Quasar suck tone?

[A1Full]

Hello, query, this happens to someone? Mod Rc, when you turn the pedal with all pots at 12 o'clock, tone sucks? and if I put some ovedrive, the worse they feel this, it gets more opaque sound, if under the gain pot, and turn up the volume this improvement, but unity is not working ok and sucks tone.
I hope someone can help me

[mgwhit]

Are you saying that the tone is too dark and that turning the overdrive up makes it darker?  (I'm trying to figure out what you mean by "opaque" here.)

Here is what we need from you in order to help:

1. A list of any part substitutions you may have made.  Different resistor or capacitor values?  Which transistors and op amp IC did you use?

2. Voltage readings from each pin of Q1, Q2 and IC1.

3. High resolution, well-lit, in-focus photographs of both sides of the board.  If you can't read the resistors or see the traces and joints clearly, neither can we.

Thank you, and good luck!

[A1Full]

I appreciate your response, but all components are ok, not a problem that is poorly armed, I believe that the design of the quasar is so, unless I indicate that does not happen to others, understand?
the pedal works ok, but in my view that happens, it gets darker
if under the gain and turn up the volume goes better this

[oldhousescott]

Did you use linear pots for treble and bass? If you used audio/log pots, the treble and bass will be rolled off when set to 12 o'clock, making the pedal sound very mid-focused.

[A1Full]

ok I'll try the log pot, thanks!

Brian you can help me with something?

[oldhousescott]

Sorry, I wasn't clear. You should be using linear pots for treble and bass, not audio/log.

[A1Full]

ah ok, but why are those who use, the plate is armed as is the rose! all components are those, for me there is any design flaw.

[nudelsuppe]

Hello there! My first most here so first of all welcome everybody and praise to the bean for his great projects .

I thought I might post here instead of starting a new topic because I have a similar problem!
I built the Quasar 2 times, the first time I wired all the traces myself (looked pretty ugly), the second time I etched madbean's layout and built it on there. Both version worked fine, but both versions have had the same volume issue decribed above. In some demonstration videos I saw, the rc has unity gain with the gain almost completly backed off and the volume to 12 or maybe 1 o' clock. this wasn't the case with both my builds (unity gain at aprox. 3pm). I started investigating into op amps and found out that through lowering R5 to 15 to 10k I could increase the amplifying factor of the op amp. I did that and the volume issue was solved. But the op amp now amplyfies at a (aproximately) 1:3 ratio instead of a 1:1. That can't be quite right, can it? Is this a problem for an op amp? I am using the 4558 instead of the 4557, that is the only substitution! Maybe someone who has successfully build the quasar can share his experiences and can tell us if unity gain only at higher settings is normal with this build!

Thanks and regards, Nudelsuppe

[oldhousescott]

Minimum gain through the first stage with RC values is a little over 2. The second stage with the baxandall eq has a gain of 1 with the bass and treble pots set at noon. Unity gain should occur with the gain pot turned fully ccw when the volume pot is at noon, if you use a linear pot for the volume. If you use a log/audio pot as Bean shows, it will occur at maybe 3 o'clock or so, as you've experienced. Opamp types will make no difference in the amount of gain.

[nudelsuppe]

Okay, thanks for the information! so a lin pot would be better suited.