Not boring rather it is INVALUABLE information, that was ONLY to be found if you being trained by a professional tech/engineer. Or maybe your dad had a radio shop or hobby. To be a fly on the shoulder of guys like you in so many areas of expertise for FREE is in my opinion one of the best uses of the internet fullstop. so please ramble away and THANKYOU TONY
Thank you for everything, Tony! Putting together so many videos is no mean feat. I’d love to see you work on a Sansui AU-D9, if you ever get ahold of one-it’s what I have, and mine is pretty temperamental. If you’re ever in the mood, I’d also like to see more turntable repairs. I have one of the horrendously complex 80s Denon full autos, which has recently transformed itself into an attractive wood-veneered paperweight. Puzzling it out has a) been a great learning experience, and b) taken years off my life. Thank you for sharing your wisdom!
excellent work mr Tony. that's a great and beautiful looking amp now. (edit: i just watched the next video and my fan question was answered, very funny of you w/ the title :D) ps: i didn't caught the reason for reversing the air flow direction of the fan during the final assembly. originally it acted as a rear exhaust thus explaining the positioning of the thermal-switches...
Hi Tony, I would really like to see the Sansui on the bench. Carver would be pretty cool too. Pretty advanced topology, but hopefully easier to service than the Yamaha B6 ;)
My guess, regarding the artifact, would be the Fluke LCD scope. That doesn’t seem like it would be a good choice for a bench set up, anyway, and it is a bit difficult to see clearly in the video. Other than that, I’m amazed, even allowing for your expert skills, how really wonderfully this turned out, given the condition it was in when you began. Excellent. Thank you.
Hi Tony, you've done an incredible job, it's amazing 👍 When I think about the placement of the temperature sensors on the coolers and its heating, I wonder if the fan is blowing in the right direction. The fan is mounted so that it pushes the air and is not affected by the heat from the cooled device, but it seems that way to me with this design. It also seems odd to me that warm air would be blown into the amp. Edit: I would reverse the operation of the fan and instead of the filter I would install only a wire grid as protection against possible contact with the fan. Nice day 🙂Tom
I would like to see the sansui ca 2000 & ba 2000 as I have both of them in need of restoration however I will watch what ever you decide to tackle as I find all your reapers informative keep up the good work 👍
Hi Tony - great video (as always 👍). Question on the fan airflow - I thought that generally (I'm from the data centre world) airflow is front to back. However, in this case, it seems to be back to front. Is that the way that amp is designed?
Did that amp sound good? The low distortion from the meter and good frequency response makes me think it should be a good sounding amplifier. Nice work on the restoration.
My Hafler DH 500 has the fan inside, with the exit at the back surface, no impedance to flow at the cooling tunnel exit. It does not have managed speed though. It’s going to be my next project.
I’m curious Tony, at the risk of me sounding stupid, would it be more beneficial to direct the fan exhaust to the rear of the amplifier rather than to the front? It just seems to me (what do I know) that pushing the fan exhaust heat to the front, could maybe damage the meter. Just a thought
I was thinking the same thing ( fan should be drawing the air out the back), it would make sense as to why the sensors for the high fan are at the back of the tunnel
I put the fan in the same way as it was when I got it. There are two possibilities: 1) Marantz configured the fan to pull fresh air in from the outside and force it through the cooling tunnel. 2) Someone at some point removed the fan and put it in backwards from its factory configuration. Judging by the condition of the mounting grommets and the solder joints on the fan and dropping resistor, it appears as though the fan had not been previously removed and was configured to work this way. Regardless of the direction of the fan, I think there will always be a "hot end" and "cool end" of the tunnel, just because of how it's designed. Of course, by running the fan in the other direction, it may cause the end with the thermal switches to heat up faster, causing the fan to go into jet engine mode sooner. Who knows??? Thanks for the comment!
