Another potential stunner from Greg Ball

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Greg has made it known that a new iteration of the SKA is comming.

He hasn't given much away other than its a few weeks away and this:

It's a nested design with the potential for < 0.00001% THD. Trouble is my test resolution is only barely 110 dB or 0.0003% so I can't finesse it further without a balanced and higher resolution soundcard with higher sampling as well.

Looks interesting and I'm a fan of the original SKA so this is good news.
 

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diyAudio Member
Joined 2004
anatech said:
Hi ShinOBIWAN,
It's always nice to hear of success. Too bad Greg didn't go for a thread in the Vendor's Bazaar. He can't market these kits through discussions in general threads. I assume this will be a kit as well?

-Chris

Sigh...

Greg isn't marketting anything, at least not here in this thread. I took the initiative and made mention of it because it looks exciting.

Since this is obviously a contravention of diya bureaucracy, feel free to close/move/delete or whatever it is you do so well. I was however hoping for some discussion, a crazy idea I know, shame on me for thinking this was a forum of all things :rolleyes:
 
sounds interesting: an updated version of one of his older successful designs with stuff he learned for the SKA.

i wish the picture was better quality. it might be fun to guess at the design until it's shared.

and how can you measure distortion that low with a pc anywhere nearby

mlloyd1
 
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Hi ShinOBIWAN,
Actually, I'm glad you mentioned it. A discussion is fine as long as we stay away from marketing. Just being cautious given the history.

I am glad to hear Greg has something else good on the go. It's just that we are talking about a product, not a project. We need to remember that. Say hi to Greg for me.

Your comments and impressions are welcome on Greg's work.

-Chris
 
diyAudio Member
Joined 2004
anatech said:
Hi ShinOBIWAN,
Actually, I'm glad you mentioned it. A discussion is fine as long as we stay away from marketing. Just being cautious given the history.

I am glad to hear Greg has something else good on the go. It's just that we are talking about a product, not a project. We need to remember that. Say hi to Greg for me.

Your comments and impressions are welcome on Greg's work.

-Chris

As you may or may not already know, I've sold my GB150's and GB300's.

So rest assured that I have little interest in anything other than the technical merits of the design. I'm thinking of giving this one a try but will likely wait for opinions to come in before purchasing. Since little is known then I guess that it will be guesswork for now.

If the SKA is anything to go by, Greg won't be detailling design specifics unfortunately. I should imagine a schematic without values will be forthcomming though but don't quote me on that.
 
ShinOBIWAN said:


As you may or may not already know, I've sold my GB150's and GB300's.

So rest assured that I have little interest in anything other than the technical merits of the design. I'm thinking of giving this one a try but will likely wait for opinions to come in before purchasing. Since little is known then I guess that it will be guesswork for now.

If the SKA is anything to go by, Greg won't be detailling design specifics unfortunately. I should imagine a schematic without values will be forthcomming though but don't quote me on that.

Shinobiwan,

Why did you sell SKA?


(Still haven't heard one... any one in Sydney??)


WRT new SKA, looks like Greg is doing the OPA627 front end
version that he has mentioned elsewhere.

Cheers

Terry
 
diyAudio Member
Joined 2004
Terry Demol said:


Shinobiwan,

Why did you sell SKA?


(Still haven't heard one... any one in Sydney??)


WRT new SKA, looks like Greg is doing the OPA627 front end
version that he has mentioned elsewhere.

Cheers

Terry

A couple of small objections to the sound were the reason for selling. I've got a bit of weakness for swapping and trying out different things audio related, so that factors in too... sometimes you don't realise how good you've got it until you swap to something else.

Greg did make mention of the opamp used:

The chip's a BB OPA134PA (not TI) and the design is totally DC coupled so no DC adjust, no servo, with < 10mV (typ 5mV) at the output. The Tcomp is the NTC bead thermistor shown.
 
ShinOBIWAN said:


A couple of small objections to the sound were the reason for selling. I've got a bit of weakness for swapping and trying out different things audio related, so that factors in too... sometimes you don't realise how good you've got it until you swap to something else.

Greg did make mention of the opamp used:


OK. What did you go back to or aquire to replace it?

cheers

Terry
 
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Hi ShinOBIWAN,
No, I didn't know you sold your amps. The never ending search for better amps - or different flavours I guess. ;)

I'd very much like to see a no value schematic as well. Just for technical interest. You never know what kind of ideas our members may have to improve it.

Ever curious, what characteristic of the sound didn't you like? I'm just wondering if it's a standard output mosfet thing, or something else.

-Chris

Edit: Did the cat come quietly, or did he make a break for it? :D
 
anatech said:
I'd very much like to see a no value schematic as well. Just for technical interest. You never know what kind of ideas our members may have to improve it.

I have to confess to being annoyed when people promote kit amps without providing any details. If a design is any good, it should be able to stand up to scrutiny, I reckon. Hiding good designs does nothing to advance the tate of the art.

Sure, for the person selling the kit, they'd prefer people bought the kit rather than copying the design, but I'd think that publishing the design openly would lead more people to buy the kit.

Hey, Fender publish the schematics for their guitar amps, and it certainly doesn't hurt their sales.

Cheers,

Suzy (just bought an Ibanez guitar and a Fender amp, after checking out its schematic on the web)
 
Hi Suzyj,
Amp guru did post the schematic but with a couple of areas blotted out or with simplifications. Someone even came up with a temp compensation arrangement that he thought would mimic the missing part of the schematic and Greg confirmed it was similar.

