Hi Guys
From post#1:
"So what is it EXACTLY, technically, that makes point-to-point wiring sound better to most musicians than PCBs??"
The question is flawed inasmuch as the subjective view is placed in the hands of musicians when really it is magazine reviewers who have promoted this idea.
The reality is that you can have good and bad PTP assemblies and good and bad PCB assemblies.
A GOOD PTP assembly is one that is airy and follows Galactic Ground principles. The airy layout reduces parasitic capacitances that join circuit points not intended to be joined by the designer. Galactic Grounding and wiring provides the lowest noise and best note articulation.
A GOOD PCB layout is designed using the same concepts as the Good-PTP layout and does NOT have to be laid out as a copy of the PTP to have the same sound, despite that intuitive solution being the usual first step by newbie PCB builders.
Parasitic capacitance is completely unavoidable in electronic assemblies of any kind, but they can be minimised. Remember that a capacitor is formed when two conductors are separated by an insulator and it does not matter how far apart the conductors are., there will be a tiny capacitance between them. Fortunately, distance between the conductors reduces the capacitance between them at an exponential rate, which is why an airy layout has lower parasitic capacitance than a tight one.
There will always be parasitic capacitance to ground which shunts high-frequencies to ground. In some case, this will make the layout more stable even if the circuit has inherent instability or a narrow stability margin. On the other hand, if the gain of the circuit is high, then parasitic coupling can promote instability. If one follows Galactic Grounding methods, then the layout will be inherently stable and parasitics will be less problematic.
PTP wiring is inherently variable in its layout despite the use of jigs etc for production, so side-by-side comparisons of same-model amps played in a music store yield different sounds from the amps. A PCB is much more consistent from unit to unit and improves productivity.
The problem with MASS PRODUCTION PCBs is wave soldering. This is an automated process that gives every solder joint the same amount of heat and the same amount of solder, which is a HUGE compromise to the reliability of the assembly. Larger leads obviously need more heat and more solder than small ones, so some amount of touch-up is required at the end of the line. Mass-produced items have built-in obsolescence and give PCBs a bad rep.
Look at early Marshall or Ampeg amps. Both brands switched to PCBs early and in both cases those early PCB amps were more reliable and easier to service than their predecessors. Their later PCB assemblies were like every other brand - difficult to service and short life. It is pretty much the rule of the service industry that 90% of all symptoms in electronic units are fixed by simply resoldering the PCB.
I used to use eyelet boards for my amps but now I use PCBs. Everything is hand assembled and hand soldered and reliability is the same as for the best PTP assembly. Sonically nothing has changed. Serviciability of PCB amps is up to the ability of the designer or the willingness to accept a more complex mechanical build.
There is an article on my site about PCB vs PTP.
Have fun
From post#1:
"So what is it EXACTLY, technically, that makes point-to-point wiring sound better to most musicians than PCBs??"
The question is flawed inasmuch as the subjective view is placed in the hands of musicians when really it is magazine reviewers who have promoted this idea.
The reality is that you can have good and bad PTP assemblies and good and bad PCB assemblies.
A GOOD PTP assembly is one that is airy and follows Galactic Ground principles. The airy layout reduces parasitic capacitances that join circuit points not intended to be joined by the designer. Galactic Grounding and wiring provides the lowest noise and best note articulation.
A GOOD PCB layout is designed using the same concepts as the Good-PTP layout and does NOT have to be laid out as a copy of the PTP to have the same sound, despite that intuitive solution being the usual first step by newbie PCB builders.
Parasitic capacitance is completely unavoidable in electronic assemblies of any kind, but they can be minimised. Remember that a capacitor is formed when two conductors are separated by an insulator and it does not matter how far apart the conductors are., there will be a tiny capacitance between them. Fortunately, distance between the conductors reduces the capacitance between them at an exponential rate, which is why an airy layout has lower parasitic capacitance than a tight one.
There will always be parasitic capacitance to ground which shunts high-frequencies to ground. In some case, this will make the layout more stable even if the circuit has inherent instability or a narrow stability margin. On the other hand, if the gain of the circuit is high, then parasitic coupling can promote instability. If one follows Galactic Grounding methods, then the layout will be inherently stable and parasitics will be less problematic.
