Vacuum Tube Preamp Repair, Harman Kardon Citation 1

[@MrCarlsonsLab]

To join my ongoing electronics course, or quietly support this channel, click here: www.patreon.com/MrCarlsonsLab Here is the Capacitor foil side map for the Harman Kardon Citation 1, click here: www.patreon.com/posts/harman-kardon-14404130

[@dave1135]

Mr Carlson's Lab I may have missed it in the video, but what year was this amp built?

[@tomdewey9907]

They were circa 1959-1963 as I recall, but don't quote me.

[@seeburgm100a]

Tom, I think you are right on. The Citation II definately came out in '59 so given the Citation I was it's companion piece that would make sense.

[@justinc8409]

What Level of electronics do you need to take your course? I am a hobbyist. I buy things from ebay and put them together would this be over my head? If so do you have any recommendation on books or courses to get to that level? thanks in advance!

[@MrCarlsonsLab]

Oh it's really relaxed, and a different way of learning. You can participate in some of the builds, or just sit back and watch. There is a mixture of both solid state and vacuum tube tech to learn from. These are all videos, like here, but more in-depth (teaching wise)

[@shawn_530]

I know nothing about electronics. I'm actually a commercial artist by trade. However, I watch everything Mr. Carlson posts even though most of it is far beyond my realm of knowledge. Mr. Carlson is not only a true master of his craft, but is an incredible teacher as well. He could talk about mowing his lawn and it would be intriguing. I actually find myself learning little bits and pieces without even consciously trying. Thank you for what you do, and for sharing your incredible knowledge and knack for teaching!

[@bwithrow011]

Keep watching Shawn. Paul has an immense amount of knowledge for someone his age and truly is a gifted teacher. It's easy to see he has a great passion for what he does.

[@wollaminfaetter]

That goes for me too.

[@ianmedium]

I’m the same, the extent of my electrical prowess goes as far as changing a fuse, wiring a plug and replacing a vacuum tube but if find this wonderful and fascinating to watch and I learn so much which is good as I love to learn about new things far beyond my comfort level.

[@ronniewall1481]

I do art I'm not allowed to draw in public my stuff makes people feel weird.

[@johninjersey]

I'm a trained electronics technician and at one time I was a tech at Heathkit but Mr Carlson knows more than I ever knew. Quite a good teacher too. And all for free here on KZbin . Thanks Mr Carlson.

[@jimbos1567]

Class is something some people have and some people will never have. This is a classy u tube experience. Thank you Mr. Carlson for sharing your class and your talents.

[@MrCarlsonsLab]

You are very welcome. Thanks for your kind comment Jim!

[@BroWCarey]

I learn so much from your videos. As an added bonus, your voice has a calming quality, so if I am feeling stressed, one of your videos not only educates me, but also helps me relax. You're the best!

[@briangallagher7776]

Excellent thorough job.This guy knows his stuff.

[@Allbbrz]

I'm amazed at the internal looks of this preamp, considering that it is (at least) 56 years old. I could not believe when you read 1964 and I had to rewind the video a couple times to make sure I was hearing it right. Then I could not believe the front face and the tubes cans are so bright and shiny as they tend to yellow with age, even for much newer equipment. Then it comes to my mind... boy, I was 4 years old when this thing was "serviced". Yes, another grabbing video to be enjoyed by all "electronics technicians by heart". ... I miss the old times since long ago.. I've been a software test engineer for the past 25 years but the old electronics person never died.

[@MichaelLloyd]

Paul... your technical skill never ceases to amaze me but this particular restoration is a work of functional art.

[@MrCarlsonsLab]

Thanks Michael!

[@johnnytheg]

I have such limited knowledge of electronics, but I have a vintage tube stereo system and I so wish I had even a fraction of Mr Carlson's immense knowledge on the subject. I can watch these entire videos and get some sort of understanding of what's going on. Truly fascinating. He has a true talent for making a complex subject understandable.

[@100amps]

Back in the 60's, we'd buy our hi-fi gear from Mom and Pop shops or small chain stores, and most had their own service and repair depots in the back. When you bought some new audio gear, the dealer would typically put their sticker on the side of the unit, to encourage you to get your service done at their shop.

