JVC m90 vs Victor m90

[aiwapanasonic]

I know a similar question has been discussed before; but it is not exactly the same, so I am opening a new thread.

I recently imported a Victor m90 from Japan. It was restored by a person who also happens to have the JVC m90 (European version). While we couldn't test them side by side on Aux In (European version has the Din in), we tested on tape, and the Victor sounds something like one notch less powered at the same volume setting. I mean, it is still awesome, but the JVC by comparison is jaw-dropping. This is a side-by-side comparison.

The Victor was powered through a step-down converter from 240V to 100V. We thought this might be due to the different power supply, but then we swapped the backs which contains the power supply and again the sound was similar as the first test.

Now I have seen a thread here about the Canadian vs US version of JVC m90 (or was it the 70W vs 61W)... The Victor is rated 28W by comparison, so not sure where that puts it. The speakers inside are labeled 20W while the 70W machines have 25W written on the speakers; but then I've read here again that there is no difference between 25W vs 20W speakers as they weigh the same.

When it comes to " music power" , the JVC (70w on the back) has the original sticker of 40W music power sticker and the Victor (28W on the back) comes with a 30W sticker on the front. The Victor was also advertised as a 30W machine in the original catalogue in Japan.

So I'm wondering if anyone knows here whether the Victor is indeed different - slightly lower powered, and why this might be. I know that some of the top models were kept for the Japanese domestic market - for example, you can only find the Toshiba RT S90, the Panasonic RX DT9 and the Aiwa CSD SR8 in Japan. Even JVC's top deck 931 was released only in Japan. I can't imagine the Japanese would have a lower quality version the domestic market. But the sound test on tape was clear - there were three people in the room, and later a recording done on an iphone, and definitely the JVC sounds slightly louder, at the same volume setting, probably about 10% louder or more definitive - it just hijacks your mind; while the Victor sounds a tiny bit softer and magical. The Victor is in a really good condition and well cleaned up inside, so I don't think it's down to the individual unit.

The tape was an original Japanese studio recording that came stuck inside the Victor.

So I'm wondering now, because I have read on this forum that the 61W and the 70W versions sound the same and the parts are interchangeable, whether someone has heard the Japanese and the US version side by side and if they are also considered identical.

ps. the only difference inside other than the transformers being different for the different volts was that the Victor has a metal shield around the transformer, as if to protect the rest of the electrical components from electrical/magnetic interference.

 

[floyd]

The 100 volt jdm Victor model is probably less powerful in the output because it's 100 volt rating. It takes power to make power and with less going in there's probably less power coming out.

 

[Hisrudeness]

As are as I am aware the speakers and amp chips are,the same on all versions are the same.
Testing them 40 years later makes no sense since wear and tear over subsequent years is different for each unit.
A fairer test would of been back in 1982/83 doing test side by side no?

 

[Reli]

If I were JVC, I would not allow one country's M90 to be noticeably stronger than another's. I would configure each version's power supply in such a way that it delivers roughly the same DC voltage to the rail, no matter if it's a 100V box, a 120V box, a 220V box, or 240V box.

If there was a substantial difference, then some of the components might need to be changed, making the production line less efficient. Also consumers might become angry if they discover that one market received a stronger box than another.

As for "Music Power", those numbers aren't based in reality. RMS or FTC is what you want to look for.

 

[caution]

The whole thing about 61W vs. 70W etc. is simply how different regions determine power consumption. That is not a measure of output.

The mains voltage doesn't have an effect on total output because it's stepped down and rectified, at which point the audio circuits, which are the same across all M90 models, only draw as much power as they're designed to. Same applies to batteries or DC jack input, the unit will still consume the same amount of current, otherwise the fuse would blow

 

[aiwapanasonic]

Thanks for your responses!
I have one final doubt / niggle in my mind: I have used a Japanese Panasonic RX DT9 for a few years now with a Laptop charger which outputs the 15v DC current which is like the batteries; there is no DC input on this model so I just soldered the cables to the battery terminals; no issues so far, after 2 years.

I have read that DC adaptots / chargers aren't equal: regulated vs unregulated. Some have electrical impulses that can interfere with the radio or other things. I don't listen to the radio; only Aux-in and most recently the Aux In is from an Amazon Echo Dot (the last model with line out output). So no problem with the sound, except it feels like the Echo Dot puts out too much power at full volume setting so I have it at 80%. The DC adapter is a solid one, a Toshiba 15V 3Amp, and its output is stable.

What I'm wondering about the m90 now is whether the best test between regional versions (which have different voltage and power ratings) would be via a DC power supply. They are all rated 15v (10 batteries).

