New amplifier for my AR-2ax pair

[LouB]

Hi all,

 

I was the lucky recipient of a nice auction site find yesterday.

A darn near pristine Hafler DH-120.

Planning to pair it with a Phase Linear 2000 preamplifier after it has had the electrolytic caps replaced.

This will be the first Hafler amplifier I have acquired. Also, the first mosfet final amp.

These will go into the rotation up in the living room, bumping the Scott 388 receiver I rebuilt a few years ago.

The 388 rebuild was mentioned briefly in a post on AK;

https://audiokarma.org/forums/index.php?threads/scott-388-rebuild.729576/

They will be driving my pair of 2-ax

Has anyone had experience with a Hafler / AR pairing previously?

Regards,

Lou

 

[JKent]

Hey Lou

Hafler stuff is good. I'm sure you know David Hafler was previously the owner/founder of Dynaco. Dynaco and AR always made a good pairing. More quality gear built here in NJ (along with Adcom, Bogen, the original Edison ?, others that escape me right now)!

Here's a good write-up on the DH-120 here: https://www.kenrockwell.com/audio/hafler/dh-120.htm

I used a kit-built Hafler DH-220 for years, then sold it, then had seller's remorse a few years later and bought a 200. Re-capped it, added inrush limiter, bigger output caps (18,000uF), gold jacks, then decided to sell that one and start on another DH-200. This time I scrapped the original boards and replaced them with new boards from Musical Concepts/Musical Design. My boards are PA-4. They're up to PA-6 with good sale prices on the PA-5. Again went with bigger output caps (22,000uF from Mouser), this time with added cascaded bypass caps (10uF mylar, 1uF PIO and a  .01uF Vishay MKP1837 on each can). Added a star ground (per Musical Concepts directions). The printed directions were not quite as good as the original Dynaco or Hafler directions but tech support from John Hillig was great.

Also replaced the power cord and bought several other mods from ebay seller qua-co (Fantasia Audio). I recommend him highly. Ed Fantasia is a former Hafler engineer and a great resource. I bought the inrush limiter, semiconductor repair kit and bridge rectifier. Prices, service, tech support were first rate.

I mention all this because I see you are experienced with recapping (etc) vintage amps so if you don't know these resources I recommend them.

So the modded 200 powers my AR-3a's and I'm very happy with it. The 200 puts out at least 175wpc into 4 ohm speakers and although the 3a's are said to like massive amounts of power, this suits me just fine. The 120 is conservatively rated at 60wpc into 8 ohms and should be more than enough with the 2ax's. 

Kent

[newandold]

I had an 11 year plus run with the Phase Linear 2000 preamp that I bought new, around 1978.

Very clean and neutral sound. It’s not as dead quiet as other preamps between source material, but a minimal issue. It should pair nicely with the Hafler, but I ran mine with the Phase 400.

I also had a pair of the 2ax, but they were long gone by the time I got to that point.

 I think you’ll have a great combination on your hands with that setup.

Very Spartan inside that 2000, When you take off the cover, there’s almost nothing in there! (Compared to a modern component)

 

Bill

 

[frankmarsi]

You forgot to mention that 'Qua-Co' is in Blackwood, N.J. 

[LouB]

On 10/5/2019 at 3:41 PM, JKent said:

Hey Lou

Hafler stuff is good. I'm sure you know David Hafler was previously the owner/founder of Dynaco. Dynaco and AR always made a good pairing. More quality gear built here in NJ (along with Adcom, Bogen, the original Edison ?, others that escape me right now)!

Here's a good write-up on the DH-120 here: https://www.kenrockwell.com/audio/hafler/dh-120.htm

I used a kit-built Hafler DH-220 for years, then sold it, then had seller's remorse a few years later and bought a 200. Re-capped it, added inrush limiter, bigger output caps (18,000uF), gold jacks, then decided to sell that one and start on another DH-200. This time I scrapped the original boards and replaced them with new boards from Musical Concepts/Musical Design. My boards are PA-4. They're up to PA-6 with good sale prices on the PA-5. Again went with bigger output caps (22,000uF from Mouser), this time with added cascaded bypass caps (10uF mylar, 1uF PIO and a  .01uF Vishay MKP1837 on each can). Added a star ground (per Musical Concepts directions). The printed directions were not quite as good as the original Dynaco or Hafler directions but tech support from John Hillig was great.

