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What is your point?

A very simple question regarding Vref and an extra opamp I have laying around on a circuit I'm working on.
I have an opportunity to use this spare opamp and was thinking of using it for Vref.

At the moment, for the Vref, I am using 2x 22k resistors with a 47uf filtering capacitor. My question is, if I add the opamp, can the resistors value be the same or would I need to adjust their values?

The SMD ones are called BC849.

I was also looking for this and had a look at both data sheets. They don't seem to be exactly the same.

The muff circuit biases it's transistors in such a way that the gain of each stage is independent of the transistor Hfe rating. I wouldn't expect the transistor choice to make too much difference. Anything with an Hfe of 325 or greater should work. That's most modern transistors. The 2N5089 is definitely hot enough.

It's not the hfe I'm interested in but the fact that these are lower noise.

I looked on the forum and couldn't find anything related to the BC459C, even though I'm pretty sure this has been debated to exhaustion.

I'm looking for an SMD version of the BC549C transistors. This is for a high gain fuzz (muff variant) and it's not easy to find smd versions of some trannys. The one that I can find is for the 2n5089...

I had already opened a similar post regarding the MPSA18 and I'm starting to realise that it's very hard to find some of these SMD versions of the transistors popularly used on so many fuzz units. 

Don't you need a matched PNP NPN pair for(optimal) push pull? May look at transistor arrays if that's the case.
I assumed this was for a pedal so didn't take voltage into account...

I'll add, check out the Alfa offerings

For this particular circuit, not really.

Thank you. I will have a look into this.

I did a search at Mouser for SMD BJT that meet or exceed all the relevant properties of the MPSA18, and they have 47 choices.  Here is the link to search results.  The noise factor and beta are not searchable properties, so you'll have to sort those qualities for yourself, but this should give you a head start.  Once you identify the part number you need, Mouser has a presence in Portugal, pt.mouser.com.   
 
https://www.mouser.com/c/semiconductors/discrete-semiconductors/transistors/bipolar-transistors-bjt/?collector-%20base%20voltage%20vcbo=45%20V~~-&collector-%20emitter%20voltage%20vceo%20max=45%20V~~-&collector-emitter%20saturation%20voltage=200%20mV~~-&configuration=Single&emitter-%20base%20voltage%20vebo=6.5%20V~~-&gain%20bandwidth%20product%20ft=160%20MHz~~-&maximum%20dc%20collector%20current=200%20mA~~-&mounting%20style=SMD%2FSMT&pd%20-%20power%20dissipation=625%20mW~~-&product%20type=BJTs%20-%20Bipolar%20Transistors&transistor%20polarity=NPN&rp=semiconductors%2Fdiscrete-semiconductors%2Ftransistors%2Fbipolar-transistors-bjt%7C~Maximum%20DC%20Collector%20Current%7C~Collector-%20Emitter%20Voltage%20VCEO%20Max%7C~Collector-%20Base%20Voltage%20VCBO%7C~Emitter-%20Base%20Voltage%20VEBO%7C~Collector-Emitter%20Saturation%20Voltage%7C~Pd%20-%20Power%20Dissipation%7C~Gain%20Bandwidth%20Product%20fT

that transistor does not have the same characteristics that I need to replace the MPSA18. I need the higher voltage handling capability, Lower noise figures and also higher gain specs. This is for a Push-pull gain stage to reduce Harmonic distortion.

I have been looking for an SMD package for the MPSA18 and I cannot find anything. Has anyone had any luck with finding this as an smd package?

Hi guys, I thought that I should ask the Peeps opinions on where to look in order to improve a little issue.
I have a design that, as many pedals, blends the clean signal with the Distorted signal. For this, I am using a Pan circuit with an inverting opamp stage. The Center of the Pot connects to VR (2x 10k resistors with a 39uf filtering cap.
The circuit works really well, except that, when completely on the clean side, there is bleeding from the distorted tone when the gain is up. I thought that the 39uf cap would be enough to filer everything, but it doesn't seem to do the trick.
I guess the question is, any idea where to look?

Hi guys, this is not a pedal enquiry, but it's actually something I'd like to lear about to end up using on a circuit.
I would like to drop the "Pot + Cap" tone system on a guitar and replace it with a switch(not sure which). The idea is to drop the potentiometer completely and instead have a 3 position switch(maybe on/on/on or on-off-on?) with two caps.
I'd like to have position 1: No cap( full sound); Position2: C1; Position 3: C2.

Is there a simple way of doing this using a 3 position spdt switch?
Any help would be appreciated.

Just looked at the afterlife comp build doc, which I assume is similar to what you are building. Brian suggest that the NSL32-R3 works well in that circuit and notes it is less expensive than the VTL5C3. A quick google makes it seem like you should be able to get it for less than $4 a pop.  Maybe that would work for you.

https://www.madbeanpedals.com/projects/_folders/1590A/pdf/Afterlife2020.pdf

I'm more looking at roling my own. To be using something else, I'd rather find the right LDR and LED combination, and that is what I'm trying to find out about and trying to see whoever has been successful with this.

I thought that the values on light and dark resistance would be less important. But then, we're left with the other parameters of the ldr...at least I know a bit better on how to proceed, I guess.

I forgot to mention that the circuit I'm basing it in is the Diamond Compressor. I have no idea what a homemade optocoupler would behave like in this circuit. For me it would be easy to use LDR's that go from hundreds of ohms up to above 200M matched with a White LED. My concern is what about the other specs, would they matter in that circuit? (The compression is gain dependent).

Thank you guys for all the info.
What do you think about this?

I took new readings from the Xvive VTL5C3 with another multimeter. The on Resisance is spot on but the dark resistance is insane. My multimeter reads up to 200M and while taking the reading, it just stopped reading. This means that when it's dark it measures more than 200M.
Isn't this completely off specs, and if so, how is this a good quality Vtlc5 replacement?