hafler 500 upgrades...

newfinish · 28th July 2005, 06:23 AM

I bought a hafler 500
lately and was wondering if changing the flimsy power cord would make a difference,and the rca connectors are grayish spotted dirty ,guess that has to go to,any other suggestions on the upgrades?
by theway its very good amp,love it

djk · 28th July 2005, 11:05 AM

Add a pair of 47µF 100V bypass caps to the main filter cans.

If your cards only have one trim pot you will need to add a pair of 0.1µF film caps per channel. One to bypass the input coupling cap, and one for the feedback loop cap.

The above gives the biggest gain for the time and money invested. Further gain becomes expensive in both time and money.

The power cord is a 16ga type used on 1.8KW space heaters, it is adequate.

still4given · 28th July 2005, 01:03 PM

Quote:

Originally posted by djk
Add a pair of 47µF 100V bypass caps to the main filter cans.

If your cards only have one trim pot you will need to add a pair of 0.1µF film caps per channel. One to bypass the input coupling cap, and one for the feedback loop cap.

The above gives the biggest gain for the time and money invested. Further gain becomes expensive in both time and money.

The power cord is a 16ga type used on 1.8KW space heaters, it is adequate.

Hi djk,

Do you add the 47uf caps directly across the terminals of the caps themselves?

Thanks, Terry

djk · 29th July 2005, 07:31 AM

I usually add four solder lugs with internal teeth on top of the existing lugs.

I also make a 1/16" thick 3/8" wide copper buss bar to replace the 16ga wire for the ground. I drill three 1/16" holes at the midpoint for the transformer center tap, speaker grounds, and signal ground.

newfinish · 29th July 2005, 09:03 PM

oooook! you kinda lost me there have a diagram or some thing to help? what twill all that do to help?

K-amps · 29th July 2005, 09:15 PM

Quote:

Originally posted by djk
Add a pair of 47µF 100V bypass caps to the main filter cans.

.

djk,

Would it be any good to bypass with 1000uF, then 100uF or 47uF then 0.1uF? (I have many 1000uF's lying around)

still4given · 29th July 2005, 10:27 PM

Quote:

Originally posted by djk
I usually add four solder lugs with internal teeth on top of the existing lugs.

I also make a 1/16" thick 3/8" wide copper buss bar to replace the 16ga wire for the ground. I drill three 1/16" holes at the midpoint for the transformer center tap, speaker grounds, and signal ground.

OK, it sounds like you are adding a type of star ground to the filter caps. I still don't understand where you are attaching the 47uf by-pass caps.

Thanks, Terry

fab · 30th July 2005, 03:11 AM

Hi newfinish

I suggest that you read this thread since the DH-500 uses the same driver board as the DH-220 (PC-19C card). It is also very similar to the DH-200 (PC-6 card).

http://www.diyaudio.com/forums/showt...323#post359323

There are plenty of stuff to do out there....

The power supply upgrade is always a good start.

Good luck

djk · 30th July 2005, 07:46 AM

"OK, it sounds like you are adding a type of star ground to the filter caps. "

It already has a star ground, but it is a piece of 16ga wire. If you drive a 2 ohm load in stereo, the peak current in this wire is on the order of 80A. The huge copper buss bar works better.

" I still don't understand where you are attaching the 47uf by-pass caps."

Kind of hard to figure out "I usually add four solder lugs with internal teeth on top of the existing lugs. "? There is only one place in the amplifier with four solder lugs. Look at the main filter caps.

"oooook! you kinda lost me there have a diagram or some thing to help?"

You can download the manuals from Hafler for free, but if you can't find the main filter caps maybe you shouldn't be inside the amplifier anyway. If you follow the wire from the input jacks you will find the input coupling caps. The feedback caps are the only cap around 220µF~470µF on the boards.

http://www.hafler.com/techsupport/in...D=3#amplifiers

"what twill all that do to help?"

Clearer mids and highs, better detail and imaging, tighter bass.