Tony, I'm a huge fan of your channel! You've even inspired me to set up my own bench and work on restoration projects. About the Marantz 510M. I've owned one for about 20 years. The unit was designed to have a foam AC air filter installed under the top cover to keep dust out of the unit as the fan draws air into the unit and exits the rear. As mentioned in other comments, this lines up temp sensors to be at the end of the tunnel where the air is hottest. It also prevents pushing all the heat from the tunnel into the unit. Keep up the great videos.
Curiosity got the better of me and I went down and looked at the back of the unit. When I compared iit to the original fan, lo and behold I had it in backwards!!!!!! The wheel was turning but the hamster was dead!!! I will correct it and see how it works. Thanks for bringing it up (along with the other dozen viewers as well), I would have never looked at it. :)
Ever think of trying an ESD mat? They are designed for working on electronics, soft and soldering resistant and good to have to eliminate static discharge. Especially for low voltage FETs and digital electronics.
Hi Tony, very good job! I've got an American 510M (110V) and I asked my technician to check the right peak indicator light (the lef one witks correctly). He checked the lamp and the command plate without finding the reason. Do you have some ideas? Thanks
Glad you got the air direction sorted out....it was starting to bug me. Also, did the amp arrive with green meters instead of the normal Marantz blue? Finally, when you were showing the original faceplate, it was labeled as a "510MR" and not "510M". Does anybody know what the "MR" designation meant?
I need to get a PA81, those things cleanly combine so much functionality into one box, it's half a crime to do any audio amplifier work without one, lol
I gave a thumbs up because you never fail to entertain. Even when you/we repair working sets. The thing I wonder about is how long did it take to find out it was working?
Would love to see you work on the Phase Linear 400 next! :) Especially interested in White Oak Audio mods if that's something you would consider doing. 👍🙂
I would have thought that they would have had the fan pulling air through the top and exhausting it out the back. That would make more sense in a rack mount and for how the sensors are installed.
as i understand it by looking at the fan during disassembly, the fan was indeed orientated as an rear exhaust... i'm not sure what was the reason for reversing the airflow direction
@@duroxkilo After I posted this, I saw a follow-up video, where Tony does explain that it should have been installed the other way and that he was going to do that.
A lot of EE's and electronics professionals turn their nose up at Sencore gear in favor of Tektronix or HP (Agilent). But I have to say, Sencore made some really useful and unique test gear like the Power Amplifier Analyzer at affordable prices. They are especially known for their easy to use LCR analyzers.
Looking good! Do you have the ability to do testing with reactive loads (other than speakers), possibly using a full band noise source? Basically, to test the ability of the amp to process aggressive music at high levels to see how well the unit works, rather than using just single tones. Dont get me wrong, 8-bit music can be fun, but when you've got highly compressed, screaming death metal assualting your very being, how well does it perform? And will it sag under such a demanding load? Food for thought on what is a very rainy Saturday morning for me.
When I fed a square wave signal source into the amp and connected a capacitor across the load, I was presenting a reactive load to the amplifier. If it can deal with the ringing created by this setup in short order, it should be OK. Between the NFB circuit and the zobel network (if properly designed), the amp will behave well, in most cases. As for parasitic oscillation, this can happen even on a pure sine wave, as it is caused by the stray capacitances in the amp (like miller capacitance).
I'm not replacing the foam. It deteriorates and gets all over the inside of the amp. If someone wants to have the filter, they can pick up some of that furnace register filter media. It won't deteriorate and is much better. Or you could just blow the dust out every couple of years when it needs it, just like your computer and have better ventilation without the filter.
My biggest takeaways from this is how big of a signal was the 510m seeing to produce the 250+ watts of output and why weren't the meters restored to the original "marantz blue". Good to know what my 510 is capable of 😁
Forgot how it's called but, there are 2 pieces of blue "paper" that change color with time, in the VU's. You should change those!. Niiice video series!!!
