Tags:
Hi Brian, yeah I always understood 25k pots in active systems.
Taff
its not that simple when you are designing an active preamp. the pot values will depend on the capacitors used and the center frequency of the frequency band you want to affect. it depends on the type of circuit you are using. will the preamp be op amp based or FET or transistor? how many stages of boost are there. will the bass and treble boost and cut the freq? do you have a circuit in mind? even a simple bass and treble cut tone circuit needs to be designed around the cutoff frequency . will treble cut start at 1KHz? 3KHz? 10KHz? bass roll off at 80Hz? 200Hz? 500Hz?
the blend pot is basically a mixer. the input of each pickup goes to one of the outside legs of the pot and the mixed signal comes out of the center or wiper contact then fed into the preamp. this pot has to be a linear pot not a volume/log pot sometimes also called a audio taper pot. your tone section will likely be in the feed back/gain loop of the preamp. then a master volume pot goes to the output jack. eventually to the guitar amp.
your original post said you were feeding the output of the blend pot to an active preamp. is this a prebuilt module? if it is it probably already has the tone and volume pots in it.
here is a good example. this is stereo but just ignore one channel..lol
the tone controls are inside the feedback loop that controls gain. its been a few years so i am not sure if this has both cut and boost at the desired frequency . here is a link to the page i found this it might help your friend or at least give him ideas..
https://www.eleccircuit.com/three-circuits-of-preamp-tone-controls-...
these type of tone circuits are based around a fixed frequency. if you want to cut and boos but also shift the center frequency then you will need to look into parametric tone control circuits. but that would add an extra 2 pots.lol 1 for cut/boost and one for frequency. double that for bass and treble add in one more for balance of the two pickups and 1 more for volume..wow thats 6 pots on 1 CBG..( gonna need a big box) lol
here is another one , this might be better as it has a 10M input impedance which is good for piezeos. the TL072 is a 1 package dual op amp with very good noise characteristics. http://www.zen22142.zen.co.uk/Circuits/Music/guitar_tc.htm
Hi again Brian, I see you also asked about using piezo disc's with a preamp. My preference when working with full size acoustic guitars is for disc type soundboard transducers, and always with a preamp.
I do not use the cheep flat disc's that I use in a CBG. The ones I use in mine and others guitars are far more expensive and are encapsulated in a plastic "jacket" or covering and have substantial wiring. Three are used under a 6 string bridge.
With piezo transducers the idea is to recreate the acoustic sound of the guitar as faithfully as possible. This is better achieved with a soundboard transducer rather than the under saddle type. One reads mainly string vibrations, due to being so close to the string [but gives the added "quack" sound so disliked by acoustic guitarists]. The other of course reads the top timber vibrations, the main producer of the acoustic sound we hear. However it is also not without certain drawbacks.
Taff
Ok Bryan, I'm not big on design and complex details of electronics soooo........
i follow the guidines of the manufacturer and place 3 discs on the bridge plate as instructed, I figure they have done the testing for me so why reinvent the wheel.lf want to blend with anther transducer or magnetic pickup I use a dedicated panpot, as they would have worked out the specs on that too. And if I remember correctly they have centre detent position.
But with a cbg there are many physical differences that would effect a piezos response, so trial and error method may be best for your situation.
If you get feed back there are few options an eq normally has controls for this, you can cover the soundhole/s and the method you suggested.
Not much help, sorry.
Taff
So if I'm getting things right, we're talking about a passive EQ to adjust the tone and a mixing stage.
The hard thing will be figuring out the value of the caps to use.
Started by J. D. Woods in Performances, How to Play, Lessons, Concerts. Last reply by J. D. Woods 6 hours ago. 3 Replies 0 Likes
Started by Southern Ray in Other stuff - off topic, fun stuff, whatever. Last reply by A.D.EKER yesterday. 4 Replies 0 Likes
Started by Rich Butters in Building Secrets, Tips, Advice, Discussion. Last reply by Crazed Fandango on Tuesday. 4 Replies 0 Likes
Started by J. D. Woods in Performances, How to Play, Lessons, Concerts. Last reply by J. D. Woods on Saturday. 7 Replies 1 Like
Started by Nomad Jack in Performances, How to Play, Lessons, Concerts. Last reply by J. D. Woods Apr 17. 7 Replies 2 Likes
Started by Moritz Voegeli in Building Secrets, Tips, Advice, Discussion. Last reply by Southern Ray Apr 14. 6 Replies 2 Likes
Started by Timothy Hunter in Other stuff - off topic, fun stuff, whatever. Last reply by Timothy Hunter Apr 10. 14 Replies 3 Likes
Started by Tom T in Building Secrets, Tips, Advice, Discussion. Last reply by Southern Ray Apr 9. 9 Replies 0 Likes
Started by Southern Ray in Building Secrets, Tips, Advice, Discussion. Last reply by Southern Ray Apr 4. 7 Replies 1 Like
Started by Timothy Hunter in Building Secrets, Tips, Advice, Discussion. Last reply by Southern Ray Mar 27. 1 Reply 2 Likes
Started by Taffy Evans in Building Secrets, Tips, Advice, Discussion. Last reply by Southern Ray Mar 10. 1 Reply 3 Likes
Started by Cigar Box Nation in Feature Articles. Last reply by BrianQ. Mar 9. 4 Replies 3 Likes
Started by Ghostbuttons in Building Secrets, Tips, Advice, Discussion. Last reply by Timothy Hunter Mar 9. 5 Replies 1 Like
Started by Justin Stanchfield in Building Secrets, Tips, Advice, Discussion. Last reply by Taffy Evans Mar 8. 6 Replies 0 Likes
Started by Ken I in Building Secrets, Tips, Advice, Discussion. Last reply by Brian partington Mar 8. 8 Replies 0 Likes
Started by Southern Ray in Cool gear discussion - that's not cigar box related. Last reply by Southern Ray Mar 6. 5 Replies 0 Likes
Started by Taffy Evans in Other stuff - off topic, fun stuff, whatever. Last reply by Taffy Evans Mar 5. 4 Replies 2 Likes
Started by Justin Stanchfield in Building Secrets, Tips, Advice, Discussion. Last reply by Carl Floyd Mar 1. 15 Replies 0 Likes
Started by Joe in Performances, How to Play, Lessons, Concerts. Last reply by Carl Floyd Feb 29. 13 Replies 0 Likes
Started by Chance in Building Secrets, Tips, Advice, Discussion. Last reply by Southern Ray Feb 22. 12 Replies 1 Like
Posted by Vlad on March 31, 2024 at 11:48pm 0 Comments 1 Like
Posted by Vlad on March 6, 2024 at 2:32am 5 Comments 2 Likes
Posted by billy jones bluez on February 28, 2024 at 2:09pm 0 Comments 0 Likes
Posted by billy jones bluez on February 17, 2024 at 11:00pm 0 Comments 0 Likes
Posted by Vlad on February 11, 2024 at 1:06am 1 Comment 1 Like
May 11, 2024 from 11am to 8pm – Speakeasy Grill
0 Comments 0 LikesMay 30, 2024 from 6:30pm to 10pm – The Casual Pint of Huntsville
0 Comments 0 Likes© 2024 Created by Ben "C. B. Gitty" Baker. Powered by
Cigar Box Nation is presented by C. B. Gitty Crafter Supply, your one-stop-shop for Cigar Box Guitar parts and accessories!