Harmon Kardon 330B Receiver question

[Squishman]

My first ever component system had a Harmon Kardon 330B. It was 1976 or 77. I was 16 years old. It was a system sold by a local small electronics chain called Schaak Electronics. It had the receiver (20 wpc), large 3-way speakers called Omega 3's with 12 inch woofers and a lower-end Technics turntable. It was a very loud and clear system. I recall like yesterday the first time I played Steely Dan's Katy Lied LP, when Black Friday tails off, there is a high-hat that is hit multiple times in rapid fashion. I was so shocked, not accustomed to a nice-sounding system that I looked around the room quickly to see what it was! I thought something was in the room, until a second later I when realized it was the LP! I still recall that every time I play the LP to this day. I do not recall what I did with the receiver, but because of nostalgic purposes, if I find a nice enough one at a good price, I will buy it. Don't need it. ha.
But I was watching this video and the guy (about the 10:30 mark on the video) said the 330B is a capacitor coupled amp and the 330C is a direct coupled amp. I have no clue what that means, but he said some people claim a cap coupled amp sounds better than a direct coupled amp. The former sounds tube-like to some people he said. He didn't make the claim as his own opinion.
But that is interesting to me that this little receiver may have been the cat's a$$ and might rival some known great ones. My question is: what do you make of this? Hogwash? I had the opinion that as far as vintage amps, the best sounding ones would be Sansui, Marantz and Pioneer. Should this particular Harmon Kardon make that list?
btw, this little amp has pre-outs! Not bad for sort of an entry-level amp.
Photos below are the 330B
Here is the video:

 

[TLS Guy]

My first ever component system had a Harmon Kardon 330B. It was 1976 or 77. I was 16 years old. It was a system sold by a local small electronics chain called Schaak Electronics. It had the receiver (20 wpc), large 3-way speakers called Omega 3's with 12 inch woofers and a lower-end Technics turntable. It was a very loud and clear system. I recall like yesterday the first time I played Steely Dan's Katy Lied LP, when Black Friday tails off, there is a high-hat that is hit multiple times in rapid fashion. I was so shocked, not accustomed to a nice-sounding system that I looked around the room quickly to see what it was! I thought something was in the room, until a second later I when realized it was the LP! I still recall that every time I play the LP to this day. I do not recall what I did with the receiver, but because of nostalgic purposes, if I find a nice enough one at a good price, I will buy it. Don't need it. ha.
But I was watching this video and the guy (about the 10:30 mark on the video) said the 330B is a capacitor coupled amp and the 330C is a direct coupled amp. I have no clue what that means, but he said some people claim a cap coupled amp sounds better than a direct coupled amp. The former sounds tube-like to some people he said. He didn't make the claim as his own opinion.
But that is interesting to me that this little receiver may have been the cat's a$$ and might rival some known great ones. My question is: what do you make of this? Hogwash? I had the opinion that as far as vintage amps, the best sounding ones would be Sansui, Marantz and Pioneer. Should this particular Harmon Kardon make that list?
btw, this little amp has pre-outs! Not bad for sort of an entry-level amp.
Photos below are the 330B
Here is the video:

A capacitor coupled amp is from the early days, where there was a cap at the output between the output transistors and the speakers. This was to prevent DC off set from getting to the speakers. The problem was that this capacitor limited deep bass and caused a phase advance at the deepest frequencies.

Around 1967 Crown introduced a direct coupled amp, the DC 300 and then 300A.

The problem was that if DC offset developed, which occurred if an output transistor failed then the whole rail voltage appeared at the speakers and they went up in smoke.

I had a Crown DC 300A do this within the first week and take out a line of eight midrange drivers on opening night of a commercial installation.

Eventually protection circuits were developed that protected the speakers. The first were clamp circuits at the output, that shorted the output transistors and totally sacrificed the amp, rather than the speakers.

Over time more sophisticated protection circuits were developed which shut the amp down without damaging the amp catastrophically.

The is why receivers go into protection if a power transistor fails in any channel.

It is nonsense that a cap coupled amp sounds better.

 

[Squishman]

A capacitor coupled amp is from the early days, where there was a cap at the output between the output transistors and the speakers. This was to prevent DC off set from getting to the speakers. The problem was that this capacitor limited deep bass and caused a phase advance at the deepest frequencies.

Around 1967 Crown introduced a direct coupled amp, the DC 300 and then 300A.

The problem was that if DC offset developed, which occurred if an output transistor failed then the whole rail voltage appeared at the speakers and they went up in smoke.

I had a Crown DC 300A do this within the first week and take out a line of eight midrange drivers on opening night of a commercial installation.

Eventually protection circuits were developed that protected the speakers. The first were clamp circuits at the output, that shorted the output transistors and totally sacrificed the amp, rather than the speakers.

Over time more sophisticated protection circuits were developed which shut the amp down without damaging the amp catastrophically.

The is why receivers go into protection if a power transistor fails in any channel.

It is nonsense that a cap coupled amp sounds better.

Thanks for explaining that.

 

[Squishman]

A capacitor coupled amp is from the early days, where there was a cap at the output between the output transistors and the speakers. This was to prevent DC off set from getting to the speakers. The problem was that this capacitor limited deep bass and caused a phase advance at the deepest frequencies.

