Unity gain buffer question

Unity gain buffer question

Postby joeriz » Wed May 11, 2011 8:42 am

I realize that this has likely been asked before but I was not able to find the answer by doing a search...

Does a UGB do anything to combat the loss of high end when rolling back your volume control? Or is the only way around this to do the typical 'treble bleed' mod with a capacitor or capacitor/resistor combination?

Thanks much,
Joe
joeriz
Rosebud
Rosebud
 
Posts: 36
Joined: Mon Dec 13, 2010 9:38 am

Re: Unity gain buffer question

Postby tcsned » Wed May 11, 2011 9:14 am

I could be wrong, as my UGB/OBEL guitar is still under construction. But I'm thinking that it wouldn't really affect the tone loss using your pickup volume control. However, if you do the OBEL with it and add a master volume like Jerry's wiring set up then the master volume would not give the tone loss that rolling back your pickup volume would.
User avatar
tcsned
Senior Member
 
Posts: 2648
Joined: Sat Mar 21, 2009 2:50 pm
Location: Blacksburg, VA

Re: Unity gain buffer question

Postby mijknahs » Wed May 11, 2011 3:34 pm

Using a UGB TOTALLY fixes the problem with the highs rolling off when turning the volume down. It makes your volume control useful.

On my non-UGB guitars I usually have the volume all the way up for maximum tone (sometimes backing off a number or two). On my UGB guitar, my normal setting is volume half way up. It sounds crystal clear. Then I use it like a clean boost. Sometimes going up to 3/4 up but never all the way up (too loud).

Jim
User avatar
mijknahs
Senior Member
 
Posts: 1515
Joined: Fri Nov 13, 2009 8:51 pm
Location: Los Angeles, CA

Re: Unity gain buffer question

Postby joeriz » Wed May 11, 2011 7:15 pm

Great...thanks for the replies!

Joe
joeriz
Rosebud
Rosebud
 
Posts: 36
Joined: Mon Dec 13, 2010 9:38 am

Re: Unity gain buffer question

Postby tcsned » Thu May 12, 2011 5:14 am

mijknahs wrote:Using a UGB TOTALLY fixes the problem with the highs rolling off when turning the volume down. It makes your volume control useful.

On my non-UGB guitars I usually have the volume all the way up for maximum tone (sometimes backing off a number or two). On my UGB guitar, my normal setting is volume half way up. It sounds crystal clear. Then I use it like a clean boost. Sometimes going up to 3/4 up but never all the way up (too loud).

Jim

I stand corrected - Jim knows of what he speaks :hail:
User avatar
tcsned
Senior Member
 
Posts: 2648
Joined: Sat Mar 21, 2009 2:50 pm
Location: Blacksburg, VA

Re: Unity gain buffer question

Postby mijknahs » Thu May 12, 2011 7:21 am

I totally recommend one. Even if you don't or aren't using an "on board effects loop". That's a cool thing in itself but the UGB totally changes the way your volume control works.

You just need to replace your 250k ohm (or 500k) with a 25k ohm pot.

Jim
User avatar
mijknahs
Senior Member
 
Posts: 1515
Joined: Fri Nov 13, 2009 8:51 pm
Location: Los Angeles, CA

Re: Unity gain buffer question

Postby TI4-1009 » Fri May 13, 2011 12:43 pm

mijknahs wrote:You just need to replace your 250k ohm (or 500k) with a 25k ohm pot.

Jim


And remove the treble bleed mod if you already have it?
"Do not write so that you can be understood, write so that you cannot be misunderstood." -Epictetus

First show: 8/16/69 (Woodstock)
Last show: 3/19/95 (Unbroken Chain breakout)
Member of the Four-Decade Club
Charter Member, President & CEO of OAD (Order of the Ancient Deadheads)
User avatar
TI4-1009
Senior Member
 
Posts: 1438
Joined: Fri Aug 20, 2010 6:27 am
Location: Upstate NY- Toodaloo

Re: Unity gain buffer question

Postby mijknahs » Fri May 13, 2011 12:54 pm

TI4-1009 wrote:
mijknahs wrote:You just need to replace your 250k ohm (or 500k) with a 25k ohm pot.

Jim


And remove the treble bleed mod if you already have it?


