comparisons are like...
Oil cans (I also own a HV stash of them) I love them.
Are you actually serious? From apples to bananas man.
Inarguable example given, but thanks anyway.
Oil cans (I also own a HV stash of them) I love them.
Are you actually serious? From apples to bananas man.
Inarguable example given, but thanks anyway.
Thanks for the feedback.
The PArasound has several features that make it work as it does.
Of course, the floating bias JFET input stage John is famous for, Use of Transient Miller compensation in the VAS, and enough output transistors to keep the current within a half-decent range to help dynamic linearity.
My MOSFET amp started as a dead Hafler 120. It now has Exicon outputs, modified the CCS vor input and VAS, modified the spreader, modified the wire architecture and my big change was switching from dominant pole filtering to Miller. Getting stability with the MOSFETS was very hard, so it is easy to see why Erno picked the simple filter. I could tune one amp parasitics not to blow up, but no way would I do that in a kit! It did take several sets of outputs. 🙂
The PArasound has several features that make it work as it does.
Of course, the floating bias JFET input stage John is famous for, Use of Transient Miller compensation in the VAS, and enough output transistors to keep the current within a half-decent range to help dynamic linearity.
My MOSFET amp started as a dead Hafler 120. It now has Exicon outputs, modified the CCS vor input and VAS, modified the spreader, modified the wire architecture and my big change was switching from dominant pole filtering to Miller. Getting stability with the MOSFETS was very hard, so it is easy to see why Erno picked the simple filter. I could tune one amp parasitics not to blow up, but no way would I do that in a kit! It did take several sets of outputs. 🙂
For those who believe their 50 year old caps are good as new, close your eyes and believe. Do not go measure the power harmonics, increased ESR, leakage, degradation of DF etc. Continue to live happy. Unfortunately, all my years in failure analysis and direct experience with old equipment forces me to know the actual facts, so I am doomed to spend money to fix what I know is wrong.
Use exactly the same brand component
At the point you see any issues, replacement would "be an easy task".
I thought that I saw *Nichicon Gold Tune caps in the HCA2200II
the amp was built very well. with good parts.
I have great respect for this ^^^ component, have used A LOT
of Nichicon LNT, MUSE and small Gold Tune = my go to caps,
their form factor will readily fit most gear.
I have always wanted to try Gold Tune in a build...
literally was recently looking at them...
They are still available, as a performance part
(looked mostly at the 80v part) they were in stock
at Mouser... inventories appear low everywhere.
I will ADMIT I RECAP WITH MODERN PARTS,
to elevate the performance of any products I use,
much like performance tuning cars.
At the point you see any issues, replacement would "be an easy task".
I thought that I saw *Nichicon Gold Tune caps in the HCA2200II
the amp was built very well. with good parts.
I have great respect for this ^^^ component, have used A LOT
of Nichicon LNT, MUSE and small Gold Tune = my go to caps,
their form factor will readily fit most gear.
I have always wanted to try Gold Tune in a build...
literally was recently looking at them...
They are still available, as a performance part
(looked mostly at the 80v part) they were in stock
at Mouser... inventories appear low everywhere.
I will ADMIT I RECAP WITH MODERN PARTS,
to elevate the performance of any products I use,
much like performance tuning cars.
Since you will be digging through a 2200ii....have you seen this blog? It is about mod done based on several comments John Curl made here on the forum and the blog reference the comments and has a link to the threads here. It's a pretty good write up, I thought if you havent seen it you may be interested. The mods are mostly just removing things....I think it costs about $20 plus main caps.
whatishifi: Restoring and modifing a Parasound HCA-2200II power amp.
Dang, those Mundorf caps are pretty dang expensive for caps!
I've re-ecapped a dozen class AB amps, three vacuum tube amps, five switcher supplies, 4 organs. I've found the long service life >3000 hours service life electrolytic capacitors from nichicon, rubicon, panasonic, kemet to restore entirely satisfactory sound. No corners cut in these premium products. CDE Chemicon and multicomp >2000 hour caps sounded okay when only they were available, but have worse ripple at end of life: see the spec sheet. Full power (volts on load or speaker) also resulted from the changes.
