15 foot RCA cables out of TT with no pre amp?


Im very limited with the space I have. This is kinda limiting me to keep the turntable on a 15’ cable. I’m using a Pro-ject Carbon Debut Evo with an Ortofon  2m blue to an Onkyo stereo with a phono input. Cables are midrange, nothing special but not total crap. Just wanted to get some opinions or suggestions on this. How bad the loss is gonna be if there is any. 
jacquesbarteaux
So, if I’m hearing this correctly. I should use the 1.23m cable provided to a phono stage. Then after the phono stage, the long cable will suffice? 
"...So, if I’m hearing this correctly. I should use the 1.23m cable provided to a phono stage. Then after the phono stage, the long cable will suffice?..."

The phono output is at a low level, you want to keep that run short.   
The main issue is not only loss but noise you want to keep the connection to the turntable as short as you can due to these reasons try to arrange a way for that to occur so you do not develop noise or hum.
Any "loss' would be overcome a noise sddition. All you can do is try and see if you can live with it.
Yes, keep the TT output cable as short as possible. It’s carrying a very low level signal, and thus is more prone to noise and other issues.

On the other hand, the phono preamp out is "line level" and fine with a longer cable. I, too, prefer balanced connections if the gear on both ends supports them. If you can use them, you can have cables made up from Mogami W2549 cable and Neutrik connectors by a Pro Audio shop (if you are in the USA, ProAudioLA does great work) for about US$100 a pair or less, depending on length, of course. I found them far superior to $2000 "audiophile" cables.