Complete Build VLOG For My Latest 102

[norburybrook]

My point was only that cap orientation is about noise floor and component tolerance has other effects. I’m in a similar place wrt being anal about component brands or vintage vs. new manufacture, but I do pay attention to material class. The effect of tolerance on resistors or caps can be estimated by how much the roll-off frequency in an RC filter would shift. Resistor tolerance is so small that it’s not worth any consideration. Caps might be 5-10%, but that means the roll-off (which is a gradual thing that occurs over an octave or two) shifts by that same amount, which is between a half and a whole step (a whole step being 1/8 or 12.5%).

Understood I was under the impression that the outer foil had other effects as well as noise floor.


so, can we say categorically then that:


orienting the outer foil's 'correctly' will always result in a slightly lower nose floor than 'incorrectly' and that it will have zero effect on the amps tone?


capacitor tolerance will effect the tone by the way it slightly moves the HPF/LPF roll offs. as you say it will be very slight, but measurable.


Resistor tolerances make no tonal differences but resistor types will effect the noise floor and can have slightly different 'tones'-eg metal film being the quietest- carbon comp being noisiest but perhaps having a preferable tonal quality in certain places in the circuit.



Interesting information though. Hope we haven't derailed the OP's thread!

M

[Charlie Wilson]

OK, I am going to have to respectfully, absolutely, disagree with the last couple posts. Coupling capacitor outer foil orientation does affect the sound of the amp and the overall feel of the amp. Guys like Gil and Tony who have built a lot of amps and play out a lot have been talking about this for years. In fact, I would argue that the sonic benefit out ways the noise reduction benefit. Take your mid cap or V1b coupler and flip them. Then tell me if you can't hear a difference. Secondly, component construction and the materials used do affect the sound. Sometimes a lot. I struggled for a long while with the Low Plate Classic amp I had built. Tried everything for the 100k plates. New production Dale RN65D, Mepco Electra, Roderstein Mk3, and NTE. I could not get rid of the high end harshness that resulted in a not so pleasant clean side and a fizzy sound on the top of the OD and I will say that the new production Vishay Dale RN65D were the worst offenders. Then I managed to get some of the pre-Vishay Dale RN65D like the ones Dumble actually used. No more harshness, nice clear glassy high end, and they even seem to compress a little when you push them. Not the same resistor as the new production. Sorry, I think this stuff is so easy to experience for yourself. Just try some different components, flip some caps around and see if you hear the difference. Then IN MY OPINION the responses are; "I don't hear a difference" or "I hear a difference but it is so slight it doesn't matter to me." or " I hear a difference and it is helpful to me in building a better sounding amp.". Notice all of the responses start with the word "I".
CW

[Chris Brown]

OK, I am going to have to respectfully, absolutely, disagree with the last couple posts. Coupling capacitor outer foil orientation does affect the sound of the amp and the overall feel of the amp. Guys like Gil and Tony who have built a lot of amps and play out a lot have been talking about this for years. In fact, I would argue that the sonic benefit out ways the noise reduction benefit. Take your mid cap or V1b coupler and flip them. Then tell me if you can't hear a difference. Secondly, component construction and the materials used do affect the sound. Sometimes a lot. I struggled for a long while with the Low Plate Classic amp I had built. Tried everything for the 100k plates. New production Dale RN65D, Mepco Electra, Roderstein Mk3, and NTE. I could not get rid of the high end harshness that resulted in a not so pleasant clean side and a fizzy sound on the top of the OD and I will say that the new production Vishay Dale RN65D were the worst offenders. Then I managed to get some of the pre-Vishay Dale RN65D like the ones Dumble actually used. No more harshness, nice clear glassy high end, and they even seem to compress a little when you push them. Not the same resistor as the new production. Sorry, I think this stuff is so easy to experience for yourself. Just try some different components, flip some caps around and see if you hear the difference. Then IN MY OPINION the responses are; "I don't hear a difference" or "I hear a difference but it is so slight it doesn't matter to me." or " I hear a difference and it is helpful to me in building a better sounding amp.". Notice all of the responses start with the word "I".
CW

If you take a basic fuzz face circuit and start swapping the caps and resistors for different composition components of the same value it's undeniable that the composition of the components in an audio signal path effect the tone.

