[Boatanchors] AR-88 comments, value?

[Richard Knoppow]

-----Original Message-----
>From: Al Klase <ark at ar88.net>
>Sent: Sep 3, 2013 1:04 PM
>To: boatanchors at mailman.qth.net
>Subject: Re: [Boatanchors] AR-88 comments, value?
>
>Ian,
>
>The AR-88 is a much better radio in almost every way than an SX-28. The 
>latter was a high-end consumer product.  The AR-88 is a PROFESSIONAL 
>receiver, and may well have been the best general coverage radio in the 
>world when it was introduced.  Don't be seduced by the PP 6V6's in the 
>28.  The single ended 6K6 in the AR-88 sounds better in side-by-side 
>tests on a quality speaker (Altec 604).  The reason is the the RCA guys 
>had a handle on negative feedback.  Reduced IMD results in better 
>performance on noisy signals.
>
>Richard K's price range is pretty good.  At the retail level, a proper 
>S-meter is a $200 adder.  I don't see any advantage to the LF model 
>unless you just hate the broadcast band.
>
>Like any radio this age, TLC, i.e. recapping, is in order.  The AR-88 is 
>pretty straight forward to repair.  Recapping the front end on an SX-28 
>is a nightmare.
>
>Go for it,
>
>Al
>
>On 9/3/2013 2:50 PM, Ian Wilson wrote:
>> There is an AR-88 available (sort of) locally. Although
>> arguably the last thing I need right now is another
>> boatanchor receiver, the AR-88 is something special.
>>
>> No special tubes needed, I see. Would be interested
>> in reports on how this stacks up against the SX-28, say.
>> Also any suggestions as to what would constitute a
>> "reasonable offer" assuming fair condition and no
>> obvious major damage would be helpful.
>>
>> 73, ian K3IMW
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>
>-- 
>Al Klase - N3FRQ
>Jersey City, NJ
>http://www.skywaves.ar88.net/
>
      First of all, Al's web site has a lot of valuable AR-88 stuff on it.  
     I have never had the chance to compare the audio of the two directly.  I used a BC-779 Super-Pro as a station receiver (with some mild modifications) for a long time. It has very good audio compared to most communication receivers but again I've never compared it directly to the AR-88.   The lack of distortion makes a surprising difference in the clarity of even CW signals in the presence of noise.  Most single-ended pentode amps have quite high distortion on the order of 10% THD at full output. Full output being around 1 to 2 watts.  You CAN hear this even on CW or SSB signals. In my current station I have a Drake R4B, and the AR-88.  The R4B is a _very_ good receiver and has decent audio.  The AR-88 just plain sounds better even when the R4B is on its maximum bandwidth.  I've tried the same speakers on both and the difference is in the receivers.  The R4B does have better selectivity for SSB and CW.  The crystal filter in the AR-88 is decent but not up to the Hammarlund design and has no phasing (nulling) adjustment.  While there is a phasing adjustment in the circuit, brought out to the front panel in later versions, it is not balanced as is the Hammarlund filter and not as effective in nulling out interference.   The Drake receiver has a very good null circuit.  Nontheless, the AR-88 has sufficient selectivity most of the time and its CW sound is better.  It is an absolutely amazing receiver.