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Orthodynamic Roundup - Page 437

post #6541 of 23459
Thread Starter 
Good, and, we should mention, it was cheap. Which is the most important spec.

Nice photos. Write that one up for the skeptics over at AK.

The switching power supply is behaving itself? Excellent.

EDIT: Oh, all right. My turn. One of the prettier of the few old (~1980) MOSFET integrated amps, this is the comparatively uncommon Hitachi HA-7700. First-gen MOSFET amp, decent but simple Hitachi preamp built in. Only imported into North America via Canada, apparently. 65 real watts per channel into 8 ohms.

Not my photos, by the way. These are from auctions, spiffed up a little.








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post #6542 of 23459
Quote:
Originally Posted by wualta View Post
Good, and, we should mention, it was cheap. Which is the most important spec.

Nice photos. Write that one up for the skeptics over at AK.

The switching power supply is behaving itself? Excellent.
Ja ja. It was $40 shipped and the specs are not that bad.

Quote:
2x80W (20-20.000Hz/0,05THD/6Ohm)
Frequency response: 10-30.000Hz
Damping factor: 50 (6Ohm/1kHz)
Distortion: <0,05%
S/N ratio: 80dB, 75dB (Phono)
Tone controls: ±10dB@50Hz, ±10dB@10kHz
Filter: -6dB/Oct below 15Hz, -6dB above 9kHz
Muting: -20dB
Power supply: P.P.S.
Transistor devices type: Hi-fT
Insides do looks crammed and scary, but it sounds surprisingly good, too good for an old cheap amp.

Insides pics:

Pic1 Pic2 Pic3
post #6543 of 23459
Quote:
Originally Posted by Faust2D View Post
I got my silly 80's Sony amp (Sony TA-V7) and it drives TK33 box as well as all my orthos without any issues and manages to sound good and look TRON like doing it. Yay for old dusty amps.
Wow, it looks great to me. Maybe having been a teen in the '80s has something to do with it.

My only question, after having my NAD 3020PE go up in flames, and an '80s compact Sony amp stop working and reveal gooey mess from old caps everywhere once opened, is if you'd better recap it and maybe check resistor values before using it regularly. My Yamaha A100 which is of a similar vintage has got very little use while I try to muster up the energy to find its schematics, order parts and get to work on it. Or am I wrong?

Smeggy, I hope those have the new pads. We can't wait on your impressions, and mods of course. And now that the UK pound is almost at unity gain with the euro, I might think of getting a pair too soon.
post #6544 of 23459
Quote:
Originally Posted by wualta View Post
Here's that slightly clearer look at DAC's handiwork
Just a comment, now you can see more details, but note that the greyish texture on the leather on the photos is black and a lot nicer in reality (the frame got a bit of grey that isn't there also).
post #6545 of 23459
Great old amps

I have an old '84 vintage NAD myself, thankfully if that goes up in flames it'll just burn work down

It'll be fun tweaking the RP, it looks like a nice driver so... and yeah, I hope it has the newer style pads.
post #6546 of 23459
Quote:
Originally Posted by Faust2D View Post
Ludoo, I was using your very cool Head-Fi Megathreads tool and have a question for you. Is there a way to just display a gallery of pictures? Searching does not always work on pics so just browsing them would help if one is looking for specific pic.
It turns out there was a way, and I forgot to tell you: you just had to click "Search" with no keywords, then click on "All pictures" from the results page.

I added a link from the home page to the picture browsing pages, fixed a couple of bugs, and added a page to browse author posts. If you notice anything missing or broken let me know.
post #6547 of 23459
Thread Starter 
Quote:
Originally Posted by DefectiveAudioComponent View Post
Just a comment, now you can see more details, but note that the greyish texture on the leather on the photos is black and a lot nicer in reality (the frame got a bit of grey that isn't there also).
Remember, black is just very dark grey. Photo hint for black headphones: shoot against a background just a little lighter than the headphone and never never use flash on camera. Use big light sources like northern sky or big windows. That way no deep shadows form that have to be cranked up in image software, a process that inevitably brings up items that we remember as black. Heavily compressed images sacrifice shadow detail, as do most "normal" modes in basic SLRs-- they're punchy but too contrasty. We should do a photo subforum.

