5 of our Favorite Vintage Stereo Amplifiers from the 70s!

[@skylabsaudio]

Sorry about the audio quality on this one- had some equiptment issues =(

[@karaDee2363]

Unfortunately I couldn't watch the video due to the audio issues

[@skylabsaudio]

Sorry Karen =(

[@chelillingworth9466]

I thought it was on purpose from the beginning like you were talking to us from outer space during the opening logo..

[@KillerKlipsch]

I'm a we bit confused... I heard everything just fine. @@skylabsaudio

[@Vercus100]

@@KillerKlipschWatch it on a computer with real speakers hooked up and you'll hear there's a wierd phase issue. Kinda sounds like it's coming from behind you or way to the side. With a phone or tablet, the sound is mono , so that effect is cancelled out.

[@dandinhofer9240]

This Skylab guy is about the only level headed, common sense, no B.S., relaxed KZbin influencer that doesn't try to overthink, overhype or overwhelm his audience. I really like his style and opinions, but then again we seem to belong to the same late boomer generation that valued engineering construction and realistically priced gear. Thank you sir for not making my ears overheat or ring with tinnitus.

[@analogguy5548]

My McIntosh MC 2105 & C26 from 1973 still rockin’ every day!

[@jimmyBside]

@analogguy5548…MC 7270 and C31V here. I’ve been dialing in a new pair of RP 600M II and wow…The old 80’s rig is amazing. Had to use the 5-band EQ and everything…😮Might be the 1st time those knobs have ever been turned...😂🍻

[@lisaharvey4373]

The 70's had some of the best consumer Audio equipment ever!!

[@stepheneson4107]

Another great video! A few comments: 1)The Pioneer 150watt/ch. Spec-4 was smaller, not larger, than the 250watt/ch. Spec-2 2) I sold Phase Linear gear in the 1970's when I was in the audio business. As you pointed out, these things would get HOT, especially if we left them turned on in the display racks all day... almost too hot to touch. We had lots of service problems. 3) Another classic from the era were the Crown amplifiers... the D150 and DC300... that were built in Elkhart Indiana. They battled with McIntosh for "top of the line" bragging rights in America.... until the Crown factory was devastated by a fire in 1971. Harmon owns them today, building equipment exclusively for the pro industry. Thanks again for a good look at great amps!.

[@willyodell7802]

I was about to post the same info as my Pioneer Spec 2 is sitting across the room from me. I had mine undergo a complete restoration while retaining all of the original output transistors. I'm lucky to have a true specialist in Minnesota who really knows this amp. The Spec 2 is such a beautiful thing (until I need to move it!) I was also in the industry most of my life, including 13 years at Sony in the hi-fi and ES audio division.

[@AngelaHenricksen]

Thank you for mentioning the significance of the pioneer branded rack. My sisters inherited my step dads system: Spec 1, Spec 4, SR 303 and RT 909, all mounted to the original rack. The RT 909 has been sent for repair and the Spec 1 and 4 will need serviced eventually but everything works well despite being stored for about a decade. The rack is a little shabby. it's has some rust and I was hesitant on if it would be worth saving. It will be saved, and eventually get the rust taken care of and the paint refreshed. These videos have been so helpful to me and my family through this process. None of us knew much about vintage audio, but we think our step dad smile knowing we kept his stereo alive for another generation.

[@fredjoel8113]

Good video: brought back memories for me having played with/owned/worked on some of these models back in the day. Another one that should be on the list is the Dynaco ST-416 with optional C100 Energy Bank. These power amps were available in kit form or assembled Spent some time building it and then some years later as an EE Tech, modifying it. Dynaco was a neat company that provided much information and support. When I was modifying my ST-416, I spoke with one of their engineers who was happy to discuss this with me. I owned several of their power amps and preamps which were heavy and well-made, all in the USA of course.

[@Alpha1545]

Wow I agree. I had a Dynaco amp years ago but I can't remember the model it was a small amp maybe 60 watts. What i liked about it was effortless bass almost twangy but not. Unfortunately it suffered a speaker wire short at a party and that ended it. If I could remember the model I would buy it. I know it's a good amp.

[@chrislj2890]

Oh baby, that Pioneer amp and pre-amp are to die for.

[@razerginn]

I sold one for $800 spec4, spec 2 and 9500 tuner

[@chrislj2890]

@@razerginn Do you regret it?

