Picked up a Sansui 7070 today untested

I'm impressed, it's performing very well. Enjoying it very much while I put my 1250 on the bench. The bass response... Are these known for above average handling of bass? Very interested to see how it sounds after some thorough service.

20191207_163537.jpg 20191207_163551.jpg 20191207_163616.jpg
 
I may be a shamelessly obsessive fan of the brand, but Sansui just has "it". I've given a fair shake to other makes, including several Pioneers that have been through my collection over the last 25 years. These include the SX-990, SX-828, SX-1010, and a couple of high range integrated amps (9xxx models).

The Pioneers I've had have all been decent gear, no doubt. I'll not say they weren't good by any means. But, they never captured my ear like nearly any Sansui made from 1966-1980 has. And the good stuff from post-1980 is also excellent, though they were pushing some underwhelming crap there for a while circa mid 1980's.

I still have the 828 (which has been my favorite Pioneer by far), traded away the 1010 for some Sansui gear, and sold the 990 and integrateds. Actually have a SA-9800 presently I just recently acquired, but needs some work so haven't done much with it yet.

I think you'll find Sansui can impress well beyond your expectations even with low range models which somehow manage to consistently out-deliver their modest specs. I do wish there was a solidly scientific, non-subjective way to quantify the quality of the Sansui sound, since I've not found anything else quite like it.

I once thought it was mostly a psychological effect of my admiration of the brand, but seeing those who previously preferred other competing makes give high praise to Sansui gear seems to negate that idea. Bottom line: yes they really are that good.
 
Cool reads, I'm having fun. Going with MBB02070 Vishay .6w 1% Metal Film resistors for all 1/2w. Will be using these filter caps: https://www.mouser.com/ProductDetail/United-Chemi-Con/EKMH800VSN103MA80T?qs=/ha2pyFadugYxVF4ws61ZhmeZRO1KsbaaBDBDhH4/hHCg584xh6wCOXHswdPuaNA

Couple of questions:

1. Output transistors - I'd like to replace them. I've seen two models used, EchoWars is suggesting (from 2006) MJ21193's and MJ21194's from here: https://audiokarma.org/forums/index...ransistors-for-sansui-7070.74486/#post-735064

Assuming it goes like this:
2x 2SC115 NPN = MJ21194
2x 2SA746 PNP = MJ21193

I used these same ones on my SX-1250. I do not know enough about transistors to determine on my own if these are compatible (obviously overkill). Anyone able to comment?

2. Measuring the Bias. It is either smack dab at 0ma~1ma or I am doing something wrong. I was able to get a 1ma reading on only one multi meter (I tried two). I did not check if the fuse was blown for the amperage function or attempt to adjust any pots. I am supposed to check for amperage correct?

upload_2019-12-9_9-57-3.png

3. Whats everyone take on replacing the lamps with LEDs? The blue/green is new to me. Right now its a blue green, I've seen where it is a vibrant blue after replacing the LEDs. I'm thinking to keep it stock as thats the way it was meant to be. Then again the ice blue looks awesome as well. Tough decision...
 
MIJ_Pioneer said:
Cool reads, I'm having fun. Going with MBB02070 Vishay .6w 1% Metal Film resistors for all 1/2w. Will be using these filter caps: https://www.mouser.com/ProductDetail/United-Chemi-Con/EKMH800VSN103MA80T?qs=/ha2pyFadugYxVF4ws61ZhmeZRO1KsbaaBDBDhH4/hHCg584xh6wCOXHswdPuaNA

Couple of questions:

1. Output transistors - I'd like to replace them. I've seen two models used, EchoWars is suggesting (from 2006) MJ21193's and MJ21194's from here: https://audiokarma.org/forums/index...ransistors-for-sansui-7070.74486/#post-735064

Assuming it goes like this:
2x 2SC115 NPN = MJ21194
2x 2SA746 PNP = MJ21193

I used these same ones on my SX-1250. I do not know enough about transistors to determine on my own if these are compatible (obviously overkill). Anyone able to comment?