And about the Japanese Victor in general - I know in the US, some people just plug it into the slightly higher voltage and don't see problems but here in Europe, a power converter is a must; or one needs to replace the original voltage transformer (but for this, you need a compatible donor, similar output plus size plus quality). So I'm wondering about DC power in general - do you think it's safer and better to use than a step-down converter? For example, if there is a power surge on the mains, I have been told this gets passed through the AC power supply. While with the DC converter, you should have this extra protection hopefully because the DC output is steady at 15v - at least that's what I'm thinking; but I could be wrong.

In summary; would you put your m90 on DC power (good quality laptop charger, for example, 15v 5 amp) and for the sound input, would you use the Aux In from your computer / phone / Alexa - would this be safe for the machine do you think?

 

[Superduper]

The M90 was produced in an era before all these portable 1/8" phone jacks with variable outputs existed. The line-in jacks are intended for line-level signals, which back then, was sort of a standard. These are high impedance inputs expecting a stable input signal, probably calibrated for around 0.7V input level.

The 1/8" audio jacks are really not intended to be used as a source for line-level RCA jacks. They are intended to be used on lower impedance loads, such as with mini speakers, headphones, etc. Therefore, some form of volume control is included to throttle that signal. True RCA inputs don't expect the signals to be throttled.

That being said, most people find that these 1/8" inputs from the sources you mentioned will usually work fine with the classic amplifiers, but you'll have to find the sweet spot where the signal is not so high that it saturates and causes the input signal to clip, or so low that you have to crank up the boombox to where the S/N ratio is so skewed that the sound is poor quality. Manufacturers typically take into consideration that these devices may be used for audio sources and therefore, the outputs are designed so that they'll work with high and low level impedance loads. However, that isn't the case for all such devices. It's entirely possible that a devices intending to be used for headphones might not perform well with a high impedance load. You'll just have to try it and see. If you start with the signal small and ramp up to a good spot, there shouldn't be much risk to either device.

As for testing, you are comparing apples to oranges with different regional boomboxes, or even the same boombox but different examples. The reason is that these things are 50 years old. Some have wear more than others, and some have more corrosion or oxidation in the connections, controls and switches. You simply can not make any conclusions based on such testing. The bottom line is that all of these M90's utilize the same output amp chips, and therefore, are essentially the same internally for the purposes of amplifier output, although the power supply sections will invariably be different and conforming to regional requirements and standards. You also tested on tape..... how do you even know that the tape heads are both in the same condition? Does one have more wear than the other? Are they both clean and adjusted correctly and degaussed? And even the aux-inputs aren't really apples to apples as you've already discovered. In this case, you probably would be better off comparing FM levels using an FM transmitter with both boomboxes tuned to the same station, but again, these are 50 year old sets. Once you've had enough experience, you'll soon discover that there can be significant performance differences between boombox examples, even of the exact same models after 50 years.

 

[aiwapanasonic]

OK, this explains a lot because I have read that the line out standard is something like 2v, but not sure this is meant to go into a boombox. Right now, even when getting a line out via a DAC (Red DragonFly), I need to lower the volume when connecting to a boombox. The DragonFly manual says I need to set the PC volume at the maximum level which should produce something like the standard 2.1v output level. But I have seen that it is too loud so I need to keep it at ~70% of the volume. There is no exact setting - it varies; on the DAC, I need to keep it at 70-80%; on the direct 1/8 output from the laptop (macbook pro), a bit higher, but no more than 90%. Anything higher, and the VUs start swinging into the red all the time, plus the sound gets too loud and I'm worried about something getting fried inside.

Incidentally, even the line out signal coming from a deck seems a bit on the loud side - so I'm starting to think the 'line in' on the boombox wasn't meant for regular playback or a type of external speaker; but was intended mainly for recording. I do have one other boombox: Sanyo MR9600 (9664), where you can actually control the input level with a dedicated knob, even for playback. But I think this is a rare feature.

Appreciate your note on the potential differences. Another way to settle this would be via the service manual but I cannot see one for the Japanese version. My questions are coming fundamentally from a concern about the condition of the box: if they are supposed to sound the same; and if the sound seems slightly different on tape, then should I look at the head - that's a good pointer.

 

[aiwapanasonic]

I’m flattered

 

[Transistorized]

I've also wondered if all variations of the M90 VU meters were red in the the beginning and then got faded to yellow. It is my belief that all were red and some faded due to sun exposure. In the video photo capture above, my opinion is that the speakers were a glossy dark blue just like the Victor in the photo above. The brownish speaker I believe is also due to sun exposure pulling the dark blue out of the speaker cone

 

[Superduper]

I've also wondered if all variations of the M90 VU meters were red in the the beginning and then got faded to yellow. It is my belief that all were red and some faded due to sun exposure. In the video photo capture above, my opinion is that the speakers were a glossy dark blue just like the Victor in the photo above. The brownish speaker I believe is also due to sun exposure pulling the dark blue out of the speaker cone

