Hafler dh-200 switch - Page 5

Original Burnedfingers · 17th March 2006, 01:14 AM

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.

GRollins · 17th March 2006, 03:18 AM

If the poor thing needs a home, send it to me. I like the silly things.

Grey

jakelm3075 · 17th March 2006, 05:33 AM

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

jakelm3075 · 17th March 2006, 05:39 AM

Quote:

Originally posted by burnedfingers

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.

Oh I know Burn. Electronics are like cars. Just cause it started yesturday dont mean it will start today

GRollins · 17th March 2006, 02:31 PM

I don't remember the DH-200 being biased heavily enough to double into 4 Ohms. Probably closer to 150W at a guess.
I've got a couple of the manuals around here somewhere. If I get a chance, I'll dredge one up and see what the 4 Ohm wattage was.

Grey

anatech · 17th March 2006, 02:36 PM

Hi Jake,
I like these amps too. I don't want to see it die.

If you bridge it, the minimum impedance is 8 ohms total. You would be further ahead to run each woofer off it's own channel, non-bridged.

-Chris

jakelm3075 · 17th March 2006, 03:19 PM

Ordered the switch yesturday morning. Still no comfirmation from Mouser. Almost 24 hours later. So aggrivating.

Jake

jakelm3075 · 17th March 2006, 03:22 PM

What I read somewhere (might have been here at DIY) that the amp is 100wpc @ 8ohms. And that is was close to double wpc @ 4ohms. Still 150wpc @ 4ohms from a solid amp like this will blow away that cheep little MTX amp.

Jake

fab · 18th March 2006, 01:34 AM

From what I remember I have measured about 130W rms / 8 ohms and I think close to 180 W rms / 4 ohms before seeing clipping on the scope...

jakelm3075 · 20th March 2006, 02:49 PM

Then thats perfect for my little MTX.

18th March 2006, 01:34 AM	#49
fab diyAudio Member Join Date: Mar 2004 Location: Canada	Power of DH-200 From what I remember I have measured about 130W rms / 8 ohms and I think close to 180 W rms / 4 ohms before seeing clipping on the scope...

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17th March 2006, 01:14 AM	#41
Original Burnedfingers diyAudio Member Join Date: Nov 2002	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.

17th March 2006, 03:18 AM	#42
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	If the poor thing needs a home, send it to me. I like the silly things. Grey

17th March 2006, 05:33 AM	#43
jakelm3075 diyAudio Member Join Date: Mar 2006 Location: La	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

17th March 2006, 02:31 PM	#45
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	I don't remember the DH-200 being biased heavily enough to double into 4 Ohms. Probably closer to 150W at a guess. I've got a couple of the manuals around here somewhere. If I get a chance, I'll dredge one up and see what the 4 Ohm wattage was. Grey

17th March 2006, 02:36 PM	#46
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Jake, I like these amps too. I don't want to see it die. If you bridge it, the minimum impedance is 8 ohms total. You would be further ahead to run each woofer off it's own channel, non-bridged. -Chris

17th March 2006, 03:19 PM	#47
jakelm3075 diyAudio Member Join Date: Mar 2006 Location: La	Ordered the switch yesturday morning. Still no comfirmation from Mouser. Almost 24 hours later. So aggrivating. Jake

17th March 2006, 03:22 PM	#48
jakelm3075 diyAudio Member Join Date: Mar 2006 Location: La	What I read somewhere (might have been here at DIY) that the amp is 100wpc @ 8ohms. And that is was close to double wpc @ 4ohms. Still 150wpc @ 4ohms from a solid amp like this will blow away that cheep little MTX amp. Jake

20th March 2006, 02:49 PM	#50
jakelm3075 diyAudio Member Join Date: Mar 2006 Location: La	Then thats perfect for my little MTX.

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