[@johncain7949]

Another great video! Just wanted to mention another great amp from the 70's, the Crown DC 300A. I truly loved this amp! Matched with the Crown IC150 pre-amp, it would really rock! Many bands such as Crosby Stills Nash & Young used this amp on tour. You can clearly see banks of DC300A's on stage with Triumph at the US festival! I heard almost all the amps at the time including my friends Phase Linear 400, Marantz and Pioneer, and my DC300A took a back seat to no one! Many thanks! John from Canada 🇨🇦

[@keetonkatt4621]

I, too, had the Crown DC 300A/IC-150 driving stacked Advent speakers. Incredible combination. The DC-300A could drive low impedance loads well and had a very solid bass. It also had a "transistory" treble, which wasn't a problem with the Advents but when I upgraded the speakers to some very bright sounding Thiels, it became objectionable. I had no trouble selling the Crown gear.

[@chinmeysway]

nice. seems like all amps will sound the same 90%, per wattage similarity.

[@johncain7949]

We must be closely related! I also had Advent speakers! I drove them with a Luxman receiver. I know there are many proud customers of 70's Crown gear!

[@drsbranch-wn2vx]

2.75 Tony is my new hero! Another excellent video, Kevin and Eric. You guys keep surpassing yourselves with each one.

[@30DirtyThirty30]

I felt horrible about the 16 I lent Kevin not powering up for the video. I had it sorted by the time I buttoned it back up there after the clip 👍

[@drsbranch-wn2vx]

@@30DirtyThirty30, don’t feel that way. We have all experienced similar situations and it is often not in our control. I have a love, like you, for HK. I bought my first HK 330b after listening to Kevin’s video and later secured an HK 870 locally from CL.

[@Dano831]

You got that backwards. Spec 4 is the lower wattage version between the Spec 2 & Spec 4. 250w/ch vs. 150w/ch for the Spec 4

[@skylabsaudio]

You're right! My bad

[@imaouima]

Beat me to it!

[@paulhare662]

That was like a walk thru the "I can't afford it" room of a 1978 stereo shop, thanks. I'm currently using a Carver C1 and a PL400 driving a pair of Infinity SM150s and a pair of Polk 10s. The Polks were found set out for trash pick up at the curb. I just hooked up a Bluetooth Dayton Audio reciever to it and I am loving it. The Danish Philharmonic Orchestra doing Ennio Moricone western theme songs is quite impressive. Heck, the Poni Tails singing Born Too Late is impressive.

[@haroldbrooks4235]

I could never be that lucky ❤

[@j.patrickmoore9137]

It's worth mentioning that 10 times the power is only twice as loud. The biggest reason for buying a higher power amplifier is to keep from frying your tweeters if you listen really loud. The higher power avoids getting into clipping, which generates lots of harmonic distortion (= lots of high frequency noise) and all the increased high frequency power sent to your speakers may fry the tweeters. As an example, the original Advents had a toggle switch on the back to adjust the amount of high frequency power to the tweeters, so that you would be less likely to fry the tweeters when playing loud music. Having more power means you're less likely to drive the bigger amplifier into clipping at the same power levels.

[@theclearsounds3911]

That sounds backwards, but, believe me, it's VERY true. The only situation that makes this not true is if you're the kind of person who always turns it up full blast no matter what. I knew a lot of kids like that when I was a kid. But, I don't think that kind of person will watch this channel anyway.

[@jimr3179]

Understood. I had an SX-1980 and to be totally honest, it looked great but I was never that impressed with the sound.I owned all of the SX-80 series with the exception of the SX-580. I also had a SX-1250. Of all of them my favorite is the SX-1080. I still have it and a 780.

[@theclearsounds3911]

@@jimr3179 I have a friend with an SX-1050, and it's also really beautiful, and he's had it restored and it works great. He's had people offer to buy it, and I told him DON'T! I'm curious why your SX-1980 didn't sound as good as your SX-1080. 🤔

[@jimr3179]

@theclearsounds3911 It's not that the 1980 didn't sound good, I thought it would sound better with over twice the power of the 1080.I'm kind of a bass guy so I have(had)a Klipsch Powered sub to help the Pioneers on the low end.

[@Mr39036ce]

I'm surprised about no Crown? Nothing? No DC300 or 300A or PSA 400 or anything?? or my personal fave,Heathkit AA-1640? A very nice 200w.p.ch job that typically does about 300 per ch.And the kit was only $479.00!!And analog meters for 20 bucks more!

[@blackwaterdogs4256]

Thanks for sharing this excellent tutorial ! There is such a wealth of great vintage equipment out there, it`s good to see a shop like yours giving them the TLC that they deserve. Rock on, Brother !

