45:47 Since the Reagan era most of us have just called them "phono pre-amp". That name alone should imply that more is going on than just amplifying the signal traveling up the tonearm.

0:25 several hundred of mV on output? I would say no, and i had 600mV on output and i fixed it, now its 20mV on one side and -20mV on the other side, thats what i say is ok, everything below 50mV is ok, people say that everything below 100mV is ok, but i would say that if the equipment output voltage is 60-80mV I rather take a look in it, its quite high, it will not gonna destroy any speakers, but it gonna make some unwanted distortion. I have a completly rebuilt SA7800: Outputs: double 2sc3519 & 2sa1386 drivers: 2sc4973 & 2sa1837 Voltage: BC639 & BC640 (Those have kinda low voltage rating and those arent low noise transistors, i would replace it with 2sc2705 & 2sa1145 those will be better, and theyre now available for me, but im kinda low on cash, but i will get them in the near future) The amplifier i got, i got it from my uncle, he used it for 30 something years, it blew up, i got it from him, he told me, whatever i can do it with, its a gift, he tried to send it to a repairman, but it didnt sound as good after repairing, it had a very bad amplifier diy made on it, it also blew up when i tried the equipment. I also got a TX -D1000 Tuner from him, it works, it finds channels quite easily, its sensitive, which is good! I would say the absent transistors are kinda bad, 2sc2525 was 80Mhz and the best that i found was 50Mhz 3:41 i had the same issue, i dumped the 5pin double transistors that controls the vdc on output, it fixed the issue for me, people say that i shouldn't have touched that, but it was faulty and after when i measured those transistors, they were leaky. Other transistors were too, i took the shotgun approach for capacitors, and transistors too, checked all the resistors, because ppl told me if i work with a non switching amplifier like that, its recommanded to check.

I have a Crate B10 xl solid state bass amp, it only has one fairly simple circuit board and I’ve tried everything I could with my knowledge and multimeter, one day it was working fine and suddenly zero audio, red light still indicates that it’s powered on but nothing through the speaker or headphones, even if I touch the aux, not even a hum aside from the transformer itself, the fuse is good and so is the speaker, I’ve checked all wiring and even re-soldered all contacts, I’ve visually inspected it, cleaned it, and tapped it with no change, I’m suspecting it’s a component but can’t quite pin point it, any suggestions would be greatly appreciated

If it's not broken, dont fix it, doesn't apply here

Are you measuring this open circuit or do you have a dummy load on the output?

Should have added a tuner in the amp.

Great piece of history.

Fixing tape decks is a fools errand. Tape is NEVER coming back, that's just a fact. For a variety of reasons: Nobody has made a decent mechanism in almost 40 years, and they're never going to start making them again. Even if they did, they can no longer use Dolby NR (that is gone forever) Nobody can manufacture high quality recording tape anymore (primarily for environmental reasons) The few companies that have started making tape again, can only manufacture Type I (which is terrible for audio quality) All of the old stock of metal, and chrome tape is gone, and like I said, it's gone forever. Putting the time and effort into old tape decks is only putting off the inevitable...

Very nice I use to have a Technics SUV8 it was a great amp pumping out 200 watts or so depending if your speakers are 4 -OHM or 8-OHM .

My Technics SA-818 is the best receiver. I own them all just about including this one.

IDK. I’m still running (bridged) Carver TFM-45’s mated to Sony TA-E9000ES Processor and my ol’ school Polk 1.2tl SDS-SRAs and Velodyne FSR15s (x2) still image as they did from the day I first purchased everything. Granted, every 10 yrs I replace the Polk drivers and tweeters, and the Carver’s had new caps, etc. installed 5 yrs ago. I will NEVER part with my gear!!

Do you accept mail in repairs?