2. Measuring the Bias. It is either smack dab at 0ma~1ma or I am doing something wrong. I was able to get a 1ma reading on only one multi meter (I tried two). I did not check if the fuse was blown for the amperage function or attempt to adjust any pots. I am supposed to check for amperage correct?

View attachment 1694877

3. Whats everyone take on replacing the lamps with LEDs? The blue/green is new to me. Right now its a blue green, I've seen where it is a vibrant blue after replacing the LEDs. I'm thinking to keep it stock as thats the way it was meant to be. Then again the ice blue looks awesome as well. Tough decision...
Click to expand...
Are the output transistors blown? If not, I would leave them alone. But yes, if they need replacing, those EW suggests are great replacements. However it certainly won't hurt to put new ones in if you like spending money. :p
I would suggest checking your fuses in your meters. It is working and sounding good and that points to an issue with your meters. OR you are somehow using the wrong test points. The positive probe stays on 05 for each channel. Using 05, and 06 for Right channel, then 05, and 07 for Left channel. I use clip-on leads instead of pointed probes. Much safer, and frees up your hands. Pomona brand is very good quality too. Search Mouser for them.
I like the Blue as well using the "light blue" LEDs, not the "deep blue" (whatever they call them). They bring out the blue dial face with a really nice contrast to the dial pointer. :thumbsup:
 
I hate the bias adjustment of the 9090DB subbing the meter for the fuse and measuring the mA. I used the measure the emitter resistors and the mV option. Hard to reach in a 9090DB but I got there and it was much better for me to do it that way. The numbers you are looking for, mA vs. mV are different and the Ohm's Law is the answer since you know the amps (spec) and resistance.
 
Blue Shadow said:
I hate the bias adjustment of the 9090DB subbing the meter for the fuse and measuring the mA. I used the measure the emitter resistors and the mV option. Hard to reach in a 9090DB but I got there and it was much better for me to do it that way. The numbers you are looking for, mA vs. mV are different and the Ohm's Law is the answer since you know the amps (spec) and resistance.
Click to expand...
Yes, it can be awkward, but I have grown used to the pulling the fuse method and bought long-reach clamp on probes for the purpose. Plus I put zip tie "handles" on the fuses. Makes it slicker than snot on a doorknob. :biggrin:
 
An order has been placed. Skipped the outputs for now. Some data pulled from visually inspecting, other data pulled from the schematic.

Filter: 2x 10,000 uf 50v = 10,000uf 63v 661-EKMH630N103MA50S


Outputs:

2x 2SC115 NPN = MJ21194

2x 2SA746 PNP = MJ21193

4x Mica for Output = 534-4636


F-2624 Driver Circuit Board

R33, R34: 180 (1 watt?) Fused = (.6w) 594-MBB02070C1800FCT or (1watt)

R35, R36: 4.7 (1 watt?) Fused 2x 594-MBB02070C4708FCT (1/2 watt) or (1watt) 594-5073NW4R700J

R37, R38: 3.9K ½ watt = 594-MBB02070C3901FC1

R39, R40: 10 ½ watt Fused = 594-MBB02070C1009FC1

R41, R42: 150 ½ watt Fused = 594-MBB02070C1500FCT

R43, R44: 150 ½ watt Fused = 594-MBB02070C1500FCT

R47, R48, R49, R50: 4.7 ½ watt Fused = 594-MBB02070C4708FCT

Zd01, ZD01: 0316070 EQa01 24r = 24v zener diode = 512-1N5252B

2x D05, 2x D06: VD1212 Varistor = 512-1N4148 "VD-1212 "varistor", use two 1N4148 in series for each one."

