Preamp w/ Single Line Input. But I have DAC and CDP


My preamp is a vintage MFA LUMI preamp which has a single line input. I've been using that connection for my CDP. However, I just got a Cambridge Audio DAC and it works great using the preamp line stage but I first have to remove the CDP interconnect cables.

What is the most elegant (simple) way for me to have two line inputs so I don't have to keep unplugging IC's?

If it's not apparent by the nature of my question, I am a complete newbie to digital audio.

Thanks in advance.

Paul
ps
You can use the CD player as a transport and connect it to one of the inputs on your DAC. And if you do it that way, you really don't need your preamp. Plug the DAC directly into the your amp.
Ahh, but Zd542 you would be eliminating a simply stunning pre-amp. I agree that the CD to DAC may work if the cambridge is nicer than his cd player. We need to know what cd player Ps has...
Yes, provided the CD player has digital output run it through the DAC. I f you like the sound as well as the stand alone player, problem solved. If the stand alone player sounds better then you might search out another DAC.

As you seem happy with your system as is, i would not be inclined to advise replacing your pre when wishing to just add additional digital sources. What source (s) are you going to use with the DAC?
Thank you all for your responses.

My CDP is a Shanling CD-T1000 SE which has a coaxial output. The Cambridge Audio DAC has S/P DIF Coaxial input and outputs. So far the only source I've fed into the DAC is Internet radio using a Macbook and Amarra. The sound is quite acceptable, IMO.

If I connect the CDP to the DAC using the coaxial output on the CDP, and then connect the DAC to the preamp line stage using conventional ICs will both the CDP and computer play through the line stage? If this would work all I'd need is a proper coax cable. I just got the DAC and it came with no cables otherwise I would have tried this already

I've had the LUMI preamp for many years and it was significantly upgraded by Scott Frankland a few years ago. Scott took it as far as he could. It's a lovely piece and I have no desire to replace it! :)

Thanks again.
Paul
Well, since I don't have a coaxial audio cable (yet) after researching further, I tried a conventional IC from the CDP coaxial output to the DAC coaxial input, and bingo, my problem is solved. SUCCESS!

I left the DAC connected to the preamp line inputs using analog ICs and can change the source from CDP to laptop by simply pressing a button on the DAC.

I had no idea it was this simple. This old dog is learning a few new tricks. Whoo-Hooo! All I need now is a proper coaxial audio cable. I can also start experimenting with the various filters on the DAC and different IC's from the DAC to the preamp.

Happy New Year.
Thank you, Mesch.
Today I did encounter a problem. When I plugged a coaxial IC into the CDP and then into either of the two digital inputs on the DAC, the DAC did not "see" nor play the CD. The USB connection is still fine and I can listen to Internet music through my laptop.

What seems odd to me is that everything was working OK before using a regular IC from the CDP except the signal would drop periodically. I just purchased a coaxial and figured that would solve the problem, but now, no matter what cable I use from the CDP to the DAC there is no signal.
There are many others that can provide you with better insights to your problem than I, however I will give it a go.

The problem could be either at the coax output of the CDP or Coax input of the DAC. It can always be a bad cable however since you had an intermittent problem with the IC this might not be the case. Since the problem seems to be at both inputs of the DAC lets start with the CDP. Can you borrow another player, even an inexpensive DVD player, to run into your DAC as a way to remove your CDP as the problem?

You should also try another cable to best remove that as a possibility.

Which Cambridge DAC do you have? Was it purchased new or used?

Take it one step at a time.
Thanks again, Mesch.
I've located the problem. I unplugged everything from the CDP, the computer, and the Cambridge Audio DacMagic. Then I reconnected the coax cable from the CDP to the DAC. I noticed that the digital inputs on the DacMagic do not grip the RCA jacks on the coaxial cable very well. It "wiggles" and the signal cuts in and out.

If I tape the cable in place, the CDP will play through the DAC fine. After I got the CDP going, I reconnected the USB cable from the computer and that worked as well, and I could then switch sources on the DacMagic.

However, as I considered this configuration, I realized that the DAC in the Shanling CDP was likely as good, if not better, that the Cambridge Audio so my "solution" is to swap ICs to the line inputs on my preamp, depending on whether I'm listening to the computer or the CDP. It's inconvenient but hardly impossible to live with. Furthermore, this enables me to use the tube outputs on the CDP which sound better to me than either the SS and the coaxial.

I'm wondering if anyone makes a simple outboard switching box which would connect to the line stage on my preamp, so I could plug both the DacMagic and the CDP into the box, and then change sources at the box?
I'm wondering if anyone makes a simple outboard switching box which would connect to the line stage on my preamp, so I could plug both the DacMagic and the CDP into the box, and then change sources at the box?
Yes there are.

A number of years ago I used the DB Systems DBP-2JAU/5, at $110, with fine results. Their home page and contact information is here. Click on the "photo" and "review" links just above the listing of that model for further information.

Or at a higher price point ($329) there is the Decware Zen Switchbox.

As you'll see, the DB Systems switchbox can also be had for $88 if you forego the gold plated jacks, but personally I wouldn't compromise on that. I suspect also that other makes and models can be found at still lower price points, but I have no specific knowledge of them or of their quality.

Enjoy! Regards,
-- Al
Al:Thank you, sir.
The DB Systems DBP-2JAU/5 is exactly the type of device I was wondering about.
Since I'm so new to digital audio, I'm finding that fine-tuning my setup and clarifying related details somewhat confusing.

I appreciate your help! These forums can be invaluable.

Ps
I was watching your other thread concerning this. The idea of a switchbox also occurred to me however have never used one. One thought I had was to contact Schiit audio, they make a 2 input passive pre for $50. It could be used as a switchbox by leaving the volume control fully open. Possibly Schiit could make one sans volume or the volume could be circumvented. I am getting caught up just thinking out loud here, as Al’s recommendation of the DB system switchbox would certainly solve the problem.

I, as others have stated, have to believe the DAC in your CDP is better than the Cambridge. Either way I would want to take advantage of the tube output stage it has.
An input selector that I believe is well built and won't break the bank is the Niles AXP-1.

http://www.amazon.com/Niles-Black-FG00002-Auxiliary-Selector/dp/B00006I5J0
Thank you all for the great info and suggestions.

I just determined that the digital output board in the DAC is indeed malfunctioning intermittently. No point in having it repaired. It'd be less expensive to get a basic switching box and use the DAC strictly for iTunes.

Mesch, the Schitt passive pre would be very economical. An excellent suggestion, sir.

Jedi: I just checked out that Niles. Also an excellent option, within my modest budget.

Man, I've learned a lot here about digital (iTunes/computer audio) over the past few days.
Just ordered a SYS from Schiit. It's a passive device which will enable me to switch back and forth between CDP and iTunes. I'll be good to go, in a few days. :)
I have added the Schiit SYS to my audio system today and am happy to report it works flawlessly. Elegant in its simplicity and functionality. Modest in cost. Very fast shipping.

Now switching from USB audio to my CDP is easy and immediate. No more swapping IC cables. :)