I have B&O turntable with the MMC5 cartridge (All original from the 1980's). I'm looking for a step-up transformer so I don't need to crank up the volume so high on my Arcam alpha 7R amplifier. (Forgetting to turn down the volume before playing a CD sounds like speakers exploding!) I know I'm not describing audiophile gear here but it's adequate for me. From the research I've tried to do I've learned I need to know the impedance of this cartridge to select a (preferably used) transformer. This isn't given in the manuals I have and I can't find it online anywhere. Short of experimentation, I also don't know what the transformer ratio should be (1:10 or 1:20). The cartridge output is listed as >2.12mV while the phono input sensitivity is 2.6mV. I've tried using a separate preamp into the AUX input of the amplifier with no change in performance. Any thoughts or suggestions would be helpful (except scrapping my low-end turntable & starting over!)
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Step up transformer for B&O MMC5
- Thread starter DTV53
- Start date
A transformer in this situation is not at all an optimal solution.
With a 2.6mV output, a normal MM stage will have no problems getting plenty of output. Which preamp did you try using?
DSJR
Major Contributor
I'm sure I remember the Arcam amp having a phono stage built into it.
Arguably, what you need is an attenuator L-pad on the CD player output, as so many amps of the period (and maybe even now) blast you at a nominal 9 o'clock volume control setting - it's done to make you think your amp is really 'powerful' when in fact, at 10 o'clock on the control and with the same level of input, the amp is now in distress and clipping...
Back in Jurassic times when I started out, an ideal setting of the volume control was around 2 o'clock (assuming 7 o'clock was minimum and 5 o'clock on the pointer was maximum on the control), this giving plenty of lower level control, but the 2V nominal CD player max level put paid to that and it seems many amps that came after didn't care to change it, although some sources increased their max output from 300 - 500mV to 750mV or higher.
2.6mV at 5cm/s isn't high, but it's not deathly low either (the popular AT models are only 3mV under similar conditions). This level should work to advantage with cheaper phono stages with marginal overload performance too (the MMC 1 - 5 models are 'gentle' in subjective tone rather than 'aggressive' I remember.
P.S. I'm cross with B&O that they stopped production of these cartridges and seemingly ditched the tooling as in their laid-back way, they 'sounded great' and the MMC4 and 2 especially at their price points were good value. Soundsmith had to reverse-engineer the concepts but look at the prices the new derivations sell for?
Arguably, what you need is an attenuator L-pad on the CD player output, as so many amps of the period (and maybe even now) blast you at a nominal 9 o'clock volume control setting - it's done to make you think your amp is really 'powerful' when in fact, at 10 o'clock on the control and with the same level of input, the amp is now in distress and clipping...
Back in Jurassic times when I started out, an ideal setting of the volume control was around 2 o'clock (assuming 7 o'clock was minimum and 5 o'clock on the pointer was maximum on the control), this giving plenty of lower level control, but the 2V nominal CD player max level put paid to that and it seems many amps that came after didn't care to change it, although some sources increased their max output from 300 - 500mV to 750mV or higher.
2.6mV at 5cm/s isn't high, but it's not deathly low either (the popular AT models are only 3mV under similar conditions). This level should work to advantage with cheaper phono stages with marginal overload performance too (the MMC 1 - 5 models are 'gentle' in subjective tone rather than 'aggressive' I remember.
P.S. I'm cross with B&O that they stopped production of these cartridges and seemingly ditched the tooling as in their laid-back way, they 'sounded great' and the MMC4 and 2 especially at their price points were good value. Soundsmith had to reverse-engineer the concepts but look at the prices the new derivations sell for?
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