Looking at options for a Non Pre Amp setup

aldcoll · « **on:** 3 Feb 2015, 06:16 am »

What I am looking into thus this post seeking some help with is I would like to run my DAC into my Amp.
I am wanting to be able to spend the money saved on a pre amp thus bolstering the rest of my setup.

What I currently have is a aged NAD 7600 Receiver. Parasound Zdac fed via a Squeezebox and then there are the pair of Daedalus Pan speakers. For me and my limited budget the Squeezebox is just fine. I don't see myself getting to wound up on the high Rez as that is a whole budget jump and I am more then willing to wait that out and see where the chips fall.

I have run the Parasound Zdac into NAD amp section and I have found the sound is better.
The problem is the DAC is 120 Ohm and the Amp like's 10 ohms.
So I could do this via some work on the DAC.
Or I could add some stepped attenuator.
Or I can use the Squeezebox Volume

I believe there are some Attenuators that can be added to the IC's?

I have the though that why add something into the signal path that will place it's own color or sound to what was recorded?
I would like to buy a nice amp (Modwright 150se) and then as easily and economically feed it with tunes.
Yes My DAC could be upgraded

And should I look at any particular model that has volume control?
So what are the options I should look at

srb · « **Reply #1 on:** 3 Feb 2015, 08:36 am »

Quote from: aldcoll on 3 Feb 2015, 06:16 am

I have run the Parasound Zdac into NAD amp section and I have found the sound is better.
The problem is the DAC is 120 Ohm and the Amp like's 10 ohms.

No sure what you're referring to. The output impedance of the Zdac (v.2) is 160 ohms unbalanced and the input impedance of the NAD 7600 power amp input is 30K ohm.

Is the problem a limited usable volume control range based on the Zdac having a 2.4V maximum output and the 7600 power amp input having a 1V input sensitivity?

Steve

JohanH · « **Reply #2 on:** 3 Feb 2015, 10:29 am »

Not familiar with the Parasound but from pics it seems you could use the headphone out into the NAD.
That would give you volume control on the DAC.

Cheers,
Johan

Letitroll98 · « **Reply #3 on:** 3 Feb 2015, 01:13 pm »

For $250 plus shipping you could get the Audio gd NFB 15 DAC with volume control. Has a nice Alps pot with I/V control topology and dual Wolfson chips.

mcgsxr · « **Reply #4 on:** 3 Feb 2015, 02:23 pm »

Does having a remote matter? That may drive the decision some.

I have in the past run Squeezebox directly into power amps and been happy. That would have a remote.

JLM · « **Reply #5 on:** 3 Feb 2015, 03:45 pm »

Stepped attenuators (between interconnects and power amp) is the simplest/lowest cost option if the ZDAC is leaving you with little useful volume control range.

I don't believe that the volume control would have any effect on the SB's digital output, so no go. Even if it did as I recall the SB volume control works in the digital realm meaning that it truncates volume (flattens the peaks), if so avoid that option.

Several nice DAC's available with built-in volume control, but IMO the iFi nano ($300) fits this circle's cost criteria nicely, is well reviewed, and would add Hi-Res, headphone output, and portability options in a very small package.

aldcoll · « **Reply #6 on:** 4 Feb 2015, 12:46 am »

So yes a remote is rather important as mcgsxr mentioned.

SRB thanks for the Ohms update on the NAD since my manual is pretty much toast after 25+ years.

So I have spent some time today looking at the input specifications on several amp's I would consider as this is a upgrade project and the budget doesn't allow any try and swap.

Letitroll98 that DAC looks pretty good on the web site and will warrant further investigation. Would you happen to be a happy owner

Parasound has a newer model of the Zdac with Volume output but the spec. doesn't give any detail of the volume out and the price increase didn't reflect a major upgrade over my version 1

So I guess I will look at a few more DAC's with Volume control and a Stepped Attenuator but I am almost back to the same price as a Pre Amp???

Thanks for the input. The hunt is still on

mcgsxr · « **Reply #7 on:** 4 Feb 2015, 01:28 am »

JLM is correct that the Squeezebox operates volume in the digital domain (by the way it can change the volume of the digital output if that matters in the future) so if you run it too low (under 60 out of 100) you run the risk of losing fidelity as it trims bits to lower the volume.

Experimentation should allow you to determine at what volume levels you like to run your Squeezebox if you run it directly into a power amp.

If you find you need to lower the volume down below 60 often, you could explore using rca based inline attenuators between your Squeezebox and your power amp. That would allow you the opportunity to use your Squeezebox directly into your power amp, and not need a pre. I recall that there are a couple of manufacturers that build those rca attenuators, but have never used them myself.

They are available in a variety of db of attenuation.