I've had many many M90s in various conditions go through my hands either through ownership or servicing. One thing I'm convinced of is that the factory M90 speakers did come with a version that is very dark gray. The factory description is that these are urethane laminated cones. They are blue paper cones (like on the M70) but they have a urethane plastic layer that is bonded with the paper on the front side, presumably for better weather protection and improved stiffness, it's not painted. The urethane is likely not completely opaque, I suspect they are transluscent. I have seen near brand new examples with virtually no signs of sun exposure anywhere have very dark gray cones. I have also seen very grey-blueish light chalky looking examples that clearly have been been faded. None are going to have the bright blue cones like on the M70 unless that is a version that JVC came out with at one time because the urethane wouldn't be clear, unless it was a blue laminate layer. However, if blue laminate versions exists, I suspect that during the life of that model, at one time, gray urethane would have been used as well. Also, meters that have faded from red seems entirely plausible. However, if an M90 with deep red meter graphics coexists with dark gray speakers, doesn't that temper the theory that non-blue cones were faded?

 

[Tinman]

My old M90 speaker thread

 

[aiwapanasonic]

Update: I have the result from some additional tests, at least when it comes to the Tape comparison:

We have compared 4 different Victor boxes versus 2 JVC boxes... The comparison of multiple machines confirmed the findings from the first 1:1 test:

The European JVC version (70w written on the back, with the Din in) is a bit louder or somehow with more pronounced highs; maybe even lows. It has a sound signature that in my opinion can be fatiguing. It just enters your brain and keeps it engaged. I imagine that if this machine had an equaliser, it was set to a V (pronounced highs and lows)

The Japanese Victor version (30w on the back) is definitely a bit more mellow. Definitely the highs don't jump out at you. I think its sound output is relaxing and I could listen to it all day long

One more finding: all the Japanese Victors we've seen recently have 20W speakers, and this is consistent. I know there's a thread about the speakers (the 25 W and the 20w types are the same in size and weight) etc ec, just posting the facts.

The sound tests were done on tape; we have tried swapping the power supplies to eliminate that variable. We have tried using 15 DC via a Toshiba laptop power adapter (make sure you reverse the cables because the JVC boxes have reversed polarity).

One more thing: the VU meters swing to the same level on these listening tests. The volume on both boxes set at 4.

I think there is a similar difference in the M70 boxes. The 'overseas' models come in two different power ratings by W at the back. The Japanese domestic version is of the lower rated one.

In summary, the domestic Japanese m90 versions were built with a sound profile that suits the Japanese preference. Not sure if this is translated to maximum power in Watts but definitely the sound profile is different. This is similar to the Sanyo 9994: the Japanese version (9600) has a wide setting while the overseas one has a knob to remove the mids, effectively creating the V.

One more finding: when you listen to a tape recorded to max 0 Db on a deck, the VUs on the M90 swing only to about -7db. When the deck is connected to the boombox line in, the VU meters swing to 0Db. The deck is an Aiwa AD F800, with a set output. So the boombox is callibrated to a different playback level than this specific deck.

 

[maxhifi]

This sounds like a matter of gain and not power.

DIN inputs require a weaker signal for full output than the RCA or stereo mini inputs will. This is because devices designed with a DIN output have a lower output voltage, to match the DIN standards.

This means that given the same source, and adapter plugs the DIN input will need a lower volume control setting for the same volume level. If the loudness switch is used, this lower volume control setting will also result in a slightly more bass and treble boost for this volume level, since the amount of loudness compensation depends on the volume control position in most stereos.

If you want your DIN equipped model to sound identical to the RCA equipped model, the solution is to attenuate the signal coming in, either by turning down the volume control of the source device, or making a resistive attenuator.

 

[BoomboxLover48]

Like on the JVC M90 VU meter panel, color of Sharp GF-9000 also had a faded red to yellow color variation.
I believe they both had two different VU meter panels one with red and another with yellow.

 

[Reli]

I think any sound difference is going to be due to the condition of each unit. Each unit has capacitors of different condition, and that can definitely affect the sound. I don't think any manufacturer would deliberately make one region's box more powerful than another. They all have the same amps. Yes, each part of the world uses different voltage, but the transformer converts it to a DC voltage of a predetermined range. There would be no reason for JVC to allow one version of the M90 to produce, say, 18-19 volts while another produces only 15-16V. There would be no logic in that, and it's bad for business.

 

[Superduper]

*How did you power all of your 4 "examples"? Did you use AC mains, or did you use 10-D batteries? If batteries, was each test done with a brand new set of batteries? If using AC mains, did you use calibrated voltage transformers to account for the differences in secondary voltages?

*Using a DIN vs RCA comparison is oranges to apples. You have no idea what the signal input strength is in one example vs another. Even if you were to use the exact same signal strength, one "type" might require you to use a different signal strength for the boombox output to meet their specification.