[@edwardbagu1252]

"It even makes the Panasonic Thrusters sound good", I love that line makes me want to go out looking for one.. Great video, thanks... interestingly most low watts receivers do not have the pre-outs and pre-inns but you are right people have a right to enjoy their music whatever way they want to as long as it does not go "ka BOOM"

[@glenncurry3041]

LED output meters tend to add noise. Many of the amps with them had switches to turn them off and the difference was audible. Basically transient noise as each LED fires. The HK 16 was a perfect example of it. And an incredible amp!

[@scotthamilton5138]

Never heard that about LED's, but will give it a test on my ST 416 - interesting maybe why they have a switch to turn the LED's off, thought it was to keep room dark. Thanks

[@glenncurry3041]

@@scotthamilton5138 Some of the more advanced designs fed a separate tap to a stand along buffer/driver section so the LEDs were not just off the amp's output directly. But then you are not actually measuring the amp's output directly.

[@paulsmallriver6066]

Last week I delivered my Fisher 401 receiver to a man for refurbishment. I was about to leave when he invited me into his work place. There he proudly showed me his Sansui G-22000, both the receiver AND the amplifier. My gawd what a treasure!

[@chevy4x466]

Fisher made my dad’s first vcr. It was a beauty, fully programmable.

[@LouisAloi]

Was nice he showed you my @ the time quite unaffordable rigs that I lusted for so I DID buy the Sansui G5500 I still own with Definitive Technology tower loudspeakers never regretted buying it despite barely being able to afford it too💸

[@NCislander]

Very much enjoying the subtle change to your channel recently. Kevin & Eric hitting it out of the park on appealing Vintage Audio topics within your shop. Super cool. -Thank you

[@PossibleAudio]

20:25... I agree. Running the 2270 pre into a McIntosh 2105 is kind of pointless as the internal amp of the 2230/2245/2270 is phenomenal. However, for example, if you want to run a Dynaco/Dynakit ST-70 or ST-35 as an amp using the pre-amp section of a 2230/2245/2270 etc etc. I can see that. Totally different sound and really brings Jazz, Singer Songwriter and Stringed Instruments to an ear candy level. A person can experiment with so many different combinations using input/output jacks. Thanks Kevin for another great video!

[@normwetherbee3403]

I used to run the pre-outs into an ancient Sony TA-30something (can’t remember as the amp is long gone) sounded better with my L100s than the internal Marantz amp section. That Sony was strange…kind of shaped like a long shoebox but worked nicely. Still have the Marantz 😊

[@normwetherbee3403]

Sorry forgot to mention it is a 2230 that I did that with

[@KillerKlipsch]

I didn't think you guys could possibly get any cooler.... Then I saw the Mullet!!!

[@skylabsaudio]

2X Tony

[@crmixman]

Great video Kevin! I love the look of the Phase Linear amps. It would be hard to choose which model looks cooler. I just kick myself for chucking a pair of Altec 9440A amps into the dumpster back in the 90s. But I needed a reliable rig for the band I was working with and those amps had too many intermittent issues and deemed not worth the expense to repair back then. If I knew back then what I know now - I would have been able to fix them myself.

[@normwetherbee3403]

Had a friend around 1981 or so with that big Phase Linear Amp and matching pre. Ran it with a pair of EV Voice of the Theater speakers( if you've never seen a set they make Klipsch Horns look small ). Good lord that was some big sound.

[@ceylonmooney]

luvin this veideo. man, i oogled the phase linear amps for years. had no idea they were bob carver. all i know of bob carver his big red expensive tube amp he said put out 75-80WPC got busted havin 15W edcor OPTs in it--thats puttin a lawnmower engine in as F150.

[@gprojectnoob4779]

My old man was a tech back then. Service manager for RShack in worcester ma in mid 70s, QC for Bose late 70s and National service manager for TechHiFi in the 80s. He had the Accuphase set which was super clean sounding when he was working at Bose. The bose 1800 amp was also a power house. They had very nice power transformers in them.

[@diver3444]

We referred to accuphase as the jap mack the p300 was a great amp as well as the crown dc300a

[@dentman67]

I agree 1000% with you. I hear the biggest differences in preamps. I feel very lucky I got to grow up looking at all this stuff in the mid/late 70's. My father was a audiophile and always had a dedicated music room. He would take me around to all the HiFi shops. There were so many of them in the Philly area. Also, when possible, please mention the damping factor when reading the specs. Thanks.