You could replace the lamps with tri-color LEDs and a diffusion glass. Then you could have any color you want. Yes I know, the audiophiles would have a fit knowing there was a PWM LED controller inside the amp.🙄
what is the chance the air flow through the fan is backwards? dumping hot air into the amp seams wrong, and the thermostat position would make more sense if the air flow were reversed. Al O'
Edit: later I saw other comments from Tony, he has changed the fan, so indeed it was designed to go the other way. But I don't think it is good practice. Then it would be better to have the fan at the beginning of the tunnel behind the front.
Hi Tony, Great job as always! I have only one comment and that is about the plastic VU meter plates. They are discollored Just as they were in my 250M. I found a guy in the past that had 100% replica's made and i got 2 of them. You can not clean these.
A friend of mine who worked with the engineer who designed the 510 told me that the designer bet that they could make the amp fail… my friend and team threw everything at it and could not make it fail… they had open it up and short some components….. closed it up and gave it back to the engineer… after investigating a bit he saw through their game… just a bit of history about the amp… @Tony: were you able to measure the voltage across r316 and r321?
@@xraytonybThanks - and I guess that if the voltages are very different like 4V in 316 and 2 V in 321 - then amp is not balanced with input at at zero.
Correct. In most cases, it is because of an issue in the feedback loop. Q304 & Q306 should each have a base voltage near 0 VDC. Usually, when you see an imbalance, Q306 will have an abnormal base voltage above or below 0 VDC, indicating a problem further down the line in the amp.
Wouldn't it be better to reverse the airflow of the fan: instead of blowing fresh air into the amp have it pull air through the amp. Chances are that the location of the thermal switches sit better this way.
Do one of the phase Linearrs next. The Carver 1.5 is more tricky with that silly triac feedback into the primary of the transformer. Be careful if you need to bypass that triac for testing. Regarding the current unit, this Marantz 500m, I find it to be aesthetically off-putting. That black and green could work in the right environment but I much prefer the silver\blue\teal theme.
36:40 If anyone feels the need to crank this unit to such a level, they must have very inefficient speakers in a gymnasium or they're simply abusive for no reason. My vote is to do the Carver next, but it doesn't matter to me.
It's not clipping. You are seeing the overload protect circuit limiting the signal to prevent overcurrent in the amp. This makes the top of the waveform fold over like that.
Not boring rather it is INVALUABLE information, that was ONLY to be found if you being trained by a professional tech/engineer.
Or maybe your dad had a radio shop or hobby. To be a fly on the shoulder of guys like you in so many areas of expertise for FREE
is in my opinion one of the best uses of the internet fullstop. so please ramble away and THANKYOU TONY
Thank you for everything, Tony! Putting together so many videos is no mean feat.
I’d love to see you work on a Sansui AU-D9, if you ever get ahold of one-it’s what I have, and mine is pretty temperamental.
If you’re ever in the mood, I’d also like to see more turntable repairs. I have one of the horrendously complex 80s Denon full autos, which has recently transformed itself into an attractive wood-veneered paperweight. Puzzling it out has a) been a great learning experience, and b) taken years off my life.
Thank you for sharing your wisdom!
It pulls the air through the top and out the back !
What an incredible project! I would love to see the insides of a Phase Linear. In the 70s I always wanted one. You probably did one and I missed it.
excellent work mr Tony.
that's a great and beautiful looking amp now.
(edit: i just watched the next video and my fan question was answered, very funny of you w/ the title :D)
ps: i didn't caught the reason for reversing the air flow direction of the fan during the final assembly.
originally it acted as a rear exhaust thus explaining the positioning of the thermal-switches...
Hi Tony, I would really like to see the Sansui on the bench. Carver would be pretty cool too. Pretty advanced topology, but hopefully easier to service than the Yamaha B6 ;)
I'd like to see you tear into the Phase Linear PL 400. Thanks for another great video! I love that PA81 ❤
wow that amp looks great
My guess, regarding the artifact, would be the Fluke LCD scope. That doesn’t seem like it would be a good choice for a bench set up, anyway, and it is a bit difficult to see clearly in the video. Other than that, I’m amazed, even allowing for your expert skills, how really wonderfully this turned out, given the condition it was in when you began. Excellent. Thank you.
