erwin_ve wrote: ↑Mon Jun 11, 2018 5:21 pm
In 3. EMFR: Electromagnetic Field Radiation ?
I think it was Electro Magnetic Static Resistance, hence ESR or EMSR.
Keep in mind, this was back in 2001, and I didn't have an iPad, iPhone or
anything to keep track of the stuff Howard was saying. And yes, he said
a lot of stuff...only some of which I retained. Sorry.
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FUCHSAUDIO wrote: ↑Mon Jun 11, 2018 8:10 pm
Not sure about the grounding, but the capacitor composition and placement have been issues for me in the past.
Apparently the grounding changes, don't quote me on this as it's from 2001, something to do with how a field between components reacts in relation to the distance to the actual ground. That's why there were two major star grounding points, one by the PT on one side, and the other (on the back side of the chassis, not the same as the PT ground) near the preamp tube. If I remember right it was also supposed to be in a symmetrical even line to each other in relation to the top and bottom of the chassis.
Or in other words, like on an equator line evenly spaced top to bottom.
All this stuff gives me a headache, gents, sorry I can't remember every detail.
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Thanks Jim, it is interesting that HAD was talking about the changes and why they are significant. I had him figured for a guy who would have said change this and that without explanation.The real tragedy with guys like HAD is the stuff they learn isn't passed on to others. Still I suppose he did the hard yards.
That is interesting about components talking to each other I remember Dave Funk building an amp which was suppose to be on the verge of oscillation due to cap placement. The idea was to get smooth sustain out of a clean amp. Gil Aron played around with that sort of thing too, he found the circuit worked well at low volume levels but was seriously unstable at high volume, I seem to recall he abandoned this component placement amp entirely.
Not sure about the grounding, but the capacitor composition and placement have been issues for me in the past. I had an early mod that sounded amazing, but oscillated at high gain settings. I added some copper foil to a coupling cap (which was near another) and grounded it, and it fixed the issue. I'm pretty OCD about my board layouts and grounding because parts talk to parts and there are subtle aspects of the tone that will suffer ! Take a guitar pickup on a cable (not on a guitar), plug it into another amp, play guitar (or pass a signal through the amp you want to test) and hold it over wires and components, and you will see what I mean....
I assume you mean a single coil pickup as opposed to a humbucker as signal isn't induced in the pickup by a string cutting the magnets lines of flux and the humbu king coils would cancel out noise. An aluminium or stainless steel chassis would be a must so you don't pick up noise from the transformers I imagine.
Actually, a dear old friend (who was one of my mentors) showed me a device he made that was apparently popular in NYC recording studio tech toolboxes. It used a recording head (usually something worn out or a cheap cassette tape player head), mounted on the end of a Bic ball point pen shell with coax on it. They used it as a 'sniffer" to read component radiation and hum fields with a scope or an audio signal tracer...you'd be amazed what you could "see".
FUCHSAUDIO wrote: ↑Tue Jun 12, 2018 2:22 pm
Actually, a dear old friend (who was one of my mentors) showed me a device he made that was apparently popular in NYC recording studio tech toolboxes. It used a recording head (usually something worn out or a cheap cassette tape player head), mounted on the end of a Bic ball point pen shell with coax on it. They used it as a 'sniffer" to read component radiation and hum fields with a scope or an audio signal tracer...you'd be amazed what you could "see".
That sounds like a tool that most of us could use... Naturally, I want one.
Also, I'm curious about what kind of mental calculation HAD was using to arrive at the spacing for the filter caps... Or that required a change in composition. Side point - Illinois caps = yuck!
This also would lend credit to the method of placing filter caps at the point they are needed, instead of stacking them up together like a battery pack.
What to read, what to read...
"Education is what you're left with after you have forgotten what you have learned" - Enzo
FUCHSAUDIO wrote: ↑Tue Jun 12, 2018 2:22 pm
Actually, a dear old friend (who was one of my mentors) showed me a device he made that was apparently popular in NYC recording studio tech toolboxes. It used a recording head (usually something worn out or a cheap cassette tape player head), mounted on the end of a Bic ball point pen shell with coax on it. They used it as a 'sniffer" to read component radiation and hum fields with a scope or an audio signal tracer...you'd be amazed what you could "see".
