mtambo44 wrote:

I have a Dynaco system consisting of PAS3 Pre-amp, FM tuner and ST-35 amp my father built in '64 or '65. When I got it from him a few years ago it came with the original KLH speakers that he used with it. When I powered it up,not surprisingly, given his engineering background all the Dynaco bits worked, but did not sound very good through those speakers. I put it away until a few weeks ago when I got a pair of KEF LS50's for a dedicated listening room I am putting together. I was blown away by the sound quality and lack of any noise or hum. I have ordered replacement tubes and am looking forward to hearing it at its potential. The volume is the only problem since the ST-35 only has as output of 17.5 watts. The KEF's, while a fine speaker, have a sensitivity of 85dB (2.83V/1m), so not the best choice for the amp.

My question is what would be a good speaker? Since the whole system will fit into the area of a couple of shoe boxes, I am looking for a bookshelf size speaker with as high a sensitivity as possible. Price? anything up to around 2K.

Thank you for your consideration of this topic.

There is a wide range of sizes for so-called "bookshelf" speakers.

What are the maximum dimensions you want?

You should get something with NO LESS than 90 db/watt sensitivity for that small amp. The LS-50 is obviously not a good choice.

You should also get only front-ported speakers if they actually will go in a cabinet or near a back wall.

The Monitor Audio Bronze 2 speakers might be perfect for you. They have 90 db/watt sensitivity, are front-ported, come in black or walnut, and are only $499/pair from Audio Advisor. They are very good-sounding speakers for their rather low price. They are around 14"x 7" x 10".

10 watts will give you 100 dbA at 1 meter with those, which will be loud enough for almost any music unless the room is huge.

Back in the 1960s and 1970s I had a Harman-Kardon A500 tube integrated amp, which was 25 watts per channel (7355 output tubes), and it worked well with my Wharfedale W70D speakers, which were large 4-way speakers with 12" woofers, so I think the amp will have enough power, with the right speakers.

Another thing you might want to look at are the Klipsch Heresy speakers, which have a sensitivity of 99db/watt!!!! Yes, 99 db/watt. That would be a perfect match for that low-power amp.

Those are excellent speakers, which Klipsch has made for over 60 years, and the current model, the Heresy III, runs $1000 each. They were designed with the low-powered tube amps of the 1960s in mind. They hardly qualify as bookshelf speakers, however (24" H x 15"W)

mtambo44 wrote:

Thank You Commsysman, I think the Heresy is a good choice. I will look for a vintage pair online. Can not beat the sensitivity.

That sounds like a great idea. They don't go real low, so a powered subwoofer might be nice with them.