Koss 76 manual Free Advice, Box 65085, Place Longueuil Longueuil, Québec, Canada J4K 5J4

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FREE ADVICE

FREE ADVICE

Box 65085, Place Longueuil

Longueuil, Québec, Canada J4K 5J4

uhfmail@uhfmag.com

I wonder whether you know of some way — for example some sort of panel — that could reduce this phenomenon, or better yet eliminate it. I have already built panels two inches thick of different shapes, using a Masonite sheet on which I had glued with liquid tar a very heavy black paper, all nailed into a frame made from two-inch wood. I had screwed the panels to the ceiling in my former home in Repentigny and the results had been very good. But now I live in the

First, let me say that I bought both of your books on high fidelity and loved them. I also received a copy of your magazine and have subscribed for the next two years. I also ordered six of the most current back issues.

I got back into hi-fi about two years ago after 15 or so years and find myself wonder- ing why I ever got out. My current two chan- nel system consists of the following: Wadia 861 standard CD player, CAT JL-2 tube amplifier, Martin Logan Odyssey speakers, and Audio Research PH3 phono preamp.

I have a small collection of vinyl record- ings that have not been played in years. I have had the itch to incorporate analog into my system. My question to you is which turntable you would suggest to match the Audio Research preamp? I don’t want to spend much more than $3500 in total for the turntable and cartridge.

I have heard good things about both Nottingham’s Spacedeck and turntables from Pro-Ject. I purchased the Audio Research PH3 used and plan to upgrade in a year or so to the CAT SL1 preamp with phono input. Any comments about this particular preamp? I have been using an old Thorens turntable that I had lying around, but I have not been very happy with its performance. I didn’t know if I should try upgrading the cartridge first or just move on right away.

Carl Waldbillig

WEST CHESTER, OH

We’d move on right away, Carl. The best argument in favor of used Thorens turntables is that people all but give them away. They were somewhat better than average, and better than the Duals, whose reputation remains a mystery to us, but their tone arms were wretched, and we wouldn’t overspend on a cartridge for a Thorens arm. Incidentally, they are unrelated to the modern Thorens tables, which seem better designed, though we still have problems with the arms.

We’ve also heard good things about the Nottingham, with which we have however no experience. We have listened to several Pro-Ject turntables, and there may be a good choice to be made from its lineup, probably in the RPM series. Note that Pro-Ject offers electronic speed control as an extra-cost accessory. In our experience, that sort of upgrade affects more than just correct speed and is worth including.

There are several cartridge brands we like, including Benz Micro and Clearaudio, and we hear the newest Dynavectors are worth a detour. You should get a moving coil pickup, or failing that a moving magnet cartridge with very low inductance, and certainly a line contact stylus. Your budget won’t let you buy the very top, but careful shopping should score you a very good experience. There are of course other possible brands of turntables, including Rega and Clearaudio, to name but two.

You may want to choose a model that is available with local service, because a top turntable that isn’t aligned properly is not going to give you what you pay for. And little things are going to count, because you have a high resolution system. We can presume that adding the SL1 preamplifier will let you hear with even greater clarity anything that may be wrong with the source. On the positive side, your system’s resolution will make you very glad you’re listening to vinyl again.

I have a question concerning acoustics, or more precisely treating my listening room for low frequencies. I have a very good sound system that reproduces highs and the midrange marvellously well. The low frequencies have good impact, but there’s a sort of boominess around 80 to 100 Hz (hard to be sure), suggesting a resonance.

Gaspé. What do you think?

Marien Desrosiers

ST-JEAN DE CHERBOURG, QC

Marien, if your home-built panels gave you good results it is certainly because the acoustical problems you then had were in a different part of the frequency band. From what you say your new room has a problem in the extreme lows. Here the solution is more complicated.

Why more complicated? It’s because sounds in the range of 80 to 100 Hz have a very long wavelength (more than 3 metres for 100 Hz!). The long wave- length will pass easily through a thin panel and bounce off whatever is on the other side. A panel that can deal with such frequencies needs to be…thicker. In the case of our Alpha room, the home of our original reference system, behind one wall is a bass trap nearly a metre deep! A radical solution to be sure.

It’s possible to build a freestanding bass trap with well-chosen dimensions (it might be 1 m by 75 cm by 60 cm, for instance, with no dimension that is a multiple of another dimension), built from materials that are relatively non- resonant put permeable to sound. You would fill it with mineral wool, so that air vibrating within the cavity would rub against the fibres and be dissipated as heat.

However certain articles of furniture can also help absorb bass, at least to a point. A well upholstered sofa can help, as can a bookcase full of books. Finally, changes in speaker placements can have a great influence on what you hear. Since moving speakers is free, that is where we would start.

My equipment consists of a Roksan Radius 5 turntable, a Rega Fono, a Rega

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Koss 76 manual Free Advice, Box 65085, Place Longueuil Longueuil, Québec, Canada J4K 5J4, uhfmail@uhfmag.com