[@theclearsounds3911]

Right, and another spec that's worth while is the 4ohm power output, which is closely related to the damping factor. Very important if your speakers are lower than 8ohms. But, you can find this info online. I also agree that power amps have no business coloring the sound at all; they should all be ruler flat from 20-20k. The preamp is the only proper place to color the sound, unless you have an EQ also.

[@sampsonpaul73]

Thanks Kevin for doing this video. Was a little sad that Sansui didn't make the cut. I'm running a BA2000, CA2000, & TU9900 going to a set of SPX11000. Bought this about 20 years ago and other than cleaning the pots it was running great until just before the COVID shutdown. I'm on Vancouver Island and would need to ship the unit to be serviced, going to be expensive. Wish me luck, thanks again for the video.

[@skylabsaudio]

If I had one, it would have been in the video for sure.

[@kentrichardson9070]

Kent in Courtenay. I had my ca/ba serviced,recapped in Cumberland 10 years ago. If you reach out I can maybe pass along a number,if he’s still there.😊

[@johnjorgensen104]

Thanks for talking about Phase Linear. I have a Phase Linear 200 that I bought new in the box. Been pumping out tunes for over 40 years now and I love the old boy. Never heard about the speaker protection relay is this something you think I should look into?

[@Cimone90]

Just finished rebuilding a JVC M3030. Great amp. Basically, dual monoblocks in a single chasis.

[@prestige2000rider]

Citation 16. One of the best amplifier s at any price! That one there was a series one I had one of the last 16A all black with relay speaker protection, and also discreet driver boards .made a difference great great series

[@johnlangdon4338]

I had the Harman/Kardon Citation 11 & 12 combo for a while and loved them. I also have experience with both Phase Linears when I worked at the hi-fi club in Germany while in the Army. Highly recommended.

[@mstorrente]

More videos like this, please. Nice and interestnig one, great

[@robertwright5487]

I at one time owned a Pioneer Spec 1 and Spec 2 with a set of Pioneer HPM 150s. Unfortunately, when I was transferred back to the states they never made it 😢.

[@ripjones5294]

Another enjoyable installment. Thanks to both you and Eric. During your "breakout" discussion, you hit upon one thing that I do find annoying -- the "switch". I am finding that I prefer the Pioneer approach to having jumpers, versus having the switch. While you and I both really like the Yamaha receivers, that switch is really a pain in the rear. My Yamaha 600 truly has reinforced my dislike of switches versus jumpers. Thanks again....

[@robertliskey420]

Excellent! I have the 700B lab one thing about them a low impedance load is no problem for them. And when you mentioned "Pulling them from a rack" First time anyone picks one up they are very "side heavy" the transformer weighs a ton. Only one I would add is the old Dyana 400 My first high power.

[@festerofest4374]

This was definitely some of the stereo gear I lusted after as a teen in the 70's! Finally in the mid 80's I was working and saved for the Carver Receiver with Ohm Walsh2's. I thought I'd finally gone to heaven with that rich sound. My Ohm's are still playing today... actually in the background at this very moment. And cool that for a KZbin audio channel you have some nice stereo sound with the video!

[@paulherbert5548]

Loved the Dynaco Stereo 400s. Great power on a budget. Used them for live sound and then turned them around for home use.

[@aadam-kz5my]

Hey, great video! Do one on SANSUI BA amps and CA pre amps when you get it!:)

[@mikeporterfi]

Hey Kevin, Really enjoy your videos. I went stupid back in the mid 80's and bought a Yamaha MX 1000 with 800 series pre and EQ. 1000 WPC. Between it and jet engines in the USAF I managed to blow my ears. I was listening to Stevie Nicks singing Silent Night at about 2 wpc according to the LED digital display and all of a sudden, pop, bang, and the magic smoke came out. Cool system but way more than a young guy needed. Lesson learned. But it was Bad AZZ.

[@williamonderlinde5068]

I bought the Spec-1 and either the Spec-2 or Spec-4 when I was in the Philippines in 1977 or 1978. Both units were dual voltage, very handy when I went to Belgium. Amps kicked ass! I agree that an AMP just passes & pumps up the signal; to Pioneer HPM-1500 speakers for example. My system was all Pioneer till I hit Belgium. Money flowed, my system "Growed".

[@danstein2467]

Great review. Much appreciated.

[@skylabsaudio]

Thank you so much, Dan. Greatly appreciated! Kevin

[@jim010109]

Great video. It nice that you also showed how to hook a external amp up.

[@billnorman2821]

The Pioneer Spec 4 is actually the lower powered unit. The Spec 4 is rated at 150 wpc. The Spec 2 is rated at 250 wpc.

