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SA-9500 II Rebuild

C

Colleton

AK Subscriber
Subscriber
So I bought an SA-9500 II last summer. The seller didn't package it well and it arrived damaged. I had to replace the case, the face plate, and the function switch knob right off the bat. The function switch shaft was badly bent as well, but I was able to straighten it out at the cost of breaking one of the forks that hold the knob in place (sadness). I was able to get the function knob to hold securely though. An internal inspection revealed that two of the filter caps had popped on the underside. So I had to replace the filter caps as well. I replaced all four, just because.

I haven't used the amp much since I picked it up. Mostly I've been rotating between my Spec system, my SX-1050 and my SA-9900. I got bored last month though and decided to rebuild the 9500 II. Several of the caps I used in a previous 9500 II rebuild are no longer available so I selected replacements. Two of the caps that I ordered for this rebuild are not currently available and will need replacing if you use this BoM. The 512-KSC3503ESTU and 512-KSA1381ES transistors are no longer available, but I had a small supply on hand. I don't know what you'd replace them with.
I replaced the 2SA798 differential pairs on the amplifier boards with a small circuit board with a surface mount transistor package I bought from Affinity for Artifacts. I've been doing surface mount soldering on old Macintosh computers for a while now, so the differential pair kits weren't difficult to assemble. They seem to work very well. If anyone knows differently please let me know.

I replaced the function switch while I had the equalizer amp board out.

The rebuild went pretty smoothly. I enjoyed myself and took my time. The bias aligned easily and the dc offset is great. I've been running the amp for the past several days with no issues. I plan to use it for a few more weeks before calling it good. Here are some pics of the rebuild process.

Here's the BoM I used:

---------------------
Control Amp (AWG-045)
---------------------
AWG-045: C15: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C16: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C17: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C18: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C25: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C26: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C27: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C28: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C31: 100uF 16v CEANL: 647-UKL1E101KPDANA 100uF 25v
AWG-045: C32: 100uF 16v CEANL: 647-UKL1E101KPDANA 100uF 25v
AWG-045: C33: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C34: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C41: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C42: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C43: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C44: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C47: 100uF 16v CEANL: 647-UKL1E101KPDANA 100uF 25v
AWG-045: C48: 100uF 16v CEANL: 647-UKL1E101KPDANA 100uF 25v
AWG-045: C49: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C50: 4.7uF 50v CEANL: 667-EEU-FC1H4R7B 4.7uF 50v
AWG-045: C51: 100uF 35v CEA: 647-UPW1V101MPD 100uF 35v
AWG-045: C52: 100uF 35v CEA: 647-UPW1V101MPD 100uF 35v
AWG-045: C53: 100uF 35v CEA: 647-UPW1V101MPD 100uF 35v
AWG-045: C54: 100uF 35v CEA: 647-UPW1V101MPD 100uF 35v

Q1: 2SA640 ecb: 512-KSA992FBU ecb
Q2: 2SA640 ecb: 512-KSA992FBU ecb
Q3: 2SA640 ecb: 512-KSA992FBU ecb
Q4: 2SA640 ecb: 512-KSA992FBU ecb
Q5: 2SC1400 ecb: 512-KSC1845FTA ecb
Q6: 2SC1400 ecb: 512-KSC1845FTA ecb
Q7: 2SC1400 ecb: 512-KSC1845FTA ecb
Q8: 2SC1400 ecb: 512-KSC1845FTA ecb
Q9: 2SC1400 ecb: 512-KSC1845FTA ecb
Q10: 2SC1400 ecb: 512-KSC1845FTA ecb

--------------------------------------------------------------------------------------
Power Amp (AWH-052), times 2, as there are two power amp boards, one for each channel.
--------------------------------------------------------------------------------------
AWH-052: C4: 22uF 50v CEA: 667-EEU-FC1H220 22uF 50v
AWH-052: C5: 470uF 6.3v CEA: 647-UPW1A471MPD 470uF 10v
AWH-052: C15: 1uF 50v XXXX: 80-R82DC4100CK60J 1uF 63v (Kemet film)

Q1: 2SA798: Replaced with a small circuit board with a surface mount transistor package
Q2, Q3: 2SC1903 ecb: 512-KSC3503ESTU ecb (Had on hand, did not order)
Q4: 2SA898 ecb: 512-KSA1381ES ecb (Had on hand, did not order)
Q5: 2SD381 bce: 863-MJE15032G bce
Q6: 2SB536 bce: 863-MJE15033G bce

