Deciphering Integrated Specs - Step Up Matching

Given @mulveling ’s comments and the Hana’s suggested load impedance of >80Ω, would the Quadratic’s input impedance in high mode of 70Ω (or 81.6 if that’s really the case) suggest any compatibility issue with the Hana or otherwise affect the considerations?

8 ohms into 70 ohms is fine - it’s far from an egregious mismatch, and the main value in these paper calculations is to avoid something egregious. For reference, 70 / 8 is a 9x ratio and I’ve used as low as a 5x ratio before. You’ll lose some effective output (like 1dB or so) in such a configuration, maybe alter the FR a bit, but it’s not a huge deal.

As @theflattire mentioned, use your ears to decide the winner at this point. For a 2-tap SUT, 12x and 24x is a really nice choice of ratios, IMO. That covers a lot of MC ground! 

I just use the setting that sounds the best.

As a post script, the 0.4mV cartridge that I’m considering using is the Hana Umami Blue. Its coil impedance is 8Ω and its suggested load impedance is >80Ω.

The input impedance of the Quadratic MC-1 is reported to be 70Ω in high mode (24x/ +28dB) mode and 200Ω in low mode (12x/+22dB), although by my calculations the impedance would really seem to be 81.6 (high) and 326 (low).

Given @mulveling ’s comments and the Hana’s suggested load impedance of >80Ω, would the Quadratic’s input impedance in high mode of 70Ω (or 81.6 if that’s really the case) suggest any compatibility issue with the Hana or otherwise affect the considerations?

Sure was @mulveling,  thank you.  And thank you all for the helpful responses. 

@mulveling, great post.

Yeah, since the spec sheet states MM sensitivity of 2.5mV, and the line stage states sensitivity of 0.25V (= 250mV), that is a factor of 100x which is 10x * 10x = 20dB + 20dB = 40dB. That’s assuming the MM output pipes into the unbalanced input line path. Typically input sensitivity means the signal level required to produce full rated output.

I’ve used SUTs configured to produce 10mV into the MM stage (even up to 12mV once, I think). It can in fact sound great. You’ll lower the relative noise floor this way, but you are cutting into the MM stage’s overload margins. Sometimes I’ve noticed a bit of harshness when pushing the MM stage like this. If the MM stage is solid state, you might have lower margins than with tubes (but it really depends). As others sad, it’s a give-and take compromise. In *most* cases, you want to shoot for 5mV. But if your system is lacking line gain and you have to really push the volume to get where you want, you might prefer the 0.4mV on 24x tap - and that’s fine! In "most" systems, the 12x tap would be more ideal.

Also when doing the calculations, higher step-up ratios are not without losses - due to loading (Ohm’s Law). The losses depend on the coil ohms. So for example, if your 0.4mV cart was 12 ohms (e.g. Benz Glider, Wood), it sees a load of 82 ohms when used with the 24x taps (82 = 47000 / 24 / 24). Then the loss is calculated as 20* log( 82 / (82 + 12) ) = -1.18dB. So you lose just over 1dB from the load the cartridge "sees". Losses are usually bad, but this -1dB actually helps you on the overload margins.

The Quadratic is a nice SUT! Really sweet bass, very clean midband, slightly relaxed top end.

Just one more note - having ample overload margin is so important because the peak levels off the record can be much higher than what the rated cartridge output indicates. I don’t have any measurements here but IIRC you can expect at least 6dB (4x) higher than the rated output, and possibly more. At 10mV (calculated) and MM overload at 80mV, that's a factor of 8x which should be "ok". Of course, the overload is frequency dependent ;) 

It is really a matter of the signal to noise ratio and whether or not you can tolerate the noise with any given cartridge. As long as you have enough gain and the noise level is ok at the volumes you listen at you are in business. It looks to me that you will be fine. 

The only data that might help to answer your many questions are in the section headed by”voltage gain”, and there are a few different possible interpretations of those data. However, I’d start with your SUTset to 1:12, not 1:24. You can always choose the higher gain setting if 1:12 proves inadequate. Since your linestage seems capable of adding unusually high gain for a linestage, you might even get by with no SUT, depending upon the correct interpretation of the given info. Do you have an owners manual? If so, read it.

You may be (are) over analyzing.  The 2.5mV input sensitivity MM phono spec is bog standard 40dB gain.  The Output 2 spec adds the maximum linestage gain.  The 80mV input overload spec is generous so a LOMC run through a 12x SUT should be perfect.  You say the 24x is fine…to me it seems like the volume range would be better at 12x, but your results speak for themselves.  Chill, enjoy!

I wasn't able to include a picture of the full specs, so here they are.

Power Output Stereo
Minimum sine wave continuous average power output per
channel, with both channels operating is:
200 watts into 8 ohm load
320 watts into 4 ohm load
Output Load Impedance
8 or 4 ohms
Rated Power Band
20Hz to 20,000Hz
Total Harmonic Distortion
0.03% maximum with both channels operating from 250
milliwatts to rated power, 20Hz to 20,000Hz
Intermodulation Distortion
0.03% maximum, if the instantaneous peak power output
does not exceed twice the rated power output for any com-
bination of frequencies from 20Hz to 20,000Hz
Dynamic Headroom
1.5dB
Wide Band Damping Factor
Greater than 200 - 8 ohm, Greater than 100 - 4 ohm
Power Guard
Less than 2% THD with up to 16dB overdrive at 1,000Hz
Frequency Response
+0, -0.5dB from 20Hz to 20,000Hz
+0, -3dB from 10Hz to 100,000Hz
Preamplifier Output Impedance
500 ohms
Sensitivity (for rated output)
High Level - 250mV unbalanced, 500mV balanced
Phono - 2.5mV
Signal To Noise Ratio (A-Weighted)
High Level - 93dB below rated output
Phono - 82dB below 5mV input
Input Impedance
High Level - 20K ohms
Phono - 47K ohms; 50pF-800pF
Preamplifier Output 2 (for rated input)
1.4V unbalanced (8V Maximun)
Maximum Input Signal
High Level - 8V unbalanced, 16V balanced
Phono - 80mV
Voltage Gain
High Level to Output 1: 44dB
High Level to Output 2: 15dB
Phono to Output 1: 84dB
Phono to Output 2: 55dB
Headphone Impedance
100 to 600 ohms

I use output 2 on my McIntosh integrated amp to run to my powered subwoofer.