1 (edited by Dan Elleson 2021-04-13 07:31:59)

Topic: Madiface Pro Hi-Z input actual impedance ?

Hi

I'm questioning if the Madiface Pro can be used as a phono preamp (with digital RIAA de-emphasis).

The manual states that the Hi-Z unbalanced line inputs are 470kOhm (manual page 74 and website), and 1MOhm (manual page 22).

Can I get clarification as to which it is???

If it's 470kOhm, this is an appropriate load for an MM phono pickup, but if it's 1MOhm, I will need an added load.

Of course I can test this, and will, but if someone who knows can let me know, less energy will be wasted and our species may live longer.

Many thanks

2

Re: Madiface Pro Hi-Z input actual impedance ?

I have no clue why you think these are 'phono' inputs or can be used as such. Not only that these are line inputs that don't work with a MM cartridge due to missing amplification - MM requires 47 kOhm, not 470 kOhm. Plus a specific input capacitance.

The 470 kOhm is a typo, it is 1 MOhm.

Regards
Matthias Carstens
RME

Re: Madiface Pro Hi-Z input actual impedance ?

Oh, right you are it should be 47kOhm and indeed the gain is too low, altho it's the SNR that counts. 

Nevertheless the point was that the specifications state 2 different input impedances and I wanted to know which it is.

Thanks for clarifying

Re: Madiface Pro Hi-Z input actual impedance ?

There is a trend in the Vinyl community to equalize by software and to get the phono-signal captured linear.

If it works the same way with madiface as it worked with the UFX I do not know.

I did this with an RME UFX. Line Jack-Input (the ones which are in front and combined with Mic XLR).
You probably want to RIAA equalize by software.

Now I connected a pickup Benz Micro Wood High Output MC, which is also 47kOhm to terminate. Now you can make an adapter which contains 47kOhm and a capacitance.
It worked, however SNR wise it was not bad but a Yamaha CX-1 RIAA amp was better. No surprise the Instrument input is not made for that.
May be the Mic input would be very good for MC pickup which need a termination of 20-500Ohm. The Mic input has I guess about 2-5kOhm impedance, now you parallel that with the correct resistor.

If the gain of the input is enough depends on the output level of the cartridge.

Anyway this is a do-it-yourself thing. So just try.

5

Re: Madiface Pro Hi-Z input actual impedance ?

That seems not correct. When an input has an impedance below 47 kOhm the only way to increase it to the desired value is a serial (!) resistor, not a parallel one. The serial resistor will cause more noise and heavy treble loss, so that solution does not work. You can only use the parallel resistor with high impedance inputs (> 47 kOhm), to reduce the impedance to 47 kOhm. And the cap is usually not needed as it is already part of the input circuit.

Also MC (Moving Coil, not me) needs much lower termination than MM, typically 100 Ohm.

Regards
Matthias Carstens
RME

6 (edited by pschelbert 2021-04-19 22:31:48)

Re: Madiface Pro Hi-Z input actual impedance ?

I connected the Benz Micro High-Ouput MC (termination recommended 1kOhm-47kOhm) to this input on UFX (800kOhm input impedance according to manual):

If the same works with Madiface I do not know.

Instrument In 9-12, Frontseite
Wie AD, aber:
• Eingang: 6,3 mm Monoklinke
• Eingangsimpedanz: 800 kOhm
• Rauschabstand (SNR): 112 dB RMS unbewertet, 115 dBA
• Regelbereich Gain: 55 dB
• Maximaler Eingangspegel, Gain 10 dB: +21 dBu
• Maximaler Eingangspegel, Gain 65 dB: -34 dBu

I actually did not add a parallel resistor, even though I should have.

This MC is a bit special as it directly connects to an MM input.

The cartridge was this one:
Benz Micro Wood SH

(Herstellerangaben, ohne Gewähr)

Konstruktionsprinzip:
High Output Moving Coil (MC) Tonabnehmersystem
Anschluss am Phono MM Eingang

Physical
Body: vented machined Bruyére wood
Cantilever: solid boron rod: 0,28mm diameter
Stylus: nude line-contact diamond, mirror polished
Stylus tip radius: 3 x 60 µm
Vertical tracking angle (VTA): 20 degrees
Coil: pure iron cross coil
Weight: 9,0 grams

Electrical
Output voltage: 2,5mV at 3,54 cm/s
Internal impedance: 95 ohms
Frequency response: 20 – 20.000 Hz +/- 1dB
Channel balance: better than 0,5dB
Channel separation: better than 35dB at 1 kHz

Dynamic
Tracking ability at 315 Hz at a tracking force of 2 grams: > 80 µm
Dynamic compliance: 15 µm/mN

Setup instructions
Recommended loading: 1000 – 47.000 ohms
Recommended tracking force: 1,7 – 2,0 grams
Optimum tracking force: 1,7 – 1,8 grams
Recommended tonearm mass: medium to high
Optimum working temperature: 23° C
Break-in period: 40 hours

Versandgewicht / Shipping weight: 1,0 kg

7

Re: Madiface Pro Hi-Z input actual impedance ?

Thanks for the clarification. Yes, the mic input might have got a bit better results. But it can not be used with real MM cartridges.

Regards
Matthias Carstens
RME

Re: Madiface Pro Hi-Z input actual impedance ?

yes that was the point I could not connect to the better Mic inputs.
However Benz Micro has real MC (Benz Wood SL) as well which would work with Mic input. But this one I dont own sad

Many other MC cartridges would work with Mic input.

Users just may try.