy is not an issue. Stray coupling is not a problem. We are not making 30 MHz amplifiers here. If stray capacitance causes the circuit to perform differently from unit to unit, then it is a bad circuit or a poor layout! Remember, there are many "conditionally stable" amplifiers out there. I know, because many of them have crossed my bench.

Sadly some builders bundle wires together for looks and this is the worst thing to do. All that bundled wire couples together. The best solution, the one which I use, is to make things as neat as possible without resorting to "pretty wiring" that doesn't perform well. If well thought out and carefully assembled,  point to point wiring is repeatable, longlasting and best sounding. Because 3 dimensions are available, it often results in the shortest paths. If parts are properly supported, shipping damage is not an issue either.

All that being said, there is no excuse for a "rats nest"either. A good layout actually makes the circuit apparent to any skilled technician where a circuit board can take hours to trace. I tend to work on most anything without a schematic, so "seeing" the circuit in my head is facilitated by good point to point wiring. PCBs rarely are so easy to "read".
 
One of the wonders of tube amplifiers is that a good technician can fix a well laid out amplifier without a schematic because he can see the circuit.  That just isn't going to happen with some PCB, solid state complex, full of IC's monster. Consider how many 1970's, 80's 90's integrated amps and receivers we are junking, piles of them, just because they are too hard to fix, or the IC is no longer made, or you can't figure out which one it is. On the other hand we aren't junking Dynaco, Eico, or ANY other decent tube amps. It causes one to wonder ask what is really obsolete.

Though I used PCB in all my preamps where heat is not an issue and there is a lot of wiring to switches that would take a very long time to hook up point to point. Over the last several years,  I have been switching over to point to point or using PCB's only for power supply where they are out of the audio path.

I am considering making a point to point drop in driver board for the RM-9 amplifiers out there as their driver boards are getting a little tired in some cases where the owner did not "ventilate" the amplifier well. One look at the underside of the board and I can tell the thermal history of the amplifier from the degree of brown board that once was green. If there is interest in this point to point conversion, let me know by email.

Roger A. Modjeski
Music Reference

[audiojerry]

That just warms my cochles  
Thank you, Roger.
I hope to have the privilege of hearing a Music Reference some day.

At the same time, I am a proud and happy owner of an SAS Audio preamp.
While I don't know alot about circuits, I've seen the internals of plenty of amps and preamps. The appearance of the SAS is simple, elegant, nicely laid out, and with few parts  It exhibits a thoughtful, hand built, circuit where every every component and every wire was carefully selected and thoroughly auditioned and tested.  Thank you, Steve, too!

[JoshK]

A good layout actually makes the circuit apparent to any skilled technician where a circuit board can take hours to trace. I tend to work on most anything without a schematic, so "seeing" the circuit in my head is facilitated by good point to point wiring. PCBs rarely are so easy to "read".

Very good point!  I agree most definitely.  As a new student of audio design, I can agree from experience.  It is really nice to be able to see the circuit readily.   I have come to learn that I don't like "modding/tweaking" components with all PCBs unless it is just caps and decoupling.  P2P is much easier to work on.

This was good food for thought.

[skrivis]

I have no innate opinion of this, I will merely weigh in with Steve Nugent/Empirical Audio on the subject from his white paper (on his website):

As this comes from the man partly responsible for bringing to us the Pentium 2 while at Intel, it's worthy of strong consideration  

If I ever need a CPU designed, I'll call him. For audio equipment, I'm not sure he's any more qualified than anyone else...

Dr. Amar Bose is brilliant, and I'd think taking classes from him would have been great.

That doesn't mean that I'd buy any Bose products...

[skrivis]

Very good point!  I agree most definitely.  As a new student of audio design, I can agree from experience.  It is really nice to be able to see the circuit readily.   I have come to learn that I don't like "modding/tweaking" components with all PCBs unless it is just caps and decoupling.  P2P is much easier to work on.

This was good food for thought.

I built an amp with Vector turrets. It was easy to do, and the layout was excellent. I'm not sure how easy it would be to figure out what's what though, since you wind up with a very compact layout right at each tube. They are point to point though...

Simple tube circuits do lend themselves well to P2P. More complex circuits could well be better off with PCBs.

You'll likely find good products built both ways.

[TheChairGuy]

If I ever need a CPU designed, I'll call him. For audio equipment, I'm not sure he's any more qualified than anyone else...

Dr. Amar Bose is brilliant, and I'd think taking classes from him would have been great.

