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MT770 review

post #1 of 54
Thread Starter 
Edit - I combined the review and the addendums, and put the edited version on the web. You can read that one here:

http://homepage.mac.com/leon/mt770/index.html

Before I begin: This is very much a snapshot of my impressions at the moment. With my forum participation I do mature, but also say lots of immature/twisted/paranoid things along the way. Please, treat this review as one of your references, not the authoritative guide. Moderators: I don't think this is worthy of sitting with the other reviews on this board. Please don't waste your time considering that.

The sound

Sharp's marketing talk, ever since they started using Ni-MH gumpack rechargeables, has mentioned a +/- power supply to the amp circuitry. If you've made your own headphone amp before, you probably know what that means. There's also no output capacitor used with these amps. The amps are made by Sharp themselves (to be discussed later on).

At its best the MT770 sounds very clean. Meaning, it's got a "high-resolution/high-definition" feeling to it, lots of details and they all fall into place the right way. It's like watching a demo program on one of those flat picture tube TV sets.

Having said that, the 770 doesn't have the kind of "spaciousness" that a 831 could provide, probably because of the smaller amp output. I'd be very happy to describe the 831 as "sweet"; the 770, while lovable in its own right, has an "unseasoned" feeling to it. With the MT770, vocals also dominates a bit more than I'd like to see, with virtually everything I listen to.

I highly recommend using the 770 without the remote. The remote is quite well-insulated (no backlight hiss), but it seems to dull the treble very slightly, and also eat into the volume. You can access the basic playback functions on the unit; group will not be a problem and bass would be the only annoyance.

I personally can live very well with LP2 recordings on the 770. Less "oomph" and detail but very usable, like LP2 is with all the Sony portables. Bass boost on the 770 seems less punchy than the 831 boost, but isn't bad in quality IMO.

Power supply?

There's a nuance in the sound that comes out of the MT770, which seems to depend on the power supply.

When you use the rechargeable battery alone, the MT770 sounds "dark" (darker than both the 831 and the 77). However, when you hook it up to its AC adaptor (supplies 2V into the unit), the treble comes back, as if someone's turned it up. I tried using a Panasonic AC adaptor (supplying 1.8V), and the result is identical.

I've tried this a dozen times over several days, and it happens every time. I'd wear down a battery, swap for a new one, and marvel at the treble. So what's happening?

The Japanese manual says something along the lines of: "Please keep the rechargeable battery in the unit, even when you're using an AA battery. If you're using the AA alone, there might be large, sudden drops in voltage, depending on the operation, that leads to the unit functioning abnormally."

Notice that this wasn't what you'd see with the 831. With the 831, the reason stated in the manual was that, the battery meter would not function properly without the rechargeable battery. If you have an AA battery attached, the 831 (many other earlier Sharps, too) will consume power from the rechargeable first, and once the rechargeable is exhausted, switches to the AA.

On the 770, however, the battery meter seems to always show the total power available to it. I can have a rechargeable that is shown as 1/3 full, throw in a full AA alkaline, and the meter will read full. I can have a 1/3 full rechargeable, with a nearly exhausted AA alkaline, and the meter will often show more than 1/3.

My suspicion at the moment is that the rechargeable and the AA battery case are connected in a way (parallel?), so that the voltage supplied is the aggregate of the two combined. This is, of course, a very loose theory with very little scientific evidence, feel free to e-mail me with your take on this issue. Opinions from 770 and other "Ni-MH" Sharp owners are also welcome!

Assuming that a higher voltage does reveal the MT770's true potential.. I was wondering bout making an external battery pack with 2 rechargeables connected to give 2.4V, and hook it up to the 770's AC adaptor jack. I don't know if the 770 will take 2.4V without problem, though; and a jack of the size used on the 770 (the really small kind you see with virtually all MD recorders now) might be hard to find. And one of you will have to fly down here and teach me soldering so I don't lose body parts. :P

So for now, I choose to always use the MT770 with both the rechargeable and an AA battery. It seems that an AA in the box will help even if it's exhausted (beware of leakage, though; it happened to me the first day).

the remote

The new display has roughly double the acreage of Sharp's previous remote display. The first impression we all get is that much space is wasted, but after half an hour you'll start to think it's actually nice. It's like white space left deliberately untouched to form a grid for easier reading. Compared to a Sony or Panasonic remote, on this remote there are less acronyms to remember; the text and icons are of a good size, too.