[@bwithrow011]

I had a Harman Kardon A50K 50 watt integrated stereo tube amp in the early 60's. Loved it. I'm loving your videos on both audio & musical instrument gear since I'm an audio engineer and a musician

[@bwithrow011]

I had an A50K. Loved mine

[@ci70telita]

this is a kind of "philosophy of classic electronics".... and I think this is right way to treat special things..... with mildens and deep understanding......

[@stimpacat]

Not sure if you know, Jim Macshane. I bought his kits for My Citation 1 and 2. My dad built in 1963 w the RCA club. I have someone up grading to Jim's Kits. The Tech doing the system was completely surprise over his parts and the upgrade. There is nothing on the planet like these pre-amp and amp. I also have JBL Harkness C-40(15"). My Dad(passed on years ago) also has the AR-XA w/Shure. Having the near best all my life, its hard to impress me today but with advancements with vintage equipment I am highly impressed. Kenrick Audio has horns that blow me away. I purchased the chrome hosing for my restoration for the pre amp. I have all the building construction books. Also have the Citation A & B w/books my Uncle(passed on years ago) built back then. The first Solid State system. I am glad I have them today. Great Job on repair. That pre-amp is in awesome condition

[@chriscoleman2128]

You are the only person I get genuinely excited to watch new videos. Thank you for the content and knowledge.

[@MrCarlsonsLab]

Thanks Chris!

[@albertoldschool6950]

Thank You from Phase III Lab's. in Chicago. This was my first PreAmp Kits I build along with the Citation 2 Power Amp. with KT88 Gold Lion Output Tubes in 1962. These were my first love and they are still working, I'm going to rebuild these units, However I use McIntosh Equ. now.

[@MrCarlsonsLab]

Thanks for your comment Albert!

[@joscallinet6260]

@@MrCarlsonsLab I'm not sure you, Paul, realized when you began this Harmon-Kardon pre-amp restoration, that they were sold as kits as well as factory-assembled units. If the Citation 1 you restored in your video was assembled from a kit by its buyer, its owner did a VERY nice job. Harmon-Kardon supplied beautiful instructions with their kits, and the quality of the parts was tops. So glad you came across this one to restore. As always, your videos are a delight in every sense of the word - beautiful camera work, very clear information well-spoken, and your manner is gentle and respectful, and not in the least bit condescending. Your really want to share your knowledge with your audience. These qualities matter a lot, and it's no wonder to me that you have such a devoted following. I, personally, have learned a great deal from you, and I have been able to make good use of your information in my own restorations.

[@chenguefer156]

I am very impressed, more than 50 years and still in almost pristine condition. Many thanks for showing us your work!.

[@MrCarlsonsLab]

You're welcome!

[@michaeltiberii8656]

Great job picking up the errors of the capacitor factory install. Interesting of the capacitor on the power supply. I will be looking for the separate video for the safety fix. You do a great job explaining the history, details of all the components. Neat and clean, pride in your craft. Something that is lacking in todays world

[@panthony1525]

Never understand why there is any negative feedback. Well done. Another great show. Look forward to the next one.

[@smbrown]

I’ve seen you discuss outside foil before but never understand why, I was one of those guy that would have said it doesn’t matter. This was great demonstration of why it does matter.

[@atbglenn]

Excellent video! I lived a few blocks from Harman Kardon in the 60's and 70's when they were made in Plainview, Long Island, NY. A couple of friends were technicians there.

[@carpetcrawler79]

As an electronic engineer myself, I'm happy I found this great channel. Cheers

[@philipoulton7730]

In awe of your forensic electronics skills. I miss the smell of my childhood amplifier (Scott Kit, built by my Dad in 62) I can almost smell it warming up while watching some of your videos.

[@peterelfesphotograph]

I'm also not an electronics wiz.. But love vintage audio gear. Thanks Paul, this kind of video really helps me communicate with my audio tech when I need to get stuff serviced.

[@smallenginedude71]

As an Audiophile i congratulate you for repairing this beauty! A very fine piece indeed, those preamplifiers sound fantastic,

[@cletusspuckler2243]

All Harman Kardon hi-fi equipment sounds great, H K is hight end audiophile equipment ! I've never had the chance to listen one of them 😢.

[@FrodeLøtvedt]

I don't understand much, but I still watch for hours!

