JVC QL-?? owners thread

[Snuck]

Did you check this post?

JVC QL-A2 Resto:Auto-Return and 33 RPM Speed Fix

Posting this primarily in case someone has similar issues and needs a reference. :) I picked this up on eBay cheap as I was curious how it sounded and I liked the look. It was listed as for parts, but arrived in pretty great condition aside from the dust cover, which is heavily scratched. It...

audiokarma.org

Replacing the foam shouldn't make you damage anything. Even me who does like you or because of health issues, can drop parts randomly (which can end expensive).

About Victor, I don't know where else to ask it : I keep reading about hifi in Japan at this time and getting document (have a 891 page document from Japanese Audio Society book to read) and will try to gather more documents to write a book about this time and this company.

I also intend to make revive some of their highest amps, in a modernized diy manner, reworking some circuits. I had the authorization of a former employee of Victor of the time who is apparently in touch with others leaders of the brand. He participated in the writing of a book whose main writer was the lead designer of most the amps we know, if not all, from Victor. Would it please some people here? I can't say which models yet may go first but I thought to a replica model and an alternative circuit without nfb for some models, ie low watts only.

 

[finisvox]

Did you check this post?

JVC QL-A2 Resto:Auto-Return and 33 RPM Speed Fix

Posting this primarily in case someone has similar issues and needs a reference. :) I picked this up on eBay cheap as I was curious how it sounded and I liked the look. It was listed as for parts, but arrived in pretty great condition aside from the dust cover, which is heavily scratched. It...

audiokarma.org

Replacing the foam shouldn't make you damage anything. Even me who does like you or because of health issues, can drop parts randomly (which can end expensive).

About Victor, I don't know where else to ask it : I keep reading about hifi in Japan at this time and getting document (have a 891 page document from Japanese Audio Society book to read) and will try to gather more documents to write a book about this time and this company.

I also intend to make revive some of their highest amps, in a modernized diy manner, reworking some circuits. I had the authorization of a former employee of Victor of the time who is apparently in touch with others leaders of the brand. He participated in the writing of a book whose main writer was the lead designer of most the amps we know, if not all, from Victor. Would it please some people here? I can't say which models yet may go first but I thought to a replica model and an alternative circuit without nfb for some models, ie low watts only.

Hi Snuck,
I'm trying to repair a Victor QL-A95 TT, but I can not found its schematics.
do you think that it would be possible to get the schematics for the Victor QL-A95 turntable with your Japanese friends?

 

[Snuck]

I can try to but actually schematics are often kept preciously by specialist repairers only.

Most of the schematics are hard to find for hobbyist who repairs their own gear, they actually use our websites to find them.

I'll try to ask but I am not sure it'll work : for reasons I fail to understand, there is no exchanges on service manuals nor blueprints which makes a lot of valuable knowledge lost even to them, while some others might need hard digging and doesn't always prove to be accurate.

I asked to many people long time ago for a special schematic and had polite yet firm refusal. To speak about crafting, technology, audio and such is one thing, but blueprints or research was a strong nay.

I hope you can repair it, I like the design of the turntable but it's usually a special IC which end up failing. I'll ask.

 

[finisvox]

ok, I understand. Anyway, I hope to have some luck when you ask to them. Thank you.

 

[best-groove]

I can try to but actually schematics are often kept preciously by specialist repairers only.

It is absurd and surprising that it is possible to find a Victor service manual and schematics diagrams for TT 81-71 etc. etc. but not for the top models TT801 or QL-A95.
The same as Pioneer or other brands; for example for the PL70II turntable you can find the s.m. instead for the PL 70 you can not find anything at all as if the manufacturer had never released it but this seems impossible to believe.
The manufacturer but also many others almost always included at least schematic diagram in the package in addition to the user manual.

