Relay problem - user error

[tk@halmi]

For a long time I have been wondering why the highs sound funky on one of my preamps, based on the JLM board. Everything checks out except it appears that the Omron relays trash the signal pretty bad. The models # is G6H-2 and supposed to be low-signal type with bifurcated contacts. On the scope it like as if I just added a large capacitor from signal to ground so the square wave gets rounded off substantially.
Has anyone found relays for this board that do not mess up the signal?
It is a ten pin miniature relay thingy dealy.

Thank You,
Tamas

 

[JLM Audio]

Hi Tamas

What voltage are the relays you have as the part number would suggest 6v? Have you adjusted the constant current resistor R8 to drop the right voltage across the relay coils? Also the relay coils have a +/- % for the coil voltage. So go for just under the highest voltage the coil can take to get the best pressure.

Have you removed the input transformer to do the tests on the relays as this does not sound like a relay problem but a wrongly loaded or internal sheilded input transfomer to me? But I do not use the Omron relays so I cannot be sure.

Let me know what you find

Joe

www.jlmaudio.com

 

[PRR]

> appears that the Omron relays trash the signal pretty bad. ... it like as if I just added a large capacitor

That does not sound like a relay. Relays either get stuck, or scratch like a dirty guitar cord. Small relays are not big enough to have much capacitance.

The only odd thing I can think of is a pinout error so that signal is passing through the relay coil. That would add series inductance, which could round-over the highs much like shunt inductance. But the other symptom would be that the relay "doesn't do anything"; doesn't change from one mode to another mode.

 

[tk@halmi]

Gentleman, I am a BIG dunce.
I had a zobel network capacitor ten times the size recommended that was loading signal down.


Tamas

 

[CJ]

Thank God! I was ready to start ripping out these relays in my MEQ-5!
Good catch!