Around 1967 Crown introduced a direct coupled amp, the DC 300 and then 300A.

The problem was that if DC offset developed, which occurred if an output transistor failed then the whole rail voltage appeared at the speakers and they went up in smoke.

I had a Crown DC 300A do this within the first week and take out a line of eight midrange drivers on opening night of a commercial installation.

Eventually protection circuits were developed that protected the speakers. The first were clamp circuits at the output, that shorted the output transistors and totally sacrificed the amp, rather than the speakers.

Over time more sophisticated protection circuits were developed which shut the amp down without damaging the amp catastrophically.

The is why receivers go into protection if a power transistor fails in any channel.

It is nonsense that a cap coupled amp sounds better.

Curious, which style is my Marantz 1060?

 

[Squishman]

I did some googling after work to check on this. Seems the 1060 is indeed a capacitor coupled amplifier. But that means it has a warmer sound apparently than a direct coupled amplifier. The 1060 sounds amazing in the room I have it hooked up in. Jaw-droppingly amazing for what is hooked up to it. Using a pair of my souped up Minimus 7's with M&K tweeters and bona-fide 2 way xovers. Plus a 10" floor-firing Klipsch subwoofer.

Vintage icon: Marantz 1060… vs. Marantz 1120 | Audio-room

audio-room.net

 

[Squishman]

Should probably have said "according this article" rather than "apparently".

 

[Squishman]

There is a very rough one on ebay. It says its untested but it powers on. https://www.ebay.com/itm/286091142633?_skw=harman+kardon+330b&epid=1524995207&itmmeta=01J9M3BWT7XX873TDGQMJQ6373&hash=item429c5c65e9:g:o6kAAOSwCT9m~zbp&itmprp=enc:AQAJAAAA0HoV3kP08IDx+KZ9MfhVJKnns7pl3Ax5+QvOXScCyCdUEoast8vKAM4RyXuk8V7Z5QE8cHKmsEBGYHrSfSc4Sc2yh8RHa5/fca3vm0icMMfrCnE8fC6jaRbc1LmSQMJAmg9WuVBiJI3jko/BB4qg8zMkyIDJxumymRxGaEMU6vU/vdEqRax5Vtdxvg9qpfVxR11W17KgG/mW9aIu2+sMIfFT4V6Rfx+tsUFEi6W0lVnoyaNXdQG/Q49Fb3uydetoZwPC/Af0bfp7CQ0r+oU5ul8=|tkp:Bk9SR6jNr4PNZA Cheap shipping. If it doesn't get much higher, I might toss in a bid at the last 5 seconds. Maybe it does work. I could paint the cover unless it just needs a good cleaning.
What do you think? Wish I could see more why the cover is crooked.

 

[Squishman]

Definetly going to pass on that unit. The cover has been off probably means it doesn't work.

 

[highfigh]

Definetly going to pass on that unit. The cover has been off probably means it doesn't work.

Having worked at a stereo store that serviced equipment, I would pass on any of the H-K 330 models. The reason they had a 330A, B and C is because they blew up frequently and when they did, the damage was extensive. Sansui is another brand that had severe damage when the amplifiers failed- it started in the stage before the outputs and then the damage spread. The Sansui R series receivers were the worst. H-K and Sansui advertised that their receivers sounded better because they were 'Direct coupled', but failed very frequently.

 

[Squishman]

Having worked at a stereo store that serviced equipment, I would pass on any of the H-K 330 models. The reason they had a 330A, B and C is because they blew up frequently and when they did, the damage was extensive. Sansui is another brand that had severe damage when the amplifiers failed- it started in the stage before the outputs and then the damage spread. The Sansui R series receivers were the worst. H-K and Sansui advertised that their receivers sounded better because they were 'Direct coupled', but failed very frequently.

Wow. Good to know. I won't look for one then. Thx!

 

[highfigh]

A capacitor coupled amp is from the early days, where there was a cap at the output between the output transistors and the speakers. This was to prevent DC off set from getting to the speakers. The problem was that this capacitor limited deep bass and caused a phase advance at the deepest frequencies.

Around 1967 Crown introduced a direct coupled amp, the DC 300 and then 300A.

The problem was that if DC offset developed, which occurred if an output transistor failed then the whole rail voltage appeared at the speakers and they went up in smoke.

I had a Crown DC 300A do this within the first week and take out a line of eight midrange drivers on opening night of a commercial installation.

Eventually protection circuits were developed that protected the speakers. The first were clamp circuits at the output, that shorted the output transistors and totally sacrificed the amp, rather than the speakers.

Over time more sophisticated protection circuits were developed which shut the amp down without damaging the amp catastrophically.

The is why receivers go into protection if a power transistor fails in any channel.

It is nonsense that a cap coupled amp sounds better.

I don't remember hearing that capacitor coupled amps sound better but we saw a lot of H-K and Sansui come in for service. Pre-drivers, drivers, emitter resistors and output transistors- Poof! Our fix for the Sansui R series was to decrease the bias that was already too high and use better emitter resistors- they didn't come back.

 

[highfigh]

Definetly going to pass on that unit. The cover has been off probably means it doesn't work.

In theory, the fact that the cover was removed could mean the controls and switches needed to be cleaned and after this long, that's a certainty. Whether the amplifier has been repaired is unknown, regardless of the info about reliability issues.