McIntosh MC225 Info & Service Part 1 of 2 - BG002

First in a two part series where I replace the output tubes in a Mcintosh MC225, rebias the output tubes, and calculate the bumble bee capacitor values in it and replace them.

[@steveseifer6784]

Around 1960 when I was 19, I remember going to Lafayette Radio in NYC. They demonstrated two McIntosh 60 Watt amps along with a McIntosh pre-amp, a high end turntable and cartage and the JBL Paragon Stereo reproducing speaker system. For those who never saw this speaker system it was a huge system about 7 feet long with elliptical horn shaped speakers aiming and an elliptical sounding board. Behind them were large woofers aiming straight out. The bottom Line is that I don't think any system today could compare with that system. The idea of this speaker system was to give the listener the stereo illusion no matter where he or she sat.

[@robertyoung1777]

From the owners manual; I understand that the two bars on the bottom of the amplifier were shipped new with the amplifier from McIntosh. They are designed to be pointed tab-side-out. The bars allow the unit to be mounted in a case. The manual says the amplifier can be mounted any way except tubes down. It says that (when side mounted) the tubes should be on top so that the heat they create will draft up and out.

[@moodyga40]

it's a piece of a art real engineering

[@navpers4764]

Awesome video !

[@emorris272]

Your voice is fine. I love your videos. You seem like a nice and smart guy!

[@joemartin6439]

Taste is in one’s mouth, like is one’s opinion, the more experienced one’s opinion the more valued it can be. I never had a 225 but it sure is on my wish list., plus the H H Scott 296. U have opened my eyes on many. If I ever get my dream amp ,I sure don’t want to run the tubes Hard. Bumblebee caps, 60 years old have to sorrily have to go.

[@asland408]

Great video

[@UnivegaSuperSport]

You mentioned something about comparing it to a muscle car. The chassis metal thickness reminds me of a '40's Buick.

[@rustyshackleford5509]

Love the video. So the potentionometer mod is basically to avoid the tubes running hot and dying early? Looks like you get a year or so more life out of the tube with this mod?

[@SteveHacker]

Can I apply your electronics principles to my electronics learning for work on guitar amps and other professional audio equipment?

[@moodyga40]

love McIntosh i amp rebuild a Mcintosh 26 preamp best Audio products ever made

[@johnsimms3957]

Aren't paper in oil caps obsolete? As they dry out their specifications change.

[@GIBKEL]

I put a pair of Tung-sol 7591 in a Reverberocket and they sounded good.

[@venturarodriguezvallejo1567]

Nice video. The image is just fine. The sound a little bit obscure but perfectly understandable. I own a Mc MC-275 and a Luxman MQ-360. It is supposed both designs have a built-in auto biasing circuitry (at least, both manufacturers claim so). Is that true? Past year I retubed the Luxman with two "matched" pairs of 6550A penthodes from Sylvania. I do not give too much credit to this "matching": I really think that's another trick for naive "audiophiles" and a way to rise the price over their real retail value, but nowadays is almost impossible to find power tubes not "matched". But I'm digressing. My question is: Are the "auto-biasing" circuits worth of trust? Many thanks.

[@peteb2]

Any chance you can tell us more about the 'Pete Malik Software associated with your HP 8903' at 12:56 please... thanks.

[@TMac473]

Loving these vids. Thanks for every single vid. This is awesome. I've avoided tube gear due to financial reasons but I'm thinking of leaping into it. I like the 275... any thoughts?

[@venturarodriguezvallejo1567]

The MC-275 is an amazing tube amp. I have one and it's delightful sounding and solid as a tank. It can drive with ease loads of 16, 8 and 4 ohms just changing the cables in the binding posts. Well; pretty sure you know all the above. The point for you, I gess, is the sensitivity of your speakers and their impedance curve. If this last is too tortured, think twice. Keep in mind tube amps are not generous current delivery devices, opposed to solid state ones. Mine are the easy to drive Mission 767. They have a good sensitivity: 92 dB/1 watt/meter, wich is pretty good. If you decide to buy it, McIntosh sell this amp in two versions: the standard and the "Anniversary Edition". The differences are mostly cosmetic, but the different prices are not so "cosmetic". Best regards.

[@motorradmike]

ventura rodríguez vallejo I agree. The MC275 is one of the finest power amps I’ve ever had in my home. The build and sound quality is second to none for breathtaking realistic soundstage imagery.

[@mikesamra9126]

Did you put in a 1N4007 diode in across the selenium and change out the bias cap?. I usually put in a 47uf at 50v Muse cap. Also change out the bumblebee caps, especially the .047uf at 400v that goes between the phase inverter and voltage amp. I use a K40Y pio cap.

[@Blueglow]

Always.

[@bronsonosborne2064]

i had a EH7591 short out in my fisher kx 200 today was only 4 months old

[@rbruce63]

What keeps these amplifiers from getting so dusty?

[@craneoperator4]

Robert Bruce by living in a bubble...lol

[@moodyga40]

i found the bumble bee caps course big problems use orange drops big improvement

[@timothyschorle2166]

seen your videos great work,ty I have the mc225 I'm just wondering if you know wear and if I can bye replacement stickers for the Tube placements,Volume controls,RCA input,etc. thanks and keep updating and keep up the good work. TJ. schorle

[@Blueglow]

Nope, those were originally stenciled on. If you find them, I'd be interested too...

[@1959Berre]

What makes a capacitor a "bumblebee"? (I'm European, please forgive my ignorance)

[@NocturneVid66]

The dark color with the colorful identification stripes or bands makes the caps look somewhat like a bumblebee.

[@JMNTN]

From the outside the new ones might look the same but the inside is night and day difference

[@danielthomas3057]

Coin base

[@exogarwinoputt4257]

I've always considered a solid state diode PS as cheating.

[@windows74001]

Even though there's logically no reason the PSU should matter so long as it's got a clean DC signal and you aren't irresponsibly contaminating your signal path with switching noise from the PSU

[@Curi0u50ne]

Shitz no el ee dees🥴

[@alexs.1965]

solo queria escuchar el sonido del equipo y el tipo no paro de hablar y hablar y nunca hizo sonar el equipo. blabla bla blablabla