That sounds like a tool that most of us could use... Naturally, I want one.
Also, I'm curious about what kind of mental calculation HAD was using to arrive at the spacing for the filter caps... Or that required a change in composition. Side point - Illinois caps = yuck!
This also would lend credit to the method of placing filter caps at the point they are needed, instead of stacking them up together like a battery pack.
What to read, what to read...
I have (for years) tried to localize my filtering to the circuit that cap served. Thanks to PC boards, I can home run audio and PS grounds back to a central point and the filter lives by the circuit node it serves. My main filters and screen stuff is on it's own board elsewhere, but they all end up at a single chassis ground.
The name for the device was a "Bag nose"..not sure what that meant, but it was a cool tool to see magnetic and audio fields from wires, caps, transformers etc.
martin manning wrote: ↑Tue Jun 12, 2018 3:25 pm
IC film caps are very good. That’s why I asked above about PS filters or couplers.
Agreed, IC audio caps are good. Easily as good as the brown CDE stuff, Mallory 150's and Mojo Dijon caps. Their electrolytics, not so much.
I like that they suck, as our repair shop makes a good buck replacing them in modern Fenders constantly...sometimes in 6 month old amps. The high end Fenders (Bonamassa Twin, EC sig amps), right down to the Blues Junior and the low end amps, use these same awful parts....what a sin.
martin manning wrote: ↑Tue Jun 12, 2018 3:25 pm
IC film caps are very good. That’s why I asked above about PS filters or couplers.
Agreed, IC audio caps are good. Easily as good as the brown CDE stuff, Mallory 150's and Mojo Dijon caps. Their electrolytics, not so much.
I like that they suck, as our repair shop makes a good buck replacing them in modern Fenders constantly...sometimes in 6 month old amps. The high end Fenders (Bonamassa Twin, EC sig amps), right down to the Blues Junior and the low end amps, use these same awful parts....what a sin. Sadly, some "bourique" companies (Two Rock comes to mind) use them too, which I don't understand. F&T's are not that expensive, sound and feel great, and last !!!
I understand... I thought that he was referring to the filter caps. I won't use IC electrolytics because of the common failures mentioned above. I see this pattern at my bench as well.
As far as the signal path caps, I don't hear any difference between any of the caps Andy mentioned. I have built more amps with them than any other brand of signal cap... no problems whatsoever.
I was a bit confused about which caps were being referenced. Now that I understand, I totally agree.
"Education is what you're left with after you have forgotten what you have learned" - Enzo
I thought I'd heard some amp techs saying that the normal IC elytics were just fine, but that Fender intentionally buys a 'lower quality' one to save money and has asked IC to make them shittier so they can get a cheaper price. If you buy their normal after market stuff, it's good quality. I may be being mislead, though, and I've just stayed away due to that reputation, but I'd definitely like to hear of people having lots of problems with non fender IC caps.
dorrisant wrote: ↑Tue Jun 12, 2018 5:46 pm
Phil, that sounds about like the deal with Fender and Eminence. The speakers in Blues Jrs are atrocious... but that is what Fender asked for.
Yup just more evidence to my point, and likely also true. I think IC and Eminence did themselves a disservice and should have branded them 'fender' instead of tainting themselves with that shit.
pompeiisneaks wrote: ↑Tue Jun 12, 2018 5:41 pm
I thought I'd heard some amp techs saying that the normal IC elytics were just fine, but that Fender intentionally buys a 'lower quality' one to save money and has asked IC to make them shittier so they can get a cheaper price. If you buy their normal after market stuff, it's good quality. I may be being mislead, though, and I've just stayed away due to that reputation, but I'd definitely like to hear of people having lots of problems with non fender IC caps.
~Phil
I've heard this as well. I just bought some caps for production. A couple of pennies moved me from IC to Nichicon, which is worth the comfort level alone.
Yup, the single most cost effective improvement is most production Fenders today is a better speaker...
