Might pull the trigger on Hafler Amps

doggie750

Hafler DH 200 and DH500
I read mixed reviews online and just wondering any thoughts from Polks here. Thank you.

marvda1

i have owned the hafler dh 200, nice sounding amp you can fry an egg on.

motorhead43026

Beware of DC offset on Haflers of this vintage. I own a XL600 and it isn't going anywhere. These amps when freshened up are still very relevant.

machone

I have an upgraded DH500 and it is sweet.

doggie750

Machone-
Is the stock DH500 not good enough? Why need the upgrade? Cost to upgrade? Is it simply changing the cap? Thanks

pitdogg2

yes caps do not last indefinitely, and in some amps will destroy anything downstream when they fail.

pkquat

IMO the DH220 (P225) is better than the DH200. The DC offset is adjustable or easier to adjust on the DH220 vs the DH200. You can easily check the DC offset with a voltmeter.

DH200's have been going for about $125, and often need some work even though they "sound great". DH220's have been going for $150-200 with minor to no work needed. I have a DH220, and IMO it punches above its weight, and I love the bass sound from it. A similar power newer Krell is more detailed but also a little harsh, and initially has more punch to start, but it falls off quicker than the Hafler. Similar power Parasounds have are more detailed, and IMO a step up. The bass is about the same, but there is a richness to Hafler I like. The Parasound wins though for the greater detail.

They will get quite warm while idle. Make sure both sides are the same temperature. if you have an IR thermometer check the temps. It can be a sign things are out of spec. I forget what the base line temps are, but they are online somewhere, or in an AudioKarma thread. Some people tweak DH220's to run hotter and potentially sound better, but that can also age components faster so be ware.

machone

doggie750 wrote: »

Machone-
Is the stock DH500 not good enough? Why need the upgrade? Cost to upgrade? Is it simply changing the cap? Thanks

Good when new but most are 30 years old and need attention.
The good news is Musical Concepts has been tweaking their upgrade kits for years and they will transform a Hafler.
The cost is significant. With new driver boards, power supply caps and recommended replacement of the thermal overload switches you will be in around $710 if you do the work. Add around $200 if they do the install plus shipping
I'm sure one could change caps and get it going but their driver boards move the Hafler into another class.
Depending what you can find one for plus the upgrades you will have a killer amp for way less less than $1500.

motorhead43026

Machone, do the boards come preassembled?

machone

Stuffed and tested with the bias and dc offset set close enough for power up.

kharp1

I have a pair of Hafler amps that will need work. One is a 220 and I thinkone is a 230. I know one is different than the other slightly, and if I recall, the 230 has Neutrik connections. Any one that is interested I'll move them CHEAP! I used the 220 for a while, but, noticed a pop through the speakers when I turned it on so I moved it to the side and never got back to it.

pkquat

kharp1 wrote: »

I have a pair of Hafler amps that will need work. One is a 220 and I think one is a 230. I know one is different than the other slightly, and if I recall, the 230 has Neutrik connections. Any one that is interested I'll move them CHEAP! I used the 220 for a while, but, noticed a pop through the speakers when I turned it on so I moved it to the side and never got back to it.

The P230 is the later version of the "professional" rack mount version of the DH-220. The early version was the P225. According to Hafler the P230 has additional MOSFETS and larger power supply fuses.

The pop or "thump" is normal for the DH-220 amps, and likely the P230. Usually they are turned on and left on. The DH-220 does not have relays on the speaker outputs. Relays were added to newer amps to prevent the thump. The click you hear after power up is the relays. Some high end amps today still don't have relays because they are considered something in the signal path and detrimental to sound for the purist. They are also always left on so they are at their stable state.

Once the amps are on, you can check the DC offset with a voltmeter. Both the DC offset and bias are adjustable. on these. The DC offset is not too hard to adjust, but with the age likely harder to get perfect zero. Less than 10mV should be possible. I think I got mine to within 5mV. The bias really needs to calibrated meters, and is more difficult. Small movements to the pots create wild swings which take time to settle.

gp4jesus

If I'm not too late, I have 2 Hafler XL-280s I'll let go. One w/ both channels working. The other, one channel stopped working, don't know why. No time to troubleshoot.

Noteworthy audiophile stuff: The XL-280 came from the factory w/ many of the known worthwhile upgrades for the DH-200/220, etc. Of particular interest to some is a separate, complete PSU for the driver boards. Further, separate L&R transformer secondaries, bridge rectifiers, & PS filtering for the finals. The DH predecessors, to my knowledge, came w/a single PSU to handle it all.

$225 for both plus shipping.

motorhead43026

^^good deal.

kharp1

@pkquat Thanks for the info. Probably should pull them back out and check them out.

gp4jesus

An addendum: 6 output devices per channel versus 4 per chnl for the DH 200/220.

Bridgeable into 4 ohms. I refer you to the manual for comprehensive specs.

It's no coincidence Musical Fidelity DH driver boards are VERY similar looking to the factory XL-280 boards.

machone

Pull the trigger

doggie750

Zip code 94544. Total cost? Thank you

gp4jesus wrote: »

If I'm not too late, I have 2 Hafler XL-280s I'll let go. One w/ both channels working. The other, one channel stopped working, don't know why. No time to troubleshoot.

Noteworthy audiophile stuff: The XL-280 came from the factory w/ many of the known worthwhile upgrades for the DH-200/220, etc. Of particular interest to some is a separate, complete PSU for the driver boards. Further, separate L&R transformer secondaries, bridge rectifiers, & PS filtering for the finals. The DH predecessors, to my knowledge, came w/a single PSU to handle it all.

$225 for both plus shipping.

gp4jesus

Final estimate ~$265?

Based upon 60lb weight, crunching numbers at the USPS web site. Hafta box 'em up & head to post office.

gp4jesus

doggie750 wrote: »

Zip code 94544. Total cost? Thank you

gp4jesus wrote: »

If I'm not too late, I have 2 Hafler XL-280s I'll let go. One w/ both channels working. The other, one channel stopped working, don't know why. No time to troubleshoot.

Noteworthy audiophile stuff: The XL-280 came from the factory w/ many of the known worthwhile upgrades for the DH-200/220, etc. Of particular interest to some is a separate, complete PSU for the driver boards. Further, separate L&R transformer secondaries, bridge rectifiers, & PS filtering for the finals. The DH predecessors, to my knowledge, came w/a single PSU to handle it all.

$225 for both plus shipping.

Yes? No? Maybe...

doggie750

I pass....I appreciate the deal though.