SAE Mark III Amplifier - Part 1a - Initial Checkout & Driver Board Repairs

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@apollorobb 4 жыл бұрын

I built one of Paul's Cap testers and it is invaluable on the bench . As well as the Super signal tracer. Great video Tony

@mackfisher4487 4 жыл бұрын

Hope your friend appreciate your work, you could never charge enough pay for your time. Thank you for teaching us so much I particularly like your circuit explanations and going into component substitution research.

@NocturneVid66 4 жыл бұрын

Great channel Tony! I was dying during this video; I was literally screaming "Change all those grey EL caps out Tony!". It was with a sigh of relief when you did finally swap the damn things out. I've worked on Apt Holman preamps where those caps are used for interstage coupling and they commonly fail. My policy has been to swap them out on sight. I suspect the SAEs suffer from thermal drift and the dual monolithic transistors are used for better thermal tracking. That dual monolithic transistor may have been a factory upgrade. I know John Curl used them on the input of his JC-80 Preamp design. Bob Carver just said, screw it, and used an Op-Amp on the inputs of his later Carver and Sunfire amplifiers. You're a brave man to undertake this repair, I fear you may end up having to re-engineer the thing. I concur with Andy that finding TO-66 driver transistors will be a major headache. I've seen McIntosh service bulletins recommending certain TO-220 case transistors to replace their old TO-66 drivers. Good luck with this beast. I fear that it should provide material for many videos.

@MrVasile 4 жыл бұрын

Tony...I love your videos. You are knowledgeable, thoughtful, informative, and very humble. Keep up the great work!

@andydelle4509 4 жыл бұрын

High power audio amplifier fact 1.01: The transistors are there to protect the fuses! Also I really dislike that connector arrangement, especially using those cheap tin connectors. Just asking for failure when the unit reaches this age. Plenty of mil spec connectors were available at the time but I guess even as a higher end audiophile product, it was still built to a price point.

@Nicholas.T 4 жыл бұрын

Andy Delle - Heartily agree Andy, couldn’t believe it when I saw those cheap tin connectors - they are totally unsuitable for an amplifier of this caliber! Actually, I’m very unimpressed with the overall internal physical layout and construction of this amplifier - it almost looks like a home built unit, rather than something from a respected hi end manufacturer. Compare it with a typical equivalent Japanese power amp of the same era( Yamaha, Pioneer, Sansui, etc ) and it doesn’t come close. I’m not talking about audio performance or specifications here, but just the internal layout, design of PCB’s, use of quality connectors, etc.

@andydelle4509 4 жыл бұрын

Another tip: Those TO-66 transistors are probably un-obtanium. But a TO-220 case style will drop right into the same foot print with the collector still being the case or tab terminal. Not sure if it's true but I read that was intentionally done when the TO-220 package was released. It's also interesting that the "Ampzilla" had TO-66 drivers. And they like the SAE it was also designed by James Bonjiorno.

@bobbyy8711 4 жыл бұрын

I am not a Tech guy but I really love watching your videos, greetings from the Philippines, thank you Tony..

@TY-ob7fz 4 жыл бұрын

That puff of smoke came from an oscilloscope for me in front of a professor at front of a lab class while he was teaching and I doodling with the switches. He just gave me the "groaning lurch" look.

@1959Berre 4 жыл бұрын

I have some reservations about the design and the horizontal orientation of the heat sink. Convection would be much better with cool air rising freely from an open bottom. 200 watts per channel is not a joke.

@richmoore5080 4 жыл бұрын

I'm 7 minutes into the vid.... SAE really made things nice if at some point it needs to get repaired! Like you noted, SAE made things that were tanks! There were a few things that sounded better, but SAE was like a big block chevy for it's time! It delivered

@hifispock 4 жыл бұрын

The Jay Leno "Balls out" insert lmao

@TrevorsBench 4 жыл бұрын

Great timing for your vid. I'm about to start a restoration on a power amp myself and all that transistor talk is good primer for that job. Thanks for the great videos

@dzee9481 4 жыл бұрын

Tony, I enjoy your videos, for several reasons one is the story you tell about the equipment under repair, the other is you uncanny ability to diagnose issue. If your profession was a cancer doctor I would believe you have a cure. Cause the way to attack the problem and diagnose and identifying the problems. I wish i was your neighbor, but I find your videos the best for fixing stereo equipment the right way. You don't do have ass work, you do the Fix RIGHT Way when you can, in those cases when you can not you design it to make it repairable and reliable.

@Mosfet510 4 жыл бұрын

I would have thought they had two independent amps in one unit, the way the transformers are arranged. A first for me. Great video!

@richmoore5080 4 жыл бұрын

COOOOL! My first love of stereo involved SAE out of Los Angeles! High power, good looks, etc. Like your friend, it blew up at one point, and my first real adventure into repairing audio equipment was on SAE. It was straight forward as there was nothing out of the norm, like you will find in ALL of Bob Carvers products! I look forward to the next few vids! :)

@carlfudger4528 4 жыл бұрын

Look forward to the rest of this series Tony!

@chrisvinicombe9947 4 жыл бұрын

Hahahaha that story with the demo for your friend is brilliant 😀😀😀

@mitkothemacedonian 4 жыл бұрын

Hi Tony. Since all of those 10V 100uF caps were changed before and the only original one left had spilled its chemical guts all over, I think that at least 16V or even 25V rated ones are in order (25V ones might not fit, but if they do, even better).