Sir, First thank you for in depth narrative and component description. I have subscribed and watch your videos from time to time. I love the vintage audio and grew up in the cassette tape era. Now I own three Nakamichi cassette decks including Dragon, a RX 303 and RX202. Also a HK 491. Recently I paid quite a bit of money getting them cleaned and restored. I would love to learn how to work on them and your videos and detail description is very useful. I would love to learn more starting from the basic. The only request I would make is that if you can, please record the videos when you are working on an equipment like this one. Thank You again for such details.

I've owned a set of 901 series 3, purchased new in 1976, and have been refoamed. These are my "sometimes" speakers, as I only sometimes really enjoy them. - The design philosophy of using 9 identical mid drivers eliminates crossovers, and phase issues with the sound that are common with "normal" 2way, 3way, and 4way speakers. - Requires much more amplifier power than one would assume, as the equalization characteristics of the speaker system requires the midrange frequencies to be greatly depressed, while the lows and highs need some additive equalization for the speaker system to present a balanced frequency response. The porting of these later models improves the "power hunger" over the original models, but these speakers still require more amp than one might think. - The sound stage is broad, and deep. Sounds spacious to the point of exaggeration, but sometimes it's what I want to hear. - Along with the large, spacious sound field is one of my dislikes, as they are not able to portray a stereo image that clearly pinpoints the location of each instrument and voice. But not a dealbreaker gripe for me, as I have had these speakers since 1976, and still listen to them at least twice a year for a couple weeks or more at a time. - My most annoying gripe back when I first owned them was a lack of high frequency response above 14k, but as I got older this improved, as my hearing has lost much recognition above 14k as well. - There is a lack of true low frequency response below 50hz, and anything below 35hz is basically absent, but again, this is not a dealbreaker for me either. - I did not like the sound of the Bose using the provided stands, and found my ideal placement for the 901's to be hung from the ceiling at a height of 48" from the floor to the dead centre of the speaker, about a foot to a foot and a half from the back wall, and about 2 to 3 feet from the bordering walls. No less than 6 feet of separation distance between them, and more is better if the room is big enough.

I was expecting bit more info from this. What specific audio test equipment is good to get? SG165?

Some good info and advice. I have six vintage units, most never touched except offset and blown out occasionally. I suppose after 50 years of bliss there could be an issue. Or ...a few years of crap, then more crap, then more all in search of that 50 year old sound with newer junk....My truck will also need repair down the road.....still I use it....

I believe the MA5100 was the first solid state integrated amp Mac put out. I have one from 65-72. Mine has been very enjoyable for decades, though it needs some love now and there are no longer any techs alive in Hawaii so it needs to go on a trip. Last time I had it worked on was over 10 years ago and the great guy who worked on it live in TN and had it singing. He was not willing to just update everything as might have been a good idea. So, now it needs the volume pot cleaned or refurbished and likely some capacitors replaced. It does not play out on one channel but sounds fine with headphones. I also have a MC250 which is the same amp as yours just without the nice blue lights and VU meters. It has also been refurbed and has worked fine for at least 15 years since Terry DeWick fixed it when I got it off Ebay. Love the sound of Mac gear. Neat to watch your video. Wish I had technical background.

I would have bypassed that pointless mode-switch so the stereo L+R signal doesnt have to solder on the L+R tags per each switch option.. (chasis is negative in all but fully ballanced) designs) ..only to come through as if it wasn't there! ...i'd have a stereo unbroken signal bypassing the thing. Of course i can imagine a few scenarios where you might need it but they're pretty wild e.g. you could play 2 seperate momo dources into seperate rooms with L+R podition. Soeaker reverse ...as you say but i vant be bothered or asked to give the other positions any valid importance except, mayby marketing men found folk liked deeing such needless switch variety back then, b4 days of latet .minimilidm where even Ballsnce wad seen as pointless, let slone your chosen R or L chanel will both come out of both or just 1 channel. Did anyone, i wonder, ever buy this model & say "Screw the sound quality, now i can constantly play with all these mode-switch options instead of actually listening to my stereo speaker's music" ?

