[hugz]

Some people have suggested that grado gets it drivers from a japanese company called primo who makes microphones and some small speaker drivers. It has been particuarely suggested that grado may use the DH-32 model.

Well, i emailed primo hoping to obtain a number of these drivers so that i could:
a) build a speaker array with them
b) get a clue as to whether or not they do seem grado-esque
c) understand how much money companies really do pay for headphone drivers.

To my first email requesting a quote on an order of 50-100 units they replied

Quote:

<blah blah> Thanks for your interest in our Primo product. However, before we begin, need you to answer below questions : - what is your application of our this DH-32 receiver ? - is the demand going to be only a spot order of 50pcs or 100pcs ? - who is the end-user ? - do you have a project name for it ? - may you please provide your company profile to us ? <blah blah>

I replied to this email basically stating that i wish to create a speaker array using a number of their drivers and that my purchase would either be a once off, or at most result in 2-3 repeat orders as i make more for friends.

To this they replied

Quote:

<blah blah> Thanks for your kind feedback. Need to inform that above part is one of our very old model and is not built frequently. Our Primo-Japan only builds for old customers, who uses for repair purposes. For your request, regret to inform that we decline to sell this item DH-32 to you as a new customer. Your understanding is needed. Please look for another supplier. Thank you for your interest in our product. <blah blah>

I'm not sure if this is of any significance but it may help provide some information for those wondering about the primo-grado connection.

I cant be entirely sure if they're telling the truth or if they're simply not interested in doing business with me since i'm so small-time (since they seemed somewhat interested in the first email but then totally rejected me in the 2nd).

This was to/from primo singapore btw because primo japan (or usa. i forgot) had a full inbox (and sg is closer to australia anyway).

edit: oh yeh, i guess the significance of this is that if they're telling the truth and this part really is not built frequently and only available in small quantity for repairs, then this would certainly rule grado out since they definately use more than just a few drivers

however, that doesn't nessesarily mean they dont outsource their drivers. it's just not the primo dh-32

 

[VR6ofpain]

where did you hear about this connection?

 

[doobooloo]

Well, that is certainly interesting. I doubt that there is a specific model number for what Grado gets if there is any driver outsourcing since Grado seems to do a lot of tweaking and experimenting as part of their product development.

From my conversations with George Alessandro, Grado seems to be able to tweak the drivers himself. Also, look at all the different models out there - especially the new 325i, MS-2i, HF-1, and PS-1... This either means that the connection between his outsourcer is really tight or he just winds the drivers himself in house.

I always thought the drivers were in-house, but I could be wrong.

 

[kramer5150]

Quote:

Originally Posted by VR6ofpain where did you hear about this connection?

x2...
Please PM me if you need to

from what I understand coils aren't terribly difficult to wind... Once you tool up with equipment accurate / precise enough. That is the key part. Tool maintenance and Maintaining batch to batch consistency is the difficult part.

Tooling for the diaphragm would be costly too though.
Garrett

 

[hugz]

I heard about it via headfi

It started out with this post which is very curious: separated at birth

and from then on there have just been bits of various speculation and some people have displayed quite a bit of interest as to whether or not grado outsources or not

Grado *claims* to produce everything in house, from memory (except mahogany parts), however if you look at the above post you get a little bit suss. how damn similar do those 2 drivers look?!

Also, with a name like "DH-32" it definately goes in line with the good ol' 32 ohm grado headphones

however, i noticed on their website somewhere a review of grado which mentioned their voice coil twisting machine in their factory

Considering how many different headphone grado has though, they'd definately either have to tweak them in house or have a strong relationship with their outsourcer so that grado can design drivers and the outsourcer can produce their custom drivers for them.

(this is of course assuming that they do outsource which is certainly unknown and everything that grado has said so far has pointed to "no")

edit: one thing that makes me suss is.. how can a small company like grado have machinery that is capable of making diaphragms, making voice coils, making plastic cups, making metal cups, pressing headbands, making those little cup clasps.

that's a whole lot of specialised equiptment it seems.

Quote:

Originally Posted by kramer5150 from what I understand coils aren't terribly difficult to wind... Once you tool up with equipment accurate / precise enough. That is the key part. Tool maintenance and Maintaining batch to batch consistency is the difficult part. Tooling for the diaphragm would be costly too though.

Taking this into account and the fact that the external review states that they do have a voice coil machine at their factory, i wouldn't be tooo supprised if they outsourced the diaphragm (from primo?) and made their own voice coils. the main difference between at least the sr series is just the voice coil, cable and and enclosure, right?

