Substitute for J201 transistor?

[caprotesta]

Hi all,

Newbie here. Can you substitute an NTE457 for a J201? A couple of weeks ago I decided to embark on making my first pedal, the EA Improved Tremolo. The original schematic calls for 2 2N5457 transistors, but the kit I got used J201s. I breadboarded the circuit, and got no sound. During troubleshooting, I found that the Q4 transistor (the first transistor coming off the B+) was producing some funky readings not in keeping with the listed output voltages. I have a couple of NTE457s laying around, so I'm thinking about switching these out and seeing if they make a difference. Looking at the datasheets, I think these should be compatible, but would like to hear what you think. And yes, before you ask...the pinouts of the transistor are correct 

[iccaros]

NTE shows a 458 as a replacement for the 201

While the NTE 458 may work in your Circuit, its does not share allot of the same specifications, you would have to BIAS it differently.
While NTE parts are easy to get a hold of, they are rebranded and expensive. you can get J201's on ebay for pennies.

Put a pot in place of R17, as Q4 is biased off that resistor. At 9v the 458 will not break (has a limit of 15v)

when you say funky.. what does that mean, this is a simple audio amplifier so funky can only mean, transistor in wrong way, Q4 is bad which you have another to test with, or the bias resistor is not correct. Do you have an audio probe to see if audio is getting past Q4?

I would assume issues would start in Q2 and Q3 affecting Q1, where Q1 is being placed in shutoff by how q2 and q3 oscillation is effecting its bias

[caprotesta]

Funky in the sense that I'm getting readings between 8.8-9.2Volts, where the voltages should be:

D: 8.8
S: 5.0
G: 4.1

I tried replacing the transistor with the other J201 and got the same readings. I turned the transistor around, and got little or no voltage coming off the pins, which led me to believe that the transistor was in the right direction to begin with. I don't have an audio probe. Could I bypass the rest of the circuit and connect the output jack off the drain pin and see if I get any audio?

[iccaros]

you could connect after Q4 and see if you get audio as it is nothing more than a Jack Orman buffer http://www.muzique.com/lab/buffers.htm

[Xavier]

2SK246 ?