I appreciate it the way you explain things to the common man not somebody that's advanced in electronics. I just have a lower knowledge of electronics so it's very helpful to keep things simple. I would appreciate any other practical video tips.

It's too bad the reciever's were not built with a front meter to monitor this issue !!

I have a Bose Spacial Control receiver with Bose 901s series IV, that I purchased new in late 1978 or early 1979 in Madison, Wisconsin. It needs a lamp replaced buy other than that it still works well. I did have the speakers refoamed asked the technician about servicing the receiver and he said he wouldn't touch it, but he did offer to purchase it all. I live in N.C. I've been unable to find a technician that will work on that I trust. If you ever work on your's again I hope you do another dedicated video on it.

Hi from Hobart Tasmania Australia. I have been loving all your videos and tutorials. I listen to them at work, as a podcast and replay most of them when I get home. I love your passionate approach and manner, I am learning so much from you, the major thing is how to really appreciate these me achines! Thanks for taking the time to make these videos and the actual amount of time it takes you to put these videos together. Cheers, Darren

40:14 []▶ DG #017 PEAK LCR45 LCR Meter Review and Teardown kzfaq.info/get/bejne/qZhpnrCb1a6ccWg.html 30:45 CHANNEL: SDG Electronics AnaTek CORPORATION [ U.S. Distributor for PEAK Electronics ] Manufactured by PEAK ELECTRONICS In Derby [ Pronounced Darby ] Derbyshire UNITED KINGDOM ENGLAND to be specific I have a number of instruments from PEAK ELECTRONICS as well as a number of relatives in Derby and surrounds. [ one of whom whose mother came from Detroit MI and was the niece of my (late) father also born in MI ( Kent County ) I have been very pleased with PEAK INSTRUMENTS as well as the after sales service - which is beyond expectations. Highly recommended to buy their products

I've always figured the different modes were for dealing with e.g. tape with 1 stereo track vs 2 mono tracks, and accommodating for others' dubs being made with with channels reversed? Mostly only because I can't imagine what else they could be for!

Hi Cris I have 2 spec 2s. I can’t work on my own equipment I have tremors in my hands but may take them to a tech my friend s don’t like their sound quality and I have to agree.if I could change out those 2 relays I may be more impressed I do love Pioneer from the 70s very well made !!

Please note: Do not place dots at the end or a TITLE. A Title is NOt a regular sentence. School brainwashed students to place dots after every single line of text And many still continue that indoctrination - placing dots at the end of a URL and at the end of an email address - where such DOTS do not belong. Neither do dots belong at the end of a numerical value - unless the dot represents a decimal point. Follow a numerical value with a new line of text below People today cannot format text into narrow columns nor do they know what paragraphs are and how to use them. So to learn writing skills - study the Chicago Style Manual. I Had to know the writing rules when writing and co-writing some eight operations and procedures manuals for the USAF

Immediaately I recognize that the cosmetic appearance has to be near to original as possible. Obtaining OEM parts is near impossible , sometimes at week-end markets there are sellers who collect what others throw out during local GOVERNMENT clean-up days - where house-holders leave their unwanted items at the kerb - these items find their way to local markets. It is amazing what people throw out - and I often find useful items. Some can be restored while others are useful for replacement parts. Most people will walk past the sellers selling what appears to be ' junk ' and it is such fro those that have no use for this ' junk ' - however for those such as myself and yourself it can be a goldmine. I was taught initially at age 8 how to repair radio & TV decades ago- by my mothers elder brother (who incidentally was Russian ) and born in Russia. My (late) mother - The youngest was born in UKRAINE My father - who died of a heart attack in 1975 was born in Kent County MI - later his family relocated to Saginaw County where almost all worked for GM. Unfortunately.. Detroit is not what it once was decades ago. In fact the Entire country is not what the UNITED STATES OF AMERICA was once. And I served on attachment to the USAF during my 30 year MILITARY career in the AIR FORCE. Now - restoring vintage equipment provides mental stimulation and something useful to do - since I surrendered my pilots License 12 years ago. I remember the Marantz 2500 very well - it was an impressive piece of equipment and still is. As well as OPTONICA [ from SHARP ] of the 1980s - which I still have - and the price when new was absolutely staggering - running into thousands of dollars.