D1: 1S2473: 512-1N4148
D3, D4: W06A: 512-1N4004RLG

VR1: 100B: 3386H-1-101LF (Bourns 100ohm 10% Trimmer)

-------------------------
Switch Assembly (AWS-109)
-------------------------
AWS-109: C7: .68uF 35v XXXX: 505-MKS2.68/63/10 .68uF 63v (Wima film)
AWS-109: C8: .68uF 35v XXXX: 505-MKS2.68/63/10 .68uF 63v (Wima film)
AWS-109: C9: .22uF 10v XXXX: 505-MKS20.22/63/5 .22uF 63v (Wima film)
AWS-109: C10: .22uF 10v XXXX: 505-MKS20.22/63/5 .22uF 63v (Wima film)
AWS-109: C11: 330uF 6.8v CEA: 647-UPW1A331MPD 330uF 10v
AWS-109: C12: 330uF 6.8v CEA: 647-UPW1A331MPD 330uF 10v
AWS-109: C13: 100uF 16v CEAL: 647-UKL1E101KPDANA 100uF 25v
AWS-109: C14: 2.2uF 50v Unknown: 647-UPW1H2R2MDD 2.2uF 50v
AWS-109: C19: 330uF 80v CEA: 647-UPW2A331MHD 330uF 100v
AWS-109: C20: 330uF 80v CEA: 647-UPW2A331MHD 330uF 100v
AWS-109: C21: 220uF 63v CEA: 647-UPW1J221MPD6 220uF 63v
AWS-109: C22: 220uF 63v CEA: 647-UPW1J221MPD6 220uF 63v
AWS-109: C25: 47uF 16v CEA: 667-EEU-FC1V470 47uF 35v
AWS-109: C26: 47uF 16v CEA: 667-EEU-FC1V470 47uF 35v
AWS-109: C29: 47uF 35v CEA: 667-EEU-FC1V470 47uF 35v
AWS-109: C30: 47uF 35v CEA: 667-EEU-FC1V470 47uF 35v
AWS-109: C34: 3.3uF 50v CEA: 667-EEU-FC1H3R3B 3.3uF 50v
AWS-109: C35: 3.3uF 50v CEA: 667-EEU-FC1H3R3B 3.3uF 50v

Q1: 2SC869 bce: 512-KSC1845FTA ecb or 512-KSC2383YTA ecb
Q2: 2SC869 bce: 512-KSC1845FTA ecb or 512-KSC2383YTA ecb
Q3: 2SC945A bce: 512-KSC945CYTA ecb
Q4: 2SC945A bce: 512-KSC945CYTA ecb
Q5: 2SA733 ecb: 512-KSA992FTA ecb
Q6: 2SC945A bce: 512-KSC945CYTA ecb
Q7: 2SC1384 ecb: 512-KSC2690AYS ecb
Q8: 2SD526 bce: 863-MJE15032G
Q9: 2SB596 bce: 863-MJE15033G
Q10: 2SC1318 ecb: 512-KSC2383YTA ecb or 512-KSC2690AYS ecb
Q11: 2SA720 ecb: 512-KSA1013YBU ecb
Q12: 2SC1318 ecb: 512-KSC2383YTA ecb or 512-KSC2690AYS ecb
Q13: 2SA720 ecb: 512-KSA1013YBU ecb
Q14: 2SD356 bce: 863-MJE15032G bce
Q15: 2SC945 ecb: 512-KSC945CYTA ecb

D1-D8: SR3AM-8: 512-1N5404RLG
D9-D12: SR1K-8: 863-1N4004RLG
D13, D14: WZ-130: 512-1N4743ATR
D15, D16: 1S2473: 512-1N4148
D17-D21: 1S2472: 512-1N4148
D22-D25: 1S2473: 512-1N4148