PTP wiring is inherently variable in its layout despite the use of jigs etc for production, so side-by-side comparisons of same-model amps played in a music store yield different sounds from the amps. A PCB is much more consistent from unit to unit and improves productivity.
The problem with MASS PRODUCTION PCBs is wave soldering. This is an automated process that gives every solder joint the same amount of heat and the same amount of solder, which is a HUGE compromise to the reliability of the assembly. Larger leads obviously need more heat and more solder than small ones, so some amount of touch-up is required at the end of the line. Mass-produced items have built-in obsolescence and give PCBs a bad rep.
Look at early Marshall or Ampeg amps. Both brands switched to PCBs early and in both cases those early PCB amps were more reliable and easier to service than their predecessors. Their later PCB assemblies were like every other brand - difficult to service and short life. It is pretty much the rule of the service industry that 90% of all symptoms in electronic units are fixed by simply resoldering the PCB.
I used to use eyelet boards for my amps but now I use PCBs. Everything is hand assembled and hand soldered and reliability is the same as for the best PTP assembly. Sonically nothing has changed. Serviciability of PCB amps is up to the ability of the designer or the willingness to accept a more complex mechanical build.
There is an article on my site about PCB vs PTP.
Have fun
Last edited:
Tubes varied tube to tube, but beyond that, so did all the other components. Look at old Fender schematics, they say right on them that all parts are 20% as are all readings. They used 20% tolerance resistors for example. That means a 100k plate resistor could be anywhere from 80k to 120k and be within spec. So amp to amp, that made a tremendous difference back then. Worse, in that era common for filter caps and other electrtolytics to have tolerances like -20/+80%. Honest, +80%.
But I'd agree that the layout varies, in that a resistor or cap might be strung between two points, but one builder might have the bodies closer to one end, while the next guy over likes them the other way. Wire harnesses made the same wires bundle, but there was no guarantee which wires were directly against which others within the bundle. Some line workers trimmed their wires longer than others, which when wired to grids altered the amount of stray signal they picked up, just as wire length affected radiation from high level wires. Got a cap and resistor parallel? WHo determines which side the cap goes on in the chassis? The line tech. etc. When wires cross at right angles, they couple less than they do at narrower angles. so when wires or components cross over one another, the positioning by the line tech can matter. How tightly are twisted pairs twisted? How far away were the heater AC wires from signal wires?
But I'd agree that the layout varies, in that a resistor or cap might be strung between two points, but one builder might have the bodies closer to one end, while the next guy over likes them the other way. Wire harnesses made the same wires bundle, but there was no guarantee which wires were directly against which others within the bundle. Some line workers trimmed their wires longer than others, which when wired to grids altered the amount of stray signal they picked up, just as wire length affected radiation from high level wires. Got a cap and resistor parallel? WHo determines which side the cap goes on in the chassis? The line tech. etc. When wires cross at right angles, they couple less than they do at narrower angles. so when wires or components cross over one another, the positioning by the line tech can matter. How tightly are twisted pairs twisted? How far away were the heater AC wires from signal wires?
Circuit boards are fine as long as you keep any substantial heat off of them. I would put 12AX7's on one, but no power tubes. Resistors pushed to half of their power rating will still get very hot, so in high current circuits you want to pay close attention to that. If an R gets too hot to put your finger on for 10 seconds, it's too hot, IMO.
In a guitar amp, the PCB will vibrate significantly, so needs to be well mounted, possibly shock mounted (soft rubber grommets). The part costs alone in my amps were higher than an entire Chinese built amp (Vox for example), and they were VERY labor intensive. Lots of hours. But now I've got some darn near perfect guitar amps. They sound excellent, are very reliable and repairable, and they make me a better guitarist since I love playing through them. I'm apparently more picky than most.
In a guitar amp, the PCB will vibrate significantly, so needs to be well mounted, possibly shock mounted (soft rubber grommets). The part costs alone in my amps were higher than an entire Chinese built amp (Vox for example), and they were VERY labor intensive. Lots of hours. But now I've got some darn near perfect guitar amps. They sound excellent, are very reliable and repairable, and they make me a better guitarist since I love playing through them. I'm apparently more picky than most.
Hi Guys
In the quest to achieve any semblance of unit-to-unit consistency, OEMs went from uncontrolled wiring, to harness made in jigs, to card-mounted components, then to PCBs. This controls the parasitic elements of the assembly.
