• Disclaimer: This Vendor's Forum is a paid-for commercial area. Unlike the rest of diyAudio, the Vendor has complete control of what may or may not be posted in this forum. If you wish to discuss technical matters outside the bounds of what is permitted by the Vendor, please use the non-commercial areas of diyAudio to do so.

Elektor PA300

This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
nel progetto di elektor del PA300 tra il piedino 5 ed 8 di IC1 viene collegato un condensatore da 33p denominato C9. qualcuno mi sa dire il motivo di questa scelta circuitale? vorrei realizzare il progetto sostituendo NE5534 con un OPA627 oppure con un OPA604 in quanto per le mie orecchie NE5534 è troppo freddo in termini di resa sonora. un grazie in anticipo a chi risponderà a questa mia domanda. ciao allego il circuito elettrico

in the draft elektor of PA300 between the leg 5 and 8 of IC1 it is connected to a capacitor 33p called C9. someone can tell me why this circuit choice? I would like to implement the project by replacing NE5534 with OPA627 or with a OPA604 as for my NE5534 ears is too cold in terms of sound. thanks in advance to those who will respond to my question. Hello Enclose the electrical circuit


  • 11.png
    735.9 KB · Views: 1,032
The 5534 is not unity gain stable, therefore a pin for frequency compensation is provided. the OPA604 is unity stable and doesen`t neet this cap. The OPA627 is different again. It maybe possible that this cap is not only responsible for the compensation of the opamp but also for the compensation of the whole amp too. difficult to tell from the schematic.
Anyway, I think easiest would be to try a OPA604 as it is unproblematic, the OPA627 is very fast so more critical to compensation and stability.
Salve, Jürgen

Hello everyone.
This several months that we walk in the threads of discussions. To see and understand.
We work for a French humanitarian work. Emmaus.
I mainly deal with recycling. So we have access to a hellish amount of material.
Just for the introduction.
We have been repairing all equipment for over 20 years.
I do not claim to know everything, far from it. But we are a whole team to tinker and build a whole bunch of things.
In short, we have fun.
Elektor circuits have been updated for some time.
Normal, Elektor in France is quite a poem.
As we can no longer get out with once again, confinement.
We decided to make a sound system in the village.
The PA.300 Elektor is still buildable, parts available. So we started. We re-route the circuit board.
For the 600, we started from the Elrad magazine, but the circuit was so equivalent to that of Elektor we directly modified the PA.300. PA.600 = 8 pairs. We have therefore modified the circuit ion feed resistances. We draw everything on Autocad, sorry. But Kikad and c ° it takes a bit of our head.
Okay, I'm attaching some of our work to give an idea.
See you everyone.


  • Elektor_Pa.300.400.jpg
    552 KB · Views: 469
I accidentally? just bought an Elektor PA300 unseen... I really want to know if it has ballansed inputs:) If not I would be gratefull if someone has links to a good kit for adding ballanced input.
I only want ballanced output cause my crossover DBX 234 doesnt have unbalanced out

1) Elektor PA300 does NOT have balanced input (attaching schematic below)
Good news is you do not need one :)

2) DBX 234 XL does have unbalanced outputs built-in, hidden in plain sight :cool:

It has "electronically balanced" outputs, actually two conventional unbalanced outputs, each referred to ground, only fed exact same signal level but out of phase, each connected to pins 2 or 3 of XLR output.
You can use them individually as what they are, unbalanced outs.

Make an adapter cable: one end connected to male XLR pins 2 (signal) and 1 (ground/shield), at the other end male RCA (or 1/4" plug if amp was built for PA use and has an 1/4" jack instead).

Presto, your problem is solved.
Clearly suggested in DBX user manual, by the way:

Input Connectors XLR
Input Type Electronically balanced/unbalanced, RF filtered
Input Impedance Balanced >50k ohm, unbalanced >25k ohm
Max Input >+21dBu balanced or unbalanced
CMRR >40dB, typically >50dB at 1kHz
Output Connectors XLR
Output Type Impedance-balanaced/unbalanced, RF filtered
Output Impedance Balanced 200 ohm, unbalanced 100 ohm
Max Output >+21dBu balanced/unbalanced into 2k or greater
As you see, both input and output can be used balanced/unbalanced.


  • Elektor PA300.png
    Elektor PA300.png
    45.4 KB · Views: 266
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.