VR01, VR02: 4.7K Ohm = 652-3386H-1-502LF

VR03, VR04: 1K Ohm = 652-3386H-1-102LF

F-2624 (driver board), TR01-04 replace with KSC1845FTA GAINED MATCHED

PW Caps:

2x 330uf 63v = 63v 647-UPW1J331MHD

2x 100uf 25v = 35v 647-UPW1V101MPD

2x 470uf 6.3v = 16v 647-UPW1C471MPD6

Audio or Film:

2x 0.47uf 50v = 63v Wima Film 505-MKS2D034701E00JI



F-2625 Power Supply Circuit Board (Mother Board)

R04: 100 ½ watt Fused = 594-MBB02070D1000BC1

R27, R28, R29, R33, R34: 4.7 ½ Watt Fused = 594-MBB02070C4708FCT

Relay: 1150370 = MY2-02-DC24

C05, C06 = 1000UF 50V (didn’t see these, from the schematics) – 50v 647-UPW1H102MHD1CV

C07, – 1000UF 80V = 100v 647-UPW2A102MHD

C08 – 470UF 80V = 100v 647-UPW2A471MHD

C10, C12 – 220UF 63V = 63v 647-UPW1J221MPD

C14 – 33UF 50V = 63v 647-UPW1J330MED

C15 – 47UF 50V = 63v 647-UPW1J470MPD

C16 – 1UF 50V BIPOLAR = 1uf 50v 647-UES1H010MDM1TD

C17 – 1UF 50V = 63v Film 505-MKS2C041001FJI00

C18 – 1000UF 6.3V = 16v 647-UPW1C102MPD

C20 – 47UF 50V = 63v 647-UPW1J470MPD

C21, C22, C23 – 4.7uf 80v BIPOLAR = 100v 647-UVP2A4R7MED


F-2626 Power Supply Circuit Board

R13, R14: 560 3 Watt = Panasonic 667-ERG-3SJ561

ZD01, ZD02: EQA01.13R = 13v Zener Diode = 512-1N5243B

C01 – 33UF 50V = 63v 647-UPW1J330MED

C04 – 100UF 16V = 35v 647-UPW1V101MPD

C05, C06 – 10UF 50V = 63v 647-UPW1J100MDD1TA

C07 – 330UF 16V = 35v 647-UPW1V331MPD6TD

C08 – 100UF 50V = 63v 647-UPW1J101MPD

C09 – 330UF 16V = 35v 647-UPW1V331MPD6TD


F-2627 Illumination Circuit Board

C01: 470uf 10v = 16v 647-UPW1C471MPD6

R01: 18 1/4W Fused =
594-MBB02070C1809FC1


F-2620 – From Schematic

C01, C02: 3.3uf 35v = 50v 647-UKL1H3R3MDDANA

C07, c08:47uf 16v = 25v 647-UPW1E470MDD

C11, C12: 100uf 10v = 25v 647-UPW1E101MED

C13, C14: 1uf 50v (probably tant) = 505-MKS2C041001FKI00

C23, C24: 470uf 50v = 50v 647-UPW1H471MHD1TO

C603, C604: 2.2uf 50v = 63v Film 505-MKS2C042201K00JO

C606: 100uf 63v = 63v 647-UPW1J101MPD

C608: 4.7uf 50v = 63v Film 505-MKS2C044701M00KS

C610: 100uf 50v = 63v 647-UPW1J101MPD


F-2622 – All Audio grade unless stated

C01, C02 – 1UF 50V = 63v Film 505-MKS2C041001FJI00

C05, C06 – 100UF 6.3V POWER PW = 25v 647-UPW1E101MED

C07, C08 – 4.7UF 50V = 63v Film 505-MKS2C044701M00KS

C09, C10 – 10UF 50V = 63v 647-UKL1J100MED

C23, C24 – 2.2UF 50V = 63v Film 505-MKS2C042201K00JO

C27, 28 – 3.3uf 50v = 63v Film 505-MKS2C043301KKSSD

C29, C30 – 100UF 6.3V POWER PW = 25v 647-UPW1E101MED

C31, C32 – 330UF 35v Power PW = 50v 647-UPW1H331MPD


Tuner

3x 1uf 50v audio = 63v Film 505-MKS2C041001FJI00

3.3uf 50v audio = 505-MKS2C043301KKSSD

.22 50v audio = 63v Film 505-MKS2C032201BKI00

3x 1.5uf 50v audio = 63v Film 505-MKS2C041501H00KI

4x 10uf 16v = 25v 647-UKL1E100MDDANA

1uf 50v = 63v Film 505-MKS2C041001FJI00

33uf 16v = 25v 647-UPW1E330MDD1TD

470uf 16v = 25v 647-UPW1E471MPD

220uf 16v = 25v 647-UPW1E221MPD


F-2620 – From Schematic

