Attn Ohm's-law-ers, help with resistors

[ShortBuSX]

I just purchased a Fender Powerhouse Strat with 12db preamp boost, its said to have the same preamp as the Eric Clapton and Buddy Guy Strats...but apparently the Powerhouse has 2 resistors that lower the boost from 25db to 12db. Ive searched online and its said that if you clip the 2 resistors youll have the full 25db...Ive even read that some say this is "too much".
I like the 12db, its very nice, but I think I want more...yeah, Im pretty sure I want more!
I guess what Id like to know is: what are these 2 resistors actually doing?
Are they just lowering the boost?
Or is one of them kinda acting as a crossover filtering out the highs?
I dont wanna just assume everything I read on the net is true, and Id really like to know bout all this before I go hackin it up.
BTW, Im also thinking, if the full 25 db is "too much" then Id kinda like to tone it down to like 20db possibly with lower valued resistors.

Here is the Powerhouse wiring diagram:
http://www.fender.com/support/diagra...500_02APg2.pdf
and this is the Clapton model:
http://www.fender.com/support/diagra...117602APg2.pdf

Ive read just about everything thats been written bout the Powerhouse and this mod, but none of it seems very sure and lacking follow ups, so here I am.
Any help, insight or advice would be appreciated, thanks!

[ShortBuSX]

BTW on the Powerhouse pdf #19 is 47kcf and #20 is 24kcf
I know its probably unrelated but the Clapton Strat has an 84k on the TBX pot, but Id imagine that hasnt much to do with what Im talkin bout doing, unless I go witht he TBX later on.

A friend also had suggested variable resistance resistors, but after looking them up I got a lil confused, as the ones Id seen had 3 leads instead of two ...but thena gain I wouldnt know where to start as far as purchasing one...so advice on that would be appreciated as well.

[ShortBuSX]

Maybe it was my topic title?

Ive checked out many forums before coming here with my question, I reckon I just dont know where else to go with my questions...this place does seem to be the authority as far electronics forums, and your pickup winders forum is a wealth of knowledge(not that Id even attempt to roll my own)...

...maybe I need to provide more information?

[tboy]

...maybe I need to provide more information?

A schematic diagram of the preamp is what would be needed.

[ShortBuSX]

The resistors Im refering to arent on the board its self, they are located on the boost pot which is #14 on the above posted link for the Powerhouse. The resistors are #19 is 47kcf and #20 is 24kcf on the same pdf...if you look at the Clapton model, those arent there, and from everything Ive gathered they use the same preamp.
Im curious what effect these resistors have, without actually removing them first...maybe somebody could shed some light on this for me?

[ShortBuSX]

A schematic diagram of the preamp is what would be needed.

Its becoming difficult to find a schematic of the preamp...would a close up pic of it help?

[ShortBuSX]

Anybody got any idea how to contact Bill Turner?
Seems the only way I may ever get to the bottom of this is to talk to the man who designed it *shrug*

[oc disorder]

Dunno how accurate this is and I cannot remember where I found it
however on first glance it seems to match the "kit" picture..

[ShortBuSX]

I dont seem to have a way to unzip that last one...so Ive no idea what that is/was?


From this pic of the Powerhouse, looks the same to me too.
So one would think I could remove the 2 resistors and the boost would be in the 25db ballpark...so what are the resistors doing exactly?
I think maybe 25db would be possibly too much, but Id probably would like somewhere in between...I dont know much bout ohm's law, so Im assuming I could use resistors at half the value to get me where I wanna be...
...so thats why Im here, am I on the right track?

[oc disorder]

The resistors are attenuating the output ..you will notice the output jack
connects to the centre lug of the pot so putting resistors there makes some of the signal go to ground.If you increase the value of the resistors less signal will go to ground (harder to get through).
Put the 47k where the 24k is and put a 100k where the 47K originally was.
Or leave them off shave your head , wear glasses and grow a half beard and start a charity concert in Texas !

[ShortBuSX]

The resistors are attenuating the output ..you will notice the output jack
connects to the centre lug of the pot so putting resistors there makes some of the signal go to ground.If you increase the value of the resistors less signal will go to ground (harder to get through).
Put the 47k where the 24k is and put a 100k where the 47K originally was.
Or leave them off shave your head , wear glasses and grow a half beard and start a charity concert in Texas !

Im looking to get more gain from my onboard preamp though, wouldnt I use less resistance to get more gain?
From what you posted Id think Id go from 12db to bout 6db, right?
Im looking to go from 12db to bout 20db...instead of the full 25db.
Im sorry, your post has me a lil confused.
Just making sure Ive got it right...I feel so dumb *eyeroll*

[oc disorder]

