RCA splitter

You won’t go wrong with that Audioquest splitter. I have used that for a subwoofer line level hookup!

Splitters usually work fine for most analog connections.

INMHO the integrity of the connection is more important than the "quality.". That said AQ makes various topologies. They along with Morrow's are better than cheap Chinese plastic adapters..

I know this example is not the same, but I think it has some applicability here.  I was using a pair of Cardas RCA to XLR adaptors on a pair of unbalanced interconnects where the source had xlr outputs and the amp only had rca inputs.  Eventually, I had a pair of Xhadow xlr plugs installed on the interconnects at the source end.  The difference in sound was obvious.  The adaptors were masking detail, blurring image outlines.....probably other compromises as well.  It's been a few years so I don't recall the exact differences.

If money isn't much an issue, perhaps the better sonic solution would be to use a pair of Y-interconnects.   

My use is temporary, for comparisons primarily.

For Stereo you need two splitters.

Pair of Jacks on a Device may be too close together for splitter gizmo, while splitter cables preserves tight spacing on the unit (i.e. my Vintage McIntosh Preamp)

Length of splitter cable can move 'joint' up for easy access

This stereo kit is available to buy by the foot

https://www.amazon.com/ROCKRIX-Female-Speaker-Adapter-Splitter/dp/B08PKS42P6/ref=asc_df_B08PKS42P6/?tag=hyprod-20&linkCode=df0&hvadid=475825775681&hvpos=&hvnetw=g&hvrand=18138763782454415975&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9003526&hvtargid=pla-1163174276384&th=1

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i.e. I temporarily hook up friend's equipment (or my other stuff) to my system by adding the splitter 'down/back there', then a pair of jacks at accessible height.

Permanent/semi-permanent split, then access less important.

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You might need 'two in' and/or 'two out' depending on what you are doing

Splitters and Y-connectors are fine. I'd defy anyone to tell when one is in use.

Thing I've noticed when trying splitters is it seems to not only split the signal but also split the strength of the output, something I've noticed on many pre-amps which have two outputs. FWIW

Thanks for your responses. I'm going to give these a try https://silversonic.com/products/connectors/y-block-connector/ as they output in two different directions which will facilitate non parallel cable routing which I believe is desirable. 

Balanced splitter, gives you locking connectors, and you choose your lengths for positioning.

https://emotiva.com/products/xbal-1x2?utm_source=google&utm_medium=cpc&utm_campaign=20042245837&utm_content=656394514266&utm_keyword=&gclid=Cj0KCQjwldKmBhCCARIsAP-0rfzAVygLkxXOubiyMyRdSxJH_tWDWfjeHkAq3ELkWv88fJgsd0va648aArnpEALw_wcB

Your chosen splitter, consider supporting the weight of the two cables to minimize downward force on the male end into the units female jack.

you can make your own to use locking connector to hold the weight and avoid possible poor connection

https://www.amazon.com/Parts-Express-Locking-Connector-Solder/dp/B0002KR26I

@santani 

Exactly what are you trying to do? Normally, when you are "biamping" you connect the outputs of your preamp to an active crossover which splits the signal in two at the selected frequency leading to two 2 channel outputs, hi and low frequency.

mijostyn - simple answer is to see if it makes a difference to my enjoyment of music. My speakers have powered woofer cabinets allowing for separating the bass loading from mid/tweeter loading on the 2 watt SET amp powering them. For anyone wanting a comprehensive write up on bi-amping see https://stereo-magazine.com/review/everything-you-need-to-know-about-bi-amping-review

I’ve recently used Audioquest splitters on a Benz Lukasheck PP-1 phono stage to add loading resistor plugs (otherwise its loading is fixed at 22K). This is not in my "best" system, but still very good. In fact I currently have a $4K WEL Signature LP cable hooked into these spitters (lol). I notice NO loss of sound quality from the splitters.

However, physical contact connections in the audio chain can be very tricky. If you have a single bad contact, it can very easily cause problems like (say) L/R channel imbalances. I’ve had headshells that have driven me literally CRAZY with this (answer: remove any rubber damping ring on the bayonet mount so the lead pins make better contact, then always tighten FULLY). Your need to periodically check and cleaning all contact connections. If and when you notice a channel imbalance, you need to go looking.

The Audioquest RCA splitters make a "death" grip on jack and plugs. The fit is VERY tight. Abnormally tight. Normally this ensures a good contact connection BUT if your equipment has those cheap PCB-mounted RCA jacks, it’s possible this tight action could crack and compromise things! Even chassis-mounted RCA jacks can become loose over time.

mulveling

"However, physical contact connections in the audio chain can be very tricky. If you have a single bad contact, it can very easily cause problems like (say) L/R channel imbalances."

so true. the basis of my comments to OP

1. I changed all my RCA cables to Locking RCA jacks

2. If Balanced option available, even for short residential use (normally balanced not needed unless long runs), I use the balanced because they are locking connectors

3. my vintage McIntosh mx100z had slightly small diameter, and corroded rca jacks, Audio Classics replaced all the RCA Jacks with new gold plated ones, hooray!