Great stuff Tony. Sansui Please. BA or CA.
Wow, you got a Phase Linear. I like the VU on this amp. It's like KID speaking from "The knight rider"
Hi Tony, you've done an incredible job, it's amazing 👍 When I think about the placement of the temperature sensors on the coolers and its heating, I wonder if the fan is blowing in the right direction. The fan is mounted so that it pushes the air and is not affected by the heat from the cooled device, but it seems that way to me with this design. It also seems odd to me that warm air would be blown into the amp.
Edit: I would reverse the operation of the fan and instead of the filter I would install only a wire grid as protection against possible contact with the fan.
Nice day 🙂Tom
I would like to see the sansui ca 2000 & ba 2000 as I have both of them in need of restoration however I will watch what ever you decide to tackle as I find all your reapers informative keep up the good work 👍
Amazing amp, Fantastic restoration!
Thanks Tony. Great series….!
Hi Tony - great video (as always 👍). Question on the fan airflow - I thought that generally (I'm from the data centre world) airflow is front to back. However, in this case, it seems to be back to front. Is that the way that amp is designed?
Maybe some crosstalk in that first setup between the in- and output cables that caused the oscillations ?
Did that amp sound good? The low distortion from the meter and good frequency response makes me think it should be a good sounding amplifier. Nice work on the restoration.
My Hafler DH 500 has the fan inside, with the exit at the back surface, no impedance to flow at the cooling tunnel exit. It does not have managed speed though. It’s going to be my next project.
Bello/Magnifico.💪💪💪💪💪💪👑
19:18 - Perhaps the dummy loads in the PA-81 are slightly inductive?
Id be curious to see if a small bushel of lupins would ignite with full power connected across them..:)
I vote for the PL 400 next. Got one with problems and need the guidance.
What issues are you having? Maybe some of us in here can help you out as well.
I’m curious Tony, at the risk of me sounding stupid, would it be more beneficial to direct the fan exhaust to the rear of the amplifier rather than to the front? It just seems to me (what do I know) that pushing the fan exhaust heat to the front, could maybe damage the meter. Just a thought
I was thinking the same thing ( fan should be drawing the air out the back), it would make sense as to why the sensors for the high fan are at the back of the tunnel
I put the fan in the same way as it was when I got it. There are two possibilities:
1) Marantz configured the fan to pull fresh air in from the outside and force it through the cooling tunnel.
2) Someone at some point removed the fan and put it in backwards from its factory configuration.
Judging by the condition of the mounting grommets and the solder joints on the fan and dropping resistor, it appears as though the fan had not been previously removed and was configured to work this way.
Regardless of the direction of the fan, I think there will always be a "hot end" and "cool end" of the tunnel, just because of how it's designed.
Of course, by running the fan in the other direction, it may cause the end with the thermal switches to heat up faster, causing the fan to go into jet engine mode sooner. Who knows??? Thanks for the comment!
I experimented with heat movement, it's better to blow it out instead of letting cool air in.
Tony, I'm a huge fan of your channel! You've even inspired me to set up my own bench and work on restoration projects.
About the Marantz 510M. I've owned one for about 20 years. The unit was designed to have a foam AC air filter installed under the top cover to keep dust out of the unit as the fan draws air into the unit and exits the rear. As mentioned in other comments, this lines up temp sensors to be at the end of the tunnel where the air is hottest. It also prevents pushing all the heat from the tunnel into the unit. Keep up the great videos.
Curiosity got the better of me and I went down and looked at the back of the unit. When I compared iit to the original fan, lo and behold I had it in backwards!!!!!! The wheel was turning but the hamster was dead!!! I will correct it and see how it works. Thanks for bringing it up (along with the other dozen viewers as well), I would have never looked at it. :)
Good Job!!!n(again) Tony!😊🙏
Ever think of trying an ESD mat? They are designed for working on electronics, soft and soldering resistant and good to have to eliminate static discharge. Especially for low voltage FETs and digital electronics.