As others have said, component tolerance is then an issue. So, as technology improves to manufacture components, OEMs have the choice to go from 20% garbage carbon-comp, to slightly better 10% then 5% carbon-film, to metal film; with power Rs going from carbon-comp to carbon-film to metal-oxide and wire-wounds. Capacitor technology improved generally, too, but OEMs again have the choice of using improved parts or not. One can substitutue poly caps for electrolytics and remove a huge factor of temperamentalness from the amp's performance.
Tubes are temperamental, especially in their first six months of use and also if they are in combo amps. After the tube breaks in, it has lost some edge and harshness but is now on its Tone Plateau where it will sound the same for the next fifty years. This is the the exact point where tube salesmen want you to throw them away and replace them. Because that guidance is loud and bombastic, players assume it must be true.
The worst thing you can do with electronic items is collect so many of them that you use them infrequently. Every six months when you take the amp out of the closet and turn it on, the electrolytics are temperamental as are the tubes. if it has carbon resistors, well, those are garbage and make all kinds of nuisance noise as they warm up and as voltage is applied, along with the variation of the signal amplitude. The amp coughs and sputters and you tell yourself this is why you only play it every six months.
Electrolytic caps need regular application of voltage to stay healthy. You don't need to play all your amps but do turn them on to the operate mode for twnety minutes every other day. The more often you use them the longer lived it will be and the more it sound consistent each time.
Galactic Grounding is my term for an organised grounding and wiring method that can be applied to all technologies of circuitry, tube, solid-state, etc. It is explained in detail in TUT3 (The Ultimate Tone vol.3) released in 2003. There is no reason why a tube amp has to be noisy.
I hate to see China-bashing. I buy many things from China and the quality is superb. China builds exactly the products that the US and Europe order and pay for. If we request something to a budget the Chinese are adept at meeting that budget and can produce whatever quality we desire - but you DO have to pay a little more for quality. The west chooses not to pay, so China builds crap-to-order for those who've ordered it.
You should take issue with the western companies who disrespect their own customers and assume that someone on a budget does is also not 'serious'. This happened long before off-shore manufacturing became the norm. The Fender Champ is a pretty crappy amp. yes, many like it, but how many novices were turned off playing by it? Just like with those Gorllia 10W chip amps of the '80s. If you wanted good tone and any kind of features, you had to go to bigger more expensive models. If you were serious you bought a Twin reverb but if not serious something little. At lest today OEMs recognise that low-power does not have to mean low-quality or not-serious - you can get low-watt amps with fully featured preamps and effects loops etc. Some things have improved but many follow the old pattern.
Magazine reviewers still have much to learn. For example, the Guitar player review of the Ampeg amps said they have baxadall EQ - which is true. Then they stated that there is no flat response position for such an EQ - which is false. There is no flat-response position for a standard tone stack, but the bax is a parallel-path EQ that inherently has a flat middle setting.
Have fun
In the quest to achieve any semblance of unit-to-unit consistency, OEMs went from uncontrolled wiring, to harness made in jigs, to card-mounted components, then to PCBs. This controls the parasitic elements of the assembly.
As others have said, component tolerance is then an issue. So, as technology improves to manufacture components, OEMs have the choice to go from 20% garbage carbon-comp, to slightly better 10% then 5% carbon-film, to metal film; with power Rs going from carbon-comp to carbon-film to metal-oxide and wire-wounds. Capacitor technology improved generally, too, but OEMs again have the choice of using improved parts or not. One can substitutue poly caps for electrolytics and remove a huge factor of temperamentalness from the amp's performance.
Tubes are temperamental, especially in their first six months of use and also if they are in combo amps. After the tube breaks in, it has lost some edge and harshness but is now on its Tone Plateau where it will sound the same for the next fifty years. This is the the exact point where tube salesmen want you to throw them away and replace them. Because that guidance is loud and bombastic, players assume it must be true.
The worst thing you can do with electronic items is collect so many of them that you use them infrequently. Every six months when you take the amp out of the closet and turn it on, the electrolytics are temperamental as are the tubes. if it has carbon resistors, well, those are garbage and make all kinds of nuisance noise as they warm up and as voltage is applied, along with the variation of the signal amplitude. The amp coughs and sputters and you tell yourself this is why you only play it every six months.
