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Sunday, February 21, 2016

Spring cleaning and the Sony STR-GX90ES Stereo receiver

Yesterday it was over 50 degrees Fahrenheit here in New York, so windows got opened and some much needed spring cleaning got started. This of course meant that a change in set up happened in the listening room.  The Yamaha A-S2000 integrated and CD-S2000 disc player had been running the show for a long time (over a year) and I was ready for something different.  I had ordered a pair of casters from Audio Advisor for the Salamander rack that holds the gear that is out of current rotation, so everything had to come off to install them anyway.  Here is the mess when it was in progress:

My only real complaint with the Yamaha A-S2000 integrated amplifier is that in my room it is impossible to determine where the volume indicator is, especially in low light.  This may not seem like a big deal, but when you are trying to make comparisons, having the volume consistent is useful.  I decided to set up a Sony STR-GX90ES stereo receiver I got for a song on EBay some years back as the heart of the system for now.  A green indicator is built into the Sony's volume knob, so that would be one matter resolved.  Here is what I would up with after some futzing around:

It's an all ES system, with the Sony SCD-X5400ES as the disc player and my TC-K700ES tape deck in the "loop."  (Heh.)  For the earlier part of the afternoon, I had the Dynaudio Excite 14s making nice noises.  

I was once the proud owner of a Sony STR-GX9ES stereo receiver that despite the best efforts of the talented folks at In House Repair (I hope Wayne is still out there) gave up the ghost.  You can read about that here. I loved the way the GX9 and its more elite sibling the GX10 looked.  The GX90 is a bit more streamlined, unfortunately, and all of the nifty buttons are hidden behind a drop down panel.   Not everyone appreciates it, but I grew up with the clutter of buttons on black boxes from the eighties, and I miss them.

I don't have the shipping container for this machine, and I am currently hunting for an original remote (I have another that works well, but I'd like to get the full set, of course).  My manual (which it shares with the GX80ES although they do not have the same feature set and performance, GX80ES omitted here for brevity, let me know if you need the information) provides the following info:

Sony STR-GX90ES FM-AM Stereo Receiver  

Power output and total harmonic distortion:

With 8 ohm load, both channels driven, from 20-20,000 Hz, rated 120 watts per channel minimum RMS power, with no more than 0.008% total harmonic distortion from 250 milliwatts to rated output.

With 4 ohm load, both channels driven, from 20-20,000 Hz, rated 120 watts per channel minimum RMS power, with no more than 0.015% total harmonic distortion from 250 milliwatts to rated output.

Amplifier Section
Dynamic power output

160 watts + 160 watts (8 ohms at 1kHz IHF)
220 watts + 220 watts (4 ohms at 1kHz IHF)
350 watts + 350 watts (2 ohms at 1kHz IHF)

Harmonic distortion less than 0.008% at rated output

Frequency response

PHONO: RIAA equalization curve +/- 0.3dB
CD, DAT, TAPE, VIDEO 1,2,3 (AUDIO), ADAPTOR: 20-20kHz  +/- 0.3dB

Damping factor 60 (8 ohms, 1 kHz)

Sensitivity: 2.5mV
Impedance: 50 kilohms
S/N (weighting network, input level): 90dB, 80dB (A, 5mV)

Sensitivity: 0.17mV
Impedance: 100 ohms
S/N (weighting network, input level): 73dB, 84dB (A, 5mV)

Sensitivity: 150mV
Impedance: 50 kilohms
S/N (weighting network, input level): 98dB, 85dB (A, 5mV)

Sensitivity: 1.1 V
Impedance: 50 kilohms
S/N (weighting network, input level): 120 dB (A, 5mV)

The STR-GX90 has a set of three tone controls which allow for fine-tuning with the use of selectable turnover levels.  The manual states:

Response +/- 10dB at 100 Hz Turnover frequency: 400 Hz
Response +/- 7.5dB at 100 Hz Turnover frequency: 200 Hz

Response +/- 6dB at 100 Hz Turnover frequency: -----------

Response +/- 10dB at 10 kHz Turnover frequency: 3 kHz
Response +/-   6dB at 10 kHz Turnover frequency: 6 kHz

Overall I find the tone controls to be pretty subtle unless they are maxed out.  There is an impedance selector switch on the rear panel that I must check as I switch speakers. 


w 18 5/8 x h 6 3/8 x d 17 1/4 inches

Weight: 32 lbs (which is a little over two pounds heavier than the GX80ES, interestingly)

Some other details from the manual:

The STR-GX90ES is equipped with a copper-plate rear panel for reducing distortion in high frequencies.

Optical Legato Linear A system allows the receiver to operate automatically as a class A amplifier when the level is low and as a class B amplifier when the level is high without disturbing the signal.  This minimizes total harmonic distortion at every sound stage.  These receivers have a spontaneous twin drive power circuit.  Condensers having large capacity are used independently for the voltage amplification drive stage of the class A and power output stage of class B.  Thus, a stable output and high quality sound are obtained, resulting in exclusion from power interferences.  The class A stage realizes a stable operation free from interference of the power stage even when an instantaneous or strong output is received.  

And they silk-screened that in Sony Gold right on the front:

Here is a so-so picture of the top.  It's very nice, but does not compare with the Yamaha A-S2000 in terms of interior eye candy:

I don't have the exact info on the MSRP of the GX90ES yet, but the previous Sony ES stereo receiver flagship, the STR GX10ES retailed for $1,200 in 1990 (which is roughly $2,175 today- that's an 80 percent inflation rate, approximately). 

How did an afternoon of listening go?  Great.  Keep in mind that I have not had the GX90 serviced, which it definitely deserves.  I do not know how close to operating spec it is functioning (I need a crash course to make this blog better . . .  any volunteers?)  but it certainly sounded different to my ear.  I am very used to a super clean and effortless sound from the Yamaha.  The Sony sounds somehow . . .  rounder, if that makes sense.  But let's not forget that I ALSO switched out disc players, going from the CD-S2000 SACD player to the SCD-XA5400 ES.  Despite owning them for some time, I still haven't done a comparison between those two.  Furthermore, the GX90ES does not accept balanced inputs, so I went from Kimber XLR to Audioquest  Golden Gates.  To some, these changes are meaningless.  To others,  well, they are a big deal.  At any rate, this is the intended set up for a while.  I think the next post will be about the TC-K700ES tape deck and its adventure in Alamogordo, New Mexico.  Stay tuned. 

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