The "2-color" display is, in the end, a display with 2-tone backgrounds, but again, quit complaining. I wish they'd gone for orange backlighting though, the MD-buying crowd has seen too much blue/green.

The volume button is worth complaining over. On the back of the remote there are five buttons:

REC - Vol down - Vol up - Mode/Display - Group/Clear

These buttons are very close to the clip, and are of the same shape, which makes them hard to press and identify without looking. Sharp could have used different shapes and textures for these buttons, make them stick out more, or at least put the 2 volume buttons on one end.

Kudos to Sharp, though, for making the menu button highly usable. It basically goes in 4 directions and down the center too. If you make the button a circular pad, what usually happens is that you're aiming for the center, but you end up pressing something else. Sharp chose a stick instead of a pad, which I believe makes it easier to press down the center.

The Menu System

Sharp makes a jump for a Sony-like menu system. It handles all the editing functions (titling, etc), recording settings (sync, etc), parameter setup (backlight, autoplay). On the MT770, the need for a REC button means there's no space for a BASS button, so the menu also handles bass boost.

Pressing the "M" stick down the center will enter "menu mode", and bring up the first layer of menus. The top line displays the initial of a menu item, and the full name is displayed on the second line. Once you enter an item, the options are also displayed in the same way.

You get an ample 25 seconds to use the menu before it cancels itself. At any point, pressing the Group/Clear button brings you one level back. Pressing Stop exits the menu. The menus are highly contextual.

While still not as easy as the non-group Sharps, I've come to like the MT770's menus. A lot of the remote's designs should help those who claim to be stupid when it comes to using technology. I'll still say Sharp's got the easiest interface for MD portables - I like not having to twist knobs and be told to "pushENTER".

Can I conclude now?
Sharp probably doesn't have the absolute lead for sound quality anymore, and they certainly didn't outdo themselves, but the MT770 is a nice effort IMO. I'd give the 831 95/100 and the 770 80/100.
post #2 of 54
Nice review! How would you rate the MT77's sound in comparison to the MT770 and the 831?
post #3 of 54
Thread Starter 

The MT770 opened up

Here's the MT770 with the backside opened up (about 200KB):

http://homepage.mac.com/leon/board.jpg

I was able to find info on a number of the ICs used on the MT770.

(1) AKM AK4551(VT)
The AKM (Asahi Kasei, www.akm.com) IC here is listed as a "digital audio 20-bit codec" on the company's product site. So what's a codec? Well, if you see Texas Instrument's website, a "codec" is listed in the same category as A/D and D/A converters, as something that does both A/D and D/A conversion.

http://www.asahi-kasei.co.jp/akm/usa...tml/ak4551.htm

(2) Sharp IR3R54N, IR3R59N
These are audio amps, mounted close to the three jacks (phones/remote, line in/optical in, mic in) on the side. The 54N has a "mike amplifier", the 59N has a "filter amplifier". Not sure if either of these are responsible for sound output, but their power supply are listed as +- 2-3.25V (1.2-3.25 for 59N), as Sharp advertised.

(3) Sharp IR3R58M
Listed in Sharp's catalog as a "RF amp IC". The RF amp, IIRC, gives the pickup instructions.

http://sharp-world.com/products/devi...on/ic_top.html

(4) Oki MSM51V17405F(-60)
This is the DRAM.

http://www.oki.com/semi/english/datapage.htm

(5) Sharp LR378161
This is a 32-bit LSI that includes the ATRAC section. The Marantz CM6200 uses Sharp's LR37816A, and I think it's safe to assume that these two are essentially the same. The CM6200 allows the user to choose between 3 types of bit allocation (I haven't found any detail on what the differences are), the MT770 doesn't let you do this. That's the only difference on paper.