@peterjmcgee4680 4 жыл бұрын

It seems like every time you get one of these large amplifiers somebody's got their hands on them before you and they've totally bald it up and that things toward that weren't supposed to be done and then you have to come along and put it back in order and I find that so much myself when I buy stuff off of eBay you know Parts not working I just did a Pioneer amplifier that every single one of the transistors that were in it we're not meant to be in it but it was all the original caps but all the transistors that were in the unit we're not meant to be in the unit which drove me nuts but when I was done and I recapped it and I put all the right transistors in and fired it up for the first time it sounds great

@xraytonyb 4 жыл бұрын

These days, it's hard to find gear from this era that wasn't worked on before. When you do, it is priced in the unobtainium range. I usually look for equipment in good cosmetic condition, which usually means its a basket case inside! Thanks for the comment!

@joeyscott4299 4 жыл бұрын

I love these videos Tony !

@johnnytoobad7785 4 жыл бұрын

I heard way back in the 70's that SAE amps had a reputation for "blowing up". I ended up with a Phase Linear 400. Never blew up, but blew fuses instead.

@xraytonyb 4 жыл бұрын

You aren't the first to mention this. I'm thinking these things have a reputation out there for letting the smoke out!

@Rickzolla 4 жыл бұрын

Nice, that might be one I helped build.

@indooroutdoorlover9906 4 жыл бұрын

Hmm. its bass are really great. I just loved this one

@PeterMilanovski 4 жыл бұрын

I don't think that there's anyone who doesn't know about Paul Carlson's channel let alone his inventions, I have seen his capacitor tester and it appears to work really well considering that it doesn't test capacitors at their rated voltage, and that's the thing that bothers me about it, if I understood how it works, then I would feel more confident in building it but it's like someone is telling me to have faith! I trust Paul even though I don't know him on a personal level, I'm positive that it works but the old way of passing rated voltage through it is basically what's happening in a circuit and you can measure, depending on how sensitive your measuring device is, uA, peta amps and so on. You can find capacitors that have extreme low leakage if you wanted to take it that far.. but Paul's capacitor tester makes it to easy and gives me doubts if the capacitor is going to still be good in the real world?.. I don't know...

@xraytonyb 4 жыл бұрын

The Carlson cap tester is fine for testing paper/foil caps, film caps, mica caps, etc. It is not good for testing electrolytics. Low capacity film/paper/foil/mica caps have a different failure mode than electrolytics.

@PeterMilanovski 4 жыл бұрын

@@xraytonyb tony, as I said, I really don't know how Paul's capacitor tester works. If I had some pretty basic description of it's workings, it might at least help to know when it works and when it isn't, if you placed a good capacitor on it, it just stays green and you won't know if it's going to show up as a fail or pass until you have had it sitting on test for a while. Wherein the old and faithful EICO or Heathkit show you via the magic eye when and how fast it charged at a particular voltage, but most importantly it shows leakage! I would love to get a Heathkit and even though they were soul here in Australia back in the day, I have seen advertising in old Australian Electronics Magazines so I know that someone has one but no one is selling one here! There's plenty in the US naturally but shipping cost more than the product and then there's import duties... It's just out of the question for me, if someone packed a shipping container with all this old school gear, and was able to get it into the country a lot cheaper, they would sell like hot cakes! But when it comes to testing electronic components, a good visual representation goes a long way! I really like your transistor tester, yeah it's simple but it works. You can, if you wanted to, add another transistor to either place a continuous load on the other transistors under test or add one of those cheap Chinese function generators to draw various types of signal through them to simulate real world situations, leave them for a while and come back to see if anything has changed! That's where the pass no pass feature on the better oscilloscopes come in handy, you get to compare the original signal from the start as a frozen image to what they are now doing! Sure, what you have there is great for go no go and a very good visual representation of how closely matched to each other they are, but if you have a situation where you really want to keep the original transistors but you wanted to test them over time to see if they are doing anything that they shouldn't be after being warmed up, then that would be the perfect way to do it without spending to much money on something from Roden Schwartz LoL. I really like your tester, I know that I asked about it in the comments section in a previous video some time ago, all I knew was that I wanted to build it at some point but at the time my anxiety wasn't allowing me to do anything, even sending an email was impossible. I have been better lately and I plan to email you about the schematic so hopefully you might get some mail from me... Your reply will come when you are good and ready, I'm not going anywhere so I have plenty of time LoL.

@jamesvw769 4 жыл бұрын

Thanks Tony. Love your vids. 👍

@gbowne1 4 жыл бұрын

Yeah, I think that's bad they put in unmatched transistors. Then again they probably only used what they had available to them

@johnsweda2999 4 жыл бұрын

Must have been he's lucky day got that cheap I suppose. Yes that Mr carlson's lab capacity tester is a good piece of kit it works in the mega ohms of leakage. I was hoping you going to test a replacement transistors the coupled thermal transistors for matching, I mean are they decent replacement they could have been used on both channels why didn't you go with that on the other channel?

@dhpbear2 4 жыл бұрын

9:04 - Good that there were no coils to 'tighten down' :)

@Digital-Dan 4 жыл бұрын

Is it possible the two sides are mirror images of each other rather than duplicates? It looks like it because of the placement of the variable resistor. I noticed you checked power resistors on each side to detect differences, but you checked as if they were duplicated left to right. No doubt that resistor was still a dead short, but . . . ?

@geoepi321975 4 жыл бұрын

nice amplifier

@jdmccorful 4 жыл бұрын

For a minute, I was seeing a dark pyramid object on the horizon.

@harryconover289 4 жыл бұрын

Having a power transformer for the negative rail and another 40 pounds of rail is unusual because it’s dumb Not really as good as having a transformer per channel check impulse power and that will prove this to be true