Hi guys, I have a preamp that I built where the tone control can be bypassed.  The issue I have is when I switch in the tonestack (passive baxandall), the volume drop is quite dramatic.  I want to put in a gain recovery after the tonestack to bring the level closer to what it is when the TS is bypassed.  I put together a simple opamp gain stage as shown here (http://www.muzique.com/lab/boost.htm) on the very bottom right (resistor values changed to what I had on hand).  The issue is that when I start to bring the gain up from unity, the signal starts to clip before very much gain is recovered.  Up to this point in the signal path, there have only been two amplification stages and then the tonestack, so I don't think my input signal is too hot to be boosted cleanly.

My question is whether this topology looks suitable for the application and whether there are any other suggestions out there.  The output of this gain recovery would go straight to volume, then power amp.  Thanks.

Hi guys, this is my first post, though I have looked around for a while.  I am in the process of building my own amp using discrete components and have a design that I like.  I have breadboarded it and all.  The thing that is troubling me is that I want to have "channel" switching.  Really what I want is to be able to send the signal either to the power amp for cleaner tones or through an extra gain section to give me a high gain tone.  I would really like to do this with a footswitch, but if the footswitch is unplugged, it just gives me clean.  I was thinking I could do it with a switched jack and a dpdt stomp switch, but I also want another button in the same footswitch to activate a single onboard effect.  The effect will also have a toggle on the front panel, so I figure I can just use a relay for that.  The problem is that I want to use a single TRS cable to flip the relay for the effect and also to route the signal from the clean stage but I don't know how I would do the routing of the clean signal with (basically) a TS connection (since the ring would be used for the relay).  I am hoping that you guys can help me out here.  Would I need to use relays for both?

Hey, I just found this place and have a couple questions for you guys who have more experience.  In my office there was an old Dean Markley kb-20 practice amp that apparently went defunct.  As far as I know the power section in it is still good, so I took it (they've been trying to get rid of it for 2 years) thinking I could at least use the transformer and rectifier and some of the other parts like large caps, etc. 

The only problem is that I am unable to figure out what kind of transformer it is.  The amp is based around two tl072's, so I am guessing that the power section all together is putting out +/- 18V, which is in the operable range of the lm3886, as I understand it.  I am just wondering if I can use the same power section virtually component for component, or if I will be running into risks with things such as current supply, voltage sagging, etc.  I just want a decent power amp for running different low-power preamp sections into.  If anyone can help me with the transformer identification, it would be greatly appreciated.