Hi Tony, very good job! I've got an American 510M (110V) and I asked my technician to check the right peak indicator light (the lef one witks correctly). He checked the lamp and the command plate without finding the reason. Do you have some ideas? Thanks
Nice solid amp again! Tnx for sharing Tony.
22:52 - How about sweeping the frequency at 250 watts/channel to find any oscillations?
Re the mat, Weathertech makes under the sink kitchen mats, that would also work,
Could you run the fan the other way, the thermal switches would be at the hotter end then?
Glad you got the air direction sorted out....it was starting to bug me. Also, did the amp arrive with green meters instead of the normal Marantz blue? Finally, when you were showing the original faceplate, it was labeled as a "510MR" and not "510M". Does anybody know what the "MR" designation meant?
The R stands for rack mount version. It has a wider faceplate.
@@xraytonyb ....and the green meters?
The velum fades and turns mcintosh green. I replaced the bulbs with royal blue led's and it's now blue.
By the way my VU meters a blue - yours look green? Or is that the camera?
Electronics servicing is NOT about instant gratification.
I need to get a PA81, those things cleanly combine so much functionality into one box, it's half a crime to do any audio amplifier work without one, lol
Did you test the new mat to see if it was conductive at all? Maybe you did and I missed it.
I gave a thumbs up because you never fail to entertain. Even when you/we repair working sets. The thing I wonder about is how long did it take to find out it was working?
And for a bi-amp speaker setup just need a second one of these babies. Strange that it doesn’t have a balanced input, at least as an option.
Would love to see you work on the Phase Linear 400 next! :) Especially interested in White Oak Audio mods if that's something you would consider doing. 👍🙂
You should have kept the fan reversed to suck cool air in from the front and push the hot air out from the back (closer to the thermal switches).
Sorry Tony, i keep adding details… on my 510 , the inside of the top cover has a thin foam filter across the entire surface to keep dust out.
Excuse me, this is part 6. Are there anywhere parts 1;2 etc ?
I would have thought that they would have had the fan pulling air through the top and exhausting it out the back. That would make more sense in a rack mount and for how the sensors are installed.
as i understand it by looking at the fan during disassembly, the fan was indeed orientated as an rear exhaust... i'm not sure what was the reason for reversing the airflow direction
@@duroxkilo After I posted this, I saw a follow-up video, where Tony does explain that it should have been installed the other way and that he was going to do that.
@@srtamplificationthank you i just watched it too, funny title :)
A lot of EE's and electronics professionals turn their nose up at Sencore gear in favor of Tektronix or HP (Agilent). But I have to say, Sencore made some really useful and unique test gear like the Power Amplifier Analyzer at affordable prices. They are especially known for their easy to use LCR analyzers.
Excuse me again, Is it possible to know who did the faceplate reproduction? Thank you
Looking good!
Do you have the ability to do testing with reactive loads (other than speakers), possibly using a full band noise source? Basically, to test the ability of the amp to process aggressive music at high levels to see how well the unit works, rather than using just single tones. Dont get me wrong, 8-bit music can be fun, but when you've got highly compressed, screaming death metal assualting your very being, how well does it perform? And will it sag under such a demanding load?
Food for thought on what is a very rainy Saturday morning for me.
When I fed a square wave signal source into the amp and connected a capacitor across the load, I was presenting a reactive load to the amplifier. If it can deal with the ringing created by this setup in short order, it should be OK. Between the NFB circuit and the zobel network (if properly designed), the amp will behave well, in most cases. As for parasitic oscillation, this can happen even on a pure sine wave, as it is caused by the stray capacitances in the amp (like miller capacitance).
Awesome stuff. Onne thing i couldnt stand tough...the faceplate screws are super ugly =)
Sansui please!
Maybe reverse the fan direction to pull the heat out, past the sensors. This would kind of void the air filter though.