My 124 in which I didn't pay attention to outer foil orientation sounds nowhere near as good as this 102 clone I just finished, but that could have a lot of culprits, and it's really an apples/oranges comparison.

[Bombacaototal]

Many thanks everyone who chimed in. Very interesting topic and I always learn a lot from all of you. Is there anyway to check the foil orientation on a soldered board or the only way would be removing the caps?

[martin manning]

so, can we say categorically then that:

orienting the outer foil's 'correctly' will always result in a slightly lower nose floor than 'incorrectly' and that it will have zero effect on the amps tone?

capacitor tolerance will effect the tone by the way it slightly moves the HPF/LPF roll offs. as you say it will be very slight, but measurable.

Resistor tolerances make no tonal differences but resistor types will effect the noise floor and can have slightly different 'tones'-eg metal film being the quietest- carbon comp being noisiest but perhaps having a preferable tonal quality in certain places in the circuit.

Interesting information though. Hope we haven't derailed the OP's thread!

I can see where outer foil orientation could have tonal effects, such as allowing more or less mixing of signals from different parts of the circuit, leading to feedback loops and intermodulation distortion, so I’ll shift my position a bit there. This is layout and location (in the circuit) dependent, of course, so it’s a very complex issue. As mentioned above some cap constructions do not exhibit this effect, which is most noticeable in rolled construction. I’m down with different materials and constructions in caps having a noticable tonal effect, as there are physical reasons for different behaviors.

Not so much with resistors, except in the case of carbon composition, where there is a physical explanation (the resistance is voltage dependent). It’s probably true that some people can hear it and some can’t, but the physical explanation is sound. Metal film vs. carbon film, and one metal film vs. another seems to be all based on anecdotal evidence, so I’m not ready to buy in. I’ve measured various MF and CF resistors with an LCR meter and didn’t find anything to suggest they would perform differently. Tolerances in modern resistors are typically 1% in MF, 5% in CF, so small enough that it doesn’t matter.

This is not to say that anecdotal evidence isn’t useful, as it may indicate that there is some gap in the understanding of the physics, but unless someone can come up with a plausible theory and evidence, I’m out. Otherwise, it’s a slippery slope down into the audiophool world.

[norburybrook]

indeed. I suppose everyone should do their own experimenting with all this stuff and use what sounds best to THEM. That's all you can really do at the end of the day, build, play and come to your own conclusions.

It's an interesting journey and fortunately there's scope for many variables one way or another which is why a living breathing tube amp is more interesting than a digital moddler at the end of the day.

The important thing is to not disappear down a rabbit hole with things that at the end of the day make so little difference it doesn't matter, and of course remember it's a tool for making music and music doesn't care about capacitors or resistors



MC

[Bombacaototal]

Before I rip all the caps off my soldered board is there anyway to check the foil orientation with them mounted already? Will I get the same results using the oscilloscope?

I know this will hunt my mind later on so I’d rather correct it sonner than later..

[talbany]

OK, I am going to have to respectfully, absolutely, disagree with the last couple posts. Coupling capacitor outer foil orientation does affect the sound of the amp and the overall feel of the amp. Guys like Gil and Tony who have built a lot of amps and play out a lot have been talking about this for years. In fact, I would argue that the sonic benefit out ways the noise reduction benefit. Take your mid cap or V1b coupler and flip them. Then tell me if you can't hear a difference. Secondly, component construction and the materials used do affect the sound. Sometimes a lot. I struggled for a long while with the Low Plate Classic amp I had built. Tried everything for the 100k plates. New production Dale RN65D, Mepco Electra, Roderstein Mk3, and NTE. I could not get rid of the high end harshness that resulted in a not so pleasant clean side and a fizzy sound on the top of the OD and I will say that the new production Vishay Dale RN65D were the worst offenders. Then I managed to get some of the pre-Vishay Dale RN65D like the ones Dumble actually used. No more harshness, nice clear glassy high end, and they even seem to compress a little when you push them. Not the same resistor as the new production. Sorry, I think this stuff is so easy to experience for yourself. Just try some different components, flip some caps around and see if you hear the difference. Then IN MY OPINION the responses are; "I don't hear a difference" or "I hear a difference but it is so slight it doesn't matter to me." or " I hear a difference and it is helpful to me in building a better sounding amp.". Notice all of the responses start with the word "I".
CW