[@larrymorgan222]

A neighbor of mine had a Phase Linear (400 or 700?). It was blowing fuses, and he asked me to take a look. It turned out there was a burr on one of the heat sinks. It had poked through the mica insulator and shorted the transistor case to the heat sink. I removed the burr, replaced the insulator, and it worked great. My system never sounded so good as when I was testing the amp.

[@tmdillon1969]

Back in the 80s, my sister's roommate, Sue, had a complete Phase Linear rack system. I found it fascinating and it weighed more than I did. It's how I ended up with my sister's Marantz 2016 receiver as my first stereo. I wonder what Sue did with that system?

[@toddellison5128]

I was amazed that you haven't mentioned Dynaco/Dynakit tube amplifiers. I have original Dynakit ST70 and Dynaco Mark IIIs. Both all original from original owners, for the Mark III the original boxes, receipts, manuals, build check lists, etc. They both run great, all original. The ST-70 from 1968 I used to push a pair of giant JBL Studio 590s. Lovely, warm sound and easy to work on with lots of readily available parts.

[@chiphill4856]

I saw and heard the full pioneer Spec rack in the 70's in a stereo store in the local mall. Impressive system, I still remember it to this day.

[@elixtido1448]

Used BGW 500Ds, 750As, 1000?s and crowns of all sizes late 70s and 80s for PA and floor monitors - always kicked ass

[@Festvangelist]

I had the Harmon Kardon Citation 16 and 17 for many years. They powered my Advents, and finally my Dalquist DQ10. Extremely reliable power.

[@hjalmarfossi5728]

First off, definitely gonna be a fun one...Second off, Spec Two is more powerful then the Spec Four, but is not dual mono.

[@skylabsaudio]

My bad! Thanks

[@ChillToMusic87]

I really do like your channel, sensible, informative and no theatricals 👌🏼💯🙂

[@nicamatt1970]

Kevin, nice review and thanks for sharing your insights! I always enjoy hearing your balanced and frank perspective. I’m looking forward to receiving my speaker risers and headphones this week and putting my Wharfdale Dovedale 3s on them and then trying out the Grado SR80x headphones on my Pioneer SX-780 and my Marantz 2218.

[@skylabsaudio]

Should get them soon. Dropping off at the post office tomorrow!

[@adsph]

Great content Kevin. Unique perspective that you provide. Keep it coming. Thank you.

[@raygarafano3633]

Thanks Kev. I have a power supply for an RCA Radiola 60 that weighs in over 12 lbs. Capacitors and filter chokes as well as a beefy Xformer with 300 volts for the tubes plates known as B+. 14 amps just to lite the tubes at 2.5 volts.

[@pauljanssen7594]

I had the question of digital and old audio the old audio is more of what music instruments play and the voices😊

[@stevefoster2700]

Great list as always Kevin. Does Rob have a preferred cap type/series for the McIntosh power supply. Considering doing my 2255. Like you displayed, it's a heck of a struggle just getting that thing on the bench! Thanks

[@johnsenuta1038]

My Carver M-500t and M-1.5t have been upgraded and rebuilt by Nelion Audio now putting out 400 and 500 watts per channel. Nelion is the only remaining Carver factory authorized center that rebuilds Carvers.

[@EdMorales-r3m]

I have a M 500t and a C 1 preamp that could use some upgrading, where is Nelion, being in Canada there isn't too many shops I would trust to work on my units, tks

[@johnsenuta1038]

@EdMorales-r3m Michigan

[@EdMorales-r3m]

@johnsenuta1038 Tks very much!!

[@johnsenuta1038]

@EdMorales-r3m He also has a website. Nelion Audio.

[@genehaire4854]

Great presentation! Consider also - Phase Linear Dual 500 late '70s.

[@--onewheelskyward--]

Heck yeah to the 2105. My buddy sold me one cheap and it was part of my initial foray into hifi. And I'll never get rid of it. :)

[@edwinhurwitz6792]

