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Sansui G-22000 Restoration/Upgrade Thread

Need to update this! Initial power up went great, bias and DC-offset were easy to set and held very stable. Hooked it to the speakers and source, played my favorite reference song and WOW! I don't even need to compare it to the SX-1980 now to know it is better sounding. This thing is a long way ahead, the detail and micro detail is amazing and the speed is insane. I have definitely found my new favorite receiver. I'll be posting performance specs and a video of it working soon! In the mean time, here it is in a temporary setup.

VGI0PcQ.jpg
 
mattsd said:
the detail and micro detail is amazing and the speed is insane.
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^^^^^^ THIS^^^^^^ couldn't agree more, I've got to find some time to get mine back together, I'm in the middle of upgrading its pre-amp, I got to the connected/separated switch, wasn't actually as bad as I thought it would be...
Parts have arrived....looking forward to inching out a little more performance with those signal path cap upgrades and getting rid of the mylars...
They are in the separates league the G22/33000....easily.
 
Matt....it looks awesome. Did you change it so it could play 4ohm speakers without shutting down? I looked at specs for the even the 33000 and it says 8ohm minimum. I love my 9090 cause it will handle the 4ohm at 50m watts of heavy bass music but afraid to test it past that. I had a G-8000 recapped that I sold because it couldn't handle the AR3's. I loved the look but it not the performance. I am thinking these big bad boys should handle a speaker without worrying about it.

Would love to check it out if you could bring it to Dave's next summer when I come down for the audio fest.
 
I finally finished up my G22000 this morning, I had already done a lot of work, a full recap, new relays, trimmers and some transistors etc etc.....
But I liked what Matt was doing with the signal path and some improvements on the driver boards so I did those too.
I have had a listen to it, and it actually makes quite an improvement, more image depth, and better resolution at high volume.
The bass was more prominent with nice sustain but improved clarity. The EQ actually shifts the phase 180˚ which is interesting, but I think the EQ sounds better than before if you have to use it.

I use 6Ω nominal JBL L7's with my G22000, and it is happy to crank along with up to 300watt peaks on the meters, no problem at all, I played it for over an hour like that, so if there is any questions about whether these amps can drive those sorts of loads or not, well, I say they can.

If anyone has a G22000, I highly recommend following Matt's thread here and do those cap upgrades....

Here's a pic of the frequency vs phase. The small less than 1/2db loss at the top, could be my sound card, I am not using my usual one, so I am not sure of its performance.
G22K Phase and Frequency.jpeg IMG_7194.JPG IMG_7196.JPG IMG_7198.JPG
 
Read this whole thread, even tho I have zero tech experience. This is a gorgeous resto, Matt. I see you're still rocking those polks! I have some SDA -1B's that I keep intending to recap and rejuvenate, tho they sound fine.

Funny, I have headphones on, as I'm using the kitchen internet computer, wife watching tv. When the music first came on, I LITERALLY turned my head to the left to see why the wife had cranked our stereo.

Even thru my Pioneer headphones, and with a compressed Youtube vid, you can TELL this is amazing sound.

Great job, Matt!
 
That's a blast from the past, that is from around 2011-2012, I was just getting started out then, first 1250 I ever did. I still have it too, pulling two channel home theater/stereo duty in the living room with some RTA-12C speakers. Thank you everyone for the kind comments, it is the biggest restoration job I've ever done so far, but it was also the most fun I've had doing one as well with all the tweaks and stuff that can be done. I learned a lot as well that I'll be able to apply to other brands also, not just Sansui. I'll be publishing bench test specs soon along with, finally, a full comparison between my restored 1980 and the 22000 now that it's restored as well!
 
mattsd said:
That's a blast from the past, that is from around 2011-2012, I was just getting started out then, first 1250 I ever did. I still have it too, pulling two channel home theater/stereo duty in the living room with some RTA-12C speakers. Thank you everyone for the kind comments, it is the biggest restoration job I've ever done so far, but it was also the most fun I've had doing one as well with all the tweaks and stuff that can be done. I learned a lot as well that I'll be able to apply to other brands also, not just Sansui. I'll be publishing bench test specs soon along with, finally, a full comparison between my restored 1980 and the 22000 now that it's restored as well!
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I'll be looking forward to reading about the SX1980 vs G22000 shootout!!

I know I very much appreciate this thread, I know how much work it is doing a resto job on a G22000, but actually taking the time to post a thread in as much detail with all the information at least doubles the amount of time and effort, so, thank you for donating your time to this thread Matt!!
 
Here are specs from the test bench! Note these tests are with it as a receiver, I did not test the two sections separately.

Max power @ 1% THD+N into 8 ohms, both channels driven:
(Input Factor: 1KHz @ .0004% THD+N)

Left channel: 47.51v, 282.15w
Right channel: 47.21v, 278.60w

THD+N at rated power (41.95v, 220W) into 8 ohms, both channels driven:
(Input Factor: 1KHz @ .0004% THD+N)

Left channel: 0.00263%
Right channel: 0.00279%

Intermodulation Distortion:
(Input Factor: 60Hz + 7KHz @ 4:1)

Left channel: 0.00267%
Right channel: 0.00271%

S/N ratio @ rated power (220W), A-weighted:
(Input Factor: 1KHz @ 1V)

Left channel: 99.07dB
Right channel: 99.32dB

Channel Separation @ 1KHz:

65.03dB

Frequency Response:

A note here, the volume control position drastically affects the frequency response. The first chart shows the volume at 9 o'clock (-36dB) and the second chart is with it all the way up (0dB)

G-22000 @ -36dB volume.png

G-22000 @ 0dB volume.png
 
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Hilarious amount of power output!! I found mine to be about the same.

What I plan to do to mine is to install another pair on transistors on each channel as there is the space for it, I think it will help with delivering more current when the impedance dips low as I am sure it does on my JBL L7's...

The frequency response seems to correspond to what I found too. So we can now confirm this is correct.

I like the way the THD+N is pretty much spot on. Pretty much 100db SNR, I can live with that!!

Nice work Matt...
 
Fun facts: Adding together max power left and right channels = 560 watts which can be mathematically converted to 3/4 horsepower.

Sansui rates the frequency response of the amp at 300,000 Hz (at 1 watt).

- Pete
 
kevzep said:
Hilarious amount of power output!! I found mine to be about the same.

What I plan to do to mine is to install another pair on transistors on each channel as there is the space for it, I think it will help with delivering more current when the impedance dips low as I am sure it does on my JBL L7's...


..
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When i said about doing the same thing on mine there where serious doubts and disputes , from some guys here.
Hehe .
 
JOMARK911 said:
When i said about doing the same thing on mine there where serious doubts and disputes , from some guys here. Hehe .
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Maybe from people (perhaps even me :yikes:) who might think/have thought, that's going a bit too far - but whatever people want to do with their gear is up to them, we can only advise caution when the proposed mods get a bit 'hairy'. ;)

I this case Kev easily has the expertise to successfully pull off such a modification, which isn't so in every case. ;)

As for me, I wouldn't like to tackle such an upgrade, but then as you get attached to a piece of gear it seems 'anything goes' in a quest to make it better - ref: my AU-D11 II. ;)
 
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