Electrolytic caps need regular application of voltage to stay healthy. You don't need to play all your amps but do turn them on to the operate mode for twnety minutes every other day. The more often you use them the longer lived it will be and the more it sound consistent each time.
Galactic Grounding is my term for an organised grounding and wiring method that can be applied to all technologies of circuitry, tube, solid-state, etc. It is explained in detail in TUT3 (The Ultimate Tone vol.3) released in 2003. There is no reason why a tube amp has to be noisy.
I hate to see China-bashing. I buy many things from China and the quality is superb. China builds exactly the products that the US and Europe order and pay for. If we request something to a budget the Chinese are adept at meeting that budget and can produce whatever quality we desire - but you DO have to pay a little more for quality. The west chooses not to pay, so China builds crap-to-order for those who've ordered it.
You should take issue with the western companies who disrespect their own customers and assume that someone on a budget does is also not 'serious'. This happened long before off-shore manufacturing became the norm. The Fender Champ is a pretty crappy amp. yes, many like it, but how many novices were turned off playing by it? Just like with those Gorllia 10W chip amps of the '80s. If you wanted good tone and any kind of features, you had to go to bigger more expensive models. If you were serious you bought a Twin reverb but if not serious something little. At lest today OEMs recognise that low-power does not have to mean low-quality or not-serious - you can get low-watt amps with fully featured preamps and effects loops etc. Some things have improved but many follow the old pattern.
Magazine reviewers still have much to learn. For example, the Guitar player review of the Ampeg amps said they have baxadall EQ - which is true. Then they stated that there is no flat response position for such an EQ - which is false. There is no flat-response position for a standard tone stack, but the bax is a parallel-path EQ that inherently has a flat middle setting.
Have fun
While I agree with most of what you said (Struth), my experience with Chinese stuff is that it's a bit of a crap shoot. Some is great and much is trash, apparently designed to break real soon. GE Lightbulbs made there last about a month (instead of a year). To be fair though, the stuff they make is often designed by non-Chinese Engineers that have a price point mandate in a very competitive market.
I don't believe that tubes sound any different (less harsh) after a break-in period. I'd sure love to hear an actual full technical explanation of how that would be possible. What I believe is that peoples ears adjust over time, and then they think the tube has changed. Magazine reviews are usually the worse, since their top priority is selling advertisement space. What company would buy advertisement space in a magazine that would tell the world that many products suck?
I don't believe that tubes sound any different (less harsh) after a break-in period. I'd sure love to hear an actual full technical explanation of how that would be possible. What I believe is that peoples ears adjust over time, and then they think the tube has changed. Magazine reviews are usually the worse, since their top priority is selling advertisement space. What company would buy advertisement space in a magazine that would tell the world that many products suck?
Since I don't have an extra $68, could you briefly explain this 'organised grounding and wiring method' ?
Hi Guys
Tubes do change their performance after about 100 hours of use. You must not have used many tubes not notice the loss of treble gain after a while? This is when most players think they should change them - and this is what tube sellers tell them too.
Guitar strings are the same. So are dynamic speakers. Once any of these things is past its break-in the performance is very stable for decades.
dotneck335: Search my other posts on this forum and you'll find a description of organised grounds. It is based on science not voodoo. 68cdn is only about 50us right now. slightly less expensive than going to school and working for forty years.
Have fun
Tubes do change their performance after about 100 hours of use. You must not have used many tubes not notice the loss of treble gain after a while? This is when most players think they should change them - and this is what tube sellers tell them too.
Guitar strings are the same. So are dynamic speakers. Once any of these things is past its break-in the performance is very stable for decades.
dotneck335: Search my other posts on this forum and you'll find a description of organised grounds. It is based on science not voodoo. 68cdn is only about 50us right now. slightly less expensive than going to school and working for forty years.
Have fun
Interesting idea. But unless you change to a new speaker (and new strings) after 100 hours, how would you know it's the tubes?
More seriously: is it just high audio frequencies that are affected, or is RF gain also reduced?
Is it the kind of thing that Scientists and Engineers can measure? If so, where are the published results?
Or, is it the kind of subtle effect that only folks with 'golden ears' can detect?
Last edited:
Hi Guys
Think of your question in reverse:
Have you played a tube amp long enough to hear a tone change?