Nice overview! I got my first MC2105 in 1979 to use as a bass power amp in high school. It was a revelation after trying to get clean sound out of a Fender Showman. It's quite heavy, but nothing compared to its big brothers, up to the MC2300, which was basically the same design (used the same driver cards, etc.) but instead of 65lbs, it was 125lbs. They were used in PA systems, in submarine communication systems and all kinds of places. I seem to be a Mac magnet, so now my living room stereo is powered by the MC2255. Similar design, but at close to 90lbs, I can't lift it. I'm not sure what I'm going to do when it needs servicing. The MC502 you showed is a fine amp, too, but it doesn't have autoformers, so it's not quite the same sound. I borrowed one for my bass rig in the early 80s and it worked well, but didn't have the oomph as that the MC2105 does. McIntosh was used to power the sound system at Woodstock, with a slew of MC3500s. Kind of my holy grail for a bass rig but the 145lbs and absurd price tag says no. facebook.com/estudio1003/photos/sistema-de-som-no-woodstock-em-1969bill-hanley-e-a-sua-empresa-hanley-sound-fora/469251193125803/

[@chiefhobbyist3203]

I moved from Arizona back to Illinois 3 years ago and sold 70% of my collection of vintage equipment including my Spec-4 and a mint Akai GX-635D. I wish I had several of those pieces back. I did keep my favorites.

[@larryjex6485]

I still have my Phase Linear 700 from the '70s, and it's a great amp. 350 WPC min RMS into 8 ohms, and you know it when you crank it. One '70s amp I would have like to see on this list was the Phase Linear Dual 505 which puts out 500 WPC and looks similar to the 400 on your bench.

[@multicyclist]

Fantastic selection. I would like to add honorable mention for Soundcraftsmen PM840 (or any of their other amps for that matter.) With a Soundcraftsmen preamp they can be bridged, and a pair will give you 600 watts RMS of per channel into 8 ohms. I have done this and WOW!

[@dylanemeraldgrey]

Just thought I'd mention: in the demo section you don't have any close-ups, so you say "pre out to the amplifier," but you can't see what you're plugging into on it. I think beginners might still be confused after that. And they might not understand channels. Anyway, another fun video. I learned about some amps i didn't know about. Question: i know dirty pots cause pops, but i just hooked up an old pioneer and it had an intermittent loud pop that echoed. It did not sound good. Is that some other issue?

[@kurtburkhardt5862]

Another good video. Separate amps can produce more and cleaner power than many receivers. I have a McIntosh C-26 pre and 2100 amp. I agree about the tube like warm sound. It doesn't have the cool blue meters on it but played through my ADS 710's it sounds great. I had a 8010 Kenwood 125wpc receiver and still have a Yamaha R-100 100wpc receiver and they both sound great, just a bit cooler and more clinical sounding. I do have a M-400a Carver Cube I use for my ADS SW-4 sub and at 200 WPC it puts out great bass.

[@lbowsk]

I've got a pair of Phase Linear 400s which are currently not in use. I used to also have the matching Pre-Amp (4000) and a Tuner. It was a pretty impressive display with the giant VU meters. After a while I sold the 4000 and then used a Pioneer SX8100 for the preamp. I am toying with the idea of using one again, this time paired with a Marantz 2240. But I am leery of using them without speaker protection. Mine have not been modified. Does anyone know if a simple inline fuse (what size fuse??) in the speaker leads would work? I was told that bands used to use them for their PA systems in larger halls. The fuses used to blow all the time so guys used to put larger and larger fuses in them. The end result was them burning up, hence the nickname. When I win the lottery I'll buy that McIntosh. Great vid. Thanks.

[@j.patrickmoore9137]

For what it's worth, I had a pair of Advents on my 700, I used a 3 amp fast blowing fuse inline. I don't think I ever blew a fuse.

[@jo15518]

i am doing exactly that...i have 2 400's was gonna bi-amp but one of the amps needs work..i will be running the Marantz 2238BL as a pre-amp and using just one of the 400's for now..i am also going to be using in-linlie fuses..starting at 2 amps and moving up to.2.5 amps if it blows....make sure they are "fast blow fuses"

[@brucemibus9523]

I still have HK Signature 2- 5 channel amp, been using it for 8 years, great design accommodating most speakers. 5 x 110W, with independent psu for each channel. Just about to change it for Theta Digital.

[@dtracy03ss]

You are correct on the Amps , that is their only Job is to amplify the Sound Signal from whatever is input, there Could be a SLIGHT difference between Tube and Solid but thats the Main reason we bought Recievers in the 70s and 80s because Living through that when you went to the Electronic Toy Stores you got to try pretty much Everything and MY Opinion was the Recievers were not only a Bit Less than Separates money wise, so you could buy the better Speakers or another piece, ie the Equalizer, Tape Deck, TT or 2 Tape Decks!! But the Recievers all had their own Signature Sounds, abd you had the Same thing with the Pre-Amp Selection si that limited what you could add to your system also! Also the Pre-owned and Teading going on Was Awesome! Anyway you are Correct IMO.