+1 on the Dales
Tony

[norburybrook]

Interesting. I've used the new dales on all my builds and none of them sound harsh to me. I used NOS Mepco metal films on my latest bluesmaster and did a very extensive A/B test with my original one that resides in a studio in London and we couldn't hear any significant difference. I also used Sozo caps in a few places and vintage transformers. All this didn't add up to a noticeable difference in sound. With a tweak of a knob here or there we could make them sound pretty much indistinguishable in the control room through the same isolated cabinet/s

we spend a whole day recording the same guitar solo back and forward between the amps and this guy is a complete anal tone head, he's Clapton, Bonnie Raitt, Van Morrison, Robert palmer guitarist and he'll go to any length for his sound.


I wish I could post sound clips but it's for a new album and obviously doesn't want stuff getting out there. I played Bass with Ringo on drums last month on this project, Peter Framton was coming in the day after to put some guitar on so is Bonnie Raitt and hopefully Eric too it will be a gtr nerd special. All produced by Rolling Stones producer Chris Kimsey. A little OT sorry but just putting it into perspective the quality 'guitar ears' that were listening to the tests.

I was frazzled at the end of the day with constant critical listening, but as I drove home my overall thought's were how close all the different amps sounded recorded in the track, even the not so subtle difference between a BM and a #102 when played in isolation at home etc. I found that obviously the amps were set differently with regards to EQ and gain settings but the overall effect was a very similar sound was got from both. The two BM didn't need much tweaking to sound the same, the two #102's did(in respect to sounding like the BM) but in the end they all sounded magnificent and I got past the point of being able to choose the 'best one'


If my latest BM with the vintage iron/sozo's and NOS Mepco would have sounded better than the first one ( InMAdOut transformers,new Dales etc)then it would have stayed in the studio. It didn't and I'm glad because I wanted to keep it


here's a pic or two with the gtrs a 58, two '59' and a beano 60 Les Pauls

IMG_20180728_112001.jpg

IMG_20180728_114615.jpg

Tony, CHarlie, I'd love to hear the NOS dales, I'll PM you to see if this might be possible somehow

cheeers

Marcus

[martin manning]

Marcus, it would be great if you could assess the effect of a swap to some holy grail resistors. I would advocate an A-B switch on both V1 plate loads (only requires DPDT switch), and really V1 and V2 loads could be switched. Soldering and unsoldering takes too long. Or, I suppose recordings could be employed.

I wonder if time isn’t a factor in claims that this or that component sounded better? Some components are known to burn in, and one’s perception of the tone could change favorably with time, or perhaps become fatigued.

[norburybrook]

Marcus, it would be great if you could assess the effect of a swap to some holy grail resistors. I would advocate an A-B switch on both V1 plate loads (only requires DPDT switch), and really V1 and V2 loads could be switched. Soldering and unsoldering takes too long. Or, I suppose recordings could be employed.

I wonder if time isn’t a factor in claims that this or that component sounded better? Some components are known to burn in, and one’s perception of the tone could change favorably with time, or perhaps become fatigued.

Martin,

I've PM tony and Charlie and if I can get hold of some then yes I can do that.

there are so many factors in all this Martin, hence even here we only really have anecdotal evidence in things like this, and also a scope can only show so much. People's hearing is different, the listening environment, the player, temperature, humidity.