[@samb3706]

The Citation I came in kit or wired form when new. Since this unit has the RCA jacks, power supply capacitors, and other items mounted with discrete screws and nuts, I believe that this is a unit built from a kit. My Citation I, which was factory wired, has rivets securing the RCA jacks, tube sockets, and power supply electrolytics. I also remember this from servicing these units in the 1961-1964 time period. I bought my Citation I in 1962.

[@highcastle1]

Yes, it's definitely the kit version. This would explain the backward caps, and perhaps the 1964 service, also. (It probably didn't work when he finished building it.) I built the companion Citation III-X Tuner in 1964 from a kit; at the time it was considered the most complicated electronic component kit being sold. BTW, the tube shields were aluminum. These have clearly been buffed or replaced. The chassis is way cleaner than when it was new, so has also been extensively worked on. It looks like the potted power transformer has been repainted, also. In general, if I were buying one of these, I would opt for a factory-wired version. Regarding the comparisons with the Marantz 7C, the Citation preamp in its wired version was more expensive than the Marantz. They also differ wildly in design. The Citation was ultra-wide band and had state-of-the art circuitry. The Marantz was narrow-band (20-20K Hz only), and had totally conventional circuit design.

[@johnthornton8591]

Brilliant. So thorough, so well explained, so educational. I've learned so much. Thank you Mr Carlson.

[@clydebaker3484]

I wish we had a reputable audio repair man in our area i could trust like Mr C.

[@thevacuumtubejunky9774]

There is nothing better than vacuum tube audio equipment.

[@John-vi5vb]

Wow! Audotronic is still around! They've moved about 15 miles away from the location on the sticker, but still in NYC!

[@someoneoutthere7512]

Nice job of electronic forensics. Good to use all of your senses when investigating problems.

[@stefanscholz2509]

Very nice video. Thanks for pointing out the requirement for changing the RF surpressor capacitors on the power input. Old capacitors are a substantial shock and fire hazard. Especially, if it is gear operated on 240 Volts, like in Europe.

[@TheRadioShop]

Thanks for showing us how it is done Paul. Nice restoration!

[@MrCarlsonsLab]

Thanks Buddy!

[@MaxKoschuh]

Paul, you did a wonderful job. excellent. I like that everything is still looking original.

[@MrCarlsonsLab]

Thanks Max!

[@jenniferwhitewolf3784]

I love your lab... you are one of the very few people that has more test gear surrounding them at work station than me. Growing up in Tek back yard, I am died in the wool Tek junkie. Nice old HK... a true survivor.

[@MrCarlsonsLab]

Thanks for your comment Jennifer!

[@Strange_Brew]

I love your voice, even your Canadian pronunciation of “out” an “House”. Sometimes I put on your videos just for background sound when I work on long complicated projects. Thank you so much!

[@MrCarlsonsLab]

I'm glad you're enjoying the content Robert!

[@MarkSeve]

I have no idea why, but I enjoy watching your repair work. Might I suggest a little more history on, why the unit came to you, and the type of work the client requested. Thanks again sir for sharing.

[@socalav]

!! I remember Audotronic! They used to have a location on Main St in Flushing Queens in the 70's and 80's. Great people.

[@scottlarson1548]

I have never seen tube shields that looked so shiny and clean.

[@victoryfirst2878]

This has got to be the cleanest preamp I have seen on KZbin. This really makes it easier to repair this old bird of music prowlice. Keep up the great work Paul. Love your channel too.

[@danielmurray8778]

The way those horizontal tube shields are mounted above the jacks In back is interesting, very industrial look. I haven't seen that before, very cool! Thanks for another great video!

[@MrCarlsonsLab]

Glad you enjoyed Daniel!

[@Damaniel3]

Mr Carlson, you're the Bob Ross of analog electronics. I could watch your channel all day, and I'm not even a hardware guy (I work at a test and measurement company, but solely in software...)

[@MrCarlsonsLab]

Thanks Damaniel3

[@MrShobar]

Bob "Let's get a little wild now…" Ross (RIP). Sounds so unlike my friend Mr. Carlson.

[@gaylandbarney2231]

@@MrCarlsonsLab i'm a painter myself , and feel this comment is an insult to you..........