Hifi guys fall victim to this just as guitar players do. After six months or so, they feel something is different about the sound and indeed there is something different. However, they are about to waste the many decades of the tube's life where the tone is consistent.
If you listen to the same model of Fender amp, both PTP and otherwise allegedly the same but one is old and one is new, they will sound markedly different side-by-side. The bulk of this difference will be the raw new harsh speaker versus the broken-in smooth old speaker. But there will also be other parts not broken in on the new and well aged in the old - sometimes too well aged if the coupling caps are paper types. If you compare them through the same speaker then you can isolate the amp effects from the speaker effects. Did this many times with many players to show them where the issues lied contrary to their initial thought.
A customer brought me a National amp that had really low output. You could turn it to ten and talk over it. The paper coupling caps had of course dried out and were decades past needing changed. Those were replaced by polys and the amp could shake the floor like it should. The player liked that change and wanted to know what else could be done, so we replaced the carbon-comps with real resistors and the amp was much less noisy. Through the two sessions the electrolytics were also replaced since the ESR on the originals was through the roof, and the grounding was fixed.
Yes, one can measure the change of tube performance but it is also easy for anyone with intact hearing to notice - no special training required. Even those Coke-bottle Chinese 6L6s can sound good if you break them in and use them in a head rather than a combo. It is also NOT an issue of NOS vs new manufacture a you can get good and bad of each.
A tube is an electromechanical assembly so its precise alignments give it the characteristics claimed (which is also why a combo amp is the worst environment for them). The cathode is particularly variable since it is the electron emitter and undergoes extreme thermal cycling. The initial gain and noise from the tube will be high, so it can sound bright and harsh during the break-in period. Some OEMs like Mesa rely on this infant tone for the tuning of their amps. After a period of use, the mechanical structure is actually more stable and the gain is slightly reduced and the tone is smoother and less noisy. Electron emission is still well within the normal operating range of the tube, so mu is still nearlky as rated. As I've said, it takes decades for most receiving tubes to get to the point where the tube manufacturer considers it dead - half the emission rating.
All these things can be measured and all can be heard easily.
Have fun
Think of your question in reverse:
Have you played a tube amp long enough to hear a tone change?
Hifi guys fall victim to this just as guitar players do. After six months or so, they feel something is different about the sound and indeed there is something different. However, they are about to waste the many decades of the tube's life where the tone is consistent.
If you listen to the same model of Fender amp, both PTP and otherwise allegedly the same but one is old and one is new, they will sound markedly different side-by-side. The bulk of this difference will be the raw new harsh speaker versus the broken-in smooth old speaker. But there will also be other parts not broken in on the new and well aged in the old - sometimes too well aged if the coupling caps are paper types. If you compare them through the same speaker then you can isolate the amp effects from the speaker effects. Did this many times with many players to show them where the issues lied contrary to their initial thought.
A customer brought me a National amp that had really low output. You could turn it to ten and talk over it. The paper coupling caps had of course dried out and were decades past needing changed. Those were replaced by polys and the amp could shake the floor like it should. The player liked that change and wanted to know what else could be done, so we replaced the carbon-comps with real resistors and the amp was much less noisy. Through the two sessions the electrolytics were also replaced since the ESR on the originals was through the roof, and the grounding was fixed.
Yes, one can measure the change of tube performance but it is also easy for anyone with intact hearing to notice - no special training required. Even those Coke-bottle Chinese 6L6s can sound good if you break them in and use them in a head rather than a combo. It is also NOT an issue of NOS vs new manufacture a you can get good and bad of each.
A tube is an electromechanical assembly so its precise alignments give it the characteristics claimed (which is also why a combo amp is the worst environment for them). The cathode is particularly variable since it is the electron emitter and undergoes extreme thermal cycling. The initial gain and noise from the tube will be high, so it can sound bright and harsh during the break-in period. Some OEMs like Mesa rely on this infant tone for the tuning of their amps. After a period of use, the mechanical structure is actually more stable and the gain is slightly reduced and the tone is smoother and less noisy. Electron emission is still well within the normal operating range of the tube, so mu is still nearlky as rated. As I've said, it takes decades for most receiving tubes to get to the point where the tube manufacturer considers it dead - half the emission rating.
