OPA2604 API Hybrid Opamp circuit

[Strawtles]

Hello, I have some spares OPA2604 and I'd like to realize some hybrid opamp to use in API 500 type modules
I have found a JLM Audio schematic but it doesn't work ... I have made it twice
Someone has an alternative schematic? 

A PCB design is welcome!

 

[RuudNL]

I think it would help if you would post (a link to) the JLM Audio schematic.
(I think nobody is clearvoyant here...)

 

[Strawtles]

Done

 

[RuudNL]

This should work!
What is the problem?
No output signal at all?
Maybe the circuit is oscillating?

 

[pucho812]

I have made that circuit a few times to play around with. It works...

 

[Strawtles]

I have realized the circuit two times and it doesn't work ... but it is possible I have done something wrong working in the small space of the 2520 op amp
In the net I have found a simplified version of this opamp
Someone has realized it?

 

[RuudNL]

In fact it is nothing more than an OpAmp with an extra current booster.
Not very much can go wrong!

 

[Andy Peters]

I have realized the circuit two times and it doesn't work ...

Define "doesn't work." Be specific.

 

[Strawtles]

No sound 

 

[Strawtles]

In the semplified schematic I have posted it has been removed half opamp (DC servo part) and it is similar to the capi BB2521 (without the 4 diodes but with a red led)
Do you think these differences are relevant in the sound?

 

[Andy Peters]

I have realized the circuit two times and it doesn't work ... but it is possible I have done something wrong working in the small space of the 2520 op amp
In the net I have found a simplified version of this opamp
Someone has realized it?

The circuit in that schematic won't work. There is no feedback. Are you testing that circuit alone, or is it part of some larger circuit which implements the feedback?

You might wish to simulate the circuit using LTSpice.

 

[PRR]

> No sound

Any DC voltages?

Since amplifiers CAN'T work unless the DC voltages are near right, and many building mistakes result in wrong DC voltages, this is always where you should start.

As Andy says, a naked op-amp "won't work" until bias and feedback is connected.

 

[Strawtles]

Thank you, I'll verify again for wrong connections

 

[Fablab]

The semplified version is tested?
If works may be interesting to drive a transformer with an IC

 

[Jano1954]

I build about 20 pcs of this JLM opamp.
I designed the PCB myself using the pictures on the JLM website.

Did you also use these pictures?
Perhaps you can publish your PCB layout here .
In that case we can help check the design.
Sometimes a fresh look will help to find the failure.

 

[Strawtles]

Jano, I realized this op amp in a prototype board and I think this is the reason why it doesn't work
If you want to share your pcb layout may help me to realize an unit without risk of mistake

 

[Andy Peters]

Jano, I realized this op amp in a prototype board and I think this is the reason why it doesn't work
If you want to share your pcb layout may help me to realize an unit without risk of mistake

I'll ask again: did you test the circuit with the required feedback resistors or not?

-a

 

[Strawtles]

I have built the circuit as in the first schematic I posted

 

[pucho812]

I have built the circuit as in the first schematic I posted

then it will never work as it needs  extra parts.
The schematic is for the JLM hybrid opamp.  once you have the opamp gotta put it in circuit and use it  and see what it do.

 

[Strawtles]

To test the circuits I put them in a 500 circuit board
I have not tried them out of the board