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Old 29th January 2005, 09:56 PM   #81
Zen Mod is offline Zen Mod  Serbia
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may I remind you on this mini thread :
J L HOOD A/AB amp
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Old 29th January 2005, 11:19 PM   #82
mona979 is offline mona979  United States
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Default About Hafler XL-280

Reply to Dick West,

I am curious about the upgraded PA-3B from:

http://www.musicaldesign.com/mc_amp_mods.htm

Which ones have you bought? What do you recommend out of the options that there are?

PA-3B modification kit
$299 kit, $429.00 installed

PA-3B Signature
$449 kit*, $629.00 installed,

NEW!!! PA-3B Platinum
$999 kit*, $1299.00 installed

Also are the: Power Amplifier options worth it?

Thanks
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Old 29th January 2005, 11:30 PM   #83
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I have tried the MC PA-3A and now its more recent version PA-3B. The PA-3B is the best. I prefer it to the sound of the DH200 or DH220, or the DH-120, Hafler 9130.

This is the extent of my experience.

As for the more expensive versions of the PA-3B some say the extra expense is worth the cost, others say that the more expensive capacitors are not. It all depends on your ears, the resolving ability of the rest of your system, and the size of your pocketbook.

The MC power supply caps make a big difference in every amp I have tried them with, if your switch and diodes can handle the extra capacitance.

Good luck.......
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Old 30th January 2005, 06:00 AM   #84
fab is offline fab  Canada
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Default pcb with mods

Quote:
Originally posted by Dick West
fab,

As I recall from a post many months ago you toyed with the idea of making a PCB that encompasses your DH-200 mods onto a circuit card which others can use to enjoy the fruits of your labor and knowledge. Any further thoughts on this?

I praise MC circuit cards highly but the price of their kit is more than I want to pay, at least not pay frequently. How about a PCB from you?
Dick and Terry

Thank you for your interest. Unfortunately, I can only say the same I said on post #29 ! Shame on me...These last months I could not do much electronics and I stayed away from the threads too. Now I am back but still working on improving the output stage, doing simulations, etc.

The project is still going but I need to "clean" my lab first and that is probably the main reason why I do simulations instead of working with real circuits at this moment...

I could eventually provide a pcb but NOT populated. The pcb would also be from a local shop so it would not be of quality such as the MC with glazing and silk screen for components locations.

BTW the MC PA-3B pcb layout is in their installation manual...
This is how I saw their enhanced cascode VAS in the circuit.
Also the MC PA-3B has supply filters on the board using higher caps (4700uf or 470uf?) instead of 100uF for stock DH-200/220. So it is closer to a regulated supply.

fab
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Old 30th January 2005, 06:13 PM   #85
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"BTW the MC PA-3B pcb layout is in their installation manual...
This is how I saw their enhanced cascode VAS in the circuit.
Also the MC PA-3B has supply filters on the board using higher caps (4700uf or 470uf?) instead of 100uF for stock DH-200/220. So it is closer to a regulated supply."

The circuit card filter caps on the PA-3B are 1,000 mfd/100 VDC.
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Old 30th January 2005, 09:48 PM   #86
Variac is offline Variac  United States
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Quote:
I have an Adcom 555 from A. Borza and a Hafler something-or-
other from Variac both of which will be turned into surprise
projects.
This is from Nelson Pass's DIY progress report thread.
Part of a long list. So I guess eventually we'll be surprised
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Old 30th January 2005, 10:54 PM   #87
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Old 5th February 2005, 08:28 AM   #88
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I own 4 PA3 modded Haflers, two DH200 and two DH220. One is the original PA3 and the other 3 are the latest PA3B revision. John Hillig is preparing to raise the price on the basic kit, so if anyone wants to get one for $199 they'd better hurry. I have the PA3 cards and the upgraded 27,000uf 80v filter caps. The only other mods I have done are beefing up the power cords , binding posts and rca's to gold plated ones and replacing the front end caps with Black Gate 100uf 100v FK and C1 and C5 with Black Gate NX bipolar caps. John recommeds the Black Gate changes , though I was leary of removing perfectly fine 1000uf 100v Nichicons and substituting the 100uf 100v FK's. It seemed like I was taking a more robust cap and going back to the stock value cap. John says the Black Gate caps will make you rethink what you have always believed, that bigger equals better and it's the quality of the component not the size that makes the difference. I believe the Black Gates were worth it, though I know many would dissagree. I've only been playing with the Haflers for the last two years but am a big fan of the Hitachi lateral mosfets as well as the Musical Concepts mods. They are very good quality and easy and fun to install. I was wondering what the general consensus around here is on the merit of Black Gate caps and if anyone else uses them.
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Old 5th February 2005, 02:45 PM   #89
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Ahem . . . Chris, I believe the PA-3B kit as actually $299, not $199. And, yes, we know the price will be going up so now is the time to buy, if one is interested.

Your comments are very similar to what Hillig has on his web site so it is obvious you are a fan of his, as are many of the rest of us. However, it is my understanding that the Black Gate caps are no longer available. Also, over on the Audio Asylum forums, many have commented about the BG caps sounding "different" but not necessarily "better," and that some of them require a long break in period. Now we know the brain plays tricks on us and we adjust our expectations of what we hear based on previous experience. Therefore a different sounding cap can begin to sound OK, in time.

We know that clearly defined audio measurements do not always agree with subjective impressions of listeners but, heck, a lot of listeners do not agree with each other. And so the story goes . . .
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Old 7th February 2005, 07:29 AM   #90
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Dick,
You are correct , my bad. I meant $299 not $199. My first post and I start with a mistake Doh! that's what happens when I post past 3am. I actually got my last three PA3B kits at dealer cost, so I paid less than the $199 figure. Anyhow, I was intentionally paraphrasing what John says on his website regarding the Black Gate caps, I just wanted to get some feedback as to whether or not other peoples think they are worth the additional cost. I don't know if Black Gate caps are out of production or not. I've read that Rubycon may be converting the current manufacturing plant to Organic Semiconductors . I've also read that Rubycon does not own the patent for Black Gates, and that it's possible another manufacturer might take over production. In any case they are available , the last time I spoke to John he had plenty. Percy's audio is another good source. I've read the long break in time threads too. I don't think it's necessarily the case though, I think they sound good without a prolonged break in, though they may possibly improve with time. My Parasound Preamp PHP-850 came with several Black Gates factory installed and it required no protracted break in period to sound decent.
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