Hello, do you have any experience with the Kenwood kr-9050 I recently acquired a one and the left aux input moves slightly and the output from the left speaker is not right what would be the best plan of action to replace this connection? Thank You.

I can't use the app as my phone only has bluetooth for sound or wifi to share audio. Ok, for any phone with a headphone jack, but that's being phased out.

THAT THINK WITH THE HOOK AND POKER IS FROM WHELLER SALDERING GUN THEY USE TO COME WITH 2 TYPES OF PICKS.❤

Thank you very much, Sir.

@vintageaudioaddict and anyone else who may be able to help! I recently purchased this exact model in mint condition (at least on the outside), and then I had an extremely experienced audio repair guy replace all transistors and capacitors in the machine, as well as cleaning heads and and all volume and buttons. The machine works perfectly on nearly all fronts with the exception of one really annoying issue. Maybe you or someone on here can help track down this issue as i have already have collectively invested $450 on this machine. The issue is this... Regardless if my VU meters are clipping or not, I get a sort of distortion/noise in the low end of my recordings when the highs of a track arent present to mask it. So areas like breaks/drums and bass on songs. I fed the machine a 50 hz sine wave and recorded that to tape and you can definitely tell the noise is there and isnt just your normal tape noise or distortion due to being over driven, specially since the recordings were specifically not being over driven on purpose. The noise seems to go away if the sine wave above 100hz or so. I'm starting to think that the recording head has gone bad... Do you, or anyone else on here, have any idea what this might be? Please let me know. I really want this machine to work correctly since ive already invested a nice chunk of change in to it. Thanks in advance!

OMG, What must I see @ 10:38...This method for the spray can is a lifesaver! When I remember how awful it is to reach into some potis most of the time - and it´s a real pain in the @ss then, this way of sticking various pipes into the original one, with different bendings and spray holes... This is awesome! But I am ashamed too. I am so old now, and being 60, I see an idea I didn´t have in mind myself so often. Normally I am proud of me for being innovative! And I am innovative because I am stingy and lazy! And just this technique here comes just from that: Being stingy with de-oxit fluid, and lazy due to not wanting to dismantle things just for a minimal amount! 😁😁

Do you know the scene from Fear and Loathing in Las Vegas when the guy shouts "Finish... The effin story man... What happened? What about the gland?". That's how I felt trying to watch this.

I've watched quite a few videos about the APL. This was the best. I'm definitely buying one in a month or two. I did build my own VPB around 10 years ago. I used future pinball as I found visual pinball very tricky. I hope eventually to do most of the mods that you have done here.

Great detailed video, Probably the best one yet, a wealth of information. thank you Sir.