The fact that some old repairman does not want to share service manuals or schematic diagrams for products that are 40 years old or more in 2024 is very sad, hardly an owner who has problems will send his broken component to another continent to a repairer capable of fixing his electronics because he has the knowledge and repair manuals with expenses that are anti-economic.
Amp 8 repair Japanese repairman who repairs everything can never hope that a European or American owner will send his broken part worth $ 500 10000 km away to have it repaired with costs between travel, repair and customs fees too inconvenient.

 

[finisvox]

Yes but, if well I'm not trying to defend to JVC, there is true that much of the top line models, as my QL-A95, in its time was only available for the internal Japanese market and not for the whole world. The Japanese have its own “way to be” and they send their failed stuff directly to the formal repair center.
We, nowadays, are trying to repair some stuff that are obsolete and that not have technical information available. I have purchased my QL-A95 in Germany (Munich) in 2017 and the thing have done a long, long way from Japan to Germany (through Russia...). Then I have take it and ported it to my house in North Italy, by car (a very, very beautiful trip). After some years, I shipped it to Chile, where I living now.
Ok, but why I'm relating this history? Simple: the thing is extremely good. Dot. EVEN without the TS-1 disc stabilizer (the vacuum pump). So, my QL-A95 MUST be repaired.
And yes, I have also the disc stabilizer TS-1, purchased some months after, in Hong-Kong. But this is another history...
br.

 

[best-groove]

And yes, I have also the disc stabilizer TS-1

I also own the TS 1 pump bought a few years after purchasing the TT801.
I checked full and sigilled well it just to be sure because it wasn't sucking hard but it does not have great suction and vacuum power like the Audio Technica AT666 disc stabilizer; in fact, with my mouth I have more suction power than the TS1 and yet the TS1 that I overhauled does not have any air leaks around inside.

 

[Snuck]

The main probable reason why they didn't share and don't share the manuals are simple : copyrights and patents. Victor spent an awful lot of money designing, researching and then developing it. To protect that, they made a lot of patents, an awful lot.

That's the same for most of the japanese companies, they couldn't really give away precious schematics and explanations to the west, risking to give away everything. Look at the jp-v1000 : beautiful item, sold in the west, no repair manual available. Only one person have it in the west world and didn't share it though he shared a huge lot of stuff which was much welcome. Sometimes, exclusivity keeps people from sharing as well.

The TS-1 is designed not to suck hard and that's normal actually, it's perfectly welcome. In one of their technical researches, Victor looked out for the way to perfectly playback the record : all simulations including computer simulations led to one result only. The lp record have to remain quite free on the platter in order to remain its original signature and energy, it have to be flying gently like an ufo. The draw was quite funny if I can find it back. More suction might sit tighter the record, yes but apparently for them, sound would have been altered despite some prefer it while others don't.

That was a major critic of the time of release but Victor stood by their researched and explained them though it's not really famous at all. Amp8 can't really free the manuals like that : he would be allowing companies to catch back freely decades of researches right away while some companies started producing again high-end turntables using those technologies. Even they low to mid end service manual can't be find in Japan. All manuals came from the west.

Regarding the QL-A95, I wouldn't be surprised if the IC were similars to those of the TT-101 which can be repurchased new by a tech who made reproductions for Victor and Technics turntables. I am not sure they are the same though. Also, a skilled tech should look for their solders cracks too the size of an hair as the board reacts, weirdly, to temperature change and doesn't like extreme climates.

 

[finisvox]

