I think I've seen these on eBay. Just search on Hafler amplifiers and you may see them among the listings for amplifiers and parts (like replacement switches).
Cheers,
Bob
That seems like a good thing to have on hand if you have an amp.
The burned contact was due to a loose connector and repairing that will likely improve the sound quality of that amplifier. You need to replace the push-on connector as well because the heat will have wrecked the terminal, even if it was the rivet that was arcing.
-Chris
The burned contact was due to a loose connector and repairing that will likely improve the sound quality of that amplifier. You need to replace the push-on connector as well because the heat will have wrecked the terminal, even if it was the rivet that was arcing.
-Chris
Disregard my last. I ordered 2 P chnl & 2 N Chnl TO3 from Profusion. Got the -s Matched type. Not Cheap but should provide interesting sonics as this is will be 1 chnl of a dual mono setup.
It will be very interesting as to whether you hear a difference one way or the other between the two amps. Keep us posted.
Ron
That is most awesome!!!
I am ..so happy.. to hear this... wg45.
I cannot wait to hear more of what you think.
Off-line (of course) wink. Please do share.
The Hafler renaissance is a great thing...
I live that on a regular basis...
Everyone, every chassis [and build]
!!!IS A WINNER!!!
I am ..so happy.. to hear this... wg45.
I cannot wait to hear more of what you think.
Off-line (of course) wink. Please do share.
The Hafler renaissance is a great thing...
I live that on a regular basis...
Everyone, every chassis [and build]
!!!IS A WINNER!!!
About to post a few recent amp builds
A suited background...
As a qualifier, to use a vintage car analogy. I am not trying to take dad's old car (Mustang, Camaro, Charger or Cuda) that has been sitting in the barn for 20-30 years, in disrepair, not running, even get it started and be able to take it for a (safe) drive. There is a great amount of prerequisite work that must take place prior to said event. With vintage electrical components there are REAL HAZARDS, damage to speakers, electrical shock and possibly even burning down your home (though extreme).
These old cars need new tires, new shocks, new brakes, maybe brake lines, new fuel, oil and air filters. To really do real justice to the venerable old champs, they need far more than just air in its' tires, and new wipers… [in addition to fresh fuel, oil, fluids and a tune up…] so many things are overlooked.
Likewise, I am not talking about taking a 30+ year old amp and just get it running. My intent, people [the comparatively few] that I build for, want it restored to modern days standards, with good parts that did not even exist when originally built, to use associated with 'better gear' in more modern audio systems, costing many multiples in cost above the base amp.
I am talking (again in car terms) dropping an energetic crate motor, a beefed up clutch and drive train, with ~fat tires~ that can plant that kind of power to the ground (with beefy brakes) that can safely stop it. Old tired, worn out stock parts do not cut it... sorry. Home audio gear is no different, TLC / balanced with safety, is an important portion of the equation to use.
I am not preaching, talking down my nose, or berating anyone… Just stating very clearly ('beyond argument' or il’chosen dispute) why I do what I do and how… Why, I am so thorough in my work effort. These old amps are tired, need to be refreshed… but are capable of extraordinary levels of performance with the right approaches. It takes the resources of time and money (just like a car) to get things right. If doing it on the cheap, is your thing… I am admittedly, the last guy to talk to or follow.
I am not trying to just 'get it good enough', pass… Shoddy work, old parts and circuits… is why most hard core audiophiles won’t even give these relics the time of day, readily dismiss them! [rightly so] Stock Hafler amps sound soft and wooly - in my book are un-listenable, that is if or after you hear, one built up proper.
I don’t even play ~any gear that I buy~ on any of my sound systems. I short the input, put a dummy load on the output and DO CHECK DC OFFSET before doing any thing else… many measure / fail miserably before ever doing incidental damage to my expensive speakers...
A suited background...
As a qualifier, to use a vintage car analogy. I am not trying to take dad's old car (Mustang, Camaro, Charger or Cuda) that has been sitting in the barn for 20-30 years, in disrepair, not running, even get it started and be able to take it for a (safe) drive. There is a great amount of prerequisite work that must take place prior to said event. With vintage electrical components there are REAL HAZARDS, damage to speakers, electrical shock and possibly even burning down your home (though extreme).
These old cars need new tires, new shocks, new brakes, maybe brake lines, new fuel, oil and air filters. To really do real justice to the venerable old champs, they need far more than just air in its' tires, and new wipers… [in addition to fresh fuel, oil, fluids and a tune up…] so many things are overlooked.
Likewise, I am not talking about taking a 30+ year old amp and just get it running. My intent, people [the comparatively few] that I build for, want it restored to modern days standards, with good parts that did not even exist when originally built, to use associated with 'better gear' in more modern audio systems, costing many multiples in cost above the base amp.
