signal loss? 1/4" TS plug into 1/4" TRS jack

[mike_mccue]

Is there a signal loss when you plug a unbalanced 1/4" TS plug into a jack wired for a balanced 1/4" TRS?

For some reason... deep in the recess of my memory I seem to recall a 3dB loss is predicted. Am I crazy?

thanks,
mike

[mike_mccue]

I don't mind if anyone wants to tell me I'm dead wrong about this. :-)

I did find a reference to the idea that plugging a TRS cable into a TS jack can cause a 6dB loss in signal strength.

Maybe my first idea was just crazy.

best,
mike

[pdf64]

Hi Mike, you're right, there will be a theoretical 6dB loss plugging an ground referenced signal into a differential input. How that actually works out in practice you'll have to give more details of the application. Peter

[mike_mccue]

Hi Peter,

This is related to my other question about the isolation transformer. First I've accepted the fact that I wasn't using it properly with regard to impedance loading/bridging but I'm trying to understand why there was such a large amount of signal loss. I suspect that while the loading helped to bring down the overall level the more noticable change was caused by mismatched connections.

As I say I could be misguided in this regard.

The situation is:

Stratocaster guitar pickup>
1/4" TS guitar cord>
1/4" TRS balanced passive jack>
10kOhm 1:1 isolation transformer>
1/4" TRS balanced passive jack>
1/4" TS guitar cord>
hi impedance preamp input.

Can you see a possibilty that I'm losing signal strength because of the mismatched connections?

best regards,
mike

[Sweetfinger]

Stratocaster guitar pickup>
1/4" TS guitar cord>
1/4" TRS balanced passive jack>
10kOhm 1:1 isolation transformer>
1/4" TRS balanced passive jack>
1/4" TS guitar cord>
hi impedance preamp input.

What I see is plenty of opportunity for bad connections, and there will ALWAYS be some loss in the transformer. Check your cables for high capacitance. No need to check that if you're using Hosa cable, Just cut it up and throw it away as a matter of course. I'll have to read your original post, but this seems like a lot of trouble to go through, where less stuff might work better.

[Steve Conner]

Like I said previously, I think it's the transformer that's draining your signal, as it's only designed for a 10k system impedance. And like I said previously, the best way I can think of to fix it is to insert a buffer before the transformer.

[mike_mccue]

Ok, thanks Steve.

The input impedance on the preamp is 470kOhm so that is a big difference.

But let's agree about that part.

Is it possible that my mismatched connection is also contributing to signal loss?

thanks,
mike