Question on Luxman L-AX550ii balanced inputs

Thanks @hasmarto.

I was in a similar situation when I got my Luxman cl-38uc preamp. My CDPs balanced output level is 3.2V, and Luxman’s input is 2.5V. I contacted both Luxman’s and CDPs representatives about the issue, they both told me it’s a bad idea. Then I called my Lux dealer, and, after consulting with his tech, he told me there is nothing to worry about, since Luxman can take up to 7V or 9V (don’t remember now). Probably they had tech papers for the insiders.

@agbrace that absolutely helps! Thanks very much!

I had the same question with a 595SE integrated and I was able to talk to Luxman US and they said 4V. Hope this helps. 

I managed to check with a Luxman dealer, and their view was that the output on balanced outs should be 4V at most.

So...I think I'm going to continue to try to get info from Luxman (though it hasn't been all _that_ long since I asked) and go for something with a more reasonable output.

In any case -- I thought maybe I could just use the single-ended inputs, but as far as I can tell, their max input voltage is 2.5V, and the Spring 3 has a single ended output of 2.9V.

I may just go to plan B and check out the Schiit Yggdrasil.

@nwres Good idea. I was thinking of Hudson Valley HiFi -- assuming they'll answer a support question from someone who is not a customer.

Maybe call a dealer who might know more?

The Cl-38uC is a different circuit than the 550AXII

The CL states: BAL.LINE: 190mV/20kΩ *2 

Thanks @dasherma

As I said I think it is to pair with the Luxman CD players. If you look their out put voltage is 2.5 V

Hey @jperry -- I did already see that, and I read the footnote. I wasn't saying I didn't believe you. I was trying to say that it seems that having such a low max voltage on the balanced input seems (to me) as if it's making the amp operate under a handicap.

I'm really new to the whole balanced input/output thing and there seems to be more to it than "hey, just plug it in."

Go to this page, and at the bottom there is a button to download "catalog".

Then go to the specifications for the Luxman CL-38uC and read footnote 2.

I was unable to post a direct link to the "catalog' in pdf

https://www.luxman.com/product/detail.php?id=27

Have a great day.

Jim Perry

@nwres the source component (that I'm only considering at this point) is a Holo Audio Spring 3.

@jperry 2.5V max? I was under the impression that the output on most modern balanced outputs was 4.0V. Is it a different case for tube amps than it is for solid state amps?

I have a CL-38u preamp with balanced inputs and the instructions indicate the maximum input voltage is 2.5 V.

I was told that this input was designed for use with a Luxman CD player.

I think you can use other input devices, but the output needs to be 2.5 v max, otherwise the input will be overdriven resulting in distorted sound

I owned and loved the 550AXII before upgrading within the lineup. It is very robust.

What is your source component?

Thanks @nwres.  The source does not have a variable output unfortunately.

I don't understand the math behind figuring the input voltage -- I have heard (but only on the internet) that a balanced input can generally take up to 10 volts input, but I'm not sure how much to trust that figure.

You state that your source has a max output of 5.8v. Does that mean your source has a variable output? If so, try it turned down low.

The manual states:

Pre-amplifier Input sensitivity/input impedance

LINE : 180 mV / 47 kΩ

MONITOR : 180 mV / 47 kΩ

BAL. LINE : 180 mV / 55 kΩ

Someone more knowledgeable may be able to assist with the math.

Good luck!