Balanced to RCA adaptors

IMO, it's likely that a difference in sound is going to be attributable more to the preamp/amp impedance match than by the use of XLR>RCA adapters to run single ended out of the preamp to the balanced inputs of your amp, especially if you're mixing a tube component with a solid state component.

Another unknown is if your preamp and/or amplifier are a differential balanced design, or if they simply have XLR outputs and inputs...perhaps transformer coupled, but not truly balanced operation.

One thing is for certain. If your amplifier is differential balanced, you will give up the noise canceling benefits of balanced operation by feeding it a single ended signal.

Without knowing the components, it's hard to say what is applicable to your situation.

Thanks for the response. The amp is Levinson 33H and I don't know if I have the right terminology, but I believe it is as you said differentially balanced...... truly balanced. Apparently Levinson did something on the 33H internal to make the RCA connection balanced as well, according to the manual. It is a very short cable run, 1.5 to 2M, so I'm hoping that will help. The preamp is the New Joule Electra LA300ME "Marianne". It is obviously tube and has an adjustable gain which should help as well.

A concern was.......can I plug in to the balanced end at the amp and the RCA end at the pre......or should I get adaptors for both ends? Anyone know? I could call Levinson and see what they say.

can I plug in to the balanced end at the amp and the RCA end at the pre...
Bullot (Answers)

Yes, you can do that. You will need RCA>XLR adapters at the amp end if you're using RCA interconnects, or you will need XLR>RCA adapters at the preamp end if you are using XLR interconnects.

...or should I get adaptors for both ends?

No.

You have the choice of using RCA interconnects with an RCA>XLR adapter at the amp end, or the choice of using XLR interconnects with XLR>RCA adapters at the preamp end. There will be no difference, IMO, since you will not be running balanced considering the Joule is not a balanced source.

Or, you can use RCA interconnects, and run single ended from the Joule and single ended into the Levinson. My hunch is this will sound best. Adapters are inexpensive, so you can experiment with both options.

The decision of which amplifier input to use, and which preamp output impedance to select is going to have the largest impact on the sound you get, due to the potential impedance matches (or mismatches).

The impedance match selecting the Joule's 350 ohm output impedance should match very well with the 33H's single ended 50k ohm input impedance.

If you use the 33H's balanced inputs, you might want to select the Joule's 1200 ohm output impedance considering the 33H's 100k ohm balanced input impedance.

You have a lot of options, and only experimentation will tell you which configuration you will prefer.

Nice combo. Have fun.

Hey, thanks very much Tvad!! I appreciate you sharing your obviously considerable exerience and knowledge!!

Check out the adaptors at sweetwater.com. I compared head-to-head vs. Cardas, and none of us heard a difference in my rig(see systems: Goosebump Factory). $5 vs. $75, or something like that...Audiophile vs. poor musician markups. Cheers,
Spencer

If as you state the RCA input on the Levinson is also "balanced" I'd go with an RCA cable and avoid the adapters. If you do try the adapters and find you prefer the sound in this configuration versus straight RCA cable, you could always have a custom cable made where it is RCA on the output end and XLR on the input end.

I'd avoid the adapters, if I could, but you've already got great advice on the options. Just make sure, if you get adapters, that they are worth a damn. I have a nice system and used a set for back channels (due to a temporary cable "changing of the guard") I pulled apart one of the adapters. It was a generic one sold here on Agon and was appallingly poorly made, horrific wire and cold soldered. It looked good on the outside, though. I guess it would serve the purpose, but you have nice gear. I would always have that suspicion that things weren't quite up to snuff, so if you do go with adaptors, get good ones with a return/inspection policy behind them.

I think we all agree that if the adaptors can be avoided, then do so........that is the direction I am going to go. As Jeffb said, I would alway be suspicious that the system is in some way not up to snuff. I will move to RCA and use the adaptors only as needed untill the RCA swap is complete. Thanks to everyone for their feedback!!

I have tried the Cardas adaptors and the BAT to run from my unbalanced Wyetech Opal pre to balanced Krell FPB 300cx. Both are very good but the BAT's, though more expensive, are better. I think Music Direct sells them.

Neal

this is from the manual of the 33h

Note
Before making balanced connections, remove the U-shaped
shorting-strap between pins 1 and 3 on the Nº33H XLR input
and save it for possible future use. This shorting-strap is
installed when the Nº33H is shipped.
4. single-ended input
Receives unbalanced audio input from a preamplifier with single-
ended outputs. These signals are converted to balanced signals
upon entering the chassis and processed as balanced signals
thereafter. One RCA connector is available.
If the associated preamplifier does not support balanced
connections, connect the RCA output on the preamplifier to
the RCA input on the Nº33H. To reduce the chance of noise at
the (otherwise unterminated) inverting XLR input, insert the
supplied U-shaped shorting strap between pins 1 and 3. (This
shorting strap is installed when the Nº33H is shipped.)

"...Receives unbalanced audio input from a preamplifier with single-ended outputs. These signals are converted to balanced signals upon entering the chassis and processed as balanced signals thereafter."

Most probably, this amplifier uses phase splitter to process unbalanced audio inputs as balanced signal thereafter.

As far as I know, Joule-Electra LA-300/150 single-ended preamps use this technology processing all input single ended signals (RCA) in balanced mode i.e. canceling preamp induced distortions and reducing the noise and before output converting these signals back to single ended in order to exploit RCA outputs.

This is very clever approach allowing these preamps to do balanced processing "on the cheap". Indeed, this is could be one of the explanations of why LA-300 is so quit (more quit then most ss preamp I auditioned) with so much "black background" making music so much more realistic.

Thank you
Rafael

Thanks for all the responsed guys, my Joule Electra Marianne will be arriving next week and I will try the adaptor and see how it all comes together!!