ATTACK OF THE CRAZY ELECTRONICS!!!

[drewfx]

Just some info on the volume pot/OBEL (On Board Effects Loop) issue:

Jerry deliberately wanted the volume after the effects return so that he could send a full level signal to his effects at all times, unaffected by his guitar's volume control, and could adjust his post-effects volume from the guitar. This allowed him to adjust his volume without screwing up his mu-tron's sensitivity, for instance.

The problem with this is, if you want to bypass the buffer (which needs to be before the effects loop to prevent signal loss), you need different valued pots for the volume depending on whether the buffer is in the circuit. So unless you use 2 volume pots or can somehow find/make a dual-ganged* pot with both 25k and 250k (or 500k), you're going to have problems.

And if you put the volume pot before the OBEL, it defeats much of the reason for having it built into the guitar in the first place.


* A "dual gang pot" means essentially 2 separate pots on a single shaft. It is not the same thing as a "concentric pot" or a "blend pot".

 

[Dan025]

well a blend pot is dual gang but has special resistive elements, you can have custom dual gang pots made with any combination or top and bottom pots. then the bypass switch (or an alternate switch so you can choose between pre or post buffer volume) can swap between which is active. it may also be possible to swithc things automatically based on what type of or how many cables are plugged in. there will already be a power source so you can use transisitors to switch modes in place of externeal switches.

 

[BDI]

Jerry deliberately wanted the volume after the effects return so that he could send a full level signal to his effects at all times, unaffected by his guitar's volume control, and could adjust his post-effects volume from the guitar.

:icon_thumright: Exactly what I want! David Gilmour also had an XLR jack installed in his strat (temporarily), trying to accomplish the same thing.

 

[line6man]

* A "dual gang pot" means essentially 2 separate pots on a single shaft. It is not the same thing as a "concentric pot" or a "blend pot".

A blend pot is indeed a dual-ganged pot. It's just that we normally refer to it as a "blend pot," because it is not dual-ganged in the sense that both resistive tracks are identical in function but independent from each other. A blend pot is instead, a pot with two resistive tracks that reach their full parallel resistance and zero Ohms series resistance (For this particular application.) at one half of the rotation, and stay that way throughout the second half of the rotation, but with one track opposite from the other. This is in contrast to the more traditional type of dual-ganged pot that is simply two normal pots stacked together on the same shaft.

Dual-ganged pots are, however, different from concentric pots, as a concentric pot has a separate shaft for each resistive track of the pot, while a dual-ganged pot has two resistive tracks sharing the same shaft.

 

[drewfx]

* A "dual gang pot" means essentially 2 separate pots on a single shaft. It is not the same thing as a "concentric pot" or a "blend pot".

A blend pot is indeed a dual-ganged pot. It's just that we normally refer to it as a "blend pot," because it is not dual-ganged in the sense that both resistive tracks are identical in function but independent from each other. A blend pot is instead, a pot with two resistive tracks that reach their full parallel resistance and zero Ohms series resistance (For this particular application.) at one half of the rotation, and stay that way throughout the second half of the rotation, but with one track opposite from the other. This is in contrast to the more traditional type of dual-ganged pot that is simply two normal pots stacked together on the same shaft.

Dual-ganged pots are, however, different from concentric pots, as a concentric pot has a separate shaft for each resistive track of the pot, while a dual-ganged pot has two resistive tracks sharing the same shaft.

You are correct of course; a blend pot is a specific type of dual-ganged pot.

I guess the point I was trying to make is that the type of dual-ganged pot needed here isn't one of the readily available, standard issue guitar pots, like blends or concentrics, that everyone is familiar with.

 

[line6man]

* A "dual gang pot" means essentially 2 separate pots on a single shaft. It is not the same thing as a "concentric pot" or a "blend pot".

A blend pot is indeed a dual-ganged pot. It's just that we normally refer to it as a "blend pot," because it is not dual-ganged in the sense that both resistive tracks are identical in function but independent from each other. A blend pot is instead, a pot with two resistive tracks that reach their full parallel resistance and zero Ohms series resistance (For this particular application.) at one half of the rotation, and stay that way throughout the second half of the rotation, but with one track opposite from the other. This is in contrast to the more traditional type of dual-ganged pot that is simply two normal pots stacked together on the same shaft.

Dual-ganged pots are, however, different from concentric pots, as a concentric pot has a separate shaft for each resistive track of the pot, while a dual-ganged pot has two resistive tracks sharing the same shaft.

You are correct of course; a blend pot is a specific type of dual-ganged pot.

I guess the point I was trying to make is that the type of dual-ganged pot needed here isn't one of the readily available, standard issue guitar pots, like blends or concentrics, that everyone is familiar with.

Well, dual-ganged pots (The "normal" kind we are referring to here.) are quite common, it's just that it can be difficult to find the proper pair of values for this application.
If you buy a R1/R1 pot and a R2/R2 pot, assuming they are not sealed, you may be able to disassemble them and swap the wafers out to get two R1/R2 pots.

 

[BDI]

Thanks a bunch for everyone's help. Finally got it all put together.  :toothy11:

 

[line6man]

Thanks a bunch for everyone's help. Finally got it all put together.  :toothy11:

Looks good. How do you like the performance and functionality of the setup?