Firstly ignore the zip file that was just some blurry pics of the board from the net which show the component designations obscured in the main shot.
I may have used KGB archiver inadvertently.
Also (tut tut) I didn't read your post thoroughly regarding where the resistors were.
OK regarding the resistance.. if a signal is going from A to B it makes sense the more the resistance between A and B the less signal will arrive at B.
Conversely the less resistance between A and B the more signal will arrive at B (just ask a True Bypass fanatic !).
Now if i was to put a bit of wire between A and Ground (call it G) like putting a piece of wire across your jack plug nothing would get through as its a dead short signal shunted to ground etc like turning your volume knob to Zero the wiper on the pot (connected to the output jack) now resting on the ground connection.Hopefully you are still with me...
Now if we were to replace that bit of wire with a resistor the smaller the ohms the less signal will arrive at B as the signal happily takes the shortest path to complete the circuit... goes back to G via low resistance hardly anythingat B.
Now if we were to increase the resistance going to ground not as much signal gets shunted to G ( its too hard to get through) so there is a lot more signal at B.
Now if we remove that resistor between A and G all the signal will arrive at B.
That pot (the 250k) boost pot has the signal .. replacing the resistors with a piece of wire no signal can escape..taking the wires off all the signal can escape.... a small resistor a small amount can escape ,a large resistor a lot more can escape..I hope you are having an Eureka moment...... x

[ShortBuSX]

Now if we were to replace that bit of wire with a resistor the smaller the ohms the less signal will arrive at B as the signal happily takes the shortest path to complete the circuit... goes back to G via low resistance hardly anythingat B.
Now if we were to increase the resistance going to ground not as much signal gets shunted to G ( its too hard to get through) so there is a lot more signal at B.
Now if we remove that resistor between A and G all the signal will arrive at B.
That pot (the 250k) boost pot has the signal .. replacing the resistors with a piece of wire no signal can escape..taking the wires off all the signal can escape.... a small resistor a small amount can escape ,a large resistor a lot more can escape..I hope you are having an Eureka moment...... x

Im not having a eureka moment yet...so Id wanna use larger valued resistors if I wanted MORE gain, or no resistors for full gain?
Theres a reason I never learned ohm's law..alot of this stuff is lost on me, but it doesnt stop me unless theres (deadly)voltage involved.(so far so good)
Thanks for your help OCD!

[oc disorder]

As there is still no sign of the Ohm's-Law-ers here some more while you are waiting!
"so Id wanna use larger valued resistors if I wanted MORE gain, or no resistors for full gain?"
Yep, because in this instance (where the resistors are placed) they are sucking (draining)some of the boosted signal to ground.
If the resistors were in series with the signal ..then.. they would reduce the signal getting through so you would want a low value to let as much through as possible.....but they are across the output !
So to answer all your questions:-
"I guess what Id like to know is: what are these 2 resistors actually doing?
Are they just lowering the boost? "
YES
"Or is one of them kinda acting as a crossover filtering out the highs?"
NO (you are probably thinking of a capacitor on a passive tone control)
"I know its probably unrelated but the Clapton Strat has an 84k on the TBX pot, but Id imagine that hasnt much to do with what Im talkin bout doing, unless I go witht he TBX later on."
Don't think we should go here but if the diagram and board numbers match what is R2 on your circuit board ? Or the two wires from the TBX pot (ignore the ground wire) one should go to a 470ohm resistor (yellow violet brown) the other to a 72k resistor (Violet red orange).
Anyway lets leave that alone 'cause 84k and 72K are close.
"A friend also had suggested variable resistance resistors, but after looking them up I got a lil confused, as the ones Id seen had 3 leads instead of two"
You could do that- another way would be to put the resistors on a switch to give two different levels.
With "a variable resistance resistor" a pot or potentiometer , wire the centre and one outside leg together.
"Im curious what effect these resistors have"
They reduce the boosted signal...
A friend has a tele with a pull switch on the volume control that when pulled disconnects all the controls and connects the pickup straight to the output jack.
This is the same principle The tone and volume controls load down the signal.
Taking them off allows all the signal to go to the amp.
"so what are the resistors doing exactly?"
Think we have answered that
"so Im assuming I could use resistors at half the value to get me where I wanna be... ...so thats why Im here, am I on the right track? "
NO You want the resistors to have half the effect they have at the moment.
You want 6 or 5dB reduction not 12dB. You dont want them to reduce the signal so much.

Look I havent got or seen one.I am trying to be of some assistance.
When there is active circuitry involved dB calculations are more complex.
A picture and a net diagram are not the stuff of accurate calculations.
Having said all that I much prefer Claptons Bluesbreaker tone or the 335 into a Plexi than his current set up.
Maybe there was somthing in the water then or perhaps I'm stuck in the '60s
but to me those tones established a yardstick and I'm guessing in another 40 years those points in time will still exist wheras this lace sensor/tbx thing will have been forgotton.
See if my awful diagram with a rough water type equivalent to the circuit helps.
The tap (do you call them faucets ?) sends water to the sprinkler (well it used to before global warming).
If tap 2 is opened less goes to the sprinkler. Small opening = High resistance (hard to get through).
Big opening = low resistance easy to get through.
When you play guitar the PU is a generator making electrons run down the wire trying to get back to the other side of the pu which is ground.
Hope this helps

[ShortBuSX]

Eureka!

Thanks man, I appreciate all of your help on this.
Im currently waiting on parts before I begin to open this up...but I now have an idea and a strategy when I do...so thanks again.

I'll try and follow up on this when Im done.