All these things can be measured and all can be heard easily.
Have fun
Last edited:
Hi Guys
PTP encompasses the use of terminal strips, tag strips, eyelet boards (circuit cards) and turret boards, along with hair-ball wiring right on the tube socket or controls and jacks. Each method has its pros and cons with respect to how quickly it goes together and how easily it can be serviced.
Of all the PTP assembly methods, circuit cards are the easiest to service and hair-balls are the worst.
Terminal strips assembly is one of the fastest but can be difficult to change or service.
Using the tube sockets for component mounting is pretty quick but leads to unreliable circuits due to the mechanical stresses of tube insertion and extraction.
Everyone will have their own preferences for assembly and will agree or disagree with the above, but generally the above represents industry norms.
Have fun
PTP encompasses the use of terminal strips, tag strips, eyelet boards (circuit cards) and turret boards, along with hair-ball wiring right on the tube socket or controls and jacks. Each method has its pros and cons with respect to how quickly it goes together and how easily it can be serviced.
Of all the PTP assembly methods, circuit cards are the easiest to service and hair-balls are the worst.
Terminal strips assembly is one of the fastest but can be difficult to change or service.
Using the tube sockets for component mounting is pretty quick but leads to unreliable circuits due to the mechanical stresses of tube insertion and extraction.
Everyone will have their own preferences for assembly and will agree or disagree with the above, but generally the above represents industry norms.
Have fun
Sorry but no.
100 hours?
NO WAY.Tubes slooooowwwwllllyyy lose emission, thus lose transconductance which depending on application circuit may produce measurable and eventually audible changes, but we are talking 3000 hours or more.
Never heard that.
Tubes which lose emission and transconductance may sound "tired" , in general an inaccurate expression which some non Techs might use , but nothing within 100 hours of use.
No they are not.
They are steel wires which get stretched (they are thin and used under great tension) which changes internal structure and even physical dimensions, absolutely unrelated to what happens in tubes.
Again not the same by a country mile.
Speakers are made out of cardboard and impregnated cotton cloth, so they change "mechanical" parameters by flexing and stretching, *this* kind of phenomenon can and does happen within the first hours of use, depending on stress applied (power level at lower frequencies)
Does not apply to tubes
, which are the main subject here.At the same times, I know no tubes stable for decades.
In a nutshell: no "break in" for tubes, the same way there is no break-in for wiring, connectors, transistors, Op Amps, etc.
It does apply to mechanical stuff, car engines included.
You may also include shoes in the verifiable break-in stuff.
The above idea of tube break-in sounds like voodoo.
Shouldn't your posts be moved to the Vendor Area, since they always push for your own books sales?
You're welcome
Last edited:
Hi Guys
DF96: Are you simply being argumentative or do you lack experience with tubes? Feedback does not enter into the equation and why do you keep referring to RF? What is more appropriate to discuss would be THD.
Fahey demonstrates the point of the wrong view being the loudest. You claim to have a lot of experience and knowledge yet you write in bombastic fashion as if this was usenet filled with 12-year-olds to impress, then make statements that show extreme lack of comprehension. Obviously you prefer to soak your customers every six months for tubes they do not need.
100 hours for burn in seems arbitrary but it has been proven scientifically.
Marce: Your view seems to be based entirely on aesthetics which makes you 100% correct. Technically, you have over-stated certain points that are not equatable. There is good and bad PTP just as there is good and bad PCB construction. When both are done correctly they are both good; when both are done poorly they are both bad.
Have fun
DF96: Are you simply being argumentative or do you lack experience with tubes? Feedback does not enter into the equation and why do you keep referring to RF? What is more appropriate to discuss would be THD.
Fahey demonstrates the point of the wrong view being the loudest. You claim to have a lot of experience and knowledge yet you write in bombastic fashion as if this was usenet filled with 12-year-olds to impress, then make statements that show extreme lack of comprehension. Obviously you prefer to soak your customers every six months for tubes they do not need.
100 hours for burn in seems arbitrary but it has been proven scientifically.
Marce: Your view seems to be based entirely on aesthetics which makes you 100% correct. Technically, you have over-stated certain points that are not equatable. There is good and bad PTP just as there is good and bad PCB construction. When both are done correctly they are both good; when both are done poorly they are both bad.
Have fun
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.