|
Post by JohnH on Oct 23, 2019 16:02:41 GMT -5
angelsbunny posted the right schematic for the PTB tone controls above. The only question is which outer lug to use on the bass cut. The reverse-log C taper pots are best, but I reckon that if that is not available I'd use a normal lov taper, using the other outer lug. Id think my way into using that based on, both treble and bass controls would be consistent if you think of them as 10 equals 'more treble, less bass'.
You can adapt and get used to things like that, like driving on the wrong (right) side of the road. (just to be crystsl clear on that, where I live driving on the left is right, so right would be wrong)
|
|
|
Post by newey on Oct 23, 2019 20:46:26 GMT -5
But since you're upside down to begin with, it all works out the same. . . . But, the Brits drive on the left as well, and there's no good explanation for that behavior, since they're right side up! The left side is the "sinister side", of course.
|
|
aufr
Rookie Solder Flinger
Posts: 7
Likes: 0
|
Post by aufr on Oct 24, 2019 9:33:46 GMT -5
Thanks for all the help guys! Just so that i understand this correctly... Would this wiring (the three pots) be correct in combination with the rest?(disregard the super switch and position guide as this is sourced from another site) Hi aufr The location where you've inserted the Bass cut pot and cap won't work well. You have it between the wiper of the volume pot and the output jack. The bass cut is dependent on the resistance of the volume pot providing a 'load' on the bass cut circuit. Instead, break the connection (blue wire) between the superswitch and the CW terminal of the volume pot and insert your bass cut circuit there. The wiper of the volume pot will connect directly to the output jack.
EDIT:Instead, remove the orange wire which connects the CW lug of the volume pot to the CCW lug of the treble cut. Then connect the blue wire from the Superswitch to the CCW lug of the treble cut instead of the CW lug of the volume pot. Then, connect the bass cut circuit between the CCW lug of the treble cut and the CW lug of the volume pot. The wiper of the volume pot should connect directly to the output jack. Also, the choice of which lugs to use on the bass cut pot depends on the taper of the pot. With a reverse-audio taper, the choice you've made will be good. With a standard audio taper, the cut will happen abruptly at the clockwise end and rotation near the counter-clockwise end will make very little difference. I think I'm getting it. My thought on the 500k cut is to only have fine adjustment of the tone. As for the treble cut, I have never used the "0"-setting on a 250k pot, so I guess I'm better served with some extra highs when in series-mode. With all that considered... does this look right to you?
|
|
aufr
Rookie Solder Flinger
Posts: 7
Likes: 0
|
Post by aufr on Oct 24, 2019 9:36:01 GMT -5
Here's the picture.
|
|
|
Post by reTrEaD on Oct 24, 2019 11:25:14 GMT -5
aufr, the connections you have will work but I suggest you use audio taper pots throughout. With linears for the treble and bass, the change will be somewhat 'quick' as you move from no cut (fully clockwise on the treble, fully counter-clockise on the bass). Also, with a 1:1 ratio of resistance for the bass cut pot and the volume control, you'll be limited to a 6dB cut for the bass. That isn't much. Maybe use a 1Meg pot for the bass cut and a 500k for the volume. That would provide you a little less that 10dB cut for the bass. Or a 1Meg for the bass cut and 250k for the volume will provide 14dB of bass cut.
|
|
|
Post by sumgai on Oct 24, 2019 12:13:07 GMT -5
aufr, Your latest looks almost good. The only problem left is the so-called treble-bleed circuit. In your image, I see two leads from a block labeled T.B. going to the Vol pot, and a third lead out the other side of that block goes through a .0022 cap to ground (on the back of the Treble pot). I'm sure you know that a T.B. circuit uses, and needs, only two leads, and those go across the "hot" and wiper terminals of the Vol pot - neither go to ground. So what's that cap doing in there? A note on your image.... Other members, please take note that this manner of making and submitting a drawing is very acceptable to us Nutz. JohnH has done this a lot over the years, because it's quick and easy for both the poster and the reader(s) of that post. Just a word to the wise. sumgai
|
|
|
Post by reTrEaD on Oct 24, 2019 12:58:07 GMT -5
In your image, I see two leads from a block labeled T.B. going to the Vol pot, and a third lead out the other side of that block goes through a .0022 cap to ground (on the back of the Treble pot). Maybe. I thought he was using two 22nF caps in the treble cut and the box for the treble bleed was in close proximity. In any case, an ambiguity like that is not so good.
|
|
|
Post by sumgai on Oct 24, 2019 16:02:10 GMT -5
I thought he was using two 22nF caps in the treble cut and the box for the treble bleed was in close proximity. In any case, an ambiguity like that is not so good. So I considered that, reTrEaD, and I said to myself "why would he put two caps in parallel, that will just increase the effective cap value, when he could've just installed a 0.047 cap in the first place". Hence my deduction, and thus we see how that ambiguity can lead to different possibilities.
Let's hope that aufr chimes back in with a correction. But once this issue is resolved, his drawing will work as desired.
sumgai
|
|
aufr
Rookie Solder Flinger
Posts: 7
Likes: 0
|
Post by aufr on Oct 25, 2019 1:02:52 GMT -5
Different time zones makes for interesting conversations for sure! Yes i did actually plan on using two ,022uf caps in paralell on the tone pot. Reason being that I already have two ,022uf Hovland Musicaps lying around from a previous build, so I don't want to buy another just for the sake of having the right number on the side of the cap. The treble bleed is only supposed to be connected to cw and wiper on the volume, but I'm pretty terrible a drawing! I'm still on the fence about LIN or LOG for tone as I've been using LOG recently and I think it drops to rapidly to zero and has no rang to adjust the tone. I might end up wiring two tone circuits (T&B with 500k LIN and T&B 500k LOG) and swap them if I necessary. The volume will be LOG either way. Thank you for looking over my plan! can't wait to hear my set of CB radioshop pickups (check out Chris Buck if haven't already)
|
|
|
Post by sumgai on Oct 25, 2019 11:17:15 GMT -5
OK, that settles it, reTrEaD has the better eye. aufr, I always prefer to use whatever parts are already on hand (scattered across the work bench, or stored in a "junk" box, etc.) instead of driving off to a store, or waiting on mail order. It's true that 0.022 doubled is 0.044, and that's way too close to 0.047 for anyone to quibble over, component value tolerances notwithstanding. So yeah, fire up the soldering iron and have at it! As to log vs. linear, that's an argument I stay away from, so use what you wish, and change as you need. HTH sumgai
|
|
|
Post by reTrEaD on Oct 25, 2019 12:46:42 GMT -5
OK, that settles it, reTrEaD has the better eye. That goes without saying.
|
|
|
Post by sumgai on Oct 25, 2019 17:29:30 GMT -5
I always did think you look better with a hood over your head!
|
|
aufr
Rookie Solder Flinger
Posts: 7
Likes: 0
|
Post by aufr on Nov 11, 2019 4:13:23 GMT -5
Finito! The mod is awesome! All very usable pickup-combos. Just thought i'd post the final alterations to the wiring. Ended up swaping the linear pots for log pots and added higher capasitance for the bass cut. Hope this helps anyone wanting to do the same later! peace!
|
|