I don't understand how the output gets voltage on it, if the brush is insulated from the coil by that plastic.

When you were checking the continuity of the hot, neutral, and ground leads you had the rotor pointing to zero. Wouldn’t you need to have the rotor pointed somewhere else on the dial to assure that there was still no continuity on the hot leads in and out?

Uuggh the hype over those old bumblebee capacitors,don't believe these things are good. I have serviced electronics for 50 years . They are never good!!! Most will be cracked lengthwise , all will be leaked or shorted. Zenith used these in b&w tvs and they are always bad,I think more so. Than the old wax caps,stay away from both of these.vitamin q seems to be the best of vintage caps.

Usually with a tape shell that's glued, I would just try to crack it open and put the tape on another shell with screws. I operated on many tapes back in the 80s and 90s.

@Flux Condenser Thanks for making and posting this video. I don't have an MC2105 but it's been hugely helpful. I have a C26 with some problems -- the power switch doesn't work reliably and there's a 60-cycle hum. The most useful part of this video was seeing you pull the knobs off. My eyes about blew out of my head. I've tried many times over the years to see if there is some way to get the knobs off. I've looked online and nobody seemed to know how to get them off. When I saw you pull off exactly the same knobs as are on my C26, I thought, well, let me try that trick with wrapping dental floss underneath the knobs so I have something more to pull on. It works with other equipment, so now I know it should work on the McIntosh. Before I wrapped the dental floss, I gave a knob a good hard tug to see how it felt, and I could feel it sliding. I pulled some more and they all came right off. I couldn't freaking believe it. I have no idea why they suddenly decided to come off. Anyway, now maybe I can fix the power switch and replace the caps. I'm very grateful that you made and posted this video.

A suggested substitute for the aluminum foil tape to improve the lighting on the panel meters... 3M makes a white Post-It tape. Like the Post-It notes, it sticks well but is easily removed when needed. The tape is sticky across its full width. It's available in various widths, with 1" being the widest I've seen. I think the white color would offer good reflection to improve the lighting of the meters without being so darned difficult to remove as that aluminum tape is. The only down side is that the 1" tape is hard to find. Sometimes Office Depot has it, usually not.

🌁

The name "Variac" came from the General Radio Company in the United States. I have an original General Radio 5 amp Variac and a large General Radio 20 amp Variac I used when I had a stereo that consisted of vintage American tube components from the 1950s. I also bought one of the cheap, knock-off Chinese Variacs like the one in this video when they appeared in the U.S. The unit sounded awful when I used it to power audio gear and I gave it away. I would not use one of these Chinese units for any reason.

Wood polish

Guitar picks please ! ;-)

You just became more ridiculous.

I was always told that the number scale stood for percentage% of your original voltage. My original voltage is 124 volts. If I had it on 25% I should have around 31 volts. My brain doesn't work in percentages! If I see 50 I want 50 volts👍

What’s the best way to plug the speakers to the MC2105?

9:00 Now I know what kind of music people who buy MacIntosh are into.

NO AMP METER? I spent my career repairing electronics and never once used a dim bulb. I always used a variac and current meter. The first thing is to have a good idea as to how much current the device being powered normally draws. As you turn up the variac, keep a close eye on the current draw. If the current draw is to high, back down the voltage. I always monitored the current and voltage. The current draw could be just a small amount beyond expected which is good information to know before you start troubleshooting. This process worked very well for me.

I wish you'd do more of these. Thank you.

Pretty cool series. Please bring them back. More😋

This is so comforting. I miss it.

I have a question, why do you break off the metal switched outlet tab? It will just change on/off swither polarity. I think you could connect hot wire to the white screw at the top right avoiding the jumper cable from top left to the bottom right by using the metal tab connector.

