Orthodynamic Roundup

[DefectiveAudioComponent]

Quote:

Originally Posted by dBel84 /img/forum/go_quote.gif Just got off the phone with the "suppliers" - no stock They claim a 10 day back order as they have to order in from Yamaha ..dB

Bummer!
No YH100 drivers either I suppose then?

 

[Hans Dorn]

How about that yh1000 service manual

 

[DefectiveAudioComponent]

Quote:

Originally Posted by Hans Dorn /img/forum/go_quote.gif How about that yh1000 service manual

It's on the wiki already, that is where to find the part numbers so search for.

 

[Hans Dorn]

Ermmm. OK

 

[DefectiveAudioComponent]

Something else... I wonder if B&O used the 1978 driver in all their production runs for their ortho. It was produced until 1984, and there were better versions of the large PMB drivers made along the way (we can assume, from looking inside the Grundig).

(I suppose it's impossible to see what year a particular unit was made anyway... but Wualta, do you know when yours was made?)

 

[wualta]

[Goes and looks at exploded U70] No clues on dates. I noticed a molded-in little code-thingy inside the TH-700 cup but inside the U70 nothing that I can see.

By the way, YH-100s have not-very-well-hidden serial numbers on the underside of their metal arches.

Anyway, my U70's and TH-700's drivers have small holes that resemble the holes in the HOK ferrite discs. It doesn't resemble the Grundig's driver, which we've only seen in the early version of the PMB 100.

 

[scompton]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif Are they being fed from the same output? Which amp is this, by the way? As for levels being slightly off on pop LPs-- yes, this did happen, though it wasn't commonly noticed, because people weren't usually listening on headphones.In the world of analog, there are no rules. Still, something may be amiss-- that's part of the Analog Mystique too. Let us know if you discover anything.

Both the Gamma and T30 were being driven by my NAD, speaker out vs. headphone out, but the headphone out is the speaker out with 470 ohm resistors in series. 1-2dB off between channels is too slight for me to notice with headphones. I only saw it in the level meters in Audacity as I was recording. It wasn't all that noticeable in the graphs in Audacity.

 

[iQEM]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif Speaker caulk. The stuff some mfrs. use to seal woofers to their baffles.

thx for the info, wualta...

 

[DefectiveAudioComponent]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif Anyway, my U70's and TH-700's drivers have small holes that resemble the holes in the HOK ferrite discs. It doesn't resemble the Grundig's driver, which we've only seen in the early version of the PMB 100.

Speaking of that... are there any photos of the U70 driver around? I couldn't find it with the search engine or in the wiki.

 

[wualta]

Well, there's the shot of the identical-looking TH-700 driver, but it doesn't show the holes. Let me know what sort of view you need and I'll take a photo.

 

[DefectiveAudioComponent]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif Well, there's the shot of the identical-looking TH-700 driver, but it doesn't show the holes. Let me know what sort of view you need and I'll take a photo.

I'd like to see the magnets with hole pattern, and if possible a glimpse of the diaphragm, if it's possible. So, without the fabric, if you feel like taking it off.

 

[mypasswordis]

Quote:

Originally Posted by bjarnetv /img/forum/go_quote.gif some non ortho updates, but still relevant as its planar news after the great results from daming the chassis and sealing the baffle of my electrostatic floats, i decided to continue the ortho style modding, and make some pads. i started out reducing the size of the baffle using "cardboard bitumen" and added some memory foam pads. so how did it sound? awful; closed in, and no bass. im not exactly sure why yet, but i had to reduce the baffle size quite a lot to make them small enough to fit the pads, meaning it was like a huge inverted reflex disc (also known as a bass lens?), and i guess it didnt like that edit: or maybe it didnt like being sealed? they sounded way better once i broke the earpad seal.

Wait, what exactly is the baffle on the Floats? And what is cardboard bitumen?

Yeah, huge reflex discs, inverted or not, generally do bad things to the sound in my experience.

I definitely think that there is no reason for the earpads to seal since they weren't sealed to start out with, and I will be making sure my pads do not seal if/when I make them. The drivers are huge enough that they don't need a seal to produce bass. In fact, a small hole may allow the huge drivers to actually build up enough air pressure for bass. At the distances from the ears we are dealing with I don't think we have to mind back wave cancellation. So I take it the memory foam does a decent job sealing, then?

 

[bjarnetv]

here is a drawing of what i did

not sure what the American equivalent of cardboard bitumen would be, but its plates of bitumen that feels and acts like heavy, sticky cardboard.

i tried the pads without blocking the rest of the baffle, and that worked much better, although the bass did become somewhat overpowering

 

[mypasswordis]

Damn, crazy good drawing there!

I assume you mean that you took out that layer of cardboard bitumen right in front (the inverted reflex disc)? And I like the idea of the cardboard bitumen "frames" that both mass damp and make sure the drivers don't rattle around in there. Have you tried sealing the drivers specifically onto the frame, for instance a thin lining of bluetak between the drivers and the little tab that makes the drivers fit in snugly? Wow that was a bad description...

Good, the bass did increase. You could try having the pads seal less or you could try making them a bit thicker to distance your ears more from the drivers, but I doubt there can be very much more since there is no size adjustment for the Floats... You could also try a foam that seals less.

 

[bjarnetv]

i had previously sealed the drivers on top of the small foam tabs with bluetack, but i had to use enormous amounts, and never got a proper seal, so now i just added one layer of bitumen to act as a ledge, and clamped the driver on top with a thin gasket of bluetack.
the bass amount was reduced slightly, but it gained a lot of slam, and the sound was overall more balanced and enjoyable.

adding good-sealing pads on top of the stock (without the big L shaped "cardboard") baffle sounds the best so far.