Ludoo, isn't the Yamaha A100 of more recent vintage? I think you're safe with that one. Does it smolder and vibrate like an Italian volcano when you have it on for extended periods?
post #6548 of 23459
My comment was just that they don't look light grey like that in normal light, it's an artifact of the photoshop edit. The camera is great, the photographer was at fault, being too impatient to post a photo to arrange proper light....

In any case, the WU-pads make the HOK sound good!
post #6549 of 23459
Quote:
Originally Posted by ludoo View Post
Wow, it looks great to me. Maybe having been a teen in the '80s has something to do with it.

My only question, after having my NAD 3020PE go up in flames, and an '80s compact Sony amp stop working and reveal gooey mess from old caps everywhere once opened, is if you'd better recap it and maybe check resistor values before using it regularly. My Yamaha A100 which is of a similar vintage has got very little use while I try to muster up the energy to find its schematics, order parts and get to work on it. Or am I wrong?

Smeggy, I hope those have the new pads. We can't wait on your impressions, and mods of course. And now that the UK pound is almost at unity gain with the euro, I might think of getting a pair too soon.
I have a lot of old gear that is 10-25 years old and it is yet to break on me. Let's see how this amp works out for me.
post #6550 of 23459
Quote:
Originally Posted by wualta View Post
EDIT: Oh, all right. My turn. One of the prettier of the old (~1980) MOSFET amps, this is the comparatively less common HA-7700. First-gen MOSFET amp, decent but simple Hitachi preamp. About 65w/channel.
Very nice looking amp. Do you have the pics of the insides?

What other amps with headphone out and ability to drive transformer boxes do you have? Pics would be nice
post #6551 of 23459
Thread Starter 
Quote:
Originally Posted by Faust2D
Very nice looking amp. Do you have the pics of the insides?
Do I have photos of the insides, he asks. Heh heh. Asks rhetorical question about the religious affiliation of the Pope. You just wait.

Quote:
Originally Posted by Faust2D
What other amps with headphone out and ability to drive transformer boxes do you have? Pics would be nice
Ah, looking for Wiki material, are we? I should have volunteered earlier. Tonight when I get home. Bug me if I forget.

By the way, I hope everyone has visited F2D's Wikiphonia. It sounds like a disease, but is, in actuality, a growing resource that he's put a lotta work into. Sign up and start contributing already.

This would also be a good time to once again acknowledge the flabbergastingly useful search engine ludoo has engineered for this thread and some significant others. Please make use of it. It's already saved me from looking entirely out of touch several times.
post #6552 of 23459
come to think of it, why arent links to both of them stickied on the headphone main page yet?
someone should make it happen
post #6553 of 23459
Glad you all find the search engine useful. Again, if there's any new feature you'd like me to add just ask.

Going slightly OT, stimulated by the recent posts on vintage amps (love that Hitachi BTW) I connected my old Polk Monitor Series 4A to the Yamaha A500 and a crappy CD player, and was floored by how natural female voices were. Lucky for me I have most of the phones I am interested in (or which I can afford, same thing), as I see more vintage/DIY speaker amps in my future.
post #6554 of 23459
Quote:
Originally Posted by ludoo View Post
Glad you all find the search engine useful. Again, if there's any new feature you'd like me to add just ask.
There is a little bug in the image browse feature. When images from a user are selected and you go to next pages the image view goes back to all users.
post #6555 of 23459
Quote:
Originally Posted by Faust2D View Post
There is a little bug in the image browse feature. When images from a user are selected and you go to next pages the image view goes back to all users.
Fixed. Thanks.
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