[@budandbean1]

Thank you so much Mr. Carlson, for all your wonderful videos and thanks for all the time you spend helping everyone understand these concepts. I enjoy your videos so much and get a lot out of every one. All the training I had thirty-years ago is slowly seeping back into my brain and it's really because of you and your great teaching technique. You are an asset to KZbin. :-)

[@MrCarlsonsLab]

Thank You Buddy for your kind words, It's comments like this that make this channel worth the effort.

[@cajuncoinhunter]

@Buddy Martin I agree with you , I had a stroke 11 years ago , and forgot a few things , but they are coming back slowly and surely watching Paul's videos and a few other channels that he promotes through shout outs for their channels ...... If Paul recommends a channel , that means it's a great channel to watch....

[@5argetech56]

Hi Paul. About the dragging the fingertips across the faceplate. A friend of mine had a old fisher receiver. Those have stacked volume and balance control in one knob. What happened was they had dragged the balance control all the way to the right when turning down the volume. Henceforth they thought that the Left channel was dead... All I did was turn the control behind the volume knob the the center position... They were flabbergasted that I solved the problem just by looking at the unit... I scored some major brownie points that day! It was my girlfriends dad. After that I could do no wrong :)

[@WV591]

TU as always. must've belong to somebody like me. my vintage 80's equipment's look as new as the day i bought them. not a single scratch or even a finger print. they have survived 12 major moves across country and still flawless.

[@fletcherreder6091]

When I was a kid, I was working on a solid-state preamp, and one of the things the guy I got it from said was wrong was that the balance didn't work right. After about two days of trying to find the problem, I finally realized that the control had been replaced with a log-taper pot! There was effectively much more resistance on one side, than the other, and the rate of change was different as well, leading to interesting behavior (almost impossible to center well). Anyway, just thought I'd share that amusing anecdote. Love your videos by the way.

[@parsifal40002]

Thank you for being such a great teacher! I know absolutely NOTHING about electronics but your explanations while still being "techie", novices like me can follow you and have some understanding of what you are doing! Makes electronics even more fascinating! Well done! I subscribed to your channel because electronics fascinates me!!

[@Kevin-cr9jt]

Im confused why there is thumbs down this is superb video work and very educational every video is of the highest quality in image and information i think some people are jealous.good work mr carlson!

[@MrCarlsonsLab]

Thanks Kevin!

[@chuckschillingvideos]

KZbin has no maturity nor intelligence requirements. Anyone, anywhere, can comment or rate.

[@mockingbirdanalog]

I think they are audiophiles that were expecting Mr Carlson to insert capacitors the size of 2 liter bottles.

[@jenniferwhitewolf3784]

I hate seeing 👎🏻 on excellent programming... Shame upon those who do such things.

[@gavincurtis]

Those were left by Yorx mini stereo owners.

[@rameshbabu1963]

sir, your narration of the repair is so professional and very informative. Your knowledge in electronics is profound. thank you

[@IdeaBoxful]

Also his work ethic and how clean he is approaching the repair process. Block diagrams, Data sheets, diagnostic manuals - he references and does it by the book! Compare that to the so called repair technicians in India!! I have seen nightmares, and nowadays avoid giving my costly equipment even to company repair shops. They are horror stories!

[@RocRizzo]

I know where that repair place was! It was outside of Elmont, down the street from the White Castle, which i think is still there. Audtronic had a good reputation for repairing anything electronic. They were a bit pricey even back in the day. Stuff like that makes me feel old.

[@ldmillerlm1]

Hello, Mr Carlson, Very nice set of videos; your video and audio engineering are first-rate! I am 80 years old and worked as an audio engineer for Ampex Corp (professional studio tape recorders) and I had a Citation I and a Citation II back in the day. They were designed by David Hafler, who was an Audio God. Judging from the comments it appears that very few of your viewers are aware that most of these units WERE BUILT FROM KITS and whoever assembled this unit did a very good job (the kit instructions were excellent). Even at that, the units were quite pricey-- especially the Citation II because of the huge transformers (2 audio and 1 power). Unfortunately. the Citation II was very weak in the power supply department: the electrolytic filter caps were all inside the chassis (where they got very hot and dried out) and the rectifiers were early silicon power diodes (also in the chassis) that were pretty fragile in the PIV department. Consequently, the Citation II required fairly frequent power supply service, which was a pain because the thing weighed a ton and all the parts that needed repair were buried inside the chassis. But when it worked, it sounded great! Keep up your excellent video series, Yours truly, Larry Miller (Ampex Audio Engineering 1957-1967)

[@MrCarlsonsLab]

Thanks for taking the time to write Larry!