[@philsnyder7302]

Love your videos.... What model was that Kenwood receiver at the end? It was beautiful

[@skylabsaudio]

KR 2120

[@philsnyder7302]

tks@@skylabsaudio

[@CDJF1]

I had a battle with a buddy and his spec 4 against my BGW 750 C. He sold the spec 4 and bought a 750 C. BGW flies under the radar but are very musical with tons of head room.

[@georgepetrovic567]

Just a clarification on the Pioneer Spec2 power rating. I've owned a Spec 1 and Spec 2 since new. It was stated that the Spec 2 had less power than the 150W per channel Spec 4. The Spec 2 is actually rated at 250W per channel min RMS at 8 ohms from 20HZ to 20,000Hz at no more than .01% THD. The owners manual was printed incorrectly at 125W but an updated sticker was added by Pioneer in the manual I have as the correction. The power bandwidth graph included in the manual supports the 250W rating. And the meters are scaled to 500W!

[@BlankBrain]

I have two Biamp TC-120s: one for low-base, the other for mid-base, and a Sony TAN-5550 V-FET for treble. I'm in the process of re-capping.

[@thevinylgrotto4767]

Please do a video on that Kenwood receiver. I have two.. the 4140 and the 5150. I very much like the tonal qualities, and the tuner I find VERY sensitive. I'd also like to see a video on the Rotel RB-5000 amp, which I also have.

[@carlhayes-ze5nd]

Don’t forget the Kenwood L series mono blocks! The L-05m are nice to work on and sound oh so lovely. I wouldn’t mind a pre-power from sansui for a second system either.

[@deanfisher1656]

Thanks Kevin….sure enjoys these. Compared Phase Linear, Luxman, and Kenwood 700m back in the day. Bought the 700m. Any thoughts on those amps? Thanks for the great channel.

[@kevin6385]

I have the Spec 1 and 2. Go big people. The Spec 4 I'm sure is great but I will take the Spec 2 any day

[@mtacoustic1]

Picked up several Carver magnetic amplifiers, rated at 400 watts/channel off ebay. One amp went out, but Carver still overhauled it and it's back in operation. It's fun to watch the house lights flicker when running these amps at higher volumes; due to the magnetic (rather than caps) maintaining the output power. You have to be careful with the speakers, however. I burned out a set of Pioneer R-300's with too much volume!

[@2visiondigital]

Despite any short comings the most punchy dynamic amp I had was a Phase Linear 400. Fortunately I pulled it before it flamed out, it started to backfire. Also enjoyed a Kenwood M2 basic, whiched punched above it's weight. Amp power corrupts in a good way.

[@thomascrill2842]

You can also use both amplifiers by using the tape in and out to accomplish the same thing. Tape out of your AV or Receiver to the tape in of the next unit and so on it was called a daisy chain system that you could use multiple amplifiers to drive lets say 4 amps 1 to your subs, the next amp to your woofers, the next amp to your midrange and the last one to your highs. You could also use it for adding individual rooms to the system.

[@frederikjacob1985]

Frankly, one that's frequently forgotten from this time era is the accuphase p400... It's an absolute beast of a power amplifier. 50 watts in class a per channel and 200 watts in class ab.

[@williamonderlinde5068]

Thanks!

[@skylabsaudio]

Thank you so much!

[@MarkSmith-vm3cs]

I used a Phase Linear700 Series 2 all through 80s and into the 90s. It has been sitting on a shelf collecting dust for roughly 30 years now. I'd hook it up to see if it still works if it wasn't so heavy! :)

[@steveearnshaw5426]

Had a Phase Linear 400 driving Maggie Tympani 1 U’s back in 1975. Just couldn’t justify Audio Research. Sounded great in my dorm room! Y

[@MarvinHartmann452]

My choices would be these: 1 : Mc 275 2 : citation 12 3 : marantz 140 4 : marantz 500 5 : marantz 240 For the simplicity of the circuits, sometimes, less is more, and I like the semi push pull amplifier. They have a distinct sound. Besides the output transformer, the citation 12 and the Mc250 are very similar, I think they were inspired by the RCA 70 watt semi pp design that came out around 1968 or 1969.

[@qb101]

I just picked up a new amp. I was considering a Spec 4, a 700B, and finally landed on a pretty rare Soundcraftsmen MA-5002. I'm reconditioning it now, but it's a pretty fantastic unit. Highly recommend checking it out if you have an opportunity.