The rail supply of switcher supply amps (& converters) usually is specified as a low ESR cap, and I haven't always been able to find >3000 hours service life in that.
BTW my speakers are specified at 2nd & 3rd harmonic distortion 20 db down at all frequencies 80-12khz , at 5 W level. I typically listen at 1/2 W level. They are the most accurate reproducers of grand piano I've heard in this flyover metropolis. 1% HD from my ST120 is clearly audible compared to the SS products. My hearing still goes to 14 khz.
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Oh good god... this is a 90s amp, is it not? Unless it runs blazing hot, used cheap caps or has a ton of hours on it, the originals are probably just fine.
If it uses electrolytic coupling caps, I might be tempted to replace them with a film cap if it's not too big a PITA, but it probably won't make much difference.
The biggest factor in electrolytic capacitor aging is heat. Keep in mind that those "1000 hour" caps will last MUCH longer than 1000 hours if they're run below their rated temperature.
I've pulled filter caps out of mid-90s MC650s and Crest 7001s that have about 100,000 hours on them, and guess what? They measure okay. Not perfect, but not bad either, and this is after 20 years and THOUSANDS of rock concerts. Mind you, they were in a climate controlled room (not sitting out in the blazing summer heat all day).
In an amp like this, you WILL NOT hear a real difference from replacing power supply caps unless they're really bad. They have a high PSRR and a lot of global negative feedback.
Now if you spend $50 and a bunch of your time recapping it... you might "hear" a difference even if none exists. It's very easy to trick yourself into hearing something that isn't there. If there is an audible issue related to caps, it is almost always really obvious when you do some bench tests.
And while caps can theoretically age sitting on a shelf, I haven't actually observed this phenomenon. True, it's not good practice to install a 50-year-old NOS electrolytic, but in practice I have not had any issues with 25-year-old NOS electrolytic filter caps.
So my advice is that unless you have good reason to believe that the caps have actually failed, leave them be.
If it uses electrolytic coupling caps, I might be tempted to replace them with a film cap if it's not too big a PITA, but it probably won't make much difference.
The biggest factor in electrolytic capacitor aging is heat. Keep in mind that those "1000 hour" caps will last MUCH longer than 1000 hours if they're run below their rated temperature.
I've pulled filter caps out of mid-90s MC650s and Crest 7001s that have about 100,000 hours on them, and guess what? They measure okay. Not perfect, but not bad either, and this is after 20 years and THOUSANDS of rock concerts. Mind you, they were in a climate controlled room (not sitting out in the blazing summer heat all day).
In an amp like this, you WILL NOT hear a real difference from replacing power supply caps unless they're really bad. They have a high PSRR and a lot of global negative feedback.
Now if you spend $50 and a bunch of your time recapping it... you might "hear" a difference even if none exists. It's very easy to trick yourself into hearing something that isn't there. If there is an audible issue related to caps, it is almost always really obvious when you do some bench tests.
And while caps can theoretically age sitting on a shelf, I haven't actually observed this phenomenon. True, it's not good practice to install a 50-year-old NOS electrolytic, but in practice I have not had any issues with 25-year-old NOS electrolytic filter caps.
So my advice is that unless you have good reason to believe that the caps have actually failed, leave them be.
I have observed and measured caps aging on the shelf. I have measured the degradation in a home-use amp. But then again, I did failure analysis for a computer company for 10 years so I know what I was looking for and I had contacts with Mallory C-D, Sprague and others.
Quite true the perceived effect if you believe you made a change. I go by measurements and I have not seen anything to change my viewpoint. I could hear the hum creep into my MOSFET amp and my Nak pre. I measured it on the 2200's I had. It is not a matter of failure, it is slow degradation.