[@garywells9478]

I really like Mr. Carlson's video. The preamp is truly beautiful inside and outside.

[@cletusspuckler2243]

I was an home electronics tech, now, when i recap a power supply stage or power output stage of an amplifier or in any electronic device I always put 105°c capacitors , i mount a new one with higter voltage tolerence, i just keep the capacity value as the orginal part. Manufacturers always (for cost reasons) use the lower value voltage caps it can be mounted ! Increasing voltage tolerence of cap extends the life of the new part that had been installed. In an amplifier's output power stage, if some electolytics caps are mounted close to the heatsinks, i recommend to ALWAYS, mount 105°C caps temp range, they will live longer !!!

[@davidportch8837]

another great video Paul... much appreciated... the capacitor polarization is something that I learned from one of your earlier vids along with lots of other useful stuff on repair and restoration. This is definitely my favourite KZbin channel...

[@MrCarlsonsLab]

Thanks David!

[@leemesenhimer2072]

I had bought a Citation-1 preamp and a Citation-5 amplifier second hand about 50-years ago: I was very satisfied with the amplifier. But after a while, I didn't need the preamp. After using them for a number of years, a man drove 150-miles to my house to buy them. I think I still have the original service manuals that I could copy into PDF files. Or I might even sell the originals. - Lee, near Cleveland OHio

[@venturarodriguezvallejo9777]

Fascinating piece of audio gear! It's awesome to see how much care and love for their products Hi-Fi brands did put in the past. Sadly, nothing to do with nowadays use-and-dispossal generalized attitude (even in the High End territory!). Thanks for your voice, so calmy, clear and relaxing.

[@burlingtonbill1]

See my note above (done 12-31-19) on this piece of gear and the early hi fi scene. Enjoy, and Happy New Year !

[@alanh8664]

I had one. Note the switch on the bottom, "phasing." Used to reverse the phase on a channel, for proper stereo. Unique.

[@johnware5312]

Refreshing to see somebody who knows how to fix old high end tube stuff right..

[@Waltkat]

Thanks so much for this video! I have one of these that needs to be gone through, so this is perfect, though your example is in much better condition. Who ever built this pre-amp did a pretty good job (remember, these where kits when new). I also have the matching Citation II power amp and Citation III tuner.

[@MrCarlsonsLab]

Thanks for taking the time to write Waltkat.

[@derkeksinator17]

Speaking of counterfeit parts, I have a very cheap poweramp for my desk and after a few years it began crackling. Opened it up and sure enough the filter caps had leaked onto and UNDER the board eating away at the copper traces. First of all they started leaking at the bottom, without signs of bloating at the top, so they looked fine. They read: 2200uF 35V 105°C nichicon(in appropriate lettering), yeah definately not... Turns out there were smaller capacitors inside, without any label whatsoever. Also the Vss and Vcc rails were at ±37 Volts. I replaced all of the capacitors, even the film ones because they looked suspicious as well. Sounds better than beforehand too.

[@paublusamericanus292]

possibly the best most conscientious restorer on ya'll tube. good job mr carlson.

[@MrCarlsonsLab]

Thanks Paublus!

[@dell177]

I was stationed on a microwave site in Korea in the late 60's as a AFKN technician to monitor the Raytheon KTR1000 microwave link equipment that distributed the TV signal to the different transmitters in the country, all of this gear was vacuum tube based. The rest of that site was STRATCOM and they were running ANTRC-24's and 29 systems that were over 20 years old in some cases. All of these systems had 50 to 100 tubes in them and the Army way was to test every tube in every system. logging the readings in a logbook every week or two. Over the decades that resulted in a lot of wear and tear on the tube sockets and some were getting pretty loose. This gear was well built and had the ability to read cathode current in almost every cathode so you had the ability to check the tube operation without pulling them. I wrote up a proposal to stop frequent tube testing (and pulling of tubes) and log the cathode currents instead. The tubes would be tested every three or six months or when ever a cathode current showed a noticeable change. About a month later I got word that the US Army had heeded the advice of a lowly Sp5 and changed their way. Hopefully that extended the life of this gear. After leaving the army I worked as a technician for a company as a calibration technician and I was amazed at how long a tube would last in a properly designed tube circuit. It was very unusual to have a tube go south earlier than 5-7 years in our Tektronix 530 and 540 series scopes and they had a ton of tubes in them.

