Know that this could go a lot of different ways but are Hafler preamps and amps worth upgrading?Been told by a few that they are not but would like opinions from knowledgeable people on the site who might have a on hands experience.Thanks for any input. 

Hi John!

If we're talking about the 1980's amps then I'd say no. I worked for one of Dolby's competitors and we OEM'd Hafler amplifier modules with our own power supplies. We bought dozens at a time.

The amps were noiseless and not terribly grainy but really lacked dynamic energy and bass, not to mention any sense of imaging. I had a little Sumo Polaris that would spank a more powerful Hafler easily, and even took it into the factory to compare. 

Could you have made it into something better with upgrades? I don't honestly know, but I would say they were overrated at the time. Much better from the period were Tandberg though as one reviewer wrote, quite grainy, and Krell. Also Sumo and Amber. Even Carver from that period was a much better choice, if it didn't start a fire. :) 

Of course IMHO this was also when Conrad Johnson's Tube amps were near their prime. There, if any flame war was going to start, this should totally do it. 


I should add Halfer was a prime example of an amplifier that measured with text-book perfection, and yet, was totally boring to listen to. 
Have a DH220 and was wondering if to sell it or keep it and upgrade? 
@john421 Sell it.
I was one of many who started on the seperates path with the affordable Hafler DH101 Pre. & DH-200 in the early 80's. In Austalia the go was to upgade/mod these. The mosfet Power Amp became quite reasonable although the Pre. was somewhat lacking. The DH-200 was virtually indestructable. However you would be far better putting your money into a more current Power Amp.

Even something like the affordable Emotiva XPA-2 will be light years ahead of a modded DH-200 in sound quality.

 So sending them to Musical Concepts and other similar companies is a waste of time and money? 
Well, I don't know if it would be a waste of time or not.  In fact those amps had a lot of room for improvement! So upgrading may in fact yield really good results.

My point is though they were never that good to begin with. Another user has been asking about upgrading a Sonic Frontiers 3 preamp. That was always a spectacular preamp, well worth keeping and buying updated parts for. 

With a unit like the Hafler in my mind it's kind of a toss up.  I don't think you'll ever get your money back, but I also haven't heard the upgrades. 

For me, having gone down this route myself, I'd rather go with an amp I thought was really good at the beginning. 

I'd check the upgrade costs and the reputation, and keep in mind what a used Sumo, Carver, Krell, Martin Logan, Threshold. 


Overall Erik has nailed it, but he didn't mention that Hafler made a few very good amps in later years... the 9300 to 9500 series were quite good... The 9505 is a Great sounding amp by any standards. 
@timlub I'll defer to your experience! I certainly did not listen to every Halfer amp/module that came out.

I just did a quick look on Agon, there's a Sumo 9 that has already been upgraded for around $900. I'd compare upgrading to that kind of deal. If you are going to spend $300-$400 on upgrades, I'd totally pass and get the 9 instead.  Of course, this is general observations. 


I think the Hafler line was one Julian Hirsch, from the long defunct Audio magazine would have loved. Bless his heart, he had no ear at all.


The DH-101 and DH-200 were my first amp and preamp in the high-end arena. At the time and for the money they were indeed excellent pieces of gear.

I was a Halfer dealer for many years and David, (R.I.P.) and I became very good friends. His gear was never intended to be State Of The Art. It was very well built, sounded decent and was affordable.

I’ve owned several upgraded/modded Hafler pieces. Most by John Hillig, (Musical Concepts).

If you had asked this several years ago, I’d say to send it in, but with the current crop of amps available today on the used market, I’d say look at the Emotiva or Parasound.

Julian had no use for ears!

Considering the age and modest performance of most of the Haflers discussed, I'm with those thinking that it's not worth investing in.

Sure we all get nostalgic about gear from when we first heard good sound, but more often than not the hype was relative to a lower bar of performance than widely available nowadays. Cheers,
+1 for Parasound! I forgot.  The A23 is a VERY nice sounding modest powered amp that is $1k new, but around $650 used. I'd probably take that over the Sumo just for age. :) 

I owned a pair. Forgot all about them as an option, since they are still pretty recent.  Runs class A up until 30 Watts or so. 

Hi Erik, 

     Funny that you mention the Sumo Nine, it is a decent amp stock, but  after upgrading I have considered it one of the better buys in Audio for quite some time.  I had/have the heaviest upgraded/modded Nines that I have seen.  I've heard the pieces done by Mike Bettinger and they are a clear improvement over the stock Sumo. My house took a lightening hit and took out my Nine.  Insurance gave me a fair price for mine.  I recently sent it to Ed Martin,  My old boss at SpeakerCraft/Marcof Electronics.  Back in the old days, we were a Sumo Dealer, I recall Ed debating with Jim Bonjiorno about making the Nine better (not a Nine Plus).  The original outputs are not available for the Nine,  Ed went and found a Motorola that he says is clearly better than the original, he is updating the boards and adding Filter capacitance, originally 40,000 mfd,  now it will be at 176,000 mfd,  he found a much lower ESR cap valued @ 22,000 mics and higher temperature rating and is doubling them up from 4 to 8.... The inputs and outputs are all wired with hand wound litz, he took the schematics and made slight changes to the boards and not only changed to higher quality parts but is changing some parts values that were left lower in the design because of significant cost difference. New high quality speaker terminals also... I already had the best Nine that I've ever heard, so I'm pumped,  I hope to have it in about 60 days.

