Pre-Out level for RS250A?

Function
#1

Hi,
Can I get a help selecting the best Pre-Out level on my RS250A, connected to McIntosh MHA200 tube amp. These are some specs for the amp:
Power Output
32 Ohm Load 500mW
100 Ohm Load 500mW
250 Ohm Load 500mW
600 Ohm Load 500mW
Output Load Impedance
32 , 100 , 250 , 600
Rated Power Band
20Hz to 20kHz
Total Harmonic Distortion
0.5%
Frequency Response
+0, -0.5dB from 20Hz to 20,000Hz
Input Sensitivity (for rated output)
1.0 Vrms Unbalanced
2.0 Vrms Balanced

Thanks in advance.

#2

Which device will you use to control the volume, the Rose or the Mac? If the Mac, I would start with 1V, but you should check with McIntosh. Their customer service is very responsive.

#3

I will control the volume on the mac.

#4

Which headphones are you using?

#5

What I would so:

  • set on the McIntosh the load to right one for your headphone
  • set the volume on the McIntosh to 11-12 clock
  • adjust on the RS250A the preOut gain so, that you have now the “normal” hearing level with your can.

But: I don’t like the DAC implementation and the preAmp from the RS250A and also it’s unbalanced. So I would add here a balanced USB DAC with high output level (the McIntosh can handle balanced upto 16 V).

#6

@OMXP

If you’re using the RS250a with a McIntosh MHA200 tube preamp via XLR and want to use it as a fixed output, we recommend setting the preout level to 1000mV or 1500mV. This provides a strong, clean signal without overloading the preamp input.

If you experience any distortion, you may lower the level slightly. Let us know if you need further

#7

There is no XLR output from RS250A as a pre-out! only RCA. I tied setting the level at 2000mV, and it sound good.

#8

Can you recommend a good DAC?
I use RS250a as a streamer, I don’t have another dac.

#9

What is wrong with the DAC of the RS250A? You are using it for your headphones I thought.

#10

It depends what is means good for you?
Take a best measured one, which you find on ASR (like Topping, SMSL, Gustardt,…).
I prefer NOS Dacs; the Holo Audio May is my primarily used DAC, but i’ve also the much cheaper Holo Audio Cyan 2 together with Hifi Rose devices in use → here DSD512 native is supported.
Also I like T+A DACs or something from Cayin.

1 Like
#11

Nothing, but MHA200 can handle up to 16V, like someone mentioned here.

I guess I will get better tube sound If I feed it more power.

#12

Use RCA and set the RS250A so it never exceeds ~1.0 Vrms equivalent.

RS250A set to Variable Output

Prefer RCA over XLR

Start volume at 30%

Increase until: Loud listening is ~45–50%

You never need 70–100%

If you’re already above 60% for normal listening → gain is too low

If you’re below 20% → input is too hot

#13

What the MHA200 wants (this is the key)

From your specs:

Input sensitivity (for rated output):**
1.0 Vrms (Unbalanced / RCA)**
2.0 Vrms (Balanced / XLR)**

That means:

  • At 1.0 V RMS (RCA) the MHA200 is already at full rated power
  • At 2.0 V RMS (XLR) it is also at full rated power

Anything above those voltages does not give you more usable power — it only pushes the tube input stage harder and raises distortion.

#14

Best DAC: aqua La Scala MkII

VOLUME COTROL - Best practice
Use the MHA200’s volume knob as the primary volume control.
Set the RS250A close to fixed line level, not as a preamp.