Quote:
Originally Posted by Steve_Bell
For such a large speaker, which is in good working order, I was expecting more bass and it seems to begin distorting at volume level 6-7. It sounds similar with battery or mains power. Is this expected performance?
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I suspect not, at least based upon a small sample of one which I’ve had from new in 1977.
These days I use mine in my (fairly small) home study, and it is almost permanently tuned to the regional RNZ Concert programme FM transmitter. RNZ Concert is our “equivalent” to BBC R3, and was originally modelled on the BBC Third Programme. RNZ Concert still maintains very high technical standards on FM transmissions with minimal compression. The Beolit 707 sound is nicely balanced for a receiver of its kind, both on music and spoken-word programmes, and does not offend an ear that is accustomed to listening to that kind of sound (“BBC neutral”, if you like) via a pair of 1995-vimtage KEF Model 3 speakers driven by a Quad 66/606. Volume control settings of 6 or 7 are well above what I normally use, but today I pushed mine up to that region for as long as I could handle it, with no evidence of distortion.
Today I also tuned into one of the local commercial stations – heavily compressed (the kind that apparently has “boy racers” driving Optimods instead of proper engineers) and where the announcers shout at you at 200+ wpm, and at the highest levels I could handle, did not hear any additional distortion.
That accounts for the FM side. The AM side of the Beolit 707 is less happy. The audio bandwidth is only 4.5 kHz, but that aside, there is an underlying distortion that I guess might come from the final IF stage or the demodulator. Mine was like that from new. These days I do not use it for AM, but several years ago, I connected my Sony SRF-A100 headphone output to the Beolit auxiliary input. The Sony is limited by its very small speakers, but it has a very good AM side, and via the Beolit, AM was noticeably clearer than from the Beolit, even with the Sony in narrow-band mode. To be fair though, I don’t think that the Beolit 707 on AM is any worse than is typical for transistor portable receivers with diode demodulators.
Cheers,