 

[hugz]

another member suggested that the DH-32 may be wrong because the primo website claims it's impendence is 27 ohm.

they suggested that maybe the dh-39A would be closer. They may be correct because it claims 30ohm. the dh-39a actually has a much closer hole patern to the grado (my grado is 1 center hole, 6 in the next ring and 16 in the next ring). dh-39A is 1-6-12. close but not perfect

dh57 has the correct hole patern (1-6-16) but claims to be 40 ohm. the dh57 also claims to have "cloth" over the hole patern area though, which certainly suits grado. it also has "accoustic filter" on the back of the driver which grado drivers have

 

[kramer5150]

Quote:

Originally Posted by hugz I heard about it via headfi It started out with this post which is very curious: separated at birth and from then on there have just been bits of various speculation and some people have displayed quite a bit of interest as to whether or not grado outsources or not Grado *claims* to produce everything in house, from memory (except mahogany parts), however if you look at the above post you get a little bit suss. how damn similar do those 2 drivers look?! Also, with a name like "DH-32" it definately goes in line with the good ol' 32 ohm grado headphones however, i noticed on their website somewhere a review of grado which mentioned their voice coil twisting machine in their factory Considering how many different headphone grado has though, they'd definately either have to tweak them in house or have a strong relationship with their outsourcer so that grado can design drivers and the outsourcer can produce their custom drivers for them. (this is of course assuming that they do outsource which is certainly unknown and everything that grado has said so far has pointed to "no") edit: one thing that makes me suss is.. how can a small company like grado have machinery that is capable of making diaphragms, making voice coils, making plastic cups, making metal cups, pressing headbands, making those little cup clasps. that's a whole lot of specialised equiptment it seems. Taking this into account and the fact that the external review states that they do have a voice coil machine at their factory, i wouldn't be tooo supprised if they outsourced the diaphragm (from primo?) and made their own voice coils. the main difference between at least the sr series is just the voice coil, cable and and enclosure, right?

Put on the Mechanical Engineer hat:

Its not out of the realm of possibility that Grado does own all tooling. The initial investment would be the big $$$ hit. How much of a hit, would depend on the tooling. If their plastic molds are high carbon tool steel (High volume, long life) the tools could theoretically cost ~10-18 grand, depending on the tolerances specified. Soft tools could be considerably less, maybe around 5-8 grand, the drawback would be limited tool lifespan.

Theoretically they could mold the driver inner grille screen, earcup inner, earcup outer and L/R blocks out of the same tool. The "C" yoke looks like a different material, probably some PP in the mix to make it more flexible. I'm guessing that requires a different tool since its a different material and has some surface graining. Tool graining is usually a secondary operation when fabricating a moild tool, and is a specialized field that some tool makers don't do.

The connecting rods are probably just bar stock. The rubber end caps look like antenna caps commonly found on RC cars.

the Vinyl headband could be heat staked on a manual press of some sort.

The cables are probably out-sourced.... there are thousands (at least) of cable-houses that span all kinds of industries. I'd be shocked if this were done in-house.

Ive seen loudspeaker coil winding tools... Resonant Engineering I think. The tool looked like nothing more than a lathe chucked with a coil bobbin and a feed for the wire. I think the epoxy process is one of the more difficult aspects. I inagine a headphone coil would be very similar, just scaled down and tighter tolerances.

Ive never seen a diaphragm mold / press / vac form tool before.

We need Zanth to do a grado Labs photo-tour as part of his Next John interview.

Garrett

Engineer hat removed

 

[hugz]

Quote:

Originally Posted by kramer5150 Put on the Mechanical Engineer hat: Its not out of the realm of possibility that Grado does own all tooling. The initial investment would be the big $$$ hit. How much of a hit, would depend on the tooling. If their plastic molds are high carbon tool steel (High volume, long life) the tools could theoretically cost ~10-18 grand, depending on the tolerances specified. Soft tools could be considerably less, maybe around 5-8 grand, the drawback would be limited tool lifespan. Theoretically they could mold the driver inner grille screen, earcup inner, earcup outer and L/R blocks out of the same tool. The "C" yoke looks like a different material, probably some PP in the mix to make it more flexible. I'm guessing that requires a different tool since its a different material and has some surface graining. Tool graining is usually a secondary operation when fabricating a moild tool, and is a specialized field that some tool makers don't do. The connecting rods are probably just bar stock. The rubber end caps look like antenna caps commonly found on RC cars. the Vinyl headband could be heat staked on a manual press of some sort. The cables are probably out-sourced.... there are thousands (at least) of cable-houses that span all kinds of industries. I'd be shocked if this were done in-house. We need Zanth to do a grado Labs photo-tour as part of his Next John interview. Garrett Engineer hat removed

Come to think of it i'm about 80% sure the cables are outsourced and grado says so himself.