[@MrCarlsonsLab]

Great write Mr Dell! That proposal of yours probably saved them huge money over the long run. Cathode current (plate current as well) is a great way to monitor a tube throughout it's life.

[@dell177]

That equipment was really well built but even mil spec tube sockets can only take so much. Replacing tube sockets is a LOT OF WORK and anything you can do to forestall it is worthwhile.

[@travis4798]

I can see why the owner kept the preamp in such good shape. Harmon Kardon Citation equipment are highly sought after and have great sound. Not too often you see very early stuff like the Citation 1.

[@mikesradiorepair]

I have seen so many of those three leg safety capacitors that have exploded. Had a Tram D201 that even had the paper insulation wrap of the transformer catch fire when the safety cap shorted out because they lay them up against the power transformer. For knobs I suggest using wax paper to tighten up loose knobs. If you use tape over the years even the non sticky side can become bonded to the knob making it hard to remove in the future. Nice to see I'm not the only person that completely removes the component leads when replacing parts. In my world (old CB radios) they use normal tie strips and frequently have 6 or 8 things tied to one terminal. I see people recap and replace all the high wattage resistors and don't desolder them. When they are done they have a giant blob of solder. Very unprofessional looking. Thanks for doing it the correct way.

[@MrCarlsonsLab]

Thanks for your comment Mike!

[@cw5059]

Hi Paul, hi Mike, you two do such a great job with your instructional offerings I get a plate of lunch or dinner and enjoy every second. I always look forward to whatever new you two post. Thanks for your channels.

[@MrCarlsonsLab]

Thanks Clark, I'm glad you're enjoying the video's!

[@garyfrombarry1]

That's exactly what I do Clark. I have enjoyed every video you have done Paul. Very informative, even to us old and seasoned Tech's. Thanks Paul

[@dontcare563]

Harman Kardon makes and made some real quality gear. This one was definitely worth saving!

[@mirelchirila]

your audio is impossibly noise free, props on the good audio work. although considering the retro electronics nature of it I feel it would benefit from some tape hiss or vinyl crackling.

[@burlingtonbill1]

The HK Citation 1 was a landmark in early-60's hi fi. I think it was designed by Stew Hegeman. It was sort of a poorer man's Marantz Model 7, considered by most of the day as the absolute top dog. The Citation 2 was its matching power amp; again, quite well-thought of. Both were universally praised as exceptional by both camps: Julian Hirsch (Hirsch-Houck Labs, writer for "Stereo Review") of the objectivist school (it can only sound good if it MEASURES well on the bench) and the newly-emerging subjectivists, (your own EARS can be the best guide) led by J. Gordon Holt ("Stereophile") and later, Harry Pearson of "The Absolute Sound.") Back then, it was possible to be a full-featured preamp (LOTS of knobs!) and still qualify for great sound. Later, at least for the "golden ear" crowd, LESS (input jacks, switches, tone controls, number of preamp stages, amount of feedback -- in essence, less COMPLEXITY) was deemed "better" as there was less between the source and the speaker to potentially muddy things up.

[@nicholaslittle2312]

I wanted to hear it working. The only part of amp restoration I have ever done is contact cleaning the pots. Your vid was fascinating. Surprised none of the tubes needed replacing. Also suprised that the foil end is not marked and not even consistant on modern cap. Cheers

[@friedmule5403]

What I especial like about your work, is that you don't "just" repair it, but you make it look like no one have touched it, like it easy could have looked original! :-)

[@JamieBulloch1]

fantastic and fascinating insight to electronics explained in a superb way, by far the most informative and educational channel on this subject...

[@psionl0]

Another fascinating video. I find myself eagerly awaiting each new release. It's a pity that we didn't see you soldering one of the new caps into the pre-amp since you went to some lengths to explain the need to avoid lead stress.