"Would it be any good to bypass with 1000uF, then 100uF or 47uF then 0.1uF? (I have many 1000uF's lying around) "

That would be OK, but the 0.1µF needs to be bigger, more like 0.47µF~1µF. This may cause the amplifier to oscillate. If it does, try adding about 5 ohms in series with this cap.

There are hundreds of things you can do for a Hafler amp, this is just the biggest bang for the buck (about $4 worth of caps).

newfinish · 30th July 2005, 11:48 AM

an dmy last question could it be possible loosing the fan?
adding more heatsinks instead?
anyone done that?

28th July 2005, 06:23 AM	#1
newfinish diyAudio Member Join Date: Jul 2005 Location: Quebec	hafler 500 upgrades... I bought a hafler 500 lately and was wondering if changing the flimsy power cord would make a difference,and the rca connectors are grayish spotted dirty ,guess that has to go to,any other suggestions on the upgrades? by theway its very good amp,love it

30th July 2005, 03:11 AM	#8
fab diyAudio Member Join Date: Mar 2004 Location: Canada	Hafler DH upgrades Hi newfinish I suggest that you read this thread since the DH-500 uses the same driver board as the DH-220 (PC-19C card). It is also very similar to the DH-200 (PC-6 card). http://www.diyaudio.com/forums/showt...323#post359323 There are plenty of stuff to do out there.... The power supply upgrade is always a good start. Good luck

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28th July 2005, 11:05 AM	#2
djk diyAudio Member Join Date: Feb 2001 Location: USA	Add a pair of 47µF 100V bypass caps to the main filter cans. If your cards only have one trim pot you will need to add a pair of 0.1µF film caps per channel. One to bypass the input coupling cap, and one for the feedback loop cap. The above gives the biggest gain for the time and money invested. Further gain becomes expensive in both time and money. The power cord is a 16ga type used on 1.8KW space heaters, it is adequate.

29th July 2005, 07:31 AM	#4
djk diyAudio Member Join Date: Feb 2001 Location: USA	I usually add four solder lugs with internal teeth on top of the existing lugs. I also make a 1/16" thick 3/8" wide copper buss bar to replace the 16ga wire for the ground. I drill three 1/16" holes at the midpoint for the transformer center tap, speaker grounds, and signal ground.

29th July 2005, 09:03 PM	#5
newfinish diyAudio Member Join Date: Jul 2005 Location: Quebec	oooook! you kinda lost me there have a diagram or some thing to help? what twill all that do to help?

30th July 2005, 07:46 AM	#9
djk diyAudio Member Join Date: Feb 2001 Location: USA	"OK, it sounds like you are adding a type of star ground to the filter caps. " It already has a star ground, but it is a piece of 16ga wire. If you drive a 2 ohm load in stereo, the peak current in this wire is on the order of 80A. The huge copper buss bar works better. " I still don't understand where you are attaching the 47uf by-pass caps." Kind of hard to figure out "I usually add four solder lugs with internal teeth on top of the existing lugs. "? There is only one place in the amplifier with four solder lugs. Look at the main filter caps. "oooook! you kinda lost me there have a diagram or some thing to help?" You can download the manuals from Hafler for free, but if you can't find the main filter caps maybe you shouldn't be inside the amplifier anyway. If you follow the wire from the input jacks you will find the input coupling caps. The feedback caps are the only cap around 220µF~470µF on the boards. http://www.hafler.com/techsupport/in...D=3#amplifiers "what twill all that do to help?" Clearer mids and highs, better detail and imaging, tighter bass. "Would it be any good to bypass with 1000uF, then 100uF or 47uF then 0.1uF? (I have many 1000uF's lying around) " That would be OK, but the 0.1µF needs to be bigger, more like 0.47µF~1µF. This may cause the amplifier to oscillate. If it does, try adding about 5 ohms in series with this cap. There are hundreds of things you can do for a Hafler amp, this is just the biggest bang for the buck (about $4 worth of caps).

30th July 2005, 11:48 AM	#10
newfinish diyAudio Member Join Date: Jul 2005 Location: Quebec	an dmy last question could it be possible loosing the fan? adding more heatsinks instead? anyone done that?

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