Dr Boogey boogie question...C21

[jimitrader]

anyone have a report on a good capacitor for c21 with this shematic? if that gets changed to a 10nf will the 2.2 m resistor change too? thanks in advance..

https://4.bp.blogspot.com/-H6kNJPEVvaw/VeRamyEIcQI/AAAAAAAAF5c/XT6Ex5JRURg/s1600/Dr%2BBoogie.pnghttps://4.bp.blogspot.com/-H6kNJPEVvaw/VeRamyEIcQI/AAAAAAAAF5c/XT6Ex5JRURg/s1600/Dr%2BBoogie.png

[antonis]

Altgough I can't see neither any C21 nor a 2M2 resistor, judging from PCB arrangemet 2M is an input pull down resistor so it doesn't have to do anything with any cap following it..!! 

But, ALWAYS, a schematic is more convenient..

[jimitrader]

Quote from: antonis on Today at 12:22:18 PM<blockquote>Altgough I can't see neither any C21 nor a 2M2 resistor, judging from PCB arrangemet 2M is an input pull down resistor so it doesn't have to do anything with any cap following it..!! 

But, ALWAYS, a schematic is more convenient..
</new schematic link>https://us-browse.startpage.com/av/anon-image?piurl=http%3A%2F%2Fwww.mrdwab.com%2Fjohn%2FBoogie_with_buff.png&sp=1593710134T45117479457b91378b62245cbd6583a71fde47361193de23dc97fb84f4cde038

[jimitrader]

Quote from: antonis on Today at 12:22:18 PM<blockquote>Altgough I can't see neither any C21 nor a 2M2 resistor, judging from PCB arrangemet 2M is an input pull down resistor so it doesn't have to do anything with any cap following it..!! 

But, ALWAYS, a schematic is more convenient..
</new schematic link>https://us-browse.startpage.com/av/anon-image?piurl=http%3A%2F%2Fwww.mrdwab.com%2Fjohn%2FBoogie_with_buff.png&sp=1593710134T45117479457b91378b62245cbd6583a71fde47361193de23dc97fb84f4cde038

I seem to not be getting enough volume? so i thought maybe that might be the problem ..what do you think could cause low vol? i have the q1 through 4 at around 5v sounds great just not very loud?

[temol]

Take the audio probe and trace the signal path. You'll find whether it is quiet from Q1 or volume drops somewhere along the way.

T

[antonis]

So, to what we'll refer on..?? Stripboard or schematic..??
('cause, as you can see, there are discrepancies in them..)

[jimitrader]

Take the audio probe and trace the signal path. You'll find whether it is quiet from Q1 or volume drops somewhere along the way.

T

thanks will check that out

[PRR]

1 to 10 nF is fine. This is not your low volume.

[jimitrader]

came out great thanks for the help !!

[antonis]

came out great thanks for the help !!

 

[GibsonGM]

came out great thanks for the help !!

 

[POTL]

My 2 cents.
1) In the third stage of amplification, the resistor (R9) 3.9 kOhm is completely wrong, you need to install a 39 kOhm resistor.
Most likely, the resistor will not allow you to set the bias correctly (a couple of years ago I assembled this circuit, but I don't remember how adequately it worked), if the bias is not set, replace the resistor with the nearest values.
This is an important element of the Mesa Boogie Rectifier sound, "cold clipping."
Your signal will become noticeably quieter, but there will be more compression.
2) The gain of the gain should be either 1 MΩ or 250 kΩ. The lower the value, the more dense the low frequencies will be, which is important for high gain.
New Mesa use 250 kOhm.
3) For good, you need to recalculate the values ​​of R3, R10, Gain pot in order to somehow simulate the values ​​of the anode resistors in the first and fourth stages, in the original circuit.
4) It is very important to ground C23, just add a 100 kOhm resistor (or more) between the second capacitor pin (which connects to the output socket) and ground.

This is actually a poor design simulating an amplifier in a box.