I have a question for you. These are your exact words. "Humans are incredibly susceptible to bias and we tend to hear what we want to hear. This is why we have so many people claiming that amps, CD players, cables, etc. sound differently from one another. But if they were put to the test, these people most often could never actually tell the difference. There’s a huge psychological element to stereo high fidelity equipment that few want to admit." Psychology is a science, and you claim literally that its a huge element to stereo equipment that few want to admit. You're claiming this is a fact. The problem I have is after looking at the information you presented, I don't see anything that is grounded in Psychology, or any other branch of science. Everything you are saying is either an opinion, or a fabrication. Whether you realize it or not, what you're doing here is what's called junk science. Junk science is when you present information that appears to be legitimate science, and its not. Kind of like when a lawyer argues a case, and they pick and choose facts to build a case. At this point, anyone who's reading this is most likely asking, can I actually back up what I'm saying? Yes I can, and all I have to do is ask a simple question. So here it is. Can you reference a test that was done by a credible source using legitimate science, not junk science, that was used to confirm people making claims they can hear a difference between certain components, when in fact there were no differences? The test can be on any piece or pieces of audio equipment ever made. Simply put, where are you getting your information from? If you can't reference a single piece of relevant science done on any type of audio equipment, then your position has to be fabricated. You may believe it, and that's fine. You can believe anything you want. But you can't prove it. I already know you won't answer my question, because you can't. I've been asking the same exact question for over 30 years now and not 1 person has ever made an attempt. Sometimes I'll get a half asser say something like, "Well, you apparently don't know what the placebo effect is.", or some other ridiculous bit of nonsense. If you are going to make a claim like that, and you can't show me the test where the placebo, or any other effect you claim is the reason, you're making it up. Also, for full disclosure, I have a masters degree in Psychology. I don't see why that would matter, but when people find out, and I didn't disclose it, they get very upset for some reason.

It's all an ilusion. You are the only one making sense.

It is so mellow and dramatic how MSM always controls the masses with fear and nothing but fear with more fear added fear makes it all the fear to fear more fear, Fast forward to 2024 AMPLIFIED 1000x All states countries cities towns all have the exact same AGENDAs and people can't live without fear. Nothing has changed.

Dear letter writer. Buy a pair of used Magnepan 1.6 and a powerful amp at 4Ohm. You will hear most information that's in the source. Every box speakers inflences the sound because the air is coming back from the driver. Kind regards, Wil (musician). Give attention to your room acoustics and NEVER put your speakers to the wall.

🥵😡😡😡Bei solchen schönen Historischen Radios sollte man die alten Kondensatoren drin lassen,!!! und nur eine Seite des Anschlusses still legen, und darüber einen neuen Installieren dann bleibt der Technische Charakter des Radios noch einigermassen Erhalten oder man Höhlt die Kondensatoren aus und Befüllt sie neu.😡😡😡

It's 2024, conditions remain the same 😂

Man sollte solche Kondensatoren nicht mehr entfernen, sondern neu Befüllen oder Einseitig Still Legen und darüber einen neuen Montieren. Die Radios werden so alle Wertlos. 😡😡😡

Not a fan of this design since the switch is obfuscated by the bulb, but good otherwise.

I would like to build my own tube kit. But where to find a descent circuit and kit manufacturer? I like point to point wiring on a tube amp. its seems more in keeping with the tech, and you can use silver wire. would that make a difference??

Yeah but it's if it's a cassette tape that you can't find anywhere that has your favorite music on it and the tape just needs to be spliced do you actually have to take the whole sale apart or is there another way of splicing the broken take back together or do you have to remove the whole shell and seal it back together ?.

Labelmakers are great ... as long as you are not trying to label anything made with oil , like plastic drawers

A $1000 power cable connecting two 50-cent connectors (wall, amp) at the end of a run of ROMEX makes total sense to me.

I watched your entire series on the renovation and theory of this radio. And I never got a proper scale of the radio from the series. When you showed it next to your hands I thought: wow his hands are enormous! 😆 Obviously it's smaller outside and more compact inside than I had imagined.

Now if you had to recoat let's say a lacquer finish you will have problems with the feednwax and the luguid gold

I need one.