Lots of other options though, I am just helping to point out what you could consider with what you already own - this IS the cheap and cheerful circle after all!

mresseguie · « **Reply #8 on:** 4 Feb 2015, 02:08 am »

Alan,

I have a Denon 2-channel receiver sitting in its box benefiting no one. I'll check to make sure, but I recall the model is DRA-685. Something like 90W/channel. It's approximately 11 years old. This receiver was recapped in Eugene about 2 years ago.

Would you like to try it to see if a) you like it, or b) it fills the gap until you buy a better amp?

Michael

aldcoll · « **Reply #9 on:** 4 Feb 2015, 02:30 am »

Thanks for the offer Michael but I will pass at this time. The NAD still works at 245 watts it was a giant slayer at it's time.
What I am looking to do is allocate the budget on this upgrade. As I have moved to digital for a music source why do I need to spend money on a Pre Amp

My approach is to allow the music/digital signal to pass through as few items as possible and thus coloring or adding a tonal value. Also reduce the amount of items in the chain, dollars saved here will be allocated there.

To me today's preamp is just a switch between items and a receiver of a remote control signal.

I tend to think that this might be the way of the future for more and more folks.

From what little looking I have done a good attenuator is darn near the price of a Pre Amp

And From what I have read ( and much more to go) the volume control on some of the DAC's are short of information as to how they work. Or at least just my quick read of the web site.

Am I missing the boat on this?

JohanH · « **Reply #10 on:** 4 Feb 2015, 04:00 am »

So that's a no on using the headphone out into the amp?

aldcoll · « **Reply #11 on:** 4 Feb 2015, 04:06 am »

That is correct. I wouldn't want the head phone cops to catch me

JohanH · « **Reply #12 on:** 4 Feb 2015, 06:12 am »

Could you explain why?
I'm trying to put focus in my help for others and the suggestion I made seemed to tick most of your boxes, so I'm puzzled as to why you dismissed it.

aldcoll · « **Reply #13 on:** 4 Feb 2015, 07:21 am »

I think there is some issues with a head phone jack. They are powered, much the same as you can't use a phono input for a CD as it is powered also. And no remote, and that brings up a thought. Do they put remotes on head phone based products?

And the biggest reason, I have spent hours on bended knee asking my budget minder that I need something new.

There was nothing personal intended at all.

I might add that I might just do a pre amp since I want to add stereo subs so I can incorporate them as stands for my Daedalus Pan's.

mresseguie · « **Reply #14 on:** 4 Feb 2015, 07:21 am »

Alan,

Yup. That NAD runs circles around my old Denon.

Johan,

That's an interesting idea. I never thought of that. Are there any reasons why that wouldn't work? Feedback issues? Distortion?

JohanH · « **Reply #15 on:** 4 Feb 2015, 07:26 am »

No, should work fine.
Might even be better than normal out if the headphone output impedance is lower than the 'normal' out.
Audiolab MDAC for example uses same circuitry for rear out and headphone out.
Don't know about Parasound though.

Cheers,
Johan

JLM · « **Reply #16 on:** 4 Feb 2015, 11:53 am »

The stepped attenuators I had years ago (during my purist stage) added only one resistor per click on the controls, but its important to connect directly on the back of the amp due to impedance issues (the same reason why a pre-amp can be of sonic value).

A forward thinking option is to trade the SB, ZDAC, and connecting cable in for a Blue Sound Node. Should be a step up on sound quality, runs off smartphone/tablet apps, plays Hi-Res, has great connectivity, and is designed to used directly to power amps. It even comes from the same parent company as your NAD and is the modern heir apparent of the SB. Down the road you could add a high-end DAC.

aldcoll · « **Reply #17 on:** 4 Feb 2015, 06:48 pm »

I like the forward thinking lifestyle

I like the SQ just fine and it's life cycle will come to a end but not yet. I believe the NAD is a choke point at this time and some of that playing around a month ago showed it. Right Michael

The whole High Rez DSD PCM and any three letter format I didn't list will be the next Beta Max and I will invest on something in a year or so.
I just took a SB3 out of the system

So now back to the week links versus budget and the NAD is in the Cross Hairs

I have read some on the Blue Sound Node and I will dig deeper.
The Parasound has a small Toridal and will drive 32-600 ohm sets so if I melt down the NAd the wife has agreed no service just move on

rajacat · « **Reply #18 on:** 4 Feb 2015, 06:58 pm »

Buy the Tortuga LDR passive preamp kit. Either buy the complete kit or the LDR3x.V2.1 Passive Preamp Controller and assemble your own unit.
Albeit, this is still a preamp but it will have very minimal effect on the signal. The plus is that you have full component switching functions.
Not that cheap but not very expensive (in audiophile terms

) either especially if you just buy the controller board.
http://www.audiocircle.com/index.php?topic=130001.0
http://www.tortugaaudio.com/product/ldr3x-v2-1/

glynnw · « **Reply #19 on:** 4 Feb 2015, 07:06 pm »

+1 for what Rajacat says. I love my Tortuga and I have tried many passives.