Grey and Chris are correct on the switch issues and about bridging. Thirty years ago when I was a pup I probably blew up more amplifiers than 1/4 of the population of people in my town own. Hell, when you can bridge a 8 ohm load why not throw caution to the wind and run her on a 4 ohm load. Heck, it will last a while. Funny thing about speakers is the impedance goes down with the frequency. What was an 8 ohm nominal speaker impedance may dip to 3 ohms at say 20 HZ. Another funny thing about amplifiers is that unless they are specifically designed to mono bridge your best bet is to leave them to hell alone. Example
An Altec model 9446 is a commercial amplifier that was designed to mono bridge. Note* Has bridging circuitry designed in. Unit will
run day in and day out bridged. The Mickey Mouse bridging adaptor is minimal at best and I could probably ramble on for a page about adequate heatsinking, DC offset, Bias circuit problems and a few other considerations.
Personally, I believe the amplifier in question has serious problems that need to be taken care of by a qualified individual.
Hook the thing up to a variac and run it up and test it. The it ran good belore answer won't cut it with some of us because we know that in the world of electronics something can work one minute and fail after that. It has age on it and **** happens. Rebuild it or send it down the road and move on.
An Altec model 9446 is a commercial amplifier that was designed to mono bridge. Note* Has bridging circuitry designed in. Unit will
run day in and day out bridged. The Mickey Mouse bridging adaptor is minimal at best and I could probably ramble on for a page about adequate heatsinking, DC offset, Bias circuit problems and a few other considerations.
Personally, I believe the amplifier in question has serious problems that need to be taken care of by a qualified individual.
Hook the thing up to a variac and run it up and test it. The it ran good belore answer won't cut it with some of us because we know that in the world of electronics something can work one minute and fail after that. It has age on it and **** happens. Rebuild it or send it down the road and move on.
I admit, I get excited and ask question after question. My fault. I will give this amp a good home as soon as I bring it back to life. I'm waiting on the Carling switch I ordered. As soon as it comes in I'll install it and see what I'm working with. I'm not bridgeing it out. I figured at 8ohms I get a good 100watts, so at 4ohm I should get close to double that. Which should be all the "naked" juice I need. Hell, I might even invest in a good DVC sub and run both channels. But for now I'll just wait on the switch and try not to get too ahead of myself.
Jake
Jake
Well the new switch came in. Soldered all the wires in place......Plugged it in.....Flipped the switch...SPARKS flew everywhere!!....Plug caught on fire and fire was spreading....
Just kidding... switch worked perfectly. Plugged it in, flipped the switch on and the little red light in the switch lit up. Just like brand new.
I unhooked the plate amp in both the MTX and the Polk. Ran the sub pre out from the reciever and used the "Y" connection to go left and right on Hafler. Hooked left and right to both subs, set the gain on the Onkyo to "0" and popped in Animusic. I believe running a raw amp is a great improvement from the plate amps. The subs disapeared in my living room.
Being I have my beautiful vintage Polk 7's as front main, I set my reciever to 60hz. Now I know some of you might think that alittle low, but the Polks handle the rest beautifuly and blend everything in very well.
I just want to thank all of you for giving me such great help. And if there is anything I can help with , let me know.
I cant wait to dismantle those terrible manufacture sub boxes and use Win Isd to create bigger, better and lower tuned boxes for my 10" Polk and 12" MTX.
Jake
Just kidding... switch worked perfectly. Plugged it in, flipped the switch on and the little red light in the switch lit up. Just like brand new.
I unhooked the plate amp in both the MTX and the Polk. Ran the sub pre out from the reciever and used the "Y" connection to go left and right on Hafler. Hooked left and right to both subs, set the gain on the Onkyo to "0" and popped in Animusic. I believe running a raw amp is a great improvement from the plate amps. The subs disapeared in my living room.
Being I have my beautiful vintage Polk 7's as front main, I set my reciever to 60hz. Now I know some of you might think that alittle low, but the Polks handle the rest beautifuly and blend everything in very well.
I just want to thank all of you for giving me such great help. And if there is anything I can help with , let me know.
I cant wait to dismantle those terrible manufacture sub boxes and use Win Isd to create bigger, better and lower tuned boxes for my 10" Polk and 12" MTX.
Jake
It works great, burnedfingers. But I didnt realize how warm that amp ran. Is it safe to just leave it on? Or should I turn it off and on everytime I use it. The rest of my electronics stay on allways. I believe that leaving them on reduces moister that can currode connection. Am I right in leaving this particular amp on?
The purests would say to let all your gear run. In todays world with the increasing cost of electricity I would suggest turning on the equipment about 1/2 hour before listening to it. To answer your question I would not let it run. I would also check the bias to make sure it is tracking correctly and is set per factory specifications. As you know the sign of heat can sometimes mean the bias is a little heavy.
Actually I would turn off your gear. Turn it on 1/2 prior to using. I wouldn't worry about a moisture problem or corrosion.
Actually I would turn off your gear. Turn it on 1/2 prior to using. I wouldn't worry about a moisture problem or corrosion.
jakelm3075 said:
The bias might be set too high. It should run a little warm, but not extremely hot. Factory standard bias current is 200ma, which you measure by replacing one of the DC power fuses with an ammeter. Turn the P2 pot (in the center of the board) a little counter clockwise to turn it down a bit. The DC fuses are the pairs of fuses, two on each side of the transformer.
I'd leave the amp on all the time, because you don't want to burn out the switch again. It's days are numbered.
I know this is an old thread, but thought I would add my two cents for anyone that is looking into this power switch issue. The original switch in the DH-200 is simply an on-off switch. It is NOT a SPDT!!! (SPDT = single pole double throw) Terminal #3 on the original switch is simply a post not connected to the internals of the switch, and is used simply as a connection post. Jake, the first switch you used was a SPDT switch, and of course, in one direction you will turn on the amp. In the other position you are shorting the AC mains, blowing the fuse!!!! So any of you that plan on replacing that switch, either use as is recommended in this forum, or modify wiring accordingly.