I know I had days recording my album when my amp didn't sound as good as it had the previous day even though the mic's hadn't moved, nothing I could 'see' had changed. In the end I put it down to me not being on it for some reason and I wasn't making the amp work like I had been. That's the wonderful thing about the Dumble IMHO, as a player it makes you work


then there's always, the term 'better' I've found that once a certian level of quality has been acheived then things tend to sound 'different' rather than better or worse. Also tone is a personal thing. I've lost count of the number of times I've heard something that someone has said listen to this, great tone, and I've thought it sounded bad, so perhaps we have to factor that in as well.


alll good stuff though and through conversations like this I think we all can learn and move forward with our understanding of what can make a great amp from a good amp.


M

[martin manning]

Agreed, many factors. That is why a test where the components can be switched back and forth quickly is the best way to hear any difference, IMO.

[talbany]

For those who want to see test results with respect to capacitor orientation.
Here you go.The test was performed by Randall Aiken and posted years ago on a site called the Ampage. The test was during a time when everyone had their doubts about how and if the caps orientation affected the signal quality in a guitar amplifier. The test made him a believer and others soon followed.
This especially apply's to overdrive amps with built in cascading gain stages like the ODS.Noise-induced into the signal path can cause many issues all the way up and including harmonic structure.


Just for grins, I set my signal generator up for it's max 28V p-p output signal (to simulate a reasonable output signal at the plate of a tube), and connected the ground of the signal
generator and the scope ground to one end of one of my 0.1uF film/foil caps, and held the signal generator "hot" lead next to the cap. I then set my scope to the 20mV/div setting,
and put the scope probe tip on the other unconnected cap terminal. I measured the amount of signal present, then I turned the cap around, connecting the signal generator and
scope grounds to the other side of the cap, and the scope probe tip to the side that was previously connected to the grounds and re-measured. I was shocked to find that in the
first position, there was no discernable signal, but in the second, there was a 5mV p-p signal!

This test would indicate that the outside foil lead is the one that results in no induced signal when the scope and generator grounds are connected to it, because it is acting as a
shield against the generator signal.

To put this into perspective, consider that most tube stages have a gain of around 50. A 5mV signal induced into the grid of that stage would result in a 0.25V signal at the plate.
Amplify that a few more times and you get a great big signal at the output. Of course, in most amps, there isn't a big signal sitting on top of the cap, but there may be one running
near it. The induced signal strength falls of with the square of the distance, so it decreases rapidly, but it doesn't take much to induce a hum or oscillation.
After playing around for a while, I found an even easier method to identify the outside foil - simply hook the scope probe up across the cap, set it to trigger on the AC line, adjust
to the 20mV per division setting (or the lowest setting you have), and grab the cap tightly between your fingers. Measure the amplitude of the induced 60Hz AC signal, then
reverse the leads and grab the cap again (better yet, keep holding the cap the same way and reverse the leads). You will find a very large difference in the induced 60Hz signal
from your fingers. The position that gives the lowest signal level is the one you want. In that position, the scope ground lead is connected to the outside foil.

I also found that larger value caps have a smaller induced signal, which is due to their lower impedance at 60Hz, so this test is hard to see on film caps above 1uF or so, unless you
have a very sensitive scope.

This test has made a believer out of me, I'm going to test and connect the outside foil of all my caps to the lowest impedance point from now on. This is usually the plate terminal on coupling caps, or the grounded end on shunt caps.

BTW. As far as the resistor debate goes? ..Some people hear it, some do not!
Just because it's a NOS hard to find part does not automatically mean it is something that sounds better to you!. This also applies to seasoned Iron.
Above all before you establish an opinion on any of these ongoing debates it becomes obvious at some point to try them for yourself and establish some frame of reference so you can compare and contrast how each component interacts in your amp and draw your own conclusions. If you don't hear a difference great!.If you do hear a difference great. Of course it's always a good thing to share your findings here and try to establish a consensus for those that may want to go in that direction. IMO If you have not done these experiments and don't have a good frame of reference it's kind of silly to debate or doubt those who have tried all the different types, built many amps and have their own opinions.It can be a beautiful thing when a bit of Mojo and Science collide and you actually hear it
Check it out!

