Troubleshooting Octahive Beetronics

[Robin28]

Hello!

I m trying to make a clone of an octahive by Beetronics.
I got pretty close (it s more or less like an octavia)
I have the original octahive and I checked the circuit.
So for the schematic I m 99% sure that I m good ( juste the first 5087 is in the other side) (and I added a eq at the end but I bypassed it for the sound check).

My problem is that I don't have the same sound and way less gain and output volume.

All the voltage in the circuit is the same.
The only difference that I have is when I check, Q3 (with a diode tester) I have 0.8 between the emetter and the base.
I found the same between the collector and the base. (Like on all the other 5088 that I have)
But I found 1.4 between the base and the collector (and nothing on all the others).

(I don't know what to conclude about that, any idea ? ^^)

(Sorry for my poor English )

[duck_arse]

hello Robin28, your english is fine. your measures need work, but yer english is good.

I don't think you need R20, unless you plan to add a bypass cap at the junction w/ R12. you don't need R19 with a pre-gain pot fitted. I don't think you need R14, and deleting that means C10 will be backwards as drawn. what is the value of R1?

is this a soldered build, or on the breadboard - either way, we always like to see photos of the thing we are trying to debug? about your voltages - we always use the Volts setting on the meter to do circuit voltages - the diode test is only for parts out of circuit and unpowered. the general rule for voltages is to put the black probe to circuit ground, and leave it there for all measures. then probe about with the red probe, that way all voltages are referred to ground, and will make more sense.

so, measure the voltages on each transistor, and write them here, e, b, c. please no "they are the same". we want the meter numbers. same goes for the opamp pins, measure and list with pin numbers. and then we might be able to say what's going on.

[Robin28]

Hi thank for the answer

I ll post all the values with a picture tomorrow when I ll be home.
About R20 and R19 I just used the same values that Beetronics used in there pedals (the part of the circuit after the master volume is totally bypassed and I removed the aop amp to just focus on the octavia part of the circuit).

The circuit is on a Pcb and work fine but sounds far far from the original .

[PRR]

Isn't Q1 drawn wrong? In this drawing style (plus up), the emitter arrows should all point down. Also the NFB from the output should go to Q1 emitter; drive to Q2 base comes from Q1 collector.

I don't know if this is a drawing error or a build error.

It is *possible*, in a 9V world, that some transistors will work "inverted". But I would not count on it.

[Robin28]

Hi again.

Yes about Q1 my bad i swaped it around during the build, but it didn't solve the issue.

about the values
Octahive /// Clone

Q1. E 4.8V /// 4.2V
B. 3.45V /// 3.7V
C 2.82V /// 2.81V

Q2. E 2.25V /// 2.26V
B. 2.82V /// 2.81V
C 8.85V /// 9.41V

Q3 E 1.59V /// 1.60V
B. 2.25V /// 2.26V
C 4.76V /// 4.87V

And here are some pictures
(sorry mine is a bit messy cause i tried about 1000 stuff ^^ around the transformer and i bypassed the end as well)
I'll do it again if i find the problem)