Yeah. You won't need that anymore.
User avatar
mijknahs
Senior Member
 
Posts: 1515
Joined: Fri Nov 13, 2009 8:51 pm
Location: Los Angeles, CA

Re: Unity gain buffer question

Postby TI4-1009 » Mon Aug 13, 2012 7:54 am

Check this out- great explanation!

http://www.youtube.com/watch?feature=player_embedded&v=3oQpr8qrwQI#

Waldo- agree?
"Do not write so that you can be understood, write so that you cannot be misunderstood." -Epictetus

First show: 8/16/69 (Woodstock)
Last show: 3/19/95 (Unbroken Chain breakout)
Member of the Four-Decade Club
Charter Member, President & CEO of OAD (Order of the Ancient Deadheads)
User avatar
TI4-1009
Senior Member
 
Posts: 1438
Joined: Fri Aug 20, 2010 6:27 am
Location: Upstate NY- Toodaloo

Re: Unity gain buffer question

Postby foolofships » Mon Aug 13, 2012 3:08 pm

mijknahs wrote:Using a UGB TOTALLY fixes the problem with the highs rolling off when turning the volume down. It makes your volume control useful.


Is that because the UGB lowers the impedence before the signal hits the volume control?

mijknahs wrote:You just need to replace your 250k ohm (or 500k) with a 25k ohm pot.

Jim


Now, I was always given to understand that the higher the resistance of the pot, the more treble frequencies would pass through; that's why guitars with single-coil pickups use 250k volume pots, guitars with humbuckers typically have 500k pots, and Gretsches have 1M pots (for the twang), and why Tiger and Wolf have a stacked tone control. Given that, why the very low resistance recommendation? Does the UGB otherwise put out too much treble? I have a UGB (of my own design), and a 500k volume pot on my single-coil guitar, and I have certainly never noticed a deficiency in its performance--although I will say that I had the treble bleed mod for a while, but removed it because it didn't seem to make a difference.
foolofships
Rosebud
Rosebud
 
Posts: 37
Joined: Mon Sep 12, 2011 11:42 am
Location: Portland, OR

Re: Unity gain buffer question

Postby mijknahs » Mon Aug 13, 2012 3:30 pm

foolofships wrote:Is that because the UGB lowers the impedence before the signal hits the volume control?

Now, I was always given to understand that the higher the resistance of the pot, the more treble frequencies would pass through; that's why guitars with single-coil pickups use 250k volume pots, guitars with humbuckers typically have 500k pots, and Gretsches have 1M pots (for the twang), and why Tiger and Wolf have a stacked tone control. Given that, why the very low resistance recommendation? Does the UGB otherwise put out too much treble? I have a UGB (of my own design), and a 500k volume pot on my single-coil guitar, and I have certainly never noticed a deficiency in its performance--although I will say that I had the treble bleed mod for a while, but removed it because it didn't seem to make a difference.


If you're using a 500K pot and you're happy with how everything is working (through the whole range of the taper), then that's fine. My understanding is that It has nothing to do with the treble (too much or too little) but with impedence matching and the usable taper of the pot.

With the 500K, do you find that you have a good taper from "zero" to "ten" (I know it's not normally numbered but you get the idea). Does it work well at about "five" or "six"?

Personally, I've always used a 10K or 25K pot with the buffer and it always worked perfectly.
User avatar
mijknahs
Senior Member
 
Posts: 1515
Joined: Fri Nov 13, 2009 8:51 pm
Location: Los Angeles, CA

Re: Unity gain buffer question

Postby foolofships » Tue Aug 14, 2012 10:48 pm

I picked up the notion of the resistance of the pot affecting treble frequencies from "Customizing Your Electric Guitar" by Adrian Legg. It must have something to do with impedance, since it is clearly a capacitor that affects treble frequencies directly--which I would have sussed had I thought about it.

I haven't noticed any inconvenience with the 500k pot. I run at about 6 - 7 on the volume, until it's time to kick it up a notch. I'm loath to try a 25k pot because I have a pot with a push-pull switch that I use for my OBEL, and it's a pain in the ass to take out and replace unless there is a clear benefit. I'm thinking of trying a different preamp, and at that time, I might just go ahead and swap the pot. Have you compared the two values? What's the difference? I imagine that "5" would come earlier in the rotation on the 25k pot, but I've never used one.
foolofships
Rosebud
Rosebud
 
Posts: 37
Joined: Mon Sep 12, 2011 11:42 am
Location: Portland, OR

Re: Unity gain buffer question

Postby 1dallek1 » Wed Aug 15, 2012 5:38 pm

just my 2 cents use the bourns pots the blue ones the model 82 for the tone pots and the 95 for the 25k pot. they don't make a 25k in model 82 or at least they didn't.
!!! ALWAYS WEAR EYE PROTECTION !!!
User avatar
1dallek1
Blues for Allah
Blues for Allah
 
Posts: 81
Joined: Thu Jun 09, 2011 10:06 am


Return to Guitar Building and Mods

Who is online

Users browsing this forum: TurnitinBot [Bot] and 0 guests