I am talking (again in car terms) dropping an energetic crate motor, a beefed up clutch and drive train, with ~fat tires~ that can plant that kind of power to the ground (with beefy brakes) that can safely stop it. Old tired, worn out stock parts do not cut it... sorry. Home audio gear is no different, TLC / balanced with safety, is an important portion of the equation to use.
I am not preaching, talking down my nose, or berating anyone… Just stating very clearly ('beyond argument' or il’chosen dispute) why I do what I do and how… Why, I am so thorough in my work effort. These old amps are tired, need to be refreshed… but are capable of extraordinary levels of performance with the right approaches. It takes the resources of time and money (just like a car) to get things right. If doing it on the cheap, is your thing… I am admittedly, the last guy to talk to or follow.
I am not trying to just 'get it good enough', pass… Shoddy work, old parts and circuits… is why most hard core audiophiles won’t even give these relics the time of day, readily dismiss them! [rightly so] Stock Hafler amps sound soft and wooly - in my book are un-listenable, that is if or after you hear, one built up proper.
I don’t even play ~any gear that I buy~ on any of my sound systems. I short the input, put a dummy load on the output and DO CHECK DC OFFSET before doing any thing else… many measure / fail miserably before ever doing incidental damage to my expensive speakers...
Stockish DH220 and crazy MM220
A few pictures of my latest “Hafler” DH220 based amps builds, referred to as MM220 amps. These amps ~ WERE NOT CHEAP TO BUILD ~ I was not building to a price point, I was building to a standard of quality, not possible in their original manufacture. Hafler amps were built to a market driven price point and to only ‘deliver spec’. I usually spend twice what I pay for the ‘working chassis / amps alone for a basic build and triple or quadruple that to create super amps ~ vastly surpassing ~ so much of what is available in todays products, up to 10 times their cost. I understand that this may only appeal to limited few here.
The one on the left, for a music appreciating, non-audiophile person, wanting vintage gear, with modern parts. He was not in a capacity to afford newer / completely modernized Musical Concepts driver boards or the more expensive power supply options. I left the speaker protection fuses, but moved them in series with the speaker outputs, while simplifying the output stage filter networks. It is rebuilt as a brand new amp, should play wonderfully for another 30 years...
I left the stock transformer to reduce costs and used the best capacitors that the collective / entire budget would permit. I used the stock PC19 driver boards, but completely rebuilt and optimized them. I did not simply only change the stock 3 electrolytic caps to audio grade caps. *These amps border unsafe with stock electrolytic caps… especially the stock white main P/S caps...
The amp on the right is an ~ ALL OUT AMP ~ which I built with 'scavenged parts’, the toroid from my original MC220 from 1985. This new amp is for a close personal friend, that will use it a bass amp in a bi-amp speaker system. I often ask people what their budget is… to establish some hierarchy in allocation of a sensible / meaningful cost structure... to spend money where it will make the biggest difference given its intended role and application in use. It matters and ever builder should look at their approach, consider where it will make the greatest impact in the collective of parts being assembled as a whole. I am paying it forward with this amp… It is the most stuffed chassis I have build in 40 years of building “Hafler” based amps.
I cannot emphasize strongly enough how important building a solid core is to the end result. Of course everyone's abilities and or limits must be considered, as it is not an easy task… but very much worth the effort. A happy chassis is always a great sounding chassis. Many older kit builders, in the day used wretched silver coated copper wiring, among other things that really harmed the beauty of these amps. I remove these sort of things, the original tinned copper wiring is not sonically in need of replacement (if in good shape) but everybody has to begin and learn somewhere. I often time ‘have to rewire’ as newer parts and chassis layout requires it, the original wire lengths will not fit the newer component placement. Modern driver boards with fuses on them eliminate chassis pan fuses, freeing up much room to do a lot of creative building..
In this build the #1 most important "component part" was the DRIVER CARDS. Goods ones ~ ARE NOT CHEAP ~ the original PC19 ones are showing their age and are profoundly limiting. I no longer even bother rebuilding original Hafler 200/500 (PC6 / PC10 boards)… I will not build any amps around them. The fully rebuilt ‘modernized’ PC19 driver boards are used in the “STOCKISH” MM220 on the left is pretty good but does not adequately showcase these fantastic vintage lateral MOSFETS
For the ~ ALL OUT AMP ~ on the right, I used my original (exemplary) Musical Concepts PA4 boards, pulled from my 2013 MM220 build, which were effortlessly running Magnepans for many years. I knew what to expect, including these in this stuffed MM200. The #2 most important part, the beefy 625va toroid, was the biggest I could squeeze in to the chassis with (the #3 most important part) 80 wvdc / 22,000 mfd, 62.5mm filter caps. The #4 in order, was the RCA inputs and the 5 way binding posts. I budgeted accordingly, am happy with the result. cannot wait to see the expressions on my buddies face when he hears this amp. He will be comparing them to Futterman OTL amps; the ones I used to own..