That doesn't mean that I'd buy any Bose products...

sk,

If it comes down to your informed opinion or Steve's 30 year research in Transmisson Line's, much of it spent at the world's finest and foremost manufacturer of processors; you're a mere twinkie to his pineapple, triple layered, cheesecake.

[JoshK]

skrivis,

you sure do know how to win friends and influence people!

[skrivis]

If I ever need a CPU designed, I'll call him. For audio equipment, I'm not sure he's any more qualified than anyone else...

Dr. Amar Bose is brilliant, and I'd think taking classes from him would have been great.

That doesn't mean that I'd buy any Bose products...

sk,

If it comes down to your informed opinion or Steve's 30 year research in Transmisson Line's, much of it spent at the world's finest and foremost manufacturer of processors; you're a mere twinkie to his pineapple, triple layered, cheesecake.

I wasn't saying that I know more than him. I was just saying that his experience at Intel doesn't mean jack when it comes to audio equipment. I fail to see the relevance of "30 year research in Transmission Line's" either.

Actually, as far as CPU designers go, Intel was kind of deficient compared to DEC's Alpha team. Maybe working for Intel isn't such a good thing after all. hehe

Finest and foremost manufacturer of processors? They're big, that's for sure, and they get very good yields, plus they make a lot of money. So they're a successful business, but then again, so is Microsoft. (And not many people would claim that MS has wonderful products.)

Intel hasn't been able to convince the industry to move to IA-64. That was going to be their future direction and they were going to lock everyone else out of it. Instead, AMD kicked Intel's butt with AMD64 (and is still doing so), and Intel had to use AMD's technology going forward. IA-64 is basically dead as the dodo.

Sun with their Niagara and IBM's Power and Cell processors are more advanced than anything Intel has. They're also doing very well in the 64-bit market - the same one Intel can't crack.

Take a look at Sun's T1000 and T2000. Then look at the x2100, x4100, and x4200 (Hint, they're x64 and not Intel.). They just stomp all over other servers using Intel processors. (Like those made by Dell - Intel's retail arm.)

So tell me again why I should be impressed by Intel or someone who worked for them. (And for all I know, he was fired.)

[skrivis]

skrivis,

you sure do know how to win friends and influence people!

I don't let it bother me. I express my opinions and let others make of them what they will. I try to keep things away from insults, but people tend to have a lot invested in their opinions and ideas, so anything contrary can raise passions and fan flames.

TCG's ok. I don't share his viewpoint about some things, but that's perfectly fine.

BTW, I'm not saying Steve Nugent is completely clueless either. I just don't see that his working for Intel in the past is a reason to revere him as an audio expert. However, he _is_ a fancy wire vendor, so that makes him suspect right there.  

[skrivis]

One thing that is not being addressed here is boards as they age. As the mateial ages it can become "leaky". Furthermore,anyone who uses PCB sockets for power tubes is asking for trouble, the heat coming down the pins fractures the solder over time (heating and cooling cycles). It even does this to some extent on driver tubes, though it takes longer.

Phenolic, fiberglass, teflon? Or are you referring to all of them? And what do you mean by "leaky?"

Won't heat coming down the tube's pins affect the solder in P2P wiring just as much?

I've seen equipment of both types of construction that needed a refreshing of solder joints to restore proper operation.

How about the waxed cardboard strips with brass eyelets used in old Fender amps? Would you consider them point to point?

[audiojerry]

skrivis ?
Dan Banquer?
I'm beginning to have a hard time distinguishing between them.  
Both seem to have superior intellect, coupled with an endearing talent for eloquent communication, while everyone else wallows in ignorance.

[Occam]

Jerry, Chair - I'm absolutely shocked! After all this time, I've just realized that you're both 13yr old girls. Do you both go to the same Jr High?

[Roger A. Modjeski]

Phenolic, fiberglass, teflon? Or are you referring to all of them? And what do you mean by "leaky?"

Won't heat coming down the tube's pins affect the solder in P2P wiring just as much?

I've seen equipment of both types of construction that needed a refreshing of solder joints to restore proper operation.

How about the waxed cardboard strips with brass eyelets used in old Fender amps? Would you consider them point to point?

Leaky refers to insulators that no longer insulate well. Tektronics used only porcelin terminal strips, there's nothing better.

Heat coming down the pins to wires is not at all the same. That holds up very well. Circuit boards have two problems. One, the adhesive that holds the traces degrades faster with heat, the base material degrades, phenolic is the worst, epoxy better, and teflon is for frying pans. Ive worked on hundreds of tube amps and I see a big difference.