[@jhowe5571]

This is way better than much of the cheap crap that's out there. Most don't have any kind of EQ anymore and have one or two inputs w/ a Bluetooth wireless connection. Although I have never heard of Harman Kardon before, I had a Realistic component system back when I was a teenager. Tower speakers, receiver/preamp that had 7 band graphic EQ, two tape decks and such. I miss having those, even though they were solid-state, they sounded great... Nice to see someone preserving these great audio devices from the past! :-)

[@parsifal40002]

This device looks fairly modern, manufactured maybe in the 50s or 60s . Very nice looking!

[@bulwinkle]

Thank you for yet another comprehensive look inside older electronic equipment.

[@raymondheath7668]

It's funny you mentioned conterfeit resistors. I had purchased several multi-paks and ended up checking all of them and matching resistors to get correct or near correct values. I learned at Boeing that putting an "S" in parts leads for stress relief and a half turn on the binding post

[@chrismosley409]

I'm definitely looking forward to that video about safety capacitors.

[@glennbillings7080]

Paul, I know an older guy that worked for HK and was on the design and test team for that pre-amp, still lives on Long Island to this day. Not going to drop any names, but retired from NBC a few years back in case you know who I mean. Great video again! I try to keep up with all your videos as time permits around here. Thanks again, Glenn

[@MrCarlsonsLab]

Thanks Glenn, I think I know who your talking about, he has contacted me about a redesign (Universal Studios)? Same fella?

[@glennbillings7080]

The name Nick ring a bell? Also worked for Sony music back in the day, then flew a 727 before he went to work for NBC

[@hugeshows]

Holy crap, that's a CLEAN Citation I. And it has the Telefunken 12AX7s and 12AT7s, which is awesome. Tele 12AX7s almost never wear out, and they have the best hi-fi preamp performance of any 12AX7 variant I have ever seen. They were also standard on a lot of the vintage Sherwood stuff, most notably the S-5000, arguably the best 7189 based integrated amplifier of that era. Also, damn you now I have to go back and check a whole bunch of foil cap orientations.

[@sunahamanagai9039]

Wow, I was shocked to see that it was serviced in 1964, meaning it is at least from the 60s if not older! Not knowing anything about these, just first seeing the design, I thought it was something more contemporary. Beautiful component inside and out. Wow wow wow

[@josephf151]

That is a beautifully designed case, a great electronic design, and of course amazing restoration work! I want one of these now even though I have no use for one as of now!

[@bwithrow011]

Dr. Carlson does it once again. Great video 📹 👍

[@markanderson350]

That is beautiful. I used to have a Mac C28 and it had the rollover and turnover for everything from a tape head, microphone to early 78's or RIAA.

[@MrBanzoid]

A very nice sympathetic restoration. Thanks Paul.

[@AB1Vampire]

Like your channel. Easy listening, the Bob Ross of electronics.

[@gregargendeli2973]

Thanks for this. I actually have one of these pre-amps; it has been in use for about 40 years (with tube replacements). Looks like I should probably get it really cleaned up. :)

[@graxjpg]

Greg Argendeli hopefully the capacitors aren’t all backwards!

[@greggaieck4808]

Mr Carlsson your vacuum tube preamp Harman kardon citation 1 it is so awesome

[@joannamendonca8629]

Love your blog great job well done I enjoy it so much my father back in the days does those jobs great pics of history with those valves are to be used to call them back and Guyana south America thank you so much for your time and effort to restore those lovely history equipment.my name is Errol Mendonca and my father is Richard Mendonca thanks very cool stuff great job

[@PeterEdin]

I love the warm glow (and smell) of tubes. Among others I have obtained eighteen CV287 tubes. You can hardly see the glow on these so visually they are dull as are the eight KT88 audio amp tubes. Both I think are directly heated. I have no use for any of my tubes, but I like them and plan someday to make "art" out of them by powering the filaments up.

[@MrCarlsonsLab]

They sound like the same principal used in "Dark Heater" 6146's

[@k5azebud988]

That preamp looked new to me. I was always afraid to pull to much on the soldier post for fear of pulling them out of the phenolic or paper board because I did that once. Nice video, interesting that those caps were all backwards.

