Recent content by dshoaf

Locate them in a small room with jazz or small ensemble classical. Headbangers would need to add more power. Make sure the 17s have been updated with new crossover components and the surrounds sealed. Cheers, David

Agreed, the whole signal chain of coupling caps has not been fully replaced. The big hole with foil was a capacitor at one point and it will lower resale value. The power supply diodes have been replaced with a more modern consolidated component that houses the 4 original diodes. The 2...

Nice candidates for a full restoration if you intend to use them and want the reliability and performance they'll have when restored. The alternative, given the really nice condition and all-original, is to leave them as-is but not use them. There are collectors out there for whom...

If you are referring to Qua-co, I believe he worked for Hafler in prior years. The other alternative would be Musical Concepts. There are plenty of threads here at AK on this topic. Cheers, David

Odds are rhat one or more of the small wheat bulbs will also need replacing. This TT is worth the time and money to do those things. Cheers, David

I run streaming of internet 'radio' stations the majority of the time. Some are in Europe and some in the US. In either case, they've introduced me to new musicians and releases. There are some excellent radio shows (Performance Today from APM, for instance) that carries recent performances...

Thus far, you have narrowed the problem down to the Intermediate Frequency circuits. This is a series of amplifiers connected by transformers that are housed in small metal cans. You'll find them all on one board. Each is fed by a series of decreasing voltages developed by a series of...

The good ones are busy. Stand in line. There’s usually a reason some one else is available immediately. Cheers, David

You're going to need to get a VOM out and start checking the power supply voltages all along the I/F strip. I see a lot of resistors and decoupling caps in the voltage rail that can affect FM performance only. Cheers, David

Plug the Tape Out jacks to the AUX input of another amp. This will tell you if audio is being generated by the FM section. If not the problem is upstream in the FM stage. If it works, the problem is downstream of the Tape Out. Have you cleaned the switches. David

Anything in the I/F strip or the stereo demodulator could be at play here. For the best approach to diagnosing it further, pull down the schematic from HiFi Engine and be prepared to post the FM section schematics. This will help the 'arm chair bench techs' here at AK to help you help...

I didn't go back and read the whole thread so these questions may have been answered. OK, so what is the exact problem with the tweeters? Have you measured the voice coil DC resistance with an ohm meter? How do they differ? What happens when you run audio through them when connected to the...

Model 301 tweeters of the same series should work just fine in the 601s of the same vintage. There's likely a small incandescent bulb in series with the tweeters mounted on the crossover. Check the metal tabs for corrosion and clean them with DeOxit while you've got the woofers out. The 601s...

Go with the PA6 - it really isn’t a Halfler any more. Then upgrade the power supply at your leisure. The XL-280 would need some updating anyway. Cheers, David

What kind of output (in terms of wattage) do you get when the preamp is driven into clipping? It seems to me that you would be driving it very hard by then. If that's the case, why worry about asymetrical clipping of the preamp when you'll never approach it with the power amp hooked up. Just...