Project: OsoMiso - SALSA - RolandJay's Tweeter 45/45 head.

Anything goes! Inventors! Artists! Cutting edge solutions to old problems. But also non-commercial usage of record cutting. Cost- effective, cost-ineffective, nutso, brilliant, terribly fabulous and sometimes fabulously terrible ideas.

Moderators: piaptk, tragwag, Steve E., Aussie0zborn

Post Reply
User avatar
EpicenterBryan
Posts: 738
Joined: Sun Aug 10, 2014 9:01 pm
Location: Eugene, OR USA

Project: OsoMiso - SALSA - RolandJay's Tweeter 45/45 head.

Post: # 45160Unread post EpicenterBryan
Sat Dec 10, 2016 9:58 pm

Hey guys,

Here is the first look at ROLANDJAY's 45/45 tweeter head. It's filed under the OsoMiso parent name. There are really three heads that MarkRob, ROLANDJAY and I are working on: ONO, PICANTE and SALSA. The end goal is to select the best performing design, and either to make a few heads for sale, or perhaps offer kits with the hard to make parts so a guy can put one together themselves.

This SALSA head uses the Souri tweeters several people are messing with, but it employs a Neumann style Torque tube and V spring (made by John). His prototype body was machined out of nylon.

One of the design constraints on this head was to try to make it as small as possible so it fits a Presto. Let's take a look at this head compared to my Presto 1D head. As you can see it's pretty small. The Neumann style stylus is a bit too far forward. John will try to move the drivers back a bit more but there is a limit to how far back the drivers can be positioned because of the size of the drivers. For 6N users, it means there will be a slight non-tangent cutting error. He will try to minimize that.

Also, although it looks like the mounting holes are in the correct position compared to the 1D shown in the photo actually the mounting holes and the rear mounting tabs need to be moved higher. That's because the Neumann stylus is so much shorter than the length of a long shank presto stylus. John doesn't have a Presto and missed that...
Salsa vs Presto sizes.jpg
John worked up this head before Mark and I ran into the loss of HF when testing the ONO head and my first tests of the Picante head with metal cone / push rods. In this head he machined plastic cones but they did not extend all the way to where the voice coil was located inside the driver. That turned out to be an issue and resulted in a similar HF loss. He also didn't make provisions for the X springs. That effected the channel separation. But we decided to run it through the paces and see how it worked anyway. Below are some photos mounted on my 8D lathe. The head is very light, so I added a super thick washer as a weight.

Also shown is what angle the 8D overhead had to be positioned at to make the cut tangent to the disc . On a 6N you can't adjust the angle to insure cutting is tangent - so on this version there would be a small error if mounted on a 6N.
Salsa Mounted.jpg
Another thing to note: The 8 degree back angle needed for the Neuman style torque tube is not incorporated on this prototype, so I used a 3D printed 8 degree shim to get the cutting stylus perpendicular to the disc. In the next version, John will incorporate that back angle in the head. Also, I had to grind the front of the head body to provide clearance from the disc. John will fix that. Again, it had to do with forgetting about that 8 degree back angle.

Here is the HF response.
Please note I forgot to bypass the iriaa low frequency boost in this plot, so it looks like the head is pretty flat in LF. It is not. It has the usual LF rise. But I didn't have iriaa engaged in the HF range and this is a flat playback from disc. So the HF roll off is real, and that's what is interesting.
John tweeter head.JPG
What you see here, is again an example of HF decoupling from coil to torque tube. I talked with John and as it turns out the area between the cone and voice coil was not stiffened.

I have sent John some bigger funnels as mentioned in this post that he can machine to fit the drivers exactly where the voice coil is:
http://lathetrolls.com/viewtopic.php?f=15&t=6942

So stay tuned for an update on SALSA when John has time for rev 2. I would say we learned a few things from Rev 1 anyway. Testing it confirmed what we saw on ONO testing.

Rock on people. Thanks to everyone involved!

Bryan
You do not have the required permissions to view the files attached to this post.