They'd also have to manufacture the pads tho

I think somewhere on the grado website it says their initial tool investment was $5000 but that's because they made their own tools or something. even so, 5 grand isn't much

looking over the primo website again, i'd say it's definately not the dh-32 so i'm kinda glad they wouldn't sell it to me the shape is kinda wrong, the hole patern is wrong, the impendence is wrong and the back of the driver is wrong design too.

on the other hand, the DH-57 has the exact right hole patern, has cloth over the front like grados do, has accoustic filter over the back like grados do and the back looks to me to be the same as my grado drivers. that's starting to get to be a fairly big coincidence since none of their other models have either the correct front of back.

however, the impendence is wrong at 40ohms. i dunno if changing the voice coil would change that or if there are other simple ways to change it but that's certainly standing in the way. aslo their sensitivity is 100db@1mw vs 98@1mw of grados

i may try and order some, since i'm not just snooping around and i really do want to build an array of little drivers

Quote:

# High quality, wide range stereo headset driver # Highest quality headset application

If grado were to use a primo driver it'd make sense for them to use the highest quality one.

 

[mjg]

it is very obvious he doesn't make the pads. (Todd's flat pads ring a bell?)


They are from the same original source supposedly.

 

[kramer5150]

Quote:

Originally Posted by hugz Come to think of it i'm about 80% sure the cables are outsourced and grado says so himself. They'd also have to manufacture the pads tho I think somewhere on the grado website it says their initial tool investment was $5000 but that's because they made their own tools or something. even so, 5 grand isn't much looking over the primo website again, i'd say it's definately not the dh-32 so i'm kinda glad they wouldn't sell it to me the shape is kinda wrong, the hole patern is wrong, the impendence is wrong and the back of the driver is wrong design too. on the other hand, the DH-57 has the exact right hole patern, has cloth over the front like grados do, has accoustic filter over the back like grados do and the back looks to me to be the same as my grado drivers. that's starting to get to be a fairly big coincidence since none of their other models have either the correct front of back. however, the impendence is wrong at 40ohms. i dunno if changing the voice coil would change that or if there are other simple ways to change it but that's certainly standing in the way. aslo their sensitivity is 100db@1mw vs 98@1mw of grados i may try and order some, since i'm not just snooping around and i really do want to build an array of little drivers If grado were to use a primo driver it'd make sense for them to use the highest quality one.

Can I get in on your batch order?

YGPM

Thanks,
Garrett

 

[hugz]

Certainly looks similar..

But not so flattering (or flat).. maybe i'm barking up the wrong tree

 

[kramer5150]

Quote:

Originally Posted by hugz Certainly looks similar.. But not so flattering (or flat).. maybe i'm barking up the wrong tree

Dont forget thats probably "free air".... No enclosure in back and no enclosed air volume in front of the driver.

Driver resonance and impedence changes to varying degrees depending on how the driver is loaded in front and behind.


Its 1 AM and Im thinking up more DIY ideas

Garrett

 

[MdRex]

This could be a BIG discovery... If you ever succeed in getting those drivers, I am interested as well...

 

[taymat]

Quote:

Originally Posted by hugz Certainly looks similar.. But not so flattering (or flat).. maybe i'm barking up the wrong tree

If you look here:
http://graphs.headphone.com/index.ph...ame=Grado+SR60
you'll notice there are so many similarities in the frequency response as well as the look of the drivers. If this driver isn't used in any of the grado lines, modified or not, I'd be surprised. The peaks are a bit up on what's been measured by headroom, and the bass is a bit rolled off.
The key point though is that they're at the same frequencies as the sr-60, and driver resonances will probably be damped by an enclosure and the bass boosted. I mean any speaker designed to work in an enclosure has zero bass out of it and clearer highs. This is probably the main reason why the rs-2/1 have better bass and lesser frequency peaks than there non-wooden counterparts as well, because the cups are bigger and they're also supposed to be daubed with some chemical, to soften the drivers a little and so their response.

 

[hugz]

Quote:

Originally Posted by taymat If you look here: http://graphs.headphone.com/index.ph...ame=Grado+SR60 you'll notice there are so many similarities in the frequency response as well as the look of the drivers. If this driver isn't used in any of the grado lines, modified or not, I'd be surprised. The peaks are about 4db up on what's been measured by headroom, and the bass is a bit rolled off. The key point though is that they're at the same frequencies as the sr-60, and driver resonances will probably be damped by an enclosure and the bass boosted. I mean any speaker designed to work in an enclosure has zero bass out of it and clearer highs. This is probably the main reason why the rs-2/1 have better bass and lesser frequency peaks than there non-wooden counterparts as well, because the cups are bigger and they're also supposed to be daubed with some chemical, to soften the drivers a little and so their response.

Hm jesus you're right.

that's freeky similar.

if any model would match it would be the sr60 because grado modifies the voice coil in sr125+

Well i sent off another email this time requesting that model. Wish me luck. I'm not feeling overly confident though- i suspect they dont like dealing with end users.