What caps would you use in place of an 82n?

[motterpaul]

What caps, possibly two in parallel, - would you use for 82n?  Or would you just try to get as close as possible? I am doing this project:

[IvIark]

If I didn't have one I'd socket it and try a 68n and a 100n and keep the one I preferred.

[motterpaul]

Fair enough. There are two in this circuit and most capacitor "packs" only give you 68 or 100, they leave out the 82n. I could put a couple is series, but I am not sure how critical the value (82n) might be.

Ironically, I ordered a pack that had 82n, then saw a cheaper and bigger pack, so I substituted and bought that instead, but forgot to check if it had the 82n. It didn't. But you don't see 82n very often, so I figured it could be somewhat critical. But if it is I could just put some in series.

[IvIark]

Well it's part of the mids section of the tone circuit so it is pretty critical if you want exactly the same frequency response as the original.  But then the original doesn't have a mids pot, so you're already altering it and whose to say the 82n is perfect for you anyway, you may like one of the other values more which is why I'd suggest socketing.  Then you should get a fairly good idea of what the "in between" 82n value will be like by comparing the higher and lower values.

[motterpaul]

In the circuit above - what kind of switch is that and how it is wired? Is it a three pole switch where I just wire to 1,2,3 as directed, or is it something else? Please help me identify the switch piece and how it is wired (a noob question I know).

[inefficiency]

It's a SPDT on/on. So one of these;

[motterpaul]

Thanks - that is what I used (although has 6 poles, I just tied them together. The switch works but doesn't give me much except a big volume drop.

Re: the cap values - I tried both 68 and 100 and neither does very much. In fact, the circuit work fine without any caps. So, I am wondering if maybe I need to go more towards the exact 82n value, or maybe look lower than 68 (which seems to do a little more).

Should I get more treble from a smaller value (68) or a larger one (100)? Because I don;t hear much with the 100 and I am thinking maybe it is out of the working range?

[inefficiency]

You don't need to tie anything together, just leave one set of poles unused. You could use a switch with 12 of them and still just use the 3 (although it wouldn't be very cost effective )

For the caps, I don't know what to suggest other than if it sounds good, then just roll with it.

Can't remember which way round it is with the caps. I know that it can have more of an effect than that in certain situations. Like, certain caps in the circuit can affect sag. That might be the power filtering caps though. However, it could have an effect on the dynamics or something. Mark or one of the other guys will have a better understanding than me.

[dbat69]

As a quick guide to switches, think of it this way:

The pole (as in SP or DP) is the number of electrical circuits the switch controls.  In a SP or "S"ingle "P"ole switch, it will have one set of circuits and therefore generally one row of contacts on the bottom.  A DP or Double Pole switch will have two rows of contacts and therefore the switch can act on two circuits independently of each other. (although controlled by the same click of the switch knob)
The 'normal' footswitch is a 3PDT - three sets of contacts (or poles) for switching 3 different circuits at the same time

The clever bit comes with the Throws (ST or DT or more...)
This is where the switch can make a contact between one circuit and another (choices), in a single throw only one circuit can be changed.  In a double throw, it can make two different circuits (choices).
Sometimes there is a 'centre OFF' position where the signal doesn't make contact (one way or another)

Join them together, and you get the normal designation of common switches, i.e. SPST, SPDT, DPST, DPDT etc.

So for a SPST you may only have 2 contacts on the bottom
for a SPDT you may have 3 contacts
for a DPST you might get two rows of 2 (its like having two switches in one )
for a DPDT you will have two rows of 3 (two switches in one, which can send the signal two ways)

BUT ... these switches can have different ways of switching (usually the DT types) which can confuse this simple theory --- confuces the hell out of me at times (especially after a few tooooo many, like now )
they can be :
ON / OFF / ON
ON / ON
ON / ON / ON  - - Mark uses these sometimes and I'm just

Easy answer is - SP - one row of contacts, DP - two rows of contacts, ST - one click of the switch, DT - two clicks of the switch (that's my simple way of looking at it , even with a couple of ... )

I think I've just confused myself now --- sorry

[motterpaul]

Thanks Dbat. I appreciate the help.

Normaly I understand how a switch works - what I did not get was the nomenclature in the diagram "switch 1, switch2, switch 3"

I assumed sw1 would be the "common" and that sw2 would the first option and sw3 the second option. But that is a fair amount of assuming. What if it meant there were three options? Then the naming (sw1, sw2, sw3) actually makes more sense. But that is actually not right, there are only two options, correct?

So, I guess I need to assume that if I see "switch 1" that means the "in" to the switch, and then "switch 2" goes to the one "on" option; and "switch 3" goes to the other "on" option - is that right?

[dbat69]

The way to think of Sw1, Sw2 etc is on the the contacts on the bottom
1 being top, 2 middle and 3 bottom on a SPDT

On a DPDT
1 and 4 are on the top
2 and 5 are in the middle
3 and 6 are at the bottom


So in a SPDT
contact 2 can be switched two ways, either to 1 or 3 with the flick of the switch

In a DPDT
contacts 2 and 5 each connect to 1 & 4 in one direction, or 3 & 6 in the other direction of the switch toggle
This is great for changing two things at the same time

[motterpaul]

Thank you. I forgot to think about the numbering on switches (geeze, being a noob is such fun). This is why we keep trying to make these things even though we make mistakes, because experience is the best teacher. I will never make that dumb mistake again. That means my switch is wired incorrectly.

The good news...  - oh wait, my wife just asked me if a dress makes her look fat, (forgot what i was going to say) be back in an hour.

[IvIark]

When my wife asks that question I usually say, "The dress looks fine, it's your arse that makes you look fat".
Then she usually slaps me.

In answer to your question, the effect will definitely work fine without the 82n position cap, but without it you will be altering the frequency response.  I'm not too sure how subtle it is in this effect because I've never built it, John K may be able to answer more specifically with him potentially experimenting with those cap values to make it more suitable for bass.

[motterpaul]

Thank you for weighing in IvIark. The switch sounds better now; a little smoother on one side, more attack on the other. I seem to be getting almost nothing out of the mid pot, tried several caps, when any are in it sounds less trebly, but I don't hear much difference in caps. Not sure it is a feature needed unless you have a very bright guitar. This is a bright circuit.

It all sounds good - love the tone and the two-step distortion (op amp plus diodes).

[Beaker]

If you want to use two caps in parallel, then a 47nF and a 33nF gives you 80nF. Alternatively a 68nF and 15nF gives you 83nF.

Close enough?