@FluxCondenser - I built one and it worked perfectly. I no longer need it to work as a limiter. How do i change the wiring so i can use it a switched 3 outlet extension cord ? Thanks in advance

Wow! Nice job with the video. I loved every minute of it.

Buster keaton was hilarious in limelight

What a Great Video, You were awesome in digging into the amp. I jsut repaired an old turn table BIC780 and now want a vintage amp. I found a Kenwood KA-87 for $60 omn line. but was unsure about the quality. For the money, It sounds like a good price and You even showed my how to clean it up safely. What a great video Amazing, thank you so much. Dennis in Virginia

Excellent series of videos, thank you. You are certainly the consummate expert and perfectionist in all you do.

Just came on this video (trying to school myself on vintage gear repair - new suscriber to your awesome channel). I played a lot with the Halfer circuit years ago. I had a NAD 7225 wired this way for a while. Poor man's surround, and when I got richer I got myself a real "surround decoder", which was made by a company called SSI. You can still find them on ebay or similar. Ancestor to the modern surround decoders that brought Dolby Stereo of movie theaters in homes. This SSI unit was an add-on the the main amp and did basically the same as the Hafler circuit, added an adjustable delay, and included a small amp for the rear speaker (like 15 watts) so the total impedance didn't get too low on the main amp (my main speakers at the time were 4ohms, so the total impedance probably dropped well below that I'm sure). It wasn't "Pro-Logic" so it didn't have a center channel (and nobody was talking about subwoofers back then). My experience is similar to yours, it sounded great with most live recordings, not so much with most studio recordings. I used it all the time for movies. The NAD was a great amp but proved unreliable and after its 2nd turn at the repair shop I got rid of it and embarked fully on the home theater bandwagon. I got a Denon 7.1 AVR. Pretty good for movies, but sounded like crap for music, no matter how Audissey was setup or surround mode I selected (or not). Music sounded 'dead'. Lightning hit my house during a storm, and a few things blew up including the Denon (unfixable). So I got rid of the home theater craziness and got back to simple stereo, I got an old Pioneer receiver that sounds very nice, now paired with my restored Dynaco A25. Now I'm thinking about getting a ST70 just so I can say I have the cool looking amp that came with the speakers in the 70s, but now I never realized that the 80Q had this cool 'surround' feature so I'll be on the lookout for one. Thank you for your videos!

I’m confused as usual lol. Your showing me an analog RF signal generator hooked up to the radio and a digital oscilloscope on the speaker to monitor the injected RF intermediate signal. Where is the digital display I see in the video for the RF and modulated audio signal fit in? Are you showing me the same thing but on 2 different devices? How do you add a modulated audio signal using the BK Precision 2005B?

They even have stereo and digital on AM now!

Hello and thank you for this beautiful series, could you explain more about why you replaced the capacitor after checking dc on the speaker outputs..i thought that low current as your meter showed was acceptable...but what do i know..im trying to learn.. Cheers

this is some magic

The FCC (aka Anything For A Buck, Inc.) is the reason AM radio is on life support in this country.

I ❤ The Dodge Boys ad. I’ve a brochure of the first generation ‘66 Charger. And the ad for a recording, “Lies,” which fooled me. Even back then, I thought it was a Beatles recording.

I remember WKBW as a TV station...Irv Winestine on the news. Commander Tom Jolls doing weather and an afternoon children's program. Dave Thomas also had a kid's show called Rocketship 7

A note of caution when disassembling and then reassembling EI type (square core lamination) xfrmrs: Be sure!!! to use the paper or plastic washers on the bolts and hardware where it engages the laminations to prevent a *magnetic short circuit* between the laminations at each end. It is extremely important to keep laminations isolated from each other, which is why they're coated in varnish.

I built and enjoyed the original ST-70 back in the day. Ironic that back then it was considered an excellent amp for its modest price, and now to be so pricey.

Hello, What would the sinad measurement be for this amp?