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Old 16th October 2010, 07:24 PM   #1
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Default Modding Parasound Halo A21

Hi

I'd love to have JC-1 monoblocks, but these are big (like two of my A21), and I do not like their 35W constant power consumption..

A21 is fabulous, I compared it against two much pricier amps and still preferred A21

What I would like to improve:
imaging, more transparency and lower noise floor..
and Class A bias.. now is it 10W? 15W would be likely better..

I like the sound signature, so I merely looking for 'more of the same'..
I am not so strong in electronics, so the advises here I will bring to my engineer..

thanks in advance,
--Michael
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Old 16th October 2010, 08:28 PM   #2
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Like I mentioned in a previous message about Parasound amps , anything you do will likely make them sound worse and compromise their longevity. Those are fantastic amps just as they are. I know it's a DIYers nightmare, but I wouldn't do a thing to them.

Paul.
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Old 6th March 2014, 11:48 AM   #3
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Quote:
Originally Posted by michael12345 View Post
Hi

I'd love to have JC-1 monoblocks, but these are big (like two of my A21), and I do not like their 35W constant power consumption..

A21 is fabulous, I compared it against two much pricier amps and still preferred A21

What I would like to improve:
imaging, more transparency and lower noise floor..
and Class A bias.. now is it 10W? 15W would be likely better..

I like the sound signature, so I merely looking for 'more of the same'..
I am not so strong in electronics, so the advises here I will bring to my engineer..

thanks in advance,
--Michael
hello, i am an owner of halo a21 and i'd like some mods but i don't have the schematic. please help.
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Old 21st March 2014, 08:28 AM   #4
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Schematics are available from Parasound... Or if I can figure out how to attach them I'll do so... Else, pm me you email and I'll send them over to you that way.

To be honest , I sort of agree with Paul, although have been tempted to try other brands of feedback resistors.
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Old 12th May 2014, 05:53 PM   #5
smatteo is offline smatteo  Italy
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Hello

I just bought an A21 and would like to have the schematics to improve the feedback resistor. Someone may help me ? Thank you in advance.
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Old 12th May 2014, 06:02 PM   #6
smatteo is offline smatteo  Italy
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Hello to all.

I just bought an Halo 21 and would like to have the schematics. Someone may help me ?
Any feedback from who has tuned the feedback resistor ? Any other suggestions ?
Thank you in advance.
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Old 12th May 2014, 06:03 PM   #7
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What resistors are you thinking of changing to?
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Old 12th May 2014, 06:46 PM   #8
smatteo is offline smatteo  Italy
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hello Mr J.Curl

I haven't schematic, so I cannot be precise. Anyway, VFA amplifier has a resistor partition as feedback, the idea was to switch to caddoc resistors (same values). A21 has a trimmer to modify the gain.. May you suggest some ideas to us ?
Thanks in advance.
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Old 15th May 2014, 06:14 PM   #9
smatteo is offline smatteo  Italy
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Hi
Maybe the only way to improve A21 is to increase CAPs or move from C-C to CLC filtering, what do you think ? Thx
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Old 15th May 2014, 06:50 PM   #10
tvrgeek is offline tvrgeek  United States
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Best way to improve an A21 is to buy better speakers. I don't care what ones you already own, the amp is better than they are. For that matter, so are my 1200's not that I would not love to have a A21 or A23.

Don't be fooled by "class A bias". It has been shown there is a correct bias. Set it correctly and worry about something else.
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