Recomendatios for cap,res type for "Thor" pedal

Frequently asked questions on capacitor types, ratings, brands, use and abuse.
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pjd3
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Post by pjd3 »

Hi, sure appreciate your time.
I like to hear some suggestions from you on component types and brand names before I fill the order.
Particularly, capacitor and resistor types for "Thor"(Marshall Superlead Tube to FEt conversion pedal) from "Runoffgroove".
Ive built a number of my own pedals for professional use but, have never done long experimentation and A/B comparsons using
different types of caps and resistors. I see that many have done these comparisons and have opinions on what may perform
better for them for the various functions in the circuit. It appears that folks are using film caps for signal coupling and
filtering caps,(say, ranging around .022uF to 10-20uF or so), Electrolytics for power fitering duties as in the two 100uF caps in
the "Thor" schematic. I am a bit foggy to whether folks are going for ceramic or silver mica for caps in the pF range.
(the "Thor calls out for a couple of 220pF, 470pF and 1000pF).
I'm hoping that with your recommendations I can get beyond this "analysis paralysis" and get the order in!! I have gigs
coming up that I'd love to have this pedal ready for. It's a one off for professional use so I'm not really concerned with saving money.
I'll spend a extra buck on a cap if it has a possibility of out performing a cheaper one in terms of tone, especially.
(low dialectric absorpsion,ESR and inductance, etc...).
I'm assuming the recommendations for many distortion pedals whould also apply to this one that I plan to build so, some of my questions have been:
- For signal caps, What type of film caps are we referring to, polycarbonate?, polypropelyne?, do they still make polystyrene?
Is there a brand and type number specifically that sticks out?
Are folks liking Panasonic for the power filter caps? (100 uF)?
For this "marshall-in-a-box" pedal, are silver mica recommended or, are decent ceramics fine? Are there good ceramics for this?(in the pico
Farad range)?
If some considerations are a matter of preference, then a safe bet will be fine. I only have your experience to go on for now.
Maybe somewhere up the road I'll cut time for alot of experimentation and make my own tweaks.
If this pedal will come 80-90% close to the "Thor" sound clips on "Runoffgroove", It will be a success.
Please excuse my rambling, I'm just really eager to get this tone in my arsenal and be prudent in the choice of components I put into it.
(Oh, any comments on resistor types,brands will be appreciated!)

Thank you for your recommendations, I'll looking forward to this!

Phil

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ckyvick
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Post by ckyvick »

You can use any caps and any resistors. The standard is poly film or ceramic capacitors for non polarized caps and electrolytics(or tantalum) for polarized capacitors. Metal film resistors are higher quality but i doubt you could hear a difference between metal film and carbon film resistors. You can order parts from smallbear or pedalpartsplus and you will be safe since they specialize in guitar pedals.

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mictester
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Post by mictester »

pjd3 wrote:
Thank you for your recommendations, I'll looking forward to this!

Phil
Just use whatever's cheapest! Don't believe the audiophools who'll tell you that there are "audio" capacitors that actually make a difference. They've just been taken in by slick salesmen. Remember - when it comes to audio or guitar gear, 95% of what you'll be told is complete nonsense.

Anything from 1µF upwards should be electrolytic (or tantalum if you're after small space and low leakage, but they're more expensive and can be noisier than electrolytics in audio paths). The only real criterion is that the working voltage of the electrolytics has to be more than the voltage that's going to be applied to it!

Smaller values (1 nF upwards) can be polyester or whatever else fits in the board. Below 1 nF, you're looking at ceramics. Don't waste your money on silvered mica caps - they're really for high stability RF work, and don't really achieve anything that justifies their expense at audio frequencies.#

Resistors - forget the "Mojo" BS. All that ancient carbon resistors will do for your sound is to add hiss. Just get good quality carbon or metal film types. Either will do.

A more significant effect on the sound will be your choice of semiconductors. A quick look at the Runoffgroove circuit suggests that there's room to experiment with the FETs.
"Why is it humming?" "Because it doesn't know the words!"

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arjepsen
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Post by arjepsen »

Actually, I think there is an audible difference for _some_ of the caps in the circuit.
I've played around with some caps on the breadboard, and for some caps there was no difference, and for others there were a clear difference between different type of caps. It wasn't any BIG change, but still enough to be able to quickly find the cap that sounded best to me in a particular spot.
I guess the best thing would be to have a wide selection of caps to try from, but this can be a costly affair.... the only reason I had different types to play with, is because I have gutted a few computer monitors for components.

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IvIark
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Post by IvIark »

arjepsen wrote:Actually, I think there is an audible difference for _some_ of the caps in the circuit.
I've played around with some caps on the breadboard, and for some caps there was no difference, and for others there were a clear difference between different type of caps. It wasn't any BIG change, but still enough to be able to quickly find the cap that sounded best to me in a particular spot.
I guess the best thing would be to have a wide selection of caps to try from, but this can be a costly affair.... the only reason I had different types to play with, is because I have gutted a few computer monitors for components.
Absolutely. You just need to remember that if 95% of what you'll be told is complete nonsense, then that means all but 5% of advice from mictester should be taken with a pinch of salt. :D Use your ears, not someone elses subjective opinion.
"If anyone is a 'genius' for putting jacks in such a pedal in the only spot where they could physically fit, then I assume I too am a genius for correctly inserting my legs into my pants this morning." - candletears7 - TGP

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