What guitar cord do you use?

[nickb]

... a higher fundamental harmonic ratio,... [/QUOTE]

It's not clear to me what you are referring to here?

@Chuck
The simplicity of passive pickup and controls does have the fundamental problem, as you alluded to in the first post, of being affected by anything downstream. What I don't like about this is once you've found a guitar, lead, pedals amp combination that works for you it's very hard to change one component without losing the plot, so to speak. For that reason, although anathema to that simplicity, it seems to me that active pups is a better way to go.

If each pup is buffered you potentially gain the ability to control the resonant frequency and level of each pup without affecting any other and it's also unaffected by the load. Downside is a small increase in complexity and a power source. The required buffers can be very simple and only draw a mA of so which gives you something like 500 playing hours from a single battery.

But maybe that takes all the fun out

[Helmholtz]

If each pup is buffered you potentially gain the ability to control the resonant frequency and level of each pup without affecting any other and it's also unaffected by the load. Downside is a small increase in complexity and a power source. The required buffers can be very simple and only draw a mA of so which gives you something like 500 playing hours from a single battery.

Well, active PU systems have been available since decades. But market acceptance is limited.

An alternative to active systems that allows the use of your favorite passive PUs and guitar cables is plugging into a buffer followed by a low resistance (10k to 100k pot, or active) volume pedal.

BTW, the influence of the cable capacitance on a PU's frequency response is just as strong as the PU's inductance. If you wonder how the PU would sound if it had twice its inductance, just use a cable having doubled capacitance (or twice the length).

[SoulFetish]

. For that reason, although anathema to that simplicity, it seems to me that active pups is a better way to go.

But then what are we supposed to do with all our fuzz faces?

[Fluoroscope 5000]

The schematics show a number of differences between SF and BF Twins. Also there are different SF versions.
What exactly do you mean with " blocking distortion filter"?

I could have misinterpreted what someone said about them at one point, but to answer your question:
http://www.aikenamps.com/index.php/w...ing-distortion

[Fluoroscope 5000]

... a higher fundamental harmonic ratio,...

It's not clear to me what you are referring to here?

Fundamental harmonic strength is related to coil density. Thinner-wire/denser coils produce stronger fundamental harmonics at a given distance, and the ratio to upper-harmonics changes more significantly with height adjustments. Pickups with stronger fundamentals and resonance peaks outside the harsh ~3kHz range generally sound warmer/sweeter.

[nickb]

It's not clear to me what you are referring to here?

Fundamental harmonic strength is related to coil density. Thinner-wire/denser coils produce stronger fundamental harmonics at a given distance, and the ratio to upper-harmonics changes more significantly with height adjustments. Pickups with stronger fundamentals and resonance peaks outside the harsh ~3kHz range generally sound warmer/sweeter.

There are fundamentals and there are harmonics, but there is no such thing as a fundamental harmonic. I think what you are saying is that if you use thinner wire and keep the number of turns the same, the DC resistance goes up and therefore the Q goes down. This means that the characteristic pup peak is suppressed somewhat. Therefore the frequencies in that region, which happen to be harmonics, are suppressed. I'm ignoring self capacitance as I expect that to be swamped by the tone cap and or cable.

If you change the number of turns as well the inductance will change too which will change the result.

[Fluoroscope 5000]

There are fundamentals and there are harmonics, but there is no such thing as a fundamental harmonic. I think what you are saying is that if you use thinner wire and keep the number of turns the same, the DC resistance goes up and therefore the Q goes down. This means that the characteristic pup peak is suppressed somewhat. Therefore the frequencies in that region, which happen to be harmonics, are suppressed. I'm ignoring self capacitance as I expect that to be swamped by the tone cap and or cable.

If you change the number of turns as well the inductance will change too which will change the result.

At some point I started to refer to the fundamental and first few harmonics as the fundamental harmonics. That may be technically incorrect. What I mean is the fundamental and the first few harmonics are of a higher ratio to the upper-harmonics compared to pickups with thicker-wire/looser coils. That, the peak characteristic, and a few other factors contribute to the pickup character.

[pdf64]

... I was never happy playing a SF Twin. Reminds me that I should convert my SF Dual Showman Reverb to BF specs.

There were quite a few SF TR model variants over the years, which one did you have?
The mid-late 70s ones tended to use bass pots with ~30% taper, hence they were a lot more bassy at the typical control settings than the BF or earlier SF models with a 10% taper bass control.

