Could someone clever please double check my schematics

[Otwa05]

[quote author =antonis link=topic=129539.msg1252236#msg1252236 date=1661427654]
Just another (minor) suggestion..

Make C1 about 150pF for more efficient HF filtering..
(at least, for R9 at high gain settings..)
[/quote]

Will do

[duck_arse]

does your "Meg" multiplier work in the simmer? I've seen on other's sim circuits 1000000 as 1000k instead.

[PRR]

The customary SPICE format is case-insensitive (originally upper-case only), so Meg has to be spelled "Meg" (or "meg") to distinguish from m=milli.

While SPICE did get re-writ from FORTRAN to C, it is still some of the oldest code on the planet outside of banking. (There may be UK bank computers still working in L/s/d units and getting put to decimal at the in/out.)

[Rob Strand]

I've seen on other's sim circuits 1000000 as 1000k instead.

That also works.

While SPICE did get re-writ from FORTRAN to C, it is still some of the oldest code on the planet outside of banking. (There may be UK bank computers still working in L/s/d units and getting put to decimal at the in/out.)

IIRC, LTspice has some options related to how the M is handled.    Even if you can set it to mean MEG, as soon as you do it you alienate yourself from what most sim'ers are used to now.  Also, I don't know what will happen if you download a schematic where M/m means milli and run it on a system where M means MEG.   That's why earlier I said it's best to get used to the M situation on simulators.
[FYI, Can't see any options on my current version of LTspice other than to treat 3k3 = 3.3k.]

[Eddododo]

I don't know anything abouts simming, nor about opamp quirks, nor even the veroboarding. I do know that when you use m instead of M when you want Megohms, you get milliohms, at least in real life. only a slight difference, I grant you [1 x 10⁹ if my thumbs count right], but I've been told sims are picky about this stuff.

I believe you have to use Meg on ltspice, it's not case sensitive.. that would indeed be a problem on their sim

[Otwa05]

Ok thanks everyone again for all the help! Unless I've made a mistake somewhere on the vero (apart from the pot possibly being wired wrong, it doesnt tell me which lug is which son I'll just figure it out when I build), this should be the final design 

[antonis]

Too much "garbage" on 4.5V point..

I'd put a cap in series with R7 and connect all 4.5V point (except R8 & R3) to GND..

[Otwa05]

Too much "garbage" on 4.5V point..

I'd put a cap in series with R7 and connect all 4.5V point (except R8 & R3) to GND..

like so?

[antonis]

Yeappp..

(with bigger C6 - up to 4.7μF..)

[Otwa05]

Yeappp..

(with bigger C6 - up to 4.7μF..)

Just tried the sim and I have to have the diodes pulling up to Vref otherwise I need another capacitor between the diodes and next op amp stage, is is too much of a problem if I keep the diodes pulling to bias, or will the bias be to cluttered as you mentioned? Also what are the actual side effects of having the Vref to cluttered?

[antonis]

is is too much of a problem if I keep the diodes pulling to bias, or will the bias be to cluttered as you mentioned? Also what are the actual side effects of having the Vref to cluttered?

From none to awful..

Just implement your previous circuit and if it's OK ignore what I've said..

[Phend]

Help, what is the color code for 1 milli (0.001) ohm resistor?

[antonis]

Help, what is the color code for 1 milli (0.001) ohm resistor?

It strongly depends on particular tolerance..

[Phend]

10% tolerance

[duck_arse]

Help, what is the color code for 1 milli (0.001) ohm resistor?

see here - competition is closed, no prizes left.
https://www.diystompboxes.com/smfforum/index.php?topic=111451.msg1036577#msg1036577

[Phend]

Would not have won. There is no such thing as a 1 milli ohm resistor other than some length of small diameter wire.

[duck_arse]

yes, after linking that post I was ruminating your 1mR, and I've decided we run out of colours on a 4 band, even starting with black first band.

[Rob Strand]

yes, after linking that post I was ruminating your 1mR, and I've decided we run out of colours on a 4 band, even starting with black first band.

I've never seen such an animal.   Smallest I've seen is brown black silver = 0.1 ohm.

The SMD era has put an end to color codes.    (Through-hole) Dale power resistors had the values marked on them in text to three decimal places, eg. 0.010 ohm = 10 milliohm, 0.275 ohm = 275 milliohm.  5W and 10W resistors are marked with fewer digits.

[anotherjim]

If you want to couple the diode clippers to ground, one cap from the diodes only to ground would do and the signal path between stages can remain DC coupled. There is then no worry of diode action kicking the Vref voltage. 10uF would do.
However, you want a switch to enable the clippers which would leave one plate of the blocking cap "floating" while the switch is open and that can create a "pop" when you close the switch and the cap plate charge catches up with the 4.5v. A large value resistor across the switch will keep the cap plate at 4.5v when the switch is open but prevent the diodes from clipping the audio. 1M would probably do.

[PRR]

Help, what is the color code for 1 milli (0.001) ohm resistor?

$$$$

> There is no such thing as a 1 milli ohm resistor other than.....



DigiKey even has some in stock (4 more non-stock). Not cheap-pedal priced, and not color-coded. And as you hint, the least added lead or PCB trace spoils the accuracy.

Note that these are all 4-terminal.