Ok, I think we all know that stuff, about patents and such. But also, the massive industrial espionage carried out by Japanese industry towards the West, especially the United States and Europe, was gigantic, especially from the 1950s (of the last century) until now.
Anyway, I know that patents are NOT for eternity. They have a defined duration, normally 20 years. Please, if somebody (a lawyer?) here could elaborate on this.
In any case, making a reproduction of a very good machine like the QL-A95 is perfectly possible. The final product could result expensive, but it would still be reasonable. The problem is that today, the goal of the businessman is no longer to become a millionaire in a week, but to become master of the universe in one day. And making high-end turntables, is definitely NOT the way to go for that purpose.
But now, getting to the point, that is the Victor QL-A95, having no schematics nor other technical information, I think that the way is to make a complete analysis, from A to Z. Once understanding how it works, there is no problem for a seasoned technician to reproduce it, as I have done years ago, with other devices, in the industrial domain, usually. The only part that I would be left for others, would be the tonearm, a piece that today it is possible to find in any desired price range.
So, I have decided to begin to making my own schematics for the QL-A95 and taking many measures and waveforms from the crucial points of the device. This, as a first thing. Then, a complete technical analysis.
I have seen that the “worst” point of the project, is the presence of a custom JVC chip; the famous VC4046. Please, do not confuse it with the CMOS PLL 4046. The VC4046 is far more than a PLL, if well it includes the main parts of a PLL. Fortunately, that chips was used in many, many turntables models and even from different brands, like Kenwood, Micro Seiki, etc. So, the chip block diagram is in the available service manuals of lesser turntable models.
The rest of the semiconductors of the QL-A95, are only classical transistors, diodes and common Ics, normally digital CMOS and some analog chip, as the 17741, that is no more than a good 741. Yes, the very old 741.
Today, all that can be done with a FPGA or CPLD plus some power stage and, wanting, adding some microcontroller for to do the show, as a beautiful screen or so.
Please, wish me health.

Now, let me go to work.

(Ah !!!, Snuck, thank you, anyway)

 

[finisvox]

Yeah !!
my QL-A95 was repaired !! It have taken only three weeks. But three weeks of very hard and methodical work.
Today, the turntable is running flawless for four days.
Greetings

 

[r_deming]

QL-A2 here.
Sold an outstanding QL5 last year and still regret it. Solid deck and the brake on it was cool. Maybe a little overkill for home use but a nice touch either way.

 

[best-groove]

my QL-A95 was repaired !! It have taken only three weeks. But three weeks of very hard and methodical work.

What problems did it have and what was replaced?

 

[finisvox]

What problems did it have and what was replaced?

The Power & Logic board, have two voltage regulators. One is for 24 Vcc, for to power the motor and the other, is an 8 Vcc small regulator, for the CMOS logic ICs on the board. That small regulator, is a TO-92 encapsulated 78L08 IC. After days of observation with the oscilloscope (in its “normal” trigger mode) I have seen that there was a small variation at the 78L08 output. This Vcc, powers all the logic circuits that are CMOS type. That small variation in the Vcc of the logic, triggered the “stop” flip-flop, randomly.
Then, I have replaced the 78L08 and the problem was solved definitively.

By the way, I would like to say that, if well I have also changed ALL the electrolytic caps, AFTER to do the repair, I have measured every of the old capacitor, without finding even one out its nominal capacity. In any case, only changing all the electrolytics, would not solve the problem.

outstanding QL5

Another NICE turntable from JVC...

 

[best-groove]

By the way, I would like to say that, if well I have also changed ALL the electrolytic caps, AFTER to do the repair, I have measured every of the old capacitor, without finding even one out its nominal capacity. In any case,

Sure, I found many out of tolerance on different Jvc TT series, they have to be changed "by default" for the negligible cost to face.
Are you using the original mat with the air holes together with the external vacuum pump on the A95?

 

[gibber]

So far I've only tried one combination of proxy and international shipping service and got good results : proxy called ''FromJapan'' and for international shipping I chose DHL. So far so good for me, I ordered a couple fragile electronic gadgets and one TT using this combo. All arrived as advertised. Maybe I'm lucky.

FromJapan didn't want to remove the platter and put it at the bottom of the box or separate box like I asked, actually they said they wouldn't take any suggestion and would pack it according to their standard (which when you think about it, could save them trouble from buyers who don't know their stuff and ask for poor packing methods, and item getting damaged because of that). They did something else and it actually wasn't too bad (could have been way worse) : they secured the platter down with several, tightly put large strips of medical tape, which grips extremely hard yet leaves no residu nor damage on the plinth. Same for securing the arm, in addition to creating an envelope of bubblewrap around it. Then they stuffed some bubblewarap around the arm and platter to make a filled ''cube''-like shape out of the TT and then they wrapped that HEAVILY in bubblewrap again, then put some stiff white styrofoam blocks around all corners(or was it sides?) and put that inside a box and then again in another box. almost overkill packaging. Honestly : the box could have been upside down for a portion of the trip, that it wouldn't have mattered.