Great Video! I know it's been 3 years since you've posted it but still very interesting. I own the MC2105 and even though I've been an audiophile since the late 70's, (and a huge Mac-centered fan since then), I was surprised to find that the MC2505 was the first SS amp by McIntosh. Honestly, I would have guessed the 2105 to have held that distinction. In addition, I was just as surprised to find that the MC2505 was rated by McIntosh at less than half the watts/PC output compared to the MC2105!! My MC2105 is rated at 105W/PC and yet the MC2505 was rated at 50W/PC. Of course, the 'actual' power output of almost any McIntosh amp is at least 15% higher than they rate it for. I did a re-cap of my 2105 and replaced the the entire glass faceplate as well. However, I didn't re-stuff the Can Caps because I just didn't know enough about the procedure. I own many instruments to measure these electronics and have a combination of analog and digital test equipment for capacitors, resistors, etc. The problem is that I'm a "junior hobbyist" at best and simply don't trust myself to do the job without close, expert, guidance. Much of the reading material that I've read over and over, can be open to my own ignorance and misinterpretation. In fact, interpreting what is being said is my biggest problem. Mostly, the material I've read requires that I have an electronics expert close by to explain what some of these things mean. But there's also the type-o's, grammatical errors, and misspellings of the reading material, which makes it even more difficult to understand when combined to my 'misinterpretation difficulties'. If you see what I'm saying, you can probably imagine the potential for just how far off a novice could be thrown when those variables are considered. Having spent many hours over a period of months trying to grasp some of the more complex procedures in the reading material that I've found, it became clear to me that I was burning myself out. Without proper guidance, I realized that I've managed to confuse myself even more than before I started. A simple 'crash-course' in electronics wouldn't cover the areas that I needed to know and would only create more questions. Therefore, unless I was prepared to enroll in a certified college or technical institution, I would have to find a place that was certified to work on these systems. I finished the basic recap of the MC2105 w/o re-stuffing the cans. The two large capacitors were likely replaced before I bought the amp. In fact, I recall that they said they had acquired original McIntosh capacitors from McIntosh itself. I placed them in my analog Cap-tester and they certainly passed 100%. I have the amp setup in my home system and the music sounds great but still, I know that my MC2105 is not performing to its best ability and that bothers me a little. I'll eventually need to address this point. Thanks again for the great video! Rich PS: That Sony pre-amp is fantastic and my search for one came up with only a single preamp availbe to buy. It's in excellent shape and located in Japan. They want about $2500 USD for it...

Hi from mallorca spain Very much enjoy your indepth testing and knowledge on the equipment you test and service. I now have my eye on a LX 5.. this will be added to my linn x3 lk100 with active cards tri-amped and tri-wired to a pair of linn ninkas kestone bases. Reason for this is i have so many tapes from back in the day..will bring back some good old memories.. Fantastic videos ive learned alot. Keep up the great work Anthony

Before you posted this video, did you consider contacting Hifiengine to get his response to your issues?

You don't see the vintage Rotel gear vary often And I don't know think that The vary early Rotel lines Were sold in the USA

Do you have a Web site anf Facebook?

Catching up on a few older ones.. nice amp and nice job. Hope you will still be doing some vids :- )

Try an Onkyo Grand Integra M-510

Very good video. Thank you! one question - where do you connect black lead of multimeter? I only see you use red. Does black go to some central "ground" on the amp?

tool @ 6:50 is a dentist tool. works great for a number of things

I disagree, that Nak hype is long gone! Only Naks I'd own: RX303 and LX 3, the rest of those 💰 pits, you can KEEP!!!

I tried to setup an account about a month ago…no joy. So I purchased(!) an original manual for my 2215B. Also, I recently found a copy of the manual for my Technics SL-Q2 on the interwebs nearly free of charge (only cost me my time).

I have the 1603 what a baest and very dependable with some killer bass

I love your knowledge on vintage stereo's but I have to mention something I seen at position 1628 the screws are Philips but at position 1753 the screw's are replaced with a standard screw. Did you lose the original one's. Just curious. My issue is I have a Pioneer SX1250 had a shop repair it at the price of a grand. No six months later there is no sound coming from the right speakers. I call the repairman he's since sold his home and left with no forwarding address and does not answer his previous phone. So being a non repair person I have been buy little by little some of the basic tools to repair it myself. To say I'm nervous is an under statement. But with no where to go, I seem to have no choice. I play it now just on the left A speaker and the left B speaker. Wish me luck. Or any pointer that might help. I bought it when I was 18 and now I'm 70 so it means a lot to me to have it still working.

excellent instruction .. should have watched this video first .. but still learning... tool prices have really increased on that de-solder gun by Hako .. may have to get it anyway .. and found the Kenwood history to be amazing ... that history lesson, and of course their reputation among Ham Radio operators, speaks volumes as to their importance as a major player in electronics .. much respect for presenting this information and for a great instructional video