It could be debated using the stock speakers terminals... however they will not accommodate too many types of good speaker cables [none, that I own or use] with modern connectors (unless using just ‘basic’ banana plugs) they are an absolute hazard with modern spade terminals and risk damaging them, even worse short circuit. I asked my friend what he would be using in making decisions. As a direct example, the 5/16” WBT spades (200.00, for a set of 4) on my Monacle Kimber Kables, would possibly only be mangled, not even work as intended. GOOD BINDING POSTS ARE A MUST… budgeting them your call… filing out the chassis to fit (is based more on your skill and ability) Not easy but worth the efforts.
A few pictures of my latest “Hafler” DH220 based amps builds, referred to as MM220 amps. These amps ~ WERE NOT CHEAP TO BUILD ~ I was not building to a price point, I was building to a standard of quality, not possible in their original manufacture. Hafler amps were built to a market driven price point and to only ‘deliver spec’. I usually spend twice what I pay for the ‘working chassis / amps alone for a basic build and triple or quadruple that to create super amps ~ vastly surpassing ~ so much of what is available in todays products, up to 10 times their cost. I understand that this may only appeal to limited few here.
The one on the left, for a music appreciating, non-audiophile person, wanting vintage gear, with modern parts. He was not in a capacity to afford newer / completely modernized Musical Concepts driver boards or the more expensive power supply options. I left the speaker protection fuses, but moved them in series with the speaker outputs, while simplifying the output stage filter networks. It is rebuilt as a brand new amp, should play wonderfully for another 30 years...
I left the stock transformer to reduce costs and used the best capacitors that the collective / entire budget would permit. I used the stock PC19 driver boards, but completely rebuilt and optimized them. I did not simply only change the stock 3 electrolytic caps to audio grade caps. *These amps border unsafe with stock electrolytic caps… especially the stock white main P/S caps...
The amp on the right is an ~ ALL OUT AMP ~ which I built with 'scavenged parts’, the toroid from my original MC220 from 1985. This new amp is for a close personal friend, that will use it a bass amp in a bi-amp speaker system. I often ask people what their budget is… to establish some hierarchy in allocation of a sensible / meaningful cost structure... to spend money where it will make the biggest difference given its intended role and application in use. It matters and ever builder should look at their approach, consider where it will make the greatest impact in the collective of parts being assembled as a whole. I am paying it forward with this amp… It is the most stuffed chassis I have build in 40 years of building “Hafler” based amps.
I cannot emphasize strongly enough how important building a solid core is to the end result. Of course everyone's abilities and or limits must be considered, as it is not an easy task… but very much worth the effort. A happy chassis is always a great sounding chassis. Many older kit builders, in the day used wretched silver coated copper wiring, among other things that really harmed the beauty of these amps. I remove these sort of things, the original tinned copper wiring is not sonically in need of replacement (if in good shape) but everybody has to begin and learn somewhere. I often time ‘have to rewire’ as newer parts and chassis layout requires it, the original wire lengths will not fit the newer component placement. Modern driver boards with fuses on them eliminate chassis pan fuses, freeing up much room to do a lot of creative building..
In this build the #1 most important "component part" was the DRIVER CARDS. Goods ones ~ ARE NOT CHEAP ~ the original PC19 ones are showing their age and are profoundly limiting. I no longer even bother rebuilding original Hafler 200/500 (PC6 / PC10 boards)… I will not build any amps around them. The fully rebuilt ‘modernized’ PC19 driver boards are used in the “STOCKISH” MM220 on the left is pretty good but does not adequately showcase these fantastic vintage lateral MOSFETS
For the ~ ALL OUT AMP ~ on the right, I used my original (exemplary) Musical Concepts PA4 boards, pulled from my 2013 MM220 build, which were effortlessly running Magnepans for many years. I knew what to expect, including these in this stuffed MM200. The #2 most important part, the beefy 625va toroid, was the biggest I could squeeze in to the chassis with (the #3 most important part) 80 wvdc / 22,000 mfd, 62.5mm filter caps. The #4 in order, was the RCA inputs and the 5 way binding posts. I budgeted accordingly, am happy with the result. cannot wait to see the expressions on my buddies face when he hears this amp. He will be comparing them to Futterman OTL amps; the ones I used to own..