The fender strips are pretty bad, but, hey maybe they help the "touch". (the guitar players know what I mean).

The essence of point to point is that there is very little area in contact with the insulators and that the insulators are of good quality. In that way, most of the dialelectric is AIR, and there's nothing better.

I hope this has been helpful.

roger

[Steve]

Hi Audiojerry,

     Thanks for the compliment. With all the confusion on this string, I thought I would clear up a couple of points, some things that might confuse or concern you.

1) I use the best boards, so no problem with heat on the preamps. Output tubes, even some driver tubes are a different story and should be mounted on the chassis.

 Heck, the military uses PC boards in equipment for decades with no problems. It all depends on what quality boards and how they are used. I have not had one return for repairs (except for shipping damage) in 10 years of business. Inspection and testing shows no deterioration of the boards or solder connections.

2) I, again, checked out a simple circuit checking out the transmission effects of a 6 inch piece of wire "A" to another 6" piece of wire "B", at 10khz.
I just condensed this post to make it easier to understand.
Depending on the values of R connected between ground and each wire (between 2.2k and 12k in this example), coupling varied from approx 59 to 72 db below the reference. Even moving my hand away and to the wires caused a radical in the reading.

As you can see, Jerry, even from this simple experiment, audio frequencies can easily couple to other portions of the circuit, depending on the impedance, parts themselves become antennas of transmission.

Sometime back, I also checked a 2uf solen cap on a chassis and approx 7pf was noted, so imagine all the other parts and total stray capacitance variation possible.
That is why, in my opinion, proper and a consistent layout is important, whether point to point or PCB. I prefer using PC boards, and been using "lead to lead" (copyrighted) connecting for at least 10 years. That is why I manually lay out the circuit instead of autotrace programs.

Hope this helps to clear things up.  

[-Richard-]

I find this discussion interesting because there is a great deal of confusion
about the implementation of circuit topologies out there...

The quivering line between fact and supposition...experience and opinion
seems to be fleshing out some fire among us...to be expected in any
distillation process...

I applaud our cumulative attempt to share important information with each other...

It's a cool night in Ojai...nice to be here by the warm fire...

Warm Regards -Richard-

[eric the red]

Jerry, Chair - I'm absolutely shocked! After all this time, I've just realized that you're both 13yr old girls. Do you both go to the same Jr High?

Pouty lips, push up bras and we love to shop  - you 'decoded' us, after all. Congrats  

fyi - I don't know what the hell you're talking about so I thought I'd just add to the non sequitur with an equally absurd post. Please stop drinking that NYC tap water - it's hell on the system.

No offense intended here, but I agree with Paul. This is a very interesting topic and the contributors to this thread are first-rate. It's not often that we get to hear from talented designers like Steve and Roger on interesting technical audio issues like the ones being discussed here. It's a little off-putting to have to try and follow what is being said here having to try and ignore some of the 13 y.o.ish attempts at humor. It kind of ruins the linearity of the discussion. Just my opinion, but I think that is what Paul was referring to.

[TheChairGuy]

Eric, I see your (and Paul's) point after a night of rollickin' good sleep.

It just plain ole' messes with what has been an informative topic with my (left field) bias I hereby consider myself self-censored.

CARLMAN (or Borg or Marbles), can you trash my post above about 'pouty' lips and any the one where I mentioned skrivis and DB?  I'll PM ya'(Carl).

[Carlman]

Eric, I see your (and Paul's) point after a night of rollickin' good sleep.

It just plain ole' messes with what has been an informative topic with my (left field) bias I hereby consider myself self-censored.

CARLMAN (or Borg or Marbles), can you trash my post above about 'pouty' lips and any the one where I mentioned skrivis and DB?  I'll PM ya'(Carl).

Done!

Also, I've moved this post to the Lab since it's really a discussion of the pro's and cons of different circuit architectures and that's not really 2-channel discussion.

Thanks,
Carl

[eric the red]

Eric, I see your (and Paul's) point after a night of rollickin' good sleep.

It just plain ole' messes with what has been an informative topic with my (left field) bias I hereby consider myself self-censored.

CARLMAN (or Borg or Marbles), can you trash my post above about 'pouty' lips and any the one where I mentioned skrivis and DB?  I'll PM ya'(Carl).

No problem-It's just that I'm very interested in this thread as the advantages of hand-wired PTP audio gear has been glorified often and it is interesting to read the different designer's viewpoints, especially on PCBs. Good day