*Speakers are all 50 years old. Tweeters, woofers, etc. How do you explain the life and history of each example? Could one example have been used more? How about environmental factors such as humidity, etc? Japan is an island nation. Much of their boomboxes that eventually get exported here have any metal covered in green corrosion. I've seen many M90s with worn or torn surrounds. If this didn't happen, I wouldn't be able to sell any M90 surround cloth replacements, but I do. I've also seen many M90's with blown tweeters.

*50 year old circuitry. That says it all. You aren't going to find 2 examples that sound exactly the same anymore after 50 years. So honestly, while your comparisons are interestings, they say nothing and the conclusions introduce more questions than answers.

All of these M90's use the same output amplifiers. That is a fact. As for speaker drivers, having different speakers in different markets with different specs or markings but with the exact same look and size and weights, etc....... well, if it looks like a duck, walks like a duck....... marking things differently is probably just a matter of complying with local regional requirements using varying testing standards. Unless you want to volunteer to drive your woofers with different markings to max using a high powered amplifier with the exact same signal, and see when each distort, or "blow", maybe then we can look at things a bit differently. But once again, 50 year old paper coned (and surround) speakers with old plastic laminate.......

 

[aiwapanasonic]

No, power was not via batteries. It was done on AC for the European JVC and AC (via an additional 240 to 100v converter, Nissyo Industry 120W) or DC (15v 5amp Toshiba laptop adapter) for the Victor. The power supply didn't make a difference. Like I mentioned, we even swapped the power supplies: we disassembled the backs and took the back from the JVC and plugged it into one of the Victors. No difference.

Only on TAPE; no radio, no DIN/Line in. Because the radio reception in this part of the country is poor; and the collectors here are purists and machines are judged mainly by tape output. And because like you said, Din vs Line in is apples vs oranges.

High and bass knobs at the same level (almost to the max); volume at the same level at about 4.

This was on freshly restored machines, with all functions fully working, with no compromise; restored by the same person. It just so happened that aquite a few came in for restoration at the same time. Obviously the different machines were in a different condition when they came in originally; some had seen more use in their life than others; some kept in better conditions than others; some with yellow VU meters and others with red ones. All with original speakers with no tears; some speakers faded and others bluish but not clear if original blue or repainted at some point. All of this prior history didn't matter to the sound coming out.

I didn't believe it either because of what I read here on the forums, and I know some of you have seen more than one JVC or Victor, so I am super puzzled too. But when you hear the same test repeated with different pairs (like I said, 4 Victors on one side and a reference 70W JVC on the other, which had previously been compared and confirmed to be identical to another 70W JVC) and the results are consistent, you start to believe. The difference on tape is definitely there, I heard it on a video recording; then I heard it again live and actually it is way more pronounced live. It depends on the type of music. With some music like techno, the highs on the JVC just pierce your ears like someone is whispering directly in your ear; whereas the Victor is mellow. Initially I was really really obsessed with the JVC; but actually now I think the Victor has the better sound profile for me. Anyway, the Victor isn't a slouch - it is still very very loud, so definitely it doesn't suffer from lack of power. When you feed it Line in or Radio, it is a lot louder than tape (well, it depends on the tape recording but I'm recording at around 0Db on an Aiwa deck); in fact, I imagine most people don't go above 3 on the volume knob; it is still king territory but I will now call it a shogun.

 

[Reli]

OK but when you say he restored them, what did he do? Did he actually replace all the caps in both units? And are the tape heads in the same condition? Otherwise it's not an apples to apples comparison.

 

[Superduper]

OK but when you say he restored them, what did he do? Did he actually replace all the caps in both units? And are the tape heads in the same condition? Otherwise it's not an apples to apples comparison.

I agree. Unless comparisons were performed on brand new units in the same years of release, before (or after) all the speaker drivers were broken in, while all the components were fresh, then any comparison is unreliable. If only vintage units are available, then the only way to get a true comparison is to truly refurbish the units using identical drivers (swap one set for listening if required). By refurbish, this means new everything. New caps, all resistor values verified, new (or same drivers), and even then, you can't rule out differing characteristics in the semiconductors depending on electrical wear. To my knowledge, victor units don't have readily available schematics as those are only available in Japan and their repair manuals aren't even called "service manuals," I believe they are called "technical manuals." A direct compare between the circuits would give a better idea of actual differences, if any. Regardless, we all have biases based on life's experiences, so I'm sure #aiwapanasonic has formed his own opinion which is fine. But based on my own knowlege, I'll remain the skeptic unless I see proof. Perhaps someday, I'll compare the 3 examples I have remaining here, including a victor, but I already know the comparison will be useless as they are all in varying conditions with the victor like new but the rest fairly worn.