C01, C02: 3.3uf 35v = 50v 647-UKL1H3R3MDDANA

C07, c08:47uf 16v = 25v 647-UPW1E470MDD

C11, C12: 100uf 10v = 25v 647-UPW1E101MED

C13, C14: 1uf 50v (probably tant) = 505-MKS2C041001FKI00

C23, C24: 470uf 50v = 50v 647-UPW1H471MHD1TO

C603, C604: 2.2uf 50v = 63v Film 505-MKS2C042201K00JO

C606: 100uf 63v = 63v 647-UPW1J101MPD

C608: 4.7uf 50v = 63v Film 505-MKS2C044701M00KS

C610: 100uf 50v = 63v 647-UPW1J101MPD
 
There are no resistors above 1/2w on the F-2624 driver board. Most are only 1/4w except where noted in the schematic. Use 1/2w in place of the fusible ones. The old technology made 3.9k (R37/38) 1/2w metal oxide resistors appear to be larger.
 
Skywatcher said:
There are no resistors above 1/2w on the F-2624 driver board. Most are only 1/4w except where noted in the schematic. Use 1/2w in place of the fusible ones. The old technology made 3.9k (R37/38) 1/2w metal oxide resistors appear to be larger.
Click to expand...

Thanks for checking, I need to edit that. That was an early note because the schematic was distorted in that area. Couldn't tell what value it was.
 
Haven't forgotten about this :)

I'm usually not a fan of taking away the original look but wow, Skywatcher you were right. The ice blue is the right choice.

20191218_231950.jpg
 
Last edited:
Fun read, and some great advice. The unit cleaned up really well. My aesthetic tends toward original lighting, but long life and cool running are definitely advantages of the LEDs if you can find a pleasing match.
Do check out the driver board transistors for black legs. Here's my post on them in my 9090.

https://audiokarma.org/forums/index...spikes-on-outputs-and-speakers-solved.890905/

If you have black leg transistors I'd follow Skywatcher's advice and replace them especially if your in there.

Also thanks for posting the replacement list.
 
markkb said:
Fun read, and some great advice. The unit cleaned up really well. My aesthetic tends toward original lighting, but long life and cool running are definitely advantages of the LEDs if you can find a pleasing match.
Do check out the driver board transistors for black legs. Here's my post on them in my 9090.

https://audiokarma.org/forums/index...spikes-on-outputs-and-speakers-solved.890905/

If you have black leg transistors I'd follow Skywatcher's advice and replace them especially if your in there.

Also thanks for posting the replacement list.
Click to expand...

Thanks, are you referring to tr01-04 on the driver board right? The 1845 gained matched pair? I replaced em, legs were black as the ace of spades :) All other transistors on that board were clean legged.

I have some photos I need to upload, need to edit the recap list, there are a few errors. here's a sneak peak

20191220_174701.jpg
 
MIJ_Pioneer said:
Thanks, are you referring to tr01-04 on the driver board right?
Click to expand...

