Chained preamps with variable and fixed output

[valicu2000]

Hello all!

I have an Emotiva PT-100 connected to XPA-DR2 with unbalanced cables (RCA). Today I've tested the Cambridge Dacmagic Plus DAC connected with balanced cables (XLR) and the sound was fenomenal.

Since the PT-100 has variable audio output and the Dacmagic Plus is able to work with fixed audio output is it ok to have this configuration:

PT-100 preamp -> Bluesound Node 2 -> Dacmagic Plus -> XPA-DR2 power amp ?

PT-100  .... controls the volume (variable output)

Bluesound Node 2 ... converts analog to digital (fixed output)

Dacmagic Plus ... converts digital to analog and sends it through XLR (fixed output)

The simplest option to get XLR output and all the input types is to get a Rotel RC-1572, but I'm low on budget for about two months.

Any ideas, please?

Thanks!

[garbulky]

valicu2000
Welcome!

I don't understand. From the way I'm reading your issue it's not going to work. The devices you mentioned don't appear to have the appropriate inputs and outputs.

So are you saying the Pt-100 is connected to the bluesound node. And the bluesound node is connected to the dac magic plus?
Can you elaborate as to why you want the Bluesound node and the PT-100 at all? What are you trying to do? Why not just use the dac magic?

[valicu2000]

Hello, garbulky!

At the moment I have my PC, Bluesound Node 2 (coaxial input), Pioneer CD player (optical input) and a QUAD cassette deck (analog input) connected at PT-100. Of course I have the subwoofer connected too.

Today I've tested the dac magic plus. It sounded great on XLR connection but has no subwoofer output (also has no analog inputs) and this is unacceptable for my ears.

I was hoping to keep the PT-100 connections and send the analog out to dac magic plus ... since it has no analog inputs, I thought to use the Bluesound node as an analog to digital encoder. I know it's a mess what I'm trying to do ... but the question was if the device with variable output must be right the last one before the power amplifier, or it can be hidden after a fixed volume output device.

[klinemj]

Like gar, I am really unclear on why you want to do what you propose. Why do you want to convert analog to digital? Then back to analog?

Mark

[garbulky]

The PT-100 does digital to analog. Then when you convert the analog back to digital in the bluesound, now you end up with a digital signal that's worse than the original digital signal before the PT-100 converted it. Then when you convert the now degraded digital signal back into analog at the DAC magic, you are converting an imperfect digital signal that has been affected by distortions introduced by the PT-100 and the Blue sound.You would do better using the PT-100 instead despite it being single ended.

WHat I'm saying is that the sound won't be better by using the DAC magic dac.
Think of there being a photograph. An artist paints his impression of the photogrpah. Then somebody takes a photograph of the painting and prints out the photograph of the painting using a printer. Then another artist paints his impression of the painting of the photograph. At the end, the final painting won't look exactly like the photograph.

[valicu2000]

Him klinemj!

I want to connect to the XPA-DR2 via XLR cables and have the subwoofer out option + PC connection. I guess Rotel RC-1792 is the way to go ...

garbulky: Yes I know there will be a sound degradation. I thought also of a DI box but it's basically pointless because I have to use a RCA cable from PT-100 to the DI box which will capture EMI radiation

[klinemj]

Have you tried it with DAC Magic plus analog outputs into the PT-100's analog inputs and then RCA outs to your amp? How did that sound compare to the DAC Magic Plus XLR out to your amp? I would not really expect much difference IF you level match the sound.

Mark

[valicu2000]

Hi, Mark!

Just tried what you told me.
The DAC Magic plus sounds wider and sharper, after switching back to PT-100 the sound become melodic but somehow dull - no instrument catch my attention.
With DAC Magic plus on XLR different instruments were on different planes (closer of further from the couch) pretty well contoured and also the scene was even wider ... it's hard to describe exactly. Perhaps the XPA-DR2 is also optimized for balanced connections, not to mention that DAC Magic plus is true balanced and has 2 Wolfson DACs inside.

Valentin

[klinemj]

Nov 9, 2018 8:43:54 GMT -5 valicu2000 said:

Hi, Mark!

Just tried what you told me.
The DAC Magic plus sounds wider and sharper, after switching back to PT-100 the sound become melodic but somehow dull - no instrument catch my attention.
With DAC Magic plus on XLR different instruments were on different planes (closer of further from the couch) pretty well contoured and also the scene was even wider ... it's hard to describe exactly. Perhaps the XPA-DR2 is also optimized for balanced connections, not to mention that DAC Magic plus is true balanced and has 2 Wolfson DACs inside.

Valentin

Did you match levels between the comparisons? I found similar things in the past went away once I level matched.

Mark

[AudioHTIT]

I think what the others are saying, and what you’re hearing, is that the difference in sound between the two DACs and preamps is greater than the difference in sound between an RCA and XLR connection. Keeping the signal path as simple and clean as possible should be your goal. If you need analog inputs and you want balanced connections you should probably replace the PT-100 with a preamp that has both balanced inputs and outputs, then you can continue to use the balanced outputs from the DAC magic, and have a balanced connection to your amps. Maybe an XSP-1?

Edit: Missed Marks latest post.

[valicu2000]

mark: the volumes were nearly the same, DAC Magic doesn't have digital display.

AudioHTIT : XSP-1 is in plan, but it will arrive in February 2019. I'll be able to go balanced from the DAC to the XSP-1 and balanced to the XPA-DR2

[klinemj]

Nov 9, 2018 10:07:33 GMT -5 valicu2000 said:

mark: the volumes were nearly the same, DAC Magic doesn't have digital display.

AudioHTIT : XSP-1 is in plan, but it will arrive in February 2019. I'll be able to go balanced from the DAC to the XSP-1 and balanced to the XPA-DR2

The readouts on the gear won't really tell you what you need to know...checking w/dB meter is really the only way to know.

I'll give you one example...I was trying to compare sound from my Oppo 105's DAC's to my DC-1, and I initially felt the Oppo 105 was decent vs. the DC-1. Then, I checked levels with my dB meter and the Oppo was playing significantly louder. When I matched levels, the differences between the Oppo and the DC-1 because much clearer. With XLR outs, you will be getting more dB than w/RCA's in a single variable comparison. This can make you perceive the sound very differently. What I am getting at here is that there may be a way to get the sound you want with RCA's and a more traditional setup (Vs. the chained preamp approach) while you wait on the XSP-1.

Mark

[valicu2000]

mark: both DACs tested on RCA and the Cambridge Audio sounds better. On XLR will sound even better because I have a lot EMI in here.

Valentin

[klinemj]

Nov 10, 2018 9:24:34 GMT -5 valicu2000 said:

mark: both DACs tested on RCA and the Cambridge Audio sounds better. On XLR will sound even better because I have a lot EMI in here.

Valentin

Could be - but don't rule out the level matching I mention in doing comparisons.

Mark

[valicu2000]

mark : The Cambridge Audio DAC was set in fixed level output and connected via RCA into the PT-100, no level matching here. It was the pure raw signal compared on changing the source on PT-100.

I'll keep the DAC Magic plus and XSP-1 when it will arrive ... Thanks!


Valentin