So, yes, you can hear my enthusiasm for this old amp.  I've compared it to a bunch in my home,  I kept my extra heater (the Nine is Hot!).... I do also have a Class D  amp that I did from Abletec modules,  it is very good,  but I still like my old Sumo  better.  Tim

"I think the Hafler line was one Julian Hirsch, from the long defunct Audio magazine would have loved.
Hirsch was with Stereo Review, not Audio. Audio magazine actually had very good reviews.

@cleeds Yet another example of how bad my memory is from back then. :) 


Power caps have gotten so much smaller and better overall than in the hey-day of SS amps.  I've re-capped a few old amps from that period, and the new caps are all so small you have to modify the cases to keep them in place.  I imagine the ESR has also dropped dramatically.

I was very sad when it seemed Sumo was going somewhere and then kind of overnight went poof. 


Have the Hafler and a Sony 55es amp that I'm not using and was thinking about using one in a second system.

John, I haven't sat in front of the Sony, but it has a very good reputation for what it is.... I wish that I could comment more on the Sony, but I'd be spitting through my teeth.  I've played a fair amount with the Haflers.

The Hafler can be modified.... John Hillig calls his a Mod, but it really isn't, he changes the boards out completely to his own boards, he simply uses the power supply and outputs.  It really is a new amp design.  It is quite good, but I recall him getting some pretty good bucks and like it was said earlier, I also believe that your better off just getting a decent amp.

However, On Ebay,  there is a guy that will do decent mods on your amp for $125, you send him your amp, he does a fair amount of parts upgrades and sends it back.... I've looked at his kits in the past.  Your Hafler would end up being fluid, smooth, very decent sounding. It won't have the detail of the better amps, nor the dynamics, but none the less, it will be a very noticeable improvement. Do a search for Hafler DH220, he always kept his ads running, I'm sure that he is still there.

John Hillig does an excellent job on Haflers.  He's been creating successful Hafler amp and preamp mods for 30plus years, knows what he's doing.  I have used his design and even cut Haflers in half (Quarterlers?) to create two mono amps each with massive power supplies.

But even the very best mods cannot overcome the biggest problem with Haflers.  They lack very fine detail of modern amps and any dynamic slam at all.  I don't know what can be done to improve this.  It's just not there. 

With the great selection of modern amps at great prices, the Haflers just don't make sense in a full range system.  That said, they might work OK with subwoofers operating below 35hz with steep crossovers.  Not much dynamic requirements down there, just pumping out bass from a big subwoofer. 
I owned one of the MC modified Haflers.  It was very powerful, deep bass, fast and very dynamic.  Cannot recall the sound of how much detail but that can come with what is feeding the amp.  If you can get one cheap and do the modifications yourself that is where I would spend some money.  If not than find one of the amps suggested above.  You can also look at the hybrid Counterpoint SA-100 power amps as another option.  Happy Listening.
Hafler gear has always been a good value.  You always got a lot of good sound for your money and I think for what it sells for today, it still does.  But how good is it really and would you be happier with something else?  Maybe...

Loudspeaker drivers present a reactive load to a loudspeaker.  Add in a passive crossover, which has resistors, caps and inductors, and you get an impedance curve that looks like a Coney Island roller coaster.  That's why people spend big bucks on power amps.

But when you go to a multi-amplified setup with an active crossover, you get a very simple load to the amp channels - just the one driver.  When you do that, you can get by with very modest amps like Haflers.  

Were you to build your own loudspeaker with a well engineered passive crossover and drive it with some new hi-end power amp, I'd suggest that it wouldn't begin to do as well as the same loudspeaker being driven by several Hafler amps being managed by an active crossover like one from miniDSP.   You could readily spend $5000 or more on a power amp and not have as good a result as a miniDSP crossover managing some old Hafler amps.
I used to own Hafler 9500 or something like that. I really liked it. I chose it over $4000 Mcintosh that I was demoing, and I remember that I made the dealer disappointed.
I'm replacing caps on XL600's and DH220's for relatively cheap.  I have Emotiva XPA 1's Gen 2's and XPA 2 Gen 1's.  I also have some early John Curl Parasound in use also.  My XL600's kick's the Emotivia's butt.  Stable down to less than 2 ohms and sound just as good.  The Emotvia's crap out with just a hint of sub 4 ohm.  The DH220's are great once you recap them.  Picked up some 80V 22000uf caps and boom the bottom end comes alive.  For the bang for the buck quotient the Haflers cant be beat.  I see once awhile up for sale and usually gone in a blink.  Unless you have lots of cash burning a hole in your pocket you will spend a lot more getting better.   
People took Hafler's amplifier modules, combined them with their own power supplies, then claim the result had no dynamics or bass response(which heavily rely on the power supply) and it's Hafler's fault?  That's kinda cute!   In the 80's, Hafler was a huge step up from mid-fi offerings.   To get closer to the higher end of the day(and- we're talking about solid state), it did take swapping out the plethora of electrolytics out for polypropylene/polystyrene caps, on the driver boards, to improve their clarity/purity/transparency/liquidity(whatever you care to call it).   Hafler offered a few mod kits for their early amps(referring to DH-120, 200, 220, and 500's) over the years.  One of the first was the DH-203 mod kit(Bailey Mod) to replace the input's DC blocking electrolytic(C1), which made a major presentation improvement by itself.   To update one of those older amps to today's standards/performance would take better input RCAs, 5 way binding posts, an IEC connector(to facilitate a better power cord) and replacing every(now over 30 year old) electrolytic cap in the unit.   Not expensive, or hard to do, if one is handy with a soldering iron and screwdriver.