Sharp calls the MT77's ATRAC version 8.3. According to press releases, it's got the same SP encoding capability as versions 6 (721, 722, 821) and 7 (831). The "0.3" suffix is apparently for the MDLP (ATRAC3) capabilities. On the press release, the MT770's ATRAC uses the exact descriptions used for the MT77, leading me to believe they're the same.
post #4 of 54
Thread Starter 
Thanks fiddler!

When I bought my MT770 I had the chance to listen to it back-to-back with the MT77. Powered both with a gumpack and played Natalie Imbruglia (sowwee! I'll resign from all my audiophile titles! :P) against loud background noise, so the environment wasn't optimal. The phone used was the MX500.

My first impression was that the MT77 is better. Its overall temperament is closer to the 831, but with a narrower "landscape" and probably also quieter. But it was "brighter" than the MT770 and more enjoyable.

I don't know if the situation might change with different power sources. At the time, using the rechargeable only, the MT770 was disappointing. Once given more power, though, it's been an enjoyable ride.

Of course we can argue that having paid so much, we shouldn't have to be doing the small tricks to make it sound pretty..

post #5 of 54
wow, nice review!
post #6 of 54
Quote:
I don't think this is worthy of sitting with the other reviews on this board. Please don't waste your time considering that.
I don't know why you think this. It's a good review, and with a couple small changes I think it should be archived.

1. The subject line/title. It should say what it is you're reviewing. For example, I didn't know the MT770 was an MD recorder/player until I got far enough into the text to glean that information from context. I'd suggest this for a subject line/title: "Sharp MT770 minidisc recorder" or something similar.

2. You should have a brief introductory paragraph. Just a couple of sentences summarizing what you're going to cover in the review. It could start with, "I use MD recorders to..." and end with "so here are my impressions of it so far:"

There's no need to make extensive changes -- I like the informal style of the review. Hopefully a moderator will agree.
post #7 of 54
Thread Starter 
It's hard to feel worthy after the brilliance of that D-25(S) review, Russ; I can't even tell you about bass, mid-bass, mid-treble and such. I haven't got any "quality" CDs with me, and I have a hard time trying not to be paranoid - these days nothing's sounding quite right to my ears.

You can probably tell I feel terribly dwarfed, but I promised to do a review, so here it is, even though I would've liked to say more on the sound than I really could express.
post #8 of 54
Quote:
Originally posted by leon
It's hard to feel worthy after the brilliance of that D-25(S) review, Russ; I can't even tell you about bass, mid-bass, mid-treble and such. I haven't got any "quality" CDs with me, and I have a hard time trying not to be paranoid - these days nothing's sounding quite right to my ears.

You can probably tell I feel terribly dwarfed, but I promised to do a review, so here it is, even though I would've liked to say more on the sound than I really could express.
I have lots of experience writing; I was an English major in college with a concentration in composition and creative writing. I have lots of experience writing product reviews, though most of them have been about camera equipment.

You shouldn't knock your own review just because you liked someone else's. Your review is informative and to the point. People can use it as a point of reference in the future, and I think it should be included in the full reviews section because of that. Like I mentioned previously -- I'd just suggest a different subject line/title and a very short introductory paragraph.

Keep writing -- the more you do, the better you'll get at it. What you've got here already is good.
post #9 of 54
Thread Starter 
That's not the point, Russ. My concern is that my experience is simply not "audiophilic" enough for this community. Hence me making a big deal of my inability to explain the low bass, mid bass, mid-treble and such.