DHL didn't wreck it, it arrived as seen in the add. The tonearm hadn't moved an iota and neither did the platter. no nicks to the plinth, nothing.

Now will ALL my futur purchases arrive in perfect condition? That I do not know. But so far I had great service.

The bubble-wrap around the tonearm is a huge drawback when carts are still mounted. I imported quite some TT from Japan and more than half of carts had cantilevers severely bent or broken off. Not sure what the wrap should protect against anyway. Fixing the arm into position and removing platter and putting it bubble-wrapped under the plinth in same box is best. Fixing platter with tape will not work If parcel is transported sideways or upside down. If platter gets loose during transport, the damage is so complete (plinth, lid, controls, tonearm, cart if any) that it will allow to claim back purchase price. Which leaves you with shipping cost, import duty, and handling fees for the importer.

 

[ftbase]

Hello,

Anyone had tonearm drifting left for JVC/Victor QL-Y5 or QL-Y7? How to fix or adjust?

Antiskating knob has no effect on the drift.

Thank you.

 

[finisvox]

I checked full and sigilled well it just to be sure because it wasn't sucking hard but it does not have great suction and vacuum power like the Audio Technica AT666 disc stabilizer; in fact, with my mouth I have more suction power than the TS1 and yet the TS1 that I overhauled does not have any air leaks around inside.

Hi !
Sorry for the late answer, but I was very busy all this last times. After removing many boxes in my cellar, and having found my Victor TS-1 pump, I have done a small video with the most important facts about that stabilizer.
First, the suction force **is** low, but enough for to do its job. You must have present that this system is NOT for to flatten bent discs. It is for to firmly have attached flat discs to the mat-platter assembly. Not more. It is not a ”Discs Flattener”
Second, as shown in the video, the lateral holes of the main shaft, MUST coincide with the openings of the platter.
Third, you must use the original mat, because it have several holes and air guides under the mat, for to make the suction job.
Fourth. The RCA connector of the pump, must be connected to the turntable, and, obviously, the suction hose. The RCA connector, makes to Star/stop the pump from the turntable console, and on the display, you will see the “TS” letters, as shown.

By the way, the TT-801, uses the same pump, the same hose, and the same RCA control as these for the QL-A95, shown in the video. Even more, the uses also the same motor. The electronics controllers are different, being those for the QL-A95 a newer version. I have had several machines of both model (between many others), and finally, I have left for me the QL-A95.
(NOTE: this thing haves not permitted to me to upload the video... I don't know how to do it. It is a 23.211 KB file, mp4 type)

 

[best-groove]

(NOTE: this thing haves not permitted to me to upload the video... I don't know how to do it. It is a 23.211 KB file, mp4 type)

Hi and thank you very for the info.
I uploaded the video to my YouTube channel and then posted the link on the post I wrote above.
I don't know if you have your own YouTube channel, if you do you can upload your video and post the link like I did; vice versa you can do a simple test similar to the video I posted with a piece of paper as a demonstration of suction yourself and then compare it with my video in order to understand if the suction of your pump is similar or equal to mine or if my TS1 unit has a tired suction and explain in a post if there are differences.

 

[KevinB]

Hope you don’t mind me sharing, I have been a fan of Victor Tables for a long time. I spent a long time gathering the parts for my TT-801 setup and it is finally “done”. Fair amount of work refinishing the plinth and the rebuilding the drive but it was worth it.

I have acquired a number of these tables because they are just awesome sounding decks.

Thanks for letting me share.

 

[best-groove]

@KevinB If it's not too much of a hassle, can you check by simulating the video I posted if your pump sucks as little as mine?