Now, some crank up the bass so loud, 30 dB of hum from their main would not be noticeable, butt for that cloud, go buy some monster Emotivias and crank it up. Leave the good stuff for the rest of us.
Read Doug Self on selection of blocking caps, film vs electrolytic. Some factors that may not be obvious why a large electrolytic may out-perform a smaller film.
Quite true the perceived effect if you believe you made a change. I go by measurements and I have not seen anything to change my viewpoint. I could hear the hum creep into my MOSFET amp and my Nak pre. I measured it on the 2200's I had. It is not a matter of failure, it is slow degradation.
Now, some crank up the bass so loud, 30 dB of hum from their main would not be noticeable, butt for that cloud, go buy some monster Emotivias and crank it up. Leave the good stuff for the rest of us.
Read Doug Self on selection of blocking caps, film vs electrolytic. Some factors that may not be obvious why a large electrolytic may out-perform a smaller film.
I'm not a high volume, tons of bass person. The amp would be paired with a set of Dahlquist DQ10's and playing mostly jazz and blues. Goal is high detail...I like hearing the drumstick attack, vibration of strings, fingers sliding across strings, breathing....including detail in the bass. But wanting the detail and soundstage without it being too bright. I was fixing to get a Phase Linear 700ii but I'm thinking the Parasound hca2200ii might have better sound (cant compare or even listen to them before purchase)
Love the DQ-10 legacy
Lived with DQ-10s for - ever, the 2200 will sound fabulous, driving them
with low relative sensitivity and the range of power of that amp.
I would love to hear / experience that combo, with exactly .that. music.
*PLEASE do not pair the DQ-10s with the Flame Linear...
what a headache of an amp...
*At least do John Curls recommended re-work of the amp.
Forget about what the unfamiliar and clueless say...
Lived with DQ-10s for - ever, the 2200 will sound fabulous, driving them
with low relative sensitivity and the range of power of that amp.
I would love to hear / experience that combo, with exactly .that. music.
*PLEASE do not pair the DQ-10s with the Flame Linear...
what a headache of an amp...
*At least do John Curls recommended re-work of the amp.
Forget about what the unfamiliar and clueless say...
My head hurts...
There are a fair number with intellect, but very few with highly trained hearing... too many with poor resolution systems, some even still using lamp cord, bare strands precariously fished through eyelets or mashed in crimp terminals like once found on my vintage L-36 or like, hey JBL used them 45 years ago, they must be good (enough)...
Some simply have poor hearing, must strictly rely on measurements..
I feel for them, but I do not get it... "why the fight"
There are a fair number with intellect, but very few with highly trained hearing... too many with poor resolution systems, some even still using lamp cord, bare strands precariously fished through eyelets or mashed in crimp terminals like once found on my vintage L-36 or like, hey JBL used them 45 years ago, they must be good (enough)...
Some simply have poor hearing, must strictly rely on measurements..
I feel for them, but I do not get it... "why the fight"
I prepared an HCA-1000 for my mom who listens to the same types of music.
I used Nichicon KW for the large filter caps, Some Nichicon KZ for the smaller electrolytic caps.
The signal-pass through cap in the servo was swapped for a Russian K71-4, 1uf. The multiple cascading smaller bypass caps were all removed, and replaced with single K71-5 .1uf for each rail.
I also replaced the servo op amp with an ad744. There’s a feedback resistor that was changed for a Caddock also.
That’s all I recall at the moment.
And you’d be doing yourself a favor to pass on the phase linear…
What kind of difference do you feel the modifications made? Was it worth the time and effort?
Phase Linears aren’t for people who obsess over detail in the sound. They are for people who play their music LOUD, but not so loud that it’s screeching and obviously clipping. That will cause it to overheat and potentially blow transistors.
Or... they're engineers who understand the power of modern signal processing. when it comes to analysis.Being able to look at the harmonic distortion components of an amplifier gives me insight as to why it sounds the way it does. Furthermore, I do not know of ANY speakers that approach the linearity of good amplifiers, so that makes testing amplifiers by listening pretty difficult.
