This is a review and detailed measurements of the Realistic (Radio Shack) model 42-2101A phono preamplifier. It is on kind loan from a member and originally cost US $20 but I now I see a used one on ebay for $35.
The 42-2101 has the basic look of a lot of Radio Shack audio products:
The thing that really got me was the text on the back:
Made in Japan for Radio Shack? Man, those were the days that Japan could make such products and still make money. Golden era of hi-fi to be sure....
Interesting that power supply is built-in. Everything today in this price range would have an external one. They went through UL certification and all.
Realistic 42-2101A Measurements
As usual we start with our dashboard:
Inclusion of AC power supply inside the unit is likely the cause of mains noise in there although some of the spikes are post rectification. Distortion is low at -90 dB. It is the power supply noise that knocks the SINAD massively down to 55 to 61 dB. No amount of grounding setup made a difference.
Frequency response is key to the "sound" of a phono stage so let's see how it does there:
Looks like they had a good intention there with the rumble filter, cutting out the low frequencies. Alas, that is causing that peaking so may make the sound bass heavy.
Last test I ran was the input level vs output distortion+noise:
As noted, there is good bit of headroom before the unit clips.
Conclusions
If you are feeling nostalgic, I guess this phono preamplifier makes a good target. Otherwise, it is not something I would recommend.
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As always, questions, comments, recommendations, etc. are welcome.
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
The 42-2101 has the basic look of a lot of Radio Shack audio products:
The thing that really got me was the text on the back:
Made in Japan for Radio Shack? Man, those were the days that Japan could make such products and still make money. Golden era of hi-fi to be sure....
Interesting that power supply is built-in. Everything today in this price range would have an external one. They went through UL certification and all.
Realistic 42-2101A Measurements
As usual we start with our dashboard:
Inclusion of AC power supply inside the unit is likely the cause of mains noise in there although some of the spikes are post rectification. Distortion is low at -90 dB. It is the power supply noise that knocks the SINAD massively down to 55 to 61 dB. No amount of grounding setup made a difference.
Frequency response is key to the "sound" of a phono stage so let's see how it does there:
Looks like they had a good intention there with the rumble filter, cutting out the low frequencies. Alas, that is causing that peaking so may make the sound bass heavy.
Last test I ran was the input level vs output distortion+noise:
As noted, there is good bit of headroom before the unit clips.
Conclusions
If you are feeling nostalgic, I guess this phono preamplifier makes a good target. Otherwise, it is not something I would recommend.
------------
As always, questions, comments, recommendations, etc. are welcome.
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
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