User avatar
Gridlock
Posts: 286
Joined: Tue Jun 21, 2011 6:41 pm
Location: eugene oregon

Re: Project: OsoMiso - SALSA - RolandJay's Tweeter 45/45 hea

Post: # 45164Unread post Gridlock
Sun Dec 11, 2016 3:06 pm

Haha Bryan you guys are RIDICULOUS! Or maybe I am for wanting to test it on the k8.
<\\\\\\\\\\\\\\\\\\\\\[[[[[[[\/]]]]]]]\\\\\\\\\\\\\\\\\>
Recordette Sr.......Presto K-8

User avatar
crowesBR
Posts: 93
Joined: Mon Apr 11, 2016 7:17 pm
Location: San Francisco, CA
Contact:

Re: Project: OsoMiso - SALSA - RolandJay's Tweeter 45/45 hea

Post: # 45978Unread post crowesBR
Mon Feb 06, 2017 5:36 pm

That's nice.
Want to test in a 6N too. :)

User avatar
crowesBR
Posts: 93
Joined: Mon Apr 11, 2016 7:17 pm
Location: San Francisco, CA
Contact:

Re: Project: OsoMiso - SALSA - RolandJay's Tweeter 45/45 hea

Post: # 45982Unread post crowesBR
Mon Feb 06, 2017 8:35 pm

What is the model of the tweeter? Pro-Tech 2/419?

Thanks

User avatar
EpicenterBryan
Posts: 738
Joined: Sun Aug 10, 2014 9:01 pm
Location: Eugene, OR USA

Re: Project: OsoMiso - SALSA - RolandJay's Tweeter 45/45 hea

Post: # 45984Unread post EpicenterBryan
Mon Feb 06, 2017 10:17 pm

crowesBR wrote:Want to test in a 6N too. :)
One of the issues with the 6N is not only trying to get the stylus really close to the position of the stylus for the 1C or 1D head to minimize cutting distortion due to non-tangent movement since the 6N over head is what it is and can't be adjusted backward. The other issue is getting the footprint as small as possible so the 6N dampener doesn't have to be re-located. The stock 6N over head is a tight fit.

John has been working on it. He should be sending me a new version to try soon.

Bryan

User avatar
EpicenterBryan
Posts: 738
Joined: Sun Aug 10, 2014 9:01 pm
Location: Eugene, OR USA

Re: Project: OsoMiso - SALSA - RolandJay's Tweeter 45/45 hea

Post: # 45985Unread post EpicenterBryan
Mon Feb 06, 2017 10:19 pm

crowesBR wrote:What is the model of the tweeter? Pro-Tech 2/419?
I think so. They are the ones Souri uses from what I understand.

Bryan

User avatar
crowesBR
Posts: 93
Joined: Mon Apr 11, 2016 7:17 pm
Location: San Francisco, CA
Contact:

Re: Project: OsoMiso - SALSA - RolandJay's Tweeter 45/45 hea

Post: # 45986Unread post crowesBR
Mon Feb 06, 2017 10:44 pm

Thanks Bryan
Keep us posted the progress.

Thanks
EpicenterBryan wrote:
One of the issues with the 6N is not only trying to get the stylus really close to the position of the stylus for the 1C or 1D head to minimize cutting distortion due to non-tangent movement since the 6N over head is what it is and can't be adjusted backward. The other issue is getting the footprint as small as possible so the 6N dampener doesn't have to be re-located. The stock 6N over head is a tight fit.

John has been working on it. He should be sending me a new version to try soon.

Bryan

User avatar
crowesBR
Posts: 93
Joined: Mon Apr 11, 2016 7:17 pm
Location: San Francisco, CA
Contact:

Re: Project: OsoMiso - SALSA - RolandJay's Tweeter 45/45 hea

Post: # 46033Unread post crowesBR
Wed Feb 08, 2017 1:20 pm

I made a quick cardboard body test and I only have a area of 4.5cm x 5cm to add a tweeter/transducer.

The main problem is that the dashpot is really close to the head.
Is hard to find a tweeter/transducer small enough.

Looks like the only solution is a custom built transducer. Maybe flozki, ROLANDJAYS or other users have some insight?

Image
Image
Image

Post Reply