As for the caps, I'm not arguing that they don't degrade with time. It's a known fact that they do. I'm just saying that in practice, most of these amps don't seem to be too picky about it. I still am not seeing very many 90s amps of this type that really benefit from replacement, and I'm reasonably thorough in my testing routines.
Obviously some will need it, but usually they have to be pretty bad for it to be noticeable. If a slight degradation of the filter caps makes a noticeable change in the performance of the amp, then the designer of the amplifier didn't do their job.
I mean, are they really that much worse than anything else from that time period? I mean, wasn't the original PL700 released in 1971? I struggle to think of any 1971 amps that I'd want to own from a fidelity point of view.
Okay, fine, McIntosh made some, but they weren't exactly affordable.
Of course, the HCA2200 blows any of the PL amps out of the water, at least when it comes to linearity.
I have noticed long time ago that you aren't a huge fan of Phase Linear amps.
Btw, Flame Linear...
Each part added a positive change, however I couldn’t confirm the large filter cap difference as the originals were pretty sacked. Most of it was maintenance with the electrolytic caps, the rest was pretty easy since it was already apart. Those Cold War era polystyrenes are very nice parts.
Not any worse sound wise than other amps of that vintage, but the 700’s reliability leaves a lot to be desired. You can’t really get crazy with it. You *can* with a 400, if you have one of several decent output transistor sets in it. Those being the Fairchild PL909, 2SD555, 2SD424, or MJ15024. Anything else really has to go. And only the MJ15024 should be used in a 700.
Actually I *am* a fan of the PL’s - for nostalgia, not for doing anything serious. One day I want to build a reliable 700 into a series 2 chassis. I have ideas.
And almost every PL I’ve ever seen needed a RECAP. Usually there isn’t much left of the reservoir caps and you’ll be lucky to make a hundred watts with one. And the usually-ubiquitous bootstrap cap goes bad leading to a very strange failure mode unique to the PL series 2. If the cap gets the slightest bit leaky it causes a latch up putting out full supply DC to the speaker. In those amps, the bootstrap is returned to the output of the driver transistor, not the actual output node. This causes the latch up. But returning the cap there is necessary to run the output stage fully class B with no bias current without causing MASSIVE crossover distortion. I’ve tried moving it to the normal location and the amp is not happy with it. Just replace the cap - it’s only a 47uF/100 volt.
Actually I *am* a fan of the PL’s - for nostalgia, not for doing anything serious. One day I want to build a reliable 700 into a series 2 chassis. I have ideas.
And almost every PL I’ve ever seen needed a RECAP. Usually there isn’t much left of the reservoir caps and you’ll be lucky to make a hundred watts with one. And the usually-ubiquitous bootstrap cap goes bad leading to a very strange failure mode unique to the PL series 2. If the cap gets the slightest bit leaky it causes a latch up putting out full supply DC to the speaker. In those amps, the bootstrap is returned to the output of the driver transistor, not the actual output node. This causes the latch up. But returning the cap there is necessary to run the output stage fully class B with no bias current without causing MASSIVE crossover distortion. I’ve tried moving it to the normal location and the amp is not happy with it. Just replace the cap - it’s only a 47uF/100 volt.
Here’s a Phase Linear 200 that I got for free with some speakers a few years back. I have just recently transplanted an amp module from a 90s Onkyo THX receiver using another transformer in series to lower the voltage, with a noise filter between the two. The entire thing fits perfectly in the compact chassis.
It has a Bluetooth receiver board inside the amp as well. Franken-amp if you will.
Sounds great with some Infinity bookshelf speakers.
But seriously, if you can manage to get ahold of an HCA-2200, I would do it.
It has a Bluetooth receiver board inside the amp as well. Franken-amp if you will.
Sounds great with some Infinity bookshelf speakers.
But seriously, if you can manage to get ahold of an HCA-2200, I would do it.