Yep those are the transistors I'm referring to. TR01-04. They were all black legged, cleaning helped stop the noise but just yesterday I heard a couple 'crackle 'snaps'! The quieting from cleaning the legs only lasted a month. I'm putting in an order to replace them.
 
markkb said:
Yep those are the transistors I'm referring to. TR01-04. They were all black legged, cleaning helped stop the noise but just yesterday I heard a couple 'crackle 'snaps'! The quieting from cleaning the legs only lasted a month. I'm putting in an order to replace them.
Click to expand...

Good idea. I measured the ones I pulled out and they were pretty far from spec from one another. The ~3hfe variance that I installed was much closer. Thanks to Skywatcher for the suggestion, turned out great.
 
markkb said:
Yep those are the transistors I'm referring to. TR01-04. They were all black legged, cleaning helped stop the noise but just yesterday I heard a couple 'crackle 'snaps'! The quieting from cleaning the legs only lasted a month. I'm putting in an order to replace them.
Click to expand...
Merely cleaning the leads does nothing for the tarnish/corrosion that creeps up inside. But they "look" good. :D
 
MIJ_Pioneer said:
An order has been placed. Skipped the outputs for now. Some data pulled from visually inspecting, other data pulled from the schematic.

Filter: 2x 10,000 uf 50v = 10,000uf 63v 661-EKMH630N103MA50S


Outputs:

2x 2SC115 NPN = MJ21194

2x 2SA746 PNP = MJ21193

4x Mica for Output = 534-4636


F-2624 Driver Circuit Board

R33, R34: 180 (1 watt?) Fused = (.6w) 594-MBB02070C1800FCT or (1watt)

R35, R36: 4.7 (1 watt?) Fused 2x 594-MBB02070C4708FCT (1/2 watt) or (1watt) 594-5073NW4R700J

R37, R38: 3.9K ½ watt = 594-MBB02070C3901FC1

R39, R40: 10 ½ watt Fused = 594-MBB02070C1009FC1

R41, R42: 150 ½ watt Fused = 594-MBB02070C1500FCT

R43, R44: 150 ½ watt Fused = 594-MBB02070C1500FCT

R47, R48, R49, R50: 4.7 ½ watt Fused = 594-MBB02070C4708FCT

Zd01, ZD01: 0316070 EQa01 24r = 24v zener diode = 512-1N5252B

2x D05, 2x D06: VD1212 Varistor = 512-1N4148 "VD-1212 "varistor", use two 1N4148 in series for each one."

VR01, VR02: 4.7K Ohm = 652-3386H-1-502LF

VR03, VR04: 1K Ohm = 652-3386H-1-102LF

F-2624 (driver board), TR01-04 replace with KSC1845FTA GAINED MATCHED

PW Caps:

2x 330uf 63v = 63v 647-UPW1J331MHD

2x 100uf 25v = 35v 647-UPW1V101MPD

2x 470uf 6.3v = 16v 647-UPW1C471MPD6

Audio or Film:

2x 0.47uf 50v = 63v Wima Film 505-MKS2D034701E00JI



F-2625 Power Supply Circuit Board (Mother Board)

R04: 100 ½ watt Fused = 594-MBB02070D1000BC1

R27, R28, R29, R33, R34: 4.7 ½ Watt Fused = 594-MBB02070C4708FCT

Relay: 1150370 = MY2-02-DC24

C05, C06 = 1000UF 50V (didn’t see these, from the schematics) – 50v 647-UPW1H102MHD1CV