Also replaced the power cord and bought several other mods from ebay seller qua-co (Fantasia Audio). I recommend him highly. Ed Fantasia is a former Hafler engineer and a great resource. I bought the inrush limiter, semiconductor repair kit and bridge rectifier. Prices, service, tech support were first rate.

I mention all this because I see you are experienced with recapping (etc) vintage amps so if you don't know these resources I recommend them.

So the modded 200 powers my AR-3a's and I'm very happy with it. The 200 puts out at least 175wpc into 4 ohm speakers and although the 3a's are said to like massive amounts of power, this suits me just fine. The 120 is conservatively rated at 60wpc into 8 ohms and should be more than enough with the 2ax's. 

Kent

Hi Kent,

Yes,  I have had a few of the Dynaco pieces along the way.

The only one I was less than impressed with was the 120.

I had that in the late 90's, it was recapped and had the output transistors replaced when I first got it.

Just didn't have the robust character I had associated with the Heath W-6M monoblocks that had disappeared from our rehearsal space.

Currently, a rebuilt ST-150 runs my pair of 3a.

I had not ever used a Hafler piece previously, nor an amp with mosfet finals.

Just received it Friday, in good condition as the photos suggested.

Checked it out to see whether there was significant DC on the terminals, there wasn't.

Nice layout in it, it'll be easy to work on.

The date codes on the caps suggest that it was made in 1987.

I have replacement PS caps on order, smaller electrolytics in stash.

Looking forward to having a but more oomph than the 1965 Scott 388 is capable of.

[LouB]

On 10/5/2019 at 4:51 PM, newandold said:

I had an 11 year plus run with the Phase Linear 2000 preamp that I bought new, around 1978.

Very clean and neutral sound. It’s not as dead quiet as other preamps between source material, but a minimal issue. It should pair nicely with the Hafler, but I ran mine with the Phase 400.

I also had a pair of the 2ax, but they were long gone by the time I got to that point.

 I think you’ll have a great combination on your hands with that setup.

Very Spartan inside that 2000, When you take off the cover, there’s almost nothing in there! (Compared to a modern component)

 

Bill

 

Hi Bill,

I had gotten the 2000 about a month ago.

It is quite spacious under the hood.

Mr. Carver could almost have put it into a pack of Kools!

After receiving it it was unbalanced and grainy.

Replacement of the caps helped, but I experienced the phenomenon of "capacitor aging" I had always sneered at.

After running it continuously for a week or so the sound quality was astoundingly better.

Think it'll be a nice pairing with the DH-120.

 

Lou

 

[JKent]

Hey Lou

Forgot to mention another good resource: https://www.updatemydynaco.com  I completely rebuilt my ST-120.  My tech tells me the ST-150 was the best Dynaco amp ever.

And you can find Hafler manuals here: https://hafler.com/archive.php

I think you'll like the Hafler.

Kent

[ar_pro]

I really liked my old Dyna ST-150, but not so much the ST-120, which literally sparked & smoked with a pair of AR-3a. ☹️

My nephew has been using a Hafler DH220 with his AR-9 systems for over 30 years; he loves it, and I don't think he's ever had a single problem with the amplifier. It's a real workhorse, like Crown.

If you ever get the chance Lou, take a look at the Hafler 915 preamplifier (photo attached); it was a later solid-state model that could remind one of an excellent tube preamp, but with a much lower noise floor.

[JKent]

1 hour ago, ar_pro said:

take a look at the Hafler 915 preamplifier

Nice. I never liked the look of the 101, even though it was a good preamp. When I had my DH-220 I used a Technics SU-A4 preamp, which was a crazy good audiophile unit. Sold it when I decided to go "All American" for the vintage setup so now use a DB-1B preamp with the DH-200.

Lou (and others) like the PL-2000 but up for your consideration is the DB-1B: 

[newandold]

17 hours ago, LouB said:

Hi Bill,

I had gotten the 2000 about a month ago.

It is quite spacious under the hood.

