BobHol
Old fart
Up to recently I had no interest in vintage amps over 80RMS. But now I’m an owner of a set of AR-9’s that came with a Hafler DH-500 (tested at 452 watts into 4 ohm by Stereo Review. The AR-9’s are 4ohm) and my Vintage audio life will never be the same.
I worked on getting the speakers usable before looking at this amp. It has been unused for about 6 years. I took off the cover and found that the fan was loosely held in place with one screw. I later determined that this wasn’t the stock fan. Everything else looked ok except for being a little dusty. The solder looked factory to me.(these had also been available as kits)
I checked DC Offset and one side was 5mV and the other was above 50mV. It looked pretty easy to adjust this so I found a plastic screw driver and adjusted the high side down to 5. From my reading on AK I got the impression that some component may be out of spec on the 50mV side and that I should have searched for out of spec components instead of just adjusting and calling it good. But that would have meant taking it in to a shop.
I secured the fan. It looked like it would be adequate. It wasn’t a cheap computer fan.
I screwed the cover back on and connected it to my Man Cave system. Power on and all I got was the relay clicking. Rechecked all my connections , powered it on again and I get sound out of one channel only. This didn’t seem good to me so I figured I’d take it in to my local repair shop.
On the day I was going to take it in I decided to try one more time. This time I get the relay click but no sound out of either speaker. I finally determined that the RCA connectors on the back of the amp were corroded enough to block the incoming current. Deoxited the outside and inside of the connector and was rewarded with plenty of sound left and right. I decided not to take it anywhere, for now.
I’ve been using it for a couple of weeks with the AR-9’s and am very very pleased. My Man Cave is in a half basement of less than 500 sq feet and the DH-500 sounds more than adequate. Soon I’ll check the DC Offset again to make sure it didn’t move. No thumps during power on or power off. It runs a lot cooler than I expected. The exhaust air is only warm and I feel no heat through the covers.
I worked on getting the speakers usable before looking at this amp. It has been unused for about 6 years. I took off the cover and found that the fan was loosely held in place with one screw. I later determined that this wasn’t the stock fan. Everything else looked ok except for being a little dusty. The solder looked factory to me.(these had also been available as kits)
I checked DC Offset and one side was 5mV and the other was above 50mV. It looked pretty easy to adjust this so I found a plastic screw driver and adjusted the high side down to 5. From my reading on AK I got the impression that some component may be out of spec on the 50mV side and that I should have searched for out of spec components instead of just adjusting and calling it good. But that would have meant taking it in to a shop.
I secured the fan. It looked like it would be adequate. It wasn’t a cheap computer fan.
I screwed the cover back on and connected it to my Man Cave system. Power on and all I got was the relay clicking. Rechecked all my connections , powered it on again and I get sound out of one channel only. This didn’t seem good to me so I figured I’d take it in to my local repair shop.
On the day I was going to take it in I decided to try one more time. This time I get the relay click but no sound out of either speaker. I finally determined that the RCA connectors on the back of the amp were corroded enough to block the incoming current. Deoxited the outside and inside of the connector and was rewarded with plenty of sound left and right. I decided not to take it anywhere, for now.
I’ve been using it for a couple of weeks with the AR-9’s and am very very pleased. My Man Cave is in a half basement of less than 500 sq feet and the DH-500 sounds more than adequate. Soon I’ll check the DC Offset again to make sure it didn’t move. No thumps during power on or power off. It runs a lot cooler than I expected. The exhaust air is only warm and I feel no heat through the covers.