[@danielmurray8778]

K5AZE Bud I agree I'm always so afraid to put any pressure or tension on any soldier joint, I have pulled out vias and lifted traces..... nothing more annoying

[@wb6wsn]

Look carefully and you will see that he's not "pulling" on the posts. Rather, he is using the diagonal cutter's jaw profile to apply a simultaneous pull to the wire and a push to the post. It creates a force strong enough to rip the wire out of the soldered joint without stressing whatever holds that post. (Component leads are usually plated steel, much stronger than solder alloy.) Warning: this is an advanced technique, you will damage a few wires and posts as you teach yourself the "feel" of doing this (remember, it's the rotation, not the pull), and even more importantly, when you can get away with this. You probably shouldn't try this if the wire you want to remove is not the top or outer wire, or if the solder blob is too generous.

[@BruceNitroxpro]

@@wb6wsn, Totally true in all respects. Especially the last observation. We all have to remember that "common sense is the most uncommon sense of all." (Samuel Clemens)

[@cajuncoinhunter]

Ok I know this is a 5 year old video , but I will comment anyway ...... I agree with Paul on a mechanical failure on that resistor and I will add to his theory on how it got broken .... I learned from my Uncle that owned a sales and repair shop for many years about electronics , He called those platform inlet backs , there are pros and cons to that design . Easier to pull the unit forward and hook up your RCA jacks and speakers is a PRO ... 2 CONS are dust settling into the outlets and ,just say a picture frame falls off of the wall above the entertainment center or shelf that it's on , it will hit the tube shields and cause problems inside the unit as in the case of the broken resistor .... I'm sure a few people will agree to that .... Have a great day everyone...

[@michaeldavidheit]

I use a product called KROIL ... just a very small drop does a fine job and seeps into the controls very well.

[@davidlisney2597]

Your content is always excellent, however the video quality here is stunning, the views of the preamplifier look like a publicity shot and yet there is movement. Lovely use of depth of field too.

[@bassmaster1953]

I also own a Citation I, as well as II and III-X. All pristine. My( I )has the bubble bees backwards as well. Some but not all have been replaced.

[@stompreaper]

Very valuable information delivered in a very digestible form!

[@antraciet]

Very nice repair. I learned a lot, thanks Mr. Carlson for putting your work in making this and all your vids.

[@seeburgm100a]

Mr Carlson, thank you for tackling this wonderful preamp. I use one as a daily driver and I can say that the Citation I is a fantastic preamp, especially if you are playing LP's and 78's. I rebuilt mine using all orange drop 716p capacitors, replaced cans with new cans as available, rebuilt the power supply. I also added a grounded power cord to mine (which I usually do to my tube preamps). I'd like your opinion on that. Lastly.. it would be nice to see you do a companion power amp and THEN demo them for us so we can hear the results of your labors (albeit via a compressed youtube signal!).

[@MrCarlsonsLab]

You are totally correct about compression, then there's the computer with speakers on the receiving side to consider as well. This all adds up to inaccurate reproduction. I do not change the power cord for ground loop isolation issues.

[@burlingtonbill1]

Great video. Really loved seeing the insides of that HK. Glad I wasn't the one who had to build it back in the day -- HUGE piece-count !! Wish you had done an overview of the circuitry, like you have done with radios on other videos. I'd love to see you assess an MC-60 or MC-275 McIntosh power amp, or an Audio Research D-79 sometime. Or even a Dyna Stereo 70. Not sure when you'd find time, though. Or, under the ham gear category, go inside a Collins KWM-2a sometime, just for giggles...

[@alimaleki217]

Thanks Paul! This is a great looking unit and as you said. incredibly clean.

[@greggaieck4808]

Mr Carlsson the owners vacuum tube preamp Harman kardon citation 1 it is so awesome

[@jeffjohnson2883]

Your the best Mr carlson...love your videos and your amazing ability and knowledge thank you for your shared greatness

[@MrCarlsonsLab]

I appreciate that Jeff!

[@johnbellas490]

A beautiful pre amp with a lot of NICE FEATURES !! Harmon Kardon made real nice equipment !! And Paul Carlson is the best to explain the circuits and what he does to repair or improve the performance of them !! Paul is a real masterful educator and technician or I really should say ENGINEER !! Thanks Paul for another great video !!!!!! John A Bellas KC2UVN

[@MrCarlsonsLab]

Thank You John!

[@joemalone3099]

Beside the incredible knowledge..you are a great story teller SIR...thank you so much