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I have made an older version of the Low Rider and compared the Octave Down vs the Octave down on my original Pearl OC-07.
They do not sound the same and it's killing me.

The Pearl has an hollowness and gritiness to the sound that the Low Rider does not have. The original Pearl has this kind of synthy quality to it while the Low Rider is cleaner and fater (it doesn't sound bad, but it doesn't sound as good).
I used an MC14013 for the Flip Flop and an LM2902 for the Driver of the Flip flop (the original uses these two).

I have tried three different diodes, one OA91 (germ), D9E(germ) and a Bat46. They all seem to offer something different to the sound (hard to say exactly what) but with none of them I get any closer to the sound of the Pearl Octaver. The Low rider sounds a bit bassier and it's deinitely cleaner (less artifacts).
Any tips on why I am not getting similar results to the original? How important is the germanium diode to the sound? Is it the diode or is it something else that I am missing?

I'm looking for a reliable 1N34A germanium diode replacement to use on the Low Rider analogue octave down project. I did some search and perhaps the BAT46 would work well on this design?

I am looking for something that is readily available.

Both the Boss OC-2 and Pearl Octaver (Low Rider) have identical single Jfet input stages followed by an opamp gain stage.

The question is, are these single jfet inputs even necessary or are they a leftover from the original bypassing mechanism? It seems like the pedal should work exactly the same if the jfet stage was left out, or am I wrong?

Input buffers. They are usually skipped when building "replicas".


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Right, that is what I thought but the Low Rider keeps this input stage.

Both the Boss OC-2 and Pearl Octaver (Low Rider) have identical single Jfet input stages followed by an opamp gain stage.

The question is, are these single jfet inputs even necessary or are they a leftover from the original bypassing mechanism? It seems like the pedal should work exactly the same if the jfet stage was left out, or am I wrong?

Gate arrow is closer to source

So S connects to VR
Though orientation probably doesn't matter.

Thank you so much!!!

I tried editing the post, but couldn't.
I have attached an actual image with the bit of the schematic that is relevant.
I understand that the Arrow indicates the Gate. How do we identify the Drain and the Source?

What exactly is the Pinout on the 2sK30 transistors. On the Lowrider schematic the pinout is not specified. I understand that the bit with the arrow is the Gate but how do I know which one is the Drain and which one is the Source?

It says that we can use 2n5457 instead but they have different pinouts, right? How do we know which one is which?
I have attached an image with the section that shows these transistors.

I found a PDF of the Low-rider (Pearl OC-7) which I built a long time ago. I no longer have the pedal but I was thinking of coming back to it.

I was looking at the schematic, and since I didn't find any use for the 2nd Octave down, I was wondering if the second Flip Flop chip (CD4013) is necessary even if we don't use the 2nd Octave down part of the schematic? Can I just omit it or is it serving some other purpose? I can see its CLK pin is connected the output pin on the other Flip Flop IC.

I have attached the schematic.

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