...What exactly do you mean with " blocking distortion filter"?

I think that the typical BF models, eg TR, mitigated blocking distortion (perhaps unwittingly) by means of the 1nF coupling cap to the LTP / power amp.
Whereas the SF TR models used much larger caps there allowing full bandwidth, but (as Aiken notes) used lower value coupling caps / grid leak resistors to the power tube control grids. The latter seems to be a better engineered method, as that's where the blocking distortion is likely to be most apparent and severe. But, together with the bass control change above, the amp's tonal balance may be seem to be shifted towards bass and low mids.

[Helmholtz]

There were quite a few SF TR model variants over the years, which one did you have?
The mid-late 70s ones tended to use bass pots with ~30% taper, hence they were a lot more bassy at the typical control settings than the BF or earlier SF models with a 10% taper bass control.

Interesting, thanks. But I wouldn't have noticed the different taper, as I use very little bass and always adjust by ear - not by numbers.

I think that the typical BF models, eg TR, mitigated blocking distortion (perhaps unwittingly) by means of the 1nF coupling cap to the LTP / power amp.

Very good point, thanks! Easy to overlook when doing a conversion.


But apart from all that, I never would play a Twin with JBLs loud enough to induce severe blocking distortion.

Actually I'm not really convinced that blocking distortion generally/necessarily means bad sound. If you look at the schematic of a JTM45 (or a '59 BM), it should be prone to lots of blocking distortion. Also I found that I mostly prefer 0.1µ to 0.02µ power tube coupling caps.

Sorry for distracting.

[Chuck H]

It's rare to avoid peripheral topic discussion. Not a big deal.

And INDEED the early Marshalls and Bassmans blocked. With the right circumstances it can add pleasantly to the phenomenon known as "swirl" which specific examples of those amps are known for. One of my favorite examples of this sound is the solo work in Hard to Handle as covered by the Black Crows. Some investigation implies that it was played by the producer of that album (not the bands guitarist) plugged straight into an early Marshall he owned. If you listen close you'll also hear some of that other Marshall dominated phenomenon known as "beating".

Solo comes in around 2:00 and then some closing work around 2:40

[big_teee]

I'm surprised not to hear the curly guitar instrument cable of old mentioned.
If it was, I missed it?
Hendrix was fond of them.
You see them used on tv concerts from time to time?
T

[Chuck H]

I'm surprised not to hear the curly guitar instrument cable of old mentioned.
If it was, I missed it?
Hendrix was fond of them.
You see them used on tv concerts from time to time?
T

Helmholtz was the first to mention them and then there was another reference I can't pinpoint by memory.

[big_teee]

I did a search before I posted and none came up.
I did it again and yours and mine were all that did.
I guess they were called something different from a curly cord.
Don't they add capacitance?
I just try to use as short a cable as possible, that doesn't get in the way, here in the man cave.
https://amzn.to/2Hpt4hR
28pf per foot.

[Chuck H]

Ah! It was Flouroscope 5000 in post#16 The other reference is probably my memory playing tricks since I've been doing a lot of cable research here and abroad.

I don't know the value of Radio Shack coil cable SRV favored, but it may well have been close to 1100pF. That should be great for typical PAF's. AFAIK, Hendrix used a very long ~2.4nF coil cable on stage and a short low C cable in studio. Plugging into a Germanium FF pedal with a 5~7k input impedance would substantially damp the guitar circuit resonance anyway.

[Helmholtz]

I used the term "coiled chord". Coiling increases effective lenght and thus capacitance. Those were prone to conductor breaks caused by frequent stretching. Still have some from the 60s and 70s.
I don't think anyone could know the cap values of Hendrix's cables. Generally the capacitance/foot values were higher in the old days.

In the early 70s I discovered that different cables changed my guitar sound and I began to collect all sorts and lenghts of cables to compare them. Later when I had access to a C-meter I bought cable by the foot (meter) and assembled my own at different lengths/capacitances until I finally found my prefered capacitance value. I was happy that this works equally well with my strats and Les Pauls. There is one exception though, namely my 1957 LP Special with high inductance P-90s. This guitar requires a lower C cable (around 700pF).
I just don't like to leave my sound to chance using random cables.

I actually have a closet full of guitar cables from all this experimenting.