Tony

[stelligan]

Regarding cap orientation, I am a believer. Wasn't hip to it when I started lurking here 12 years ago. Now I test and mark all my caps before they go in the parts bin. My first builds sounded fine to me. My more recent builds, finer....

P.S. Cool video, OP. I guess we have veered a wee bit...
My last build was a 102 as well. Should not have waited so long to finish it - great sounding amp.

[Bombacaototal]

For those who want to see test results with respect to capacitor orientation.
Here you go.The test was performed by Randall Aiken and posted years ago on a site called the Ampage. The test was during a time when everyone had their doubts about how and if the caps orientation affected the signal quality in a guitar amplifier. The test made him a believer and others soon followed.
This especially apply's to overdrive amps with built in cascading gain stages like the ODS.Noise-induced into the signal path can cause many issues all the way up and including harmonic structure.


Just for grins, I set my signal generator up for it's max 28V p-p output signal (to simulate a reasonable output signal at the plate of a tube), and connected the ground of the signal
generator and the scope ground to one end of one of my 0.1uF film/foil caps, and held the signal generator "hot" lead next to the cap. I then set my scope to the 20mV/div setting,
and put the scope probe tip on the other unconnected cap terminal. I measured the amount of signal present, then I turned the cap around, connecting the signal generator and
scope grounds to the other side of the cap, and the scope probe tip to the side that was previously connected to the grounds and re-measured. I was shocked to find that in the
first position, there was no discernable signal, but in the second, there was a 5mV p-p signal!

This test would indicate that the outside foil lead is the one that results in no induced signal when the scope and generator grounds are connected to it, because it is acting as a
shield against the generator signal.

To put this into perspective, consider that most tube stages have a gain of around 50. A 5mV signal induced into the grid of that stage would result in a 0.25V signal at the plate.
Amplify that a few more times and you get a great big signal at the output. Of course, in most amps, there isn't a big signal sitting on top of the cap, but there may be one running
near it. The induced signal strength falls of with the square of the distance, so it decreases rapidly, but it doesn't take much to induce a hum or oscillation.
After playing around for a while, I found an even easier method to identify the outside foil - simply hook the scope probe up across the cap, set it to trigger on the AC line, adjust
to the 20mV per division setting (or the lowest setting you have), and grab the cap tightly between your fingers. Measure the amplitude of the induced 60Hz AC signal, then
reverse the leads and grab the cap again (better yet, keep holding the cap the same way and reverse the leads). You will find a very large difference in the induced 60Hz signal
from your fingers. The position that gives the lowest signal level is the one you want. In that position, the scope ground lead is connected to the outside foil.

I also found that larger value caps have a smaller induced signal, which is due to their lower impedance at 60Hz, so this test is hard to see on film caps above 1uF or so, unless you
have a very sensitive scope.

This test has made a believer out of me, I'm going to test and connect the outside foil of all my caps to the lowest impedance point from now on. This is usually the plate terminal on coupling caps, or the grounded end on shunt caps.

BTW. As far as the resistor debate goes? ..Some people hear it, some do not!
Just because it's a NOS hard to find part does not automatically mean it is something that sounds better to you!. This also applies to seasoned Iron.
Above all before you establish an opinion on any of these ongoing debates it becomes obvious at some point to try them for yourself and establish some frame of reference so you can compare and contrast how each component interacts in your amp and draw your own conclusions. If you don't hear a difference great!.If you do hear a difference great. Of course it's always a good thing to share your findings here and try to establish a consensus for those that may want to go in that direction. IMO If you have not done these experiments and don't have a good frame of reference it's kind of silly to debate or doubt those who have tried all the different types, built many amps and have their own opinions.It can be a beautiful thing when a bit of Mojo and Science collide and you actually hear it
Check it out!

Tony

Thanks for the detailed post and a bit of history on this topic Tony. I found a video which uses the second method you detailed

https://youtu.be/BnR_DLd1PDI

Would I achieve the same results doing this method on a soldered board or would be best to remove the caps for this testing