Mr. Carver could almost have put it into a pack of Kools!

After receiving it it was unbalanced and grainy.

Replacement of the caps helped, but I experienced the phenomenon of "capacitor aging" I had always sneered at.

After running it continuously for a week or so the sound quality was astoundingly better.

Think it'll be a nice pairing with the DH-120.

 

Lou

 

Hi Lou,

Yes I agree it should be an excellent paring.

 I made use of that “Ambience” circuitry, continually and kept it around 2 o’clock or so....opened up the soundstage nicely.

Some purists have a tendency to dismiss that kind of embellishment, but my ears liked it!

Years later when I made one serious system for both film and music, I was back to Carver (Sunfire) with his Theater Grand Processor that has an evolved version of that circuitry.

Bill

[LouB]

1 hour ago, newandold said:

Hi Lou,

Yes I agree it should be an excellent paring.

 I made use of that “Ambience” circuitry, continually and kept it around 2 o’clock or so....opened up the soundstage nicely.

Some purists have a tendency to dismiss that kind of embellishment, but my ears liked it!

Years later when I made one serious system for both film and music, I was back to Carver (Sunfire) with his Theater Grand Processor that has an evolved version of that circuitry.

Bill

Hi Bill,

Back when I was in high school I remember that a buddy used a Dynaco Quadraptor.

It was kinda cool, a soundstage was created which complimented most material nicely.

IIRC he had a pair of large KLH for the front and a couple of 8" Fisher (maybe XP-56) for the rear.

I hadn't thought of using this preamp to take advantage of the effect.

Since this is for the living room system which also is a Video setup with 2 channel audio, this could be fun.

The only smaller ones I have right now are a pair of diminutive DLK 1/4.

I have a Crown D75 I could use for the back channels.

I'm imagining that balancing the whole mess can be tricky.

Aaaahhh.... So much fun, So little time....

[newandold]

1 hour ago, LouB said:

Hi Bill,

Back when I was in high school I remember that a buddy used a Dynaco Quadraptor.

It was kinda cool, a soundstage was created which complimented most material nicely.

IIRC he had a pair of large KLH for the front and a couple of 8" Fisher (maybe XP-56) for the rear.

I hadn't thought of using this preamp to take advantage of the effect.

Since this is for the living room system which also is a Video setup with 2 channel audio, this could be fun.

The only smaller ones I have right now are a pair of diminutive DLK 1/4.

I have a Crown D75 I could use for the back channels.

I'm imagining that balancing the whole mess can be tricky.

Aaaahhh.... So much fun, So little time....

You said it! 

If you wanted to go the quasi surround (quad) mode and stay vintage, the Phase Linear 4000 is still not too hard to come up with.

[LouB]

1 hour ago, newandold said:

You said it! 

If you wanted to go the quasi surround (quad) mode and stay vintage, the Phase Linear 4000 is still not too hard to come up with.

Aargh!

The boss would give me a quizzical look and ask “ Why is is again, that we need these extra two speakers and all these confusing controls? “

[newandold]

14 minutes ago, LouB said:

Aargh!

The boss would give me a quizzical look and ask “ Why is is again, that we need these extra two speakers and all these confusing controls? “

Admittedly, I'm too lucky in that regard.

Not long ago, someone saw my living room and said it looks like a bachelor's pad.

My bride is a huge fan of the Home Theater, and that has given me creative license in that room. 

A 115 lb. subwoofer sits in the corner, and I think it was at least a year before she even asked me what that was.

[ar_pro]

21 hours ago, JKent said:

Nice. I never liked the look of the 101, even though it was a good preamp. When I had my DH-220 I used a Technics SU-A4 preamp, which was a crazy good audiophile unit. Sold it when I decided to go "All American" for the vintage setup so now use a DB-1B preamp with the DH-200.

 

The DB-1B is a beauty in its wooden case, and it will probably last forever.

DB Systems never seemed to get the amount of attention it should have from either the mainstream stereo magazines or even the "underground" publications. I remember a long conversation with the owner/designer many, many years ago, and he was really dedicated to putting out a very high quality product at an affordable price. The early Mark Levinson company seemed to have a similar philosophy.