These are incredible amplifiers. Insanely low distortion, bags of current and conservatively rated output, lovely design and well built. Some of the best amps of the '80s and thoroughly underrated.
JVC and their Super A amps allowed for super low THD, in the area of 0.005% . SEA was an acronym for Special Effects Amplifier which was a multiband graphic equalizer for Left and Right channels. JVC always used novel engineering to solve various audio problems. I have a JVC DD-7 cassette deck that has been refurbished and I love it. All of their stuff suffered from scratches due to stacking components which led to insufficient cooling problems and thermal damage.
Nice find, nice work. I was impressed with square wave response, too. The marketing guys definitely hand their fun - their engineers didn't compromise either. 👏
Great find! Very rare! The SuperA series from JVC/Victor of this era are very good. Especially the AX-7 and AX-9. Very "audiophile" sounding even by today's standards! When some pop up for sale, they go for WAYYY more than the 25$ you paid for! I have an AX-7. I've compared it to many many other amplifiers (vintage and new and at very different prices) and its a keeper! I have a few JVC amps. All i can say is that they made some really good stuff throughout the years. It's just sad that most people when they see a vintage JVC stuff marketplace, most of the time, they ignore it. JVC (just like Hitachi) don't have the "hype factor" of other brands like Kenwood, Pioneer, Sansui, Marantz ... even though they made some pretty serious hi end stuff!
JVC moved into home theater add on systems using cheap components and cheap construction techniques which ruined their reputation. Cutting corners and costs to maximise profit in the short term meant they went from being well respected to being known as a cheap brand which nobody trusted. There are still some people who remember how good the old JVC products were but most people only know their later products which were poor quality.
@@ianc4901 Yep, like many other brands like Sansui, Fisher, Toshiba... Through the 80's and 90'S they started making low quality and cheap audio components. It's a good thing some of us had the chance to have/hear the great stuff that those brands made back then! ;)
"Dynamic Super-A is JVC's exclusive technology which combines the silky, distortion-free sound of a class-A amplifier and the robust efficiency of a class-B amplfier."
SEA was, I think, a JVC thing. Basically, a JVC limited graphic equaliser could be connected, as was included on some amplifiers and receivers they made back in the day. I have a JVC JRS-201 receiver with an SEA built in, the letters stood for 'Sound Effects Amplifier', not really a full graphic equaliser, but it gave you a useful tone control set up.
I rebuilt an A-X5 and it’s been my daily driver. Great amp….mine has a fully functional bottom flap. Don’t see too many 7’s and a 9 would be top of this line.
Hey Trevor, good to see you. I did a rebuild on an A-X5 and was really impressed with the results. Punchy and clear as a bell. Every one I’ve seen was missing the door.
Normally an amp with super a or similar means that’s it’s a class a/b amp that can run in class a up to a certain power output, usually 5w or so. This maybe different, but I doubt it. S.E.A. Is JVCs version of a graphic equaliser. JVC made some lovely amps during the 80’s then they turned into junk by the mid 90s like most HiFi brands of the 70s.
When you first opened the lid, I thought the heatsink looked a little small for 100 watts per channel. I bet it would get very hot into 4 ohms. Still, probably fine with music. Quite a voltage drop from the power supply on load. Not what I would expect from a toroid. Bigger caps might help a little. Overall, quite a good performer for a medium-priced amplifier. Even better for $25.
Courage Trevor, this is the era that scares me to Death. Tape 2 on the front, never ever seen that configuration. JVC Service Caps..........1980 Built. Never seen that relay. Actually surprised how few the issues were. Keep in mind us American are in Fahrenheit mode.
I still use the smaller A-X5 that i got for cheap over a decade ago. I also had to replace the lytics in the phono and poweramp- input board because they got backed over time. Other than that just cleaning the pots and switches. And so far it works fine. BTW: There is no IC for the Super-A circuit in the X5. Its build discretly instead. And the output stages are smaller models of the Fujitsu RET`s in the X7,hence just 70 W/8Ohm per channel. The transformer in the X5 is a "normal" one instead of the encapsulated torodial. Other than that both amps appear to be very similar. And yeah,i had the luck to get one with the frontflap intact. Anyway,these integrated amps are still top class and were engineered with the old hifi ideals in mind. The concept: phonopre passive pre with passive tonecontrols,filters and loudness,poweramps in true DC (well the fat foilcaps after the phono out are the only coupling caps in the entire amp). Its classic high quality of the audio JFet era of the late seventies: meaning JFets in the inputstages and ultrafast BJT`s as output powerstages - and realy high quality phonostages for both MM and MC. What is lacking somewhat is build quality imho. And by that i dont mean the electronic parts used,but how the amp is internaly structured. But i guess even back then the budget had its limits,although this amps werent cheap back then.
Yea, I do remember that amp. As a boy I would like to have it if I would have had the money for. 😢 So my first amp was the Technics SU-8022k with ST-8011k tuner, still with me. I as well remember that JVC offered a very interesting tape deck that time I had seen in a shop.
I wonder why they chose such a strange way to power and control the lamp ? They must have been either trying to prevent them flickering with power fluctuations or trying to prevent interference in the amp but I've never seen anything like it ! I was half expecting to see a few more modifications to this one to try to deal with some of the heat issues it has.
Hi Trevor, just a thought that you might try a piece of vcr or audio tape deck head cleaner, I was wondering if it would work better than paper to clean the contacts in old relays
Hi Trevor, When you are replacing caps, I noticed on Digikey that there are many choices for brands and series types of capacitors with prices that can range for 0.08 to 0.52 cents. Do you have any recommendations or would like to comment on which caps you purchase for audio repairs. I just opened up my HK 590i after 40 years and see many leaking caps. Thanks.
The volume goes to 11 (120 decibels) when playing "Rush " only in Canada EH ! Why would you connect the speakers to the unit if you don't know if their is DC on the ouput NOT GOOD Yet another changes all the capacitor video
@@Reflectiveness training for what ? Are you going to apply for a job and say your qualification are you watch Trevor's videos because you know have electronics experience
