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Parasound Halo a-21 , One overlooked great amp

I have owned many pieces of audio gear.I can spend 3 x this much money
And still not do to much better or at all. John Curl the ex chief designer
For Mark Levenson designed theParasound Halo line and the A-21
Is a true classic in every sence this unconventional amp
Uses J fets for the input stage, Mosfets, for the driver stage and
8 matched Sanken Bipolar transistors for the output stage per channel even the specs are under rated by some 50 wpc into pushing over 450 wpc
And over 60 amps peak per channel .the 4 huge Elna capacitors
Gives plenty of storage. As well as the custom transformer.2 things I have found that dramatically improve this amplifier since this is a a A- AB design the1 st 10 watts are in pure class-A
Because of the current on tap there are 4-8amp T fuses inthe circuit board
1 for the plus and minus rails per channel, and a 12 amp Tforthe main fuse on back the Hifi tuning fuses- Supreme although expensive for these30 mm Fuses transform this amp across the board , also the better the high current Power cord you use the more you will be rewarded,
I am using a Synergistic Research T3 HC which may be expensive
And the fuses retail for $450 but the end result is like a major preamp upgrade over 10 percent across the board which is Huge inAudiophile
Terms. This amp is unique in that there is no negative feedback inthe circuit, and it is direct coupled ,with NO coupling capacitors at all in the amplifier signal path to dilute the signal,just the big power supply caps that have a
Small .1 uf cap used just as a bypass for hi frequency noise.
My friends new Bryston 4bsst2 was no where as natural once I gave the
hifi tuning fuses time to settle in . I got rid of the Bat vk500with bat pack
It was to colored compared. For under $2600 with fuses this amp can easilly compete with any amp at 2 x it 's price. The only amp I found that is a little Better in several areas is the Hegal-20 amp but it is more than 2 x the cost. Don' t let the reasonable price make you over look this classic
Amplifier the Parasound Halo A-21 is one of the best buys in all of audio
And can drive planers ,stats, or big cone speakers with ease and sound
Excellent doing it !!
128x128audioman58
audioman58's avatar
audioman58 OP
4,130 posts
 
Balanced is really no better ,Because the A-21 is not a true balanced amplifier
True balanced means you have to have transformer for each channel
Plus and minus. This amplifier RCA -balanced still connect together down stream
thankful
222 posts
 
I owned the JC-1's a few years back and they were great mono-blocks. Parasound makes some fine gear. The only reason I sold them was because I went to tubes.
milpai's avatar
milpai
2,372 posts
 
Well, after Thankful resurrected this thread, all I can say Audioman is - Balanced on this amp makes a ton of a difference in my system, as it provided me with the gain I needed. Also I feel the sound stage is also raised up considerably. The next thing I await is a Balanced CDP. The current CDP is RCA only and that is how it connects to the TVC.
audioman58's avatar
audioman58 OP
4,130 posts
 
Yes you are right ,you get more out put for the impedance is 66 which Is 2x the
Single ended, and therefor more output
The point I was trying to make is that it is not a true balanced amplifier
Pull the cover and see if you have a transformer plus and minus for each channel .
ziffle
11 posts
 
Audioman... you have good taste in what a great amp should do, or shouldn't!

Back in my home country my main system consists of a Pass front end onto the Krell 300cx. My system here while overseas is a Rowland front end onto the A-21. I should add the A-21 has nudged aside some Rowland 201 mono blocks for now... and they may just end up on the market!

This A-21 is one of the most musical amps I've owned, or heard. I've found decent power cords help significantly, I might give those fuses some serious consideration - thanks!! Allan
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