-----------------------
Equalizer Amp (AWF-024)
-----------------------
AWF-024: C1: 1uF 50v XXXX: 80-R82DC4100CK60J 1uF 63v (Kemet film)
AWF-024: C2: 1uF 50v XXXX: 80-R82DC4100CK60J 1uF 63v (Kemet film)
AWF-024: C9: 470uF 6.3v CEA: 647-UPW1A471MPD 470uF 10v
AWF-024: C10: 470uF 6.3v CEA: 647-UPW1A471MPD 470uF 10v
AWF-024: C17: 3.3uF 50v CEA: 667-EEU-FC1H3R3B 3.3uF 50v
AWF-024: C18: 3.3uF 50v CEA: 667-EEU-FC1H3R3B 3.3uF 50v
AWF-024: C21: 4.7uF 25v (NP): 667-ECE-A1EN4R7U 4.7uF 25v
AWF-024: C22: 4.7uF 25v (NP): 667-ECE-A1EN4R7U 4.7uF 25v
AWF-024: C31: 47uF 35v CEA: 667-EEU-FC1V470 47uF 35v
AWF-024: C32: 47uF 35v CEA: 667-EEU-FC1V470 47uF 35v
AWF-024: C35: 47uF 35v CEA: 667-EEU-FC1V470 47uF 35v

Q1: 2SA906 bce: 512-KSA992FBU ecb
Q2: 2SA906 bce: 512-KSA992FBU ecb
Q3: 2SA906 bce: 512-KSA992FBU ecb
Q4: 2SA906 bce: 512-KSA992FBU ecb
Q5: 2SC1400 ecb: 512-KSC1845FTA ecb
Q6: 2SC1400 ecb: 512-KSC1845FTA ecb
Q7: 2SC1400 ecb: 512-KSC1845FTA ecb
Q8: 2SC1400 ecb: 512-KSC1845FTA ecb
Q9: 2SA750 ecb: 512-KSA992FBU ecb
Q10: 2SA750 ecb: 512-KSA992FBU ecb

-----------------
FILTER CAPACITORS
-----------------
C6, C7, C8, C9: 12000uf 63v: ALT22A153DE063 15000uf 63v

------------------
OUTPUT TRANSISTORS
------------------
Q1, Q2, Q5, Q6: 2SD588A bce - Did not replace
Q3, Q4, Q7, Q8: 2SB618A bce - Did not replace

---------------------
BOM
---------------------

667-EEU-FC1H4R7B | 16
647-UKL1E101KPDANA | 5
647-UPW1V101MPD | 4
667-EEU-FC1H220 | 2
647-UPW1A471MPD | 4
80-R82DC4100CK60J | 4
505-MKS2.68/63/10 | 2
505-MKS20.22/63/5 | 2
647-UPW1A331MPD | 2
647-UPW1H2R2MDD | 1
647-UHE2A331MHD | 2
647-UPW1J221MPD6 | 2
667-EEU-FC1V470 | 7
667-EEU-FC1H3R3B | 4
667-ECE-A1EN4R7U | 2
ALT22A153DE063 | 4
512-KSA1381ES | 2
512-KSC3503ESTU | 4
863-MJE15032G | 4
863-MJE15033G | 2
512-KSA1013YBU | 2
512-KSC2383YTA | 2
512-KSC2690AYS | 1
512-KSC945CYTA | 4
512-KSA992FBU | 10
512-KSC1845FTA | 12
512-1N4148 | 5
512-1N4004RLG | 4
512-1N5404RLG | 8
512-1N4743ATR | 2
3386H-1-101LF | 2
 
Last edited:
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Switch Amp / PSU. I didn't remember to take a pic of the parts replaced in the B pic. I replaced the transistor heat sinks with larger, beefier parts. Also notice the browning of the circuit board under R52. I'm thinking of buying a replacement resistor and install it sitting further off the board. Any thoughts?
 

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Equalizer amp. I neglected to order bipolar caps for C21 and C22. I have them now and will get them installed soon. The EQ amp is working very well as is though.
 

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Left amp.
 

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Right amp
 

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Alignment and testing.
 

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Nice job and great documentation!

I noticed the (4) Nichicon 15,000 uF filter caps (647-LKG1J153MKNF) you used are no longer available. I used Kemet ALT22A153DE063 for the filter caps when I restored two of these units several years ago. They're still available and the cost is still reasonable. The Kemet specs show they have a whopping 26,000 hour life, but I don't know if I'd really believe that.
 
Colleton said:
I replaced the 2SA798 differential pairs on the amplifier boards with a small circuit board with a surface mount transistor package I bought from Affinity for Artifacts. I've been doing surface mount soldering on old Macintosh computers for a while now, so the differential pair kits weren't difficult to assemble. They seem to work very well. If anyone knows differently please let me know.
Click to expand...

i've used these on a couple units and i have measured them and measured dc offset after getting the units running.

i have found that i can get lower dc offset by hand matching ksa992s.

the difference is minimal and would cause no problems but it is measurable.

anyway...nice job. i did one a couple years ago and they are solid amps.
 