It could be debated using the stock speakers terminals... however they will not accommodate too many types of good speaker cables [none, that I own or use] with modern connectors (unless using just ‘basic’ banana plugs) they are an absolute hazard with modern spade terminals and risk damaging them, even worse short circuit. I asked my friend what he would be using in making decisions. As a direct example, the 5/16” WBT spades (200.00, for a set of 4) on my Monacle Kimber Kables, would possibly only be mangled, not even work as intended. GOOD BINDING POSTS ARE A MUST… budgeting them your call… filing out the chassis to fit (is based more on your skill and ability) Not easy but worth the efforts.
Attachments
@OzaDoc
From what I can see, you've removed the thermal sensor/breakers. How come? If you replaced these, which units did you install? And where?
Incidentally, I like the idea of the IXSYs but I wonder if the real reason for the significant improvement was (and I'm assuming here) the dual secondary transformer and the resultant channel separation?
From what I can see, you've removed the thermal sensor/breakers. How come? If you replaced these, which units did you install? And where?
Incidentally, I like the idea of the IXSYs but I wonder if the real reason for the significant improvement was (and I'm assuming here) the dual secondary transformer and the resultant channel separation?
IXSYs HEXFRED is a robust device...
I have used them in every build for 8 years. 1 IXSY for single secondary and (of course) 2 for dual secondary toroid. These clearly are only single secondary transformers. The one on the left, is 'stockish' The one on the right will be used mono [application specific] is a ball buster, a brute. My buddy will likely pull fuses from one channel and devote the full supply to driving only one channel. Potentially will be(come) like my P230 mono, with an even bigger supply.
No thermal 'protection' is likely point of contention for some, a point of 35+years of experience, on my part... I have never overheated any Hafler amp, even on demanding loads. [on Revels and/or Maggies] If a person is going to enclose the amp in a cabinet, I might feel and build differently. At over 100 builds... it has NEVER BEEN A PROBLEM. I carefully manage my bias settings (typically above stock settings) NEVER have had a heat problem... I am not using crazy low impedance amps loads (though many are) like on paralleled bass drivers / cabinets... *we must face the fact people 'abuse' these amps... punish them, fuses and heat protection [are favorable] for that use model. They serve as an impediment in my designs and use, serve no direct benefit.
As you know, the temperature sensor / switch is on the primary side of the transformer and if not wired with heavy enough gauge wire or is failing, it can prove to be current limiting... YMMV, each builder has their own approach, level of comfort and experience.
My approach might not be yours or others. It is also another thing to fail...
I have used them in every build for 8 years. 1 IXSY for single secondary and (of course) 2 for dual secondary toroid. These clearly are only single secondary transformers. The one on the left, is 'stockish' The one on the right will be used mono [application specific] is a ball buster, a brute. My buddy will likely pull fuses from one channel and devote the full supply to driving only one channel. Potentially will be(come) like my P230 mono, with an even bigger supply.
No thermal 'protection' is likely point of contention for some, a point of 35+years of experience, on my part... I have never overheated any Hafler amp, even on demanding loads. [on Revels and/or Maggies] If a person is going to enclose the amp in a cabinet, I might feel and build differently. At over 100 builds... it has NEVER BEEN A PROBLEM. I carefully manage my bias settings (typically above stock settings) NEVER have had a heat problem... I am not using crazy low impedance amps loads (though many are) like on paralleled bass drivers / cabinets... *we must face the fact people 'abuse' these amps... punish them, fuses and heat protection [are favorable] for that use model. They serve as an impediment in my designs and use, serve no direct benefit.
As you know, the temperature sensor / switch is on the primary side of the transformer and if not wired with heavy enough gauge wire or is failing, it can prove to be current limiting... YMMV, each builder has their own approach, level of comfort and experience.
My approach might not be yours or others. It is also another thing to fail...
I'll 'assume' stock driver cards?
Among a number of issues, I have expressed as bottlenecks common to many Hafler amps, I see. Any pictures to share, or "would you dare"?
Funds must be applied in hierarchical terms. *not a criticism of you, though common, prospect. I am sorry this is your experience.
Among a number of issues, I have expressed as bottlenecks common to many Hafler amps, I see. Any pictures to share, or "would you dare"?
Funds must be applied in hierarchical terms. *not a criticism of you, though common, prospect. I am sorry this is your experience.
All good.
I do understand, was not referring to you.
No worries. I wanted to be clear (to any)
that may read my reasoning.
Everyone has their own comfort,
experiences and rationale.
I do understand, was not referring to you.
No worries. I wanted to be clear (to any)
that may read my reasoning.
Everyone has their own comfort,
experiences and rationale.
IXSYs? Would these improve any amp’s*? First I’m hearing of these. Where to buy? I have several Rotels that would benefit accordingly - 2 for “slam” the others musical clarity. This hobby has no limits
Side note: add internal wiring as fuel lines to your “resto” analogy. I think XL-280 internal wire must have steel in it because it’s kinda stiff for being so thin.
Thanks. Tony
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