Check out my response to @jaybats7865
I'm not replacing the foam. It deteriorates and gets all over the inside of the amp. If someone wants to have the filter, they can pick up some of that furnace register filter media. It won't deteriorate and is much better. Or you could just blow the dust out every couple of years when it needs it, just like your computer and have better ventilation without the filter.
My biggest takeaways from this is how big of a signal was the 510m seeing to produce the 250+ watts of output and why weren't the meters restored to the original "marantz blue". Good to know what my 510 is capable of 😁
Forgot how it's called but, there are 2 pieces of blue "paper" that change color with time, in the VU's. You should change those!. Niiice video series!!!
... It's called Vellum Paper, is is availlable on the Bay :)
You could replace the lamps with tri-color LEDs and a diffusion glass. Then you could have any color you want. Yes I know, the audiophiles would have a fit knowing there was a PWM LED controller inside the amp.🙄
what is the chance the air flow through the fan is backwards? dumping hot air into the amp seams wrong, and the thermostat position would make more sense if the air flow were reversed. Al O'
I would have expected that your fan pulled air out rather than pushing air in. How about reversing the direction of the fan?
Pulling air out destroys the fan in time, just to hot.
Edit: later I saw other comments from Tony, he has changed the fan, so indeed it was designed to go the other way. But I don't think it is good practice. Then it would be better to have the fan at the beginning of the tunnel behind the front.
Hi Tony, Great job as always! I have only one comment and that is about the plastic VU meter plates. They are discollored Just as they were in my 250M. I found a guy in the past that had 100% replica's made and i got 2 of them. You can not clean these.
A friend of mine who worked with the engineer who designed the 510 told me that the designer bet that they could make the amp fail… my friend and team threw everything at it and could not make it fail… they had open it up and short some components….. closed it up and gave it back to the engineer… after investigating a bit he saw through their game… just a bit of history about the amp…
@Tony: were you able to measure the voltage across r316 and r321?
316 and 321 should be around 3.1 volts, +/- 100 mV.
@@xraytonybThanks - and I guess that if the voltages are very different like 4V in 316 and 2 V in 321 - then amp is not balanced with input at at zero.
Correct. In most cases, it is because of an issue in the feedback loop. Q304 & Q306 should each have a base voltage near 0 VDC. Usually, when you see an imbalance, Q306 will have an abnormal base voltage above or below 0 VDC, indicating a problem further down the line in the amp.
Tony, hear me out, great video idea, "Tony replaces all the noisy fans in his equipment"
Wouldn't it be better to reverse the airflow of the fan: instead of blowing fresh air into the amp have it pull air through the amp. Chances are that the location of the thermal switches sit better this way.
Perfect
Sansui CA
i'm good with whatever project you choose to do next. maybe throw numbers in a hat and do a live drawing during your next video.
All your projects a great Tony….
Sansui please
Do one of the phase Linearrs next. The Carver 1.5 is more tricky with that silly triac feedback into the primary of the transformer. Be careful if you need to bypass that triac for testing.
Regarding the current unit, this Marantz 500m, I find it to be aesthetically off-putting. That black and green could work in the right environment but I much prefer the silver\blue\teal theme.
36:40 If anyone feels the need to crank this unit to such a level, they must have very inefficient speakers in a gymnasium or they're simply abusive for no reason. My vote is to do the Carver next, but it doesn't matter to me.
If the equipment doesn't like 20 Hz, test it at 40 Hz, it's still good enough.
You didn't run a square wave test 😮😮😮😮😮
Watch the video again.
37:00 square wave test
Uh Sansui :)
Shouldn't be black knopp, Aluminum color seems weird 🤔 😕 😪
Good work! Thanks for your time and skills.Always enjoy! As far as what you do next, what ever tickles your fancy.
Very bad clipping,
It's not clipping. You are seeing the overload protect circuit limiting the signal to prevent overcurrent in the amp. This makes the top of the waveform fold over like that.