Shikaka said:
Nice job and great documentation!

I noticed the (4) Nichicon 15,000 uF filter caps (647-LKG1J153MKNF) you used are no longer available. I used Kemet ALT22A153DE063 for the filter caps when I restored two of these units several years ago. They're still available and the cost is still reasonable. The Kemet specs show they have a whopping 26,000 hour life, but I don't know if I'd really believe that.
Click to expand...

I knew I'd miss something in the BoM. If you look in the link to my previous thread about this amp you'll see that I used the Kemet caps you mention. I did it last summer and had forgotten to change the BoM. Thanks for the reminder!
 
painttoad said:
i've used these on a couple units and i have measured them and measured dc offset after getting the units running.

i have found that i can get lower dc offset by hand matching ksa992s.

the difference is minimal and would cause no problems but it is measurable.

anyway...nice job. i did one a couple years ago and they are solid amps.
Click to expand...

Good to know. What do you use to match the 992s? I'd been making differential pairs using 992s bonded with thermal glue, but the last one I made didn't work well. The dc offset drifted negative over time. I tried to match hfe and vbe. I must not have matched them as well as I'd hoped. Anyways, that's why I tried these. Thanks!
 
Colleton said:
Good to know. What do you use to match the 992s? I'd been making differential pairs using 992s bonded with thermal glue, but the last one I made didn't work well. The dc offset drifted negative over time. I tried to match hfe and vbe. I must not have matched them as well as I'd hoped. Anyways, that's why I tried these. Thanks!
Click to expand...
first i use my mini component tester and test a batch of like 25. i write hfe and vbe on the tape strip. then i choose matched pairs and test again with my peak atlas tester and write the numbers on the back of the tape strip. if they still match up, i put them in my vbe comparator. if the traces match, i go with them.
 
painttoad said:
first i use my mini component tester and test a batch of like 25. i write hfe and vbe on the tape strip. then i choose matched pairs and test again with my peak atlas tester and write the numbers on the back of the tape strip. if they still match up, i put them in my vbe comparator. if the traces match, i go with them.
Click to expand...
So then you test them while still taped?
I guess I could test to answer the question, but have you ever found the tape altering measurements?
 
Dingman said:
but have you ever found the tape altering measurements?
Click to expand...
no and i don't know how it would.

holding them in your hands will.

touching them to install in a tester will alter the measurement unless you wait

breathing on them will alter the numbers.
 
painttoad said:
no and i don't know how it would.

holding them in your hands will.

touching them to install in a tester will alter the measurement unless you wait

breathing on them will alter the numbers.
Click to expand...
Right, I'm familiar with the effect of fingers and\or heat - I've just never been sure of the tape and so I typically cut them free before measuring. But like you said, writing on the tape itself would be convenient.
 
Hi Team how are you, I hope everything's going well. I'm restoring a recently buy Pioneer SA-9500 II, it was original as far as I see. I'm using the BOM's founded here.

I finish yesterday the Equalizer Amplifier Assembly (AWF-024), I replace the electrolytics, ceramics, and transistors. This morning I finish the Control Amplifier Assembly board (AWG-045) (electrolytics, ceramics, and transistors).

I'm starting the Switch Assembly Board (AWS-109), I just find the KSC2690AYS looks pretty big (specs) VS the 2SC1384, and the typical voltages isn't to big. There's any other better substitute? or can I confidently use the KSC2690AYS? Regards.

Captura de pantalla 2025-11-05 133155.png
 
Luis Sanchez said:
Hi Team how are you, I hope everything's going well. I'm restoring a recently buy Pioneer SA-9500 II, it was original as far as I see. I'm using the BOM's founded here.

I finish yesterday the Equalizer Amplifier Assembly (AWF-024), I replace the electrolytics, ceramics, and transistors. This morning I finish the Control Amplifier Assembly board (AWG-045) (electrolytics, ceramics, and transistors).

I'm starting the Switch Assembly Board (AWS-109), I just find the KSC2690AYS looks pretty big (specs) VS the 2SC1384, and the typical voltages isn't to big. There's any other better substitute? or can I confidently use the KSC2690AYS? Regards.

View attachment 3628203
Click to expand...
That’s a good sub. Technically you could use something even bigger. It’s just turning the relay off and on.
 
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