C07, – 1000UF 80V = 100v 647-UPW2A102MHD

C08 – 470UF 80V = 100v 647-UPW2A471MHD

C10, C12 – 220UF 63V = 63v 647-UPW1J221MPD

C14 – 33UF 50V = 63v 647-UPW1J330MED

C15 – 47UF 50V = 63v 647-UPW1J470MPD

C16 – 1UF 50V BIPOLAR = 1uf 50v 647-UES1H010MDM1TD

C17 – 1UF 50V = 63v Film 505-MKS2C041001FJI00

C18 – 1000UF 6.3V = 16v 647-UPW1C102MPD

C20 – 47UF 50V = 63v 647-UPW1J470MPD

C21, C22, C23 – 4.7uf 80v BIPOLAR = 100v 647-UVP2A4R7MED


F-2626 Power Supply Circuit Board

R13, R14: 560 3 Watt = Panasonic 667-ERG-3SJ561

ZD01, ZD02: EQA01.13R = 13v Zener Diode = 512-1N5243B

C01 – 33UF 50V = 63v 647-UPW1J330MED

C04 – 100UF 16V = 35v 647-UPW1V101MPD

C05, C06 – 10UF 50V = 63v 647-UPW1J100MDD1TA

C07 – 330UF 16V = 35v 647-UPW1V331MPD6TD

C08 – 100UF 50V = 63v 647-UPW1J101MPD

C09 – 330UF 16V = 35v 647-UPW1V331MPD6TD


F-2627 Illumination Circuit Board

C01: 470uf 10v = 16v 647-UPW1C471MPD6

R01: 18 1/4W Fused =
594-MBB02070C1809FC1


F-2620 – From Schematic

C01, C02: 3.3uf 35v = 50v 647-UKL1H3R3MDDANA

C07, c08:47uf 16v = 25v 647-UPW1E470MDD

C11, C12: 100uf 10v = 25v 647-UPW1E101MED

C13, C14: 1uf 50v (probably tant) = 505-MKS2C041001FKI00

C23, C24: 470uf 50v = 50v 647-UPW1H471MHD1TO

C603, C604: 2.2uf 50v = 63v Film 505-MKS2C042201K00JO

C606: 100uf 63v = 63v 647-UPW1J101MPD

C608: 4.7uf 50v = 63v Film 505-MKS2C044701M00KS

C610: 100uf 50v = 63v 647-UPW1J101MPD


F-2622 – All Audio grade unless stated

C01, C02 – 1UF 50V = 63v Film 505-MKS2C041001FJI00

C05, C06 – 100UF 6.3V POWER PW = 25v 647-UPW1E101MED

C07, C08 – 4.7UF 50V = 63v Film 505-MKS2C044701M00KS

C09, C10 – 10UF 50V = 63v 647-UKL1J100MED

C23, C24 – 2.2UF 50V = 63v Film 505-MKS2C042201K00JO

C27, 28 – 3.3uf 50v = 63v Film 505-MKS2C043301KKSSD

C29, C30 – 100UF 6.3V POWER PW = 25v 647-UPW1E101MED

C31, C32 – 330UF 35v Power PW = 50v 647-UPW1H331MPD


Tuner

3x 1uf 50v audio = 63v Film 505-MKS2C041001FJI00

3.3uf 50v audio = 505-MKS2C043301KKSSD

.22 50v audio = 63v Film 505-MKS2C032201BKI00

3x 1.5uf 50v audio = 63v Film 505-MKS2C041501H00KI

4x 10uf 16v = 25v 647-UKL1E100MDDANA

1uf 50v = 63v Film 505-MKS2C041001FJI00

33uf 16v = 25v 647-UPW1E330MDD1TD

470uf 16v = 25v 647-UPW1E471MPD

220uf 16v = 25v 647-UPW1E221MPD


F-2620 – From Schematic

C01, C02: 3.3uf 35v = 50v 647-UKL1H3R3MDDANA

C07, c08:47uf 16v = 25v 647-UPW1E470MDD

C11, C12: 100uf 10v = 25v 647-UPW1E101MED

C13, C14: 1uf 50v (probably tant) = 505-MKS2C041001FKI00

C23, C24: 470uf 50v = 50v 647-UPW1H471MHD1TO

C603, C604: 2.2uf 50v = 63v Film 505-MKS2C042201K00JO

C606: 100uf 63v = 63v 647-UPW1J101MPD

C608: 4.7uf 50v = 63v Film 505-MKS2C044701M00KS

C610: 100uf 50v = 63v 647-UPW1J101MPD
Click to expand...
 
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