I wanted to cut all the crap out of the review... glad people seem to appreciate the effort.
post #10 of 54
Theres no need to feel bad about your review. It was good! 100% better than writing nothing at all. So thanks for your oppinion on the mt770 .
post #11 of 54
Quote:
Originally posted by leon
That's not the point, Russ. My concern is that my experience is simply not "audiophilic" enough for this community. Hence me making a big deal of my inability to explain the low bass, mid bass, mid-treble and such.
Leon,

I must confess, you've posted one of the best MD reviews that I have ever seen. I render it even more useful personally for myself than Brian Youn's picturesque portable reviews that read truly like an MD manual Believe it or not - yours looks more like an audiophile review.

Your power supply section prompted me to look at the area that I had been overlooking.

I have been doing comparisons between my newest R909 Sony portable and the 2-year old Kenwood J7 (a clone of the Sharp's 702).

Although the R909 is a very stylish and decent unit (have owned it since Nov), I had major complaints regarding its driving output.

What I did - I originally put its regargeable gumstick into a hideout and until recently have used AA baterries only, which I felt more comfortable with. As a result, the sound was very rich tonally (better than Sharp's)... but lacked drive and power altogether - I attributed this to R909's weak 5 mW x 2 headphone output, and was almost decided on looking for an external headphone amp (a la Porta Corda).

Having read your review, and put the regargeable back into the unit and... voila! - with both rehargeable and AA in, the sound was different! It became dynamic and transparent. Same with AC power (I barely used it before).

I listened with Grado SR-60 and Koss Sporta Pro - i even tossed aside the SR60s as totally lacking - now they are back on... and I really can't take them off my head for several days and nights already

I think it all has to do with voltage. Looks like adequate voltage has become all MD manufacturers' trouble, and they sacrified a little bit of sound quality in favor of playtime durability.

I still haven't listened with the rechargeable only...

Looking forward to other people's experience related to the subject.
post #12 of 54
Thread Starter 

Addendum to review

Thanks Nallyvaico!

Now, more on the circuitry of the MT770.

I had the pleasure of opening up my 831 again, this time comparing it to the 770. Here's a picture for you readers.

http://homepage.mac.com/leon/770831.jpg

The 770 and the 831 have a very similar amount of space on the circuitboard. Although the 831's is larger, the back of its circuit board is complete occupied by the pickup and the spindle motor. The 770 has slightly more space behind the circuit board.

This picture also tells us a very painful story. Why switch to Ni-MH battery? Because if it wasn't for the battery, the 831 might have been as small as the Sony R90. If you create a Li-ion battery in the "Gumpack" form factor, the capacity drops quite a bit.

Same phones amp?
The IR3R59N, an audio amp with +- power supply, appears on both the 770 and the 831. So, in contrary to Sharp's own marketing, this amp might have been in use for years, but detuned for the more recent models (10+10 --> 5+5mW, both rated at 32ohm). There are no other chips on the 831 that is clearly an audio amp, as far as my limited knowledge goes.

Power supply
Sitting near the aforementioned audio amp on the 831, is the IR3M12N, a DC/DC converter. It operates between 2.2-6.5V (not sure what that means).

On the 770, there are two much smaller chips near the AA battery case contacts, labelled "3M14". In Sharp's catalog, an IR3M14N is offered. It has the same specs as the 3M12, but is in a different "package". Makes me wonder...

Enjoy
post #13 of 54
ooh, nice

I actually saw a brandnew 831 in a store a few days back. they havent disappeared yet!
post #14 of 54
Quote:
Originally posted by Russ Arcuri



Keep writing -- the more you do, the better you'll get at it. What you've got here already is good.


I agree. Good review and Russ' advice to keep writing is so true. Writers write and write and rewrite. Keep at it.
post #15 of 54
Thread Starter 
Quote:
Originally posted by Braver
ooh, nice

I actually saw a brandnew 831 in a store a few days back. they havent disappeared yet!
Yeah, there are quite a few 831s around in certain places. I've seen them in Bangkok too. Wonder if the new MT190 is really some kind of an MDLP 831.

Looks like there won't be a Kenwood clone this year.
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