[@mysterybryan358]

In 78 I had a mr77 Macintosh receiver and a m a 2300 amp and it still works fine

[@Notawhitchhunt]

When did Bryston amps come out, I heard a system in the Eighties based on a Bryston amp at 300 watts per channel that sounded quite excellent

[@mrz80]

Mr. Mc ran a pair of 2105s into ML4Ms in his home system in New York. After he sold the company and moved to Arizona he went with a pair of 2205s into a paralleled combo of the ML4m and XR7 speakers. He loved showing it off to company, usually resulting in a hollereed "FRANK! TURN THAT THING DOWN!" from the other end of the house. 😀

[@chrissmith7669]

I have the DBX BX-3 mkII. It’s been a beast for me the last 40 years

[@ronheetman564]

I have got a Proton D1200 power amp, also from the 80’ It got DPD, that means dynamic power on demand. It can go up to 1000W for a very brief time. Proton was a precursor from NAD. Do you guys know this one. I run it with the Proton P1100 pre-amp.

[@AUTISTICLYCAN]

Sir first thank you for answering my question during your live stream. I was BLOWN AWAY! Another question. I love that McIntosh 2105 Amplifier. I have 9 quality receivers what do you love about that McIntosh 2015 that makes experiencing it "better, worth it or unique?" Is there something about the "separate amp, pre-amp, tuner and EQ" vintage audio experience that is transcending, special or a must hear unique experience. To simplify what am I missing by not having a McIntosh 2105 and its accessories in my collection. You've been so kind I will be going to the bank so I can make a one time donation to your channel. I like that you are a honest straight shooter, a swell egg & this werewolf's idea of a cool human! CHEERS!

[@ethimself5064]

Curious - What is a speaker protection relay? Same as a thermal relay? Old school here

[@andydelle4509]

Two functions: 1) If any transistor shorts in a DC coupled amplifier you can have either the full B+ or B- power rail go to the speaker terminals. This will destroy just about any woofer ever made. Fuses are not good enough as they are too slow. Sometimes even a speaker protection relays are not good enough but better then none at all. 2) Many amps produce turn-on and turn-off thumps. The speaker relay is typically delayed turn-on and instantaneous turn-off to prevent speaker damage.

[@ethimself5064]

@@andydelle4509 Like a thermal relay in general? And a delay system?

[@andydelle4509]

@@ethimself5064 What do you mean by a "thermal relay"?

[@ethimself5064]

@@andydelle4509 Typical audio and electric kitchen equipment etc have built in thermal relays that when something gets hot enough it will trip a circuit to break the connection until things cool down enough the connect again.

[@andydelle4509]

@elf5064 OK, now I know what you mean. Some manufactures, Hafler for example, did use these devices to monitor the heat sink temperature. If too hot they opened killing the AC line to the power transformer. But the speaker protection relay is different for a different function.

[@jeffadams5510]

Nice video! Little surprised the sansui ba series, ampzilla, and bose 1800 amps weren't mentioned though. All of these mentions were from the 70's.....right?

[@Sunnbobb]

phase linear speaker protection relay is made by Watts Abundant

[@MarcoC72186]

Have a pioneer spec 1/spec 4 on my bench atm.

[@ForeverAnalog]

That Harman Kardon amp is WILD!

[@LakeNipissing]

Yes. Remarkable to have 10 output transistors / channel for 150 Watts, when Pioneer and Hitachi had 4 output transistors / channel with more than 200 Watts output. HK is either extremely over engineered, or extremely underrated.

[@30DirtyThirty30]

I'd say they are very conservative with the 150 W rating.

[@jackhastings9800]

Great video. Usually you don't want to biamp with different amps.

[@TheSaj6780]

Great info! Thanks for the Video!

[@msshmv24]

If your receiver doesn't have pre-amp outs you can also use aftermarket speaker level to line level adapters.

[@fredflyingv3863]

I live in France, and I like your vids ! 👍

[@alm5693]

My second (and sentimental favorite) stereo was a Harman Kardon 930 that had JBL L-100s attached to it. I'd also picked up a HK Citation 12 amp and a pair of JBL L-77s (Lancers?) used. What I was doing for a while was running the L100s with the 60w/ch Citation and the L77s with the Y-cable thing back into the 930. I thought it sounded killer, but I was kind of a headbanger back then. I sold the Citation and the L77s to help come up with a down payment on my first brand new car -a 1978 Toyota Corolla wagon that cost about $3,700. When the guy came over to listen to the L77s, I used the Citation for power and cranked up Toys In The Attic by Aerosmith. I sold them instantly.