dougi
Addicted to Fun and Learning
I just got this stepup this week and thought I would post some comparative measurements with it in use/not-in use.
It is a mid-level one in Ortofon's offerings. Still expensive! Weird pricing, Euro 899 via Ortofon or I could get it locally for A$700-800.
Stock pics:
I wanted to use it for my "cheap" MCs, (AT OC9XEN and Denon DL103R) into either my NAD C3050LE directly or to get lower noise with my Dynavox TPR-2 phono stage which is quieter in mm mode.
Specs are as follows:
With the turns ratio it should be well suited to the two carts, having impedances of 12 and 14 ohms respectively.
There was a bit of hum in my test setup, audible with ear near speaker but OK at the listening position. It was better with the Dynavox than the QUAD Artera PRE used for testing. (Say -60dBu hum vs -55dBu hum going by the ADI-2 peak meters).
I grounded from the turntable to the stepup only. Continuing grounding to the preamp did not improve hum.
I didn't measure the gain, my interest was how the transformers were affecting the frequency response and distortion.
To measure I used @Balle Clorin 's wonderful measurement script and a test record in twosetups:
NO STEPUP
WITH STEPUP
A COMPARISON PLOT OF LEFT CHANNELS, NORMALISED
CONCLUSIONS
It is a mid-level one in Ortofon's offerings. Still expensive! Weird pricing, Euro 899 via Ortofon or I could get it locally for A$700-800.
Stock pics:
I wanted to use it for my "cheap" MCs, (AT OC9XEN and Denon DL103R) into either my NAD C3050LE directly or to get lower noise with my Dynavox TPR-2 phono stage which is quieter in mm mode.
Specs are as follows:
With the turns ratio it should be well suited to the two carts, having impedances of 12 and 14 ohms respectively.
There was a bit of hum in my test setup, audible with ear near speaker but OK at the listening position. It was better with the Dynavox than the QUAD Artera PRE used for testing. (Say -60dBu hum vs -55dBu hum going by the ADI-2 peak meters).
I grounded from the turntable to the stepup only. Continuing grounding to the preamp did not improve hum.
I didn't measure the gain, my interest was how the transformers were affecting the frequency response and distortion.
To measure I used @Balle Clorin 's wonderful measurement script and a test record in twosetups:
- Denon DL-103R cart into QUAD Artera PRE MC setting, no stepup, into RME ADI-2 PRO.
- Denon DL-103R cart into QUAD Artera PRE mm setting, with the stetup, into RME ADI-2 PRO.
- Note capacitance incorrect in the plot headers, total capacitance seen by the mm stage would be around 300pF (200pF cable, 100pF loading)
NO STEPUP
WITH STEPUP
A COMPARISON PLOT OF LEFT CHANNELS, NORMALISED
CONCLUSIONS
- As hinted at by the specs, a bit of lower bass roll-off, probably ~3dB @20Hz in my setup. It actually flattens the response a bit above that.
- Slight high treble rolloff, ~1dB at 20 kHz.
- No significant noticable distortion added to the cart, but some at 18kHz+
- In-use, hum is fine and plenty of gain for my carts. Bass is fine with my speakers (Heritage Linton's).
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