He is trying to start up a business and was hoping that this Forum would give him access to a market to make a bit of money, but not a lot.

I believe the full schematic is released with the kit when one purchases it.
To date all purchasers have kindly refrained from making public the full schematic.
 
suzyj said:


I have to confess to being annoyed when people promote kit amps without providing any details. If a design is any good, it should be able to stand up to scrutiny, I reckon. Hiding good designs does nothing to advance the tate of the art.

Sure, for the person selling the kit, they'd prefer people bought the kit rather than copying the design, but I'd think that publishing the design openly would lead more people to buy the kit.

Hey, Fender publish the schematics for their guitar amps, and it certainly doesn't hurt their sales.

Cheers,

Suzy (just bought an Ibanez guitar and a Fender amp, after checking out its schematic on the web)

Hi Suzy,

If someone really wants the circuit they're going to get it.

It's funny you mention Fender, because the original Marshall
JTM45 was, I believe, copied from a (Fender) Bassman almost
directly.

And I think Jim (Marshall) sold a few of them :)

Which Ibanez and Fender did you get Suzy?

I have an old Ibanez electric something from 20 years or so ago
that has a light Basswood body and Floyd Rose on it.

Swapped the pickups out for Bill Lawrence (humbuckers) and a
mini humbucker in the neck, built an active pre amp (buffer),
completely stripped the 1mm thick 2 pack finish, replaced the
scratch plate with a hand made (Jarra) one and it sounds pretty
good.

I also have a '63 (Fender) Bandmaster that is great.



Oh... did you get that SS amp finished?

Cheers,

Terry
 
This new design is based on Greg's unique SKA topology and
I doubt he would want his schematics published until his patents come through. It does say Patent Pending for a reason.

There has already been a suggestion that his original design IP has been sold to China and I notice he has removed the conceptual design from his website.

Would you give your livelihood IP away by posting it on the internet, Suzy? :)
 
Terry Demol said:
Hi Suzy,

If someone really wants the circuit they're going to get it.


Yeah, I agree. Especially with something as simple as an audio power amp, and especially if he's offering kits.

Terry Demol said:
Which Ibanez and Fender did you get Suzy?


It's an Ibanez SA160. A very pretty guitar, methinks. I was looking for a Strat copy, and was really impressed at the quality of the Ibanez for the money.

I've had "learn guitar" on the to-do list for the last couple of decades. It's really good now to finally be doing it, though my fingers are quite sore, and I really am hopeless at it :) It'll be quite a while before I'm a match for Mark Knopfler, methinks.

The amp is just a straight-forward 15W frontman (transistor) one. It's cheap and cheerful, and surprisingly loud. I toyed with making one, and did a bunch of simulations under LTspice, but in the end simply bought a cheap amp, as there was no way I could build an equivalent for the money.

Truth be told, the thought of deliberately designing distortion into an amp makes me cringe!

Terry Demol said:
Oh... did you get that SS amp finished?


It's on the go at the moment. I'm expecting PCBs back from BEC on Monday (actually Tuesday as I've taken Monday off). I've been working on a matching preamp as well (see http://www.littlefishbicycles.com/preamp/) which has been heaps of fun.

After I've put the power amp and supply boards together, I'll start on the enclosures. I'm thinking of having some nice machined front panels made to match my other NAD components (which will probably end up costing me an arm and a leg). Have you seen the emachineshop software? I've used it to design my front panels, and it's heaps of fun.

HiFiddle said:
This new design is based on Greg's unique SKA topology and I doubt he would want his schematics published until his patents come through. It does say Patent Pending for a reason.

There has already been a suggestion that his original design IP has been sold to China and I notice he has removed the conceptual design from his website.

A patent, huh? That would mean that there's something in there that's totally new. If he's really found something new, then he should publish his results for peer review.

HiFiddle said:
Would you give your livelihood IP away by posting it on the internet, Suzy? :)

Yes, I would (and do). As they say, publish or perish.

Regards,

Suzy
 
Ex-Moderator
Joined 2002
Certainly in the UK, if you publicise your invention before the patent is granted, it is invalid. Patent Applied For means absolutely nothing in legal terms. If there is a patent, we will see it all when it's published. Until then all we can do is speculate pointlessly, or just buy the kit and find out. ;)
 
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Paid Member
Hi HiFiddle,
I feel for Greg, but as I told him, the first item you sell, the secret is out. Schematics with values will not make a successful rip off. Getting the entire device means you have the latest rev and a working model. It's only a copy job after that.

At least all of us know it's his IP. We can accredit Greg with the design (well, maybe. Since we haven't seen it). I don't understand how all the patent laws work. I do have the feeling they only give you the right to bring suite. Not that helpful for a small guy like most of us. Money then becomes the deciding factor.

Professional ethics are the only thing that maintain order. For those in the world who have none, they degrade life for the rest of us.

-Chris
 
pinkmouse said:
Certainly in the UK, if you publicise your invention before the patent is granted, it is invalid. Patent Applied For means absolutely nothing in legal terms. If there is a patent, we will see it all when it's published. Until then all we can do is speculate pointlessly, or just buy the kit and find out. ;)

Not exactly true. In most of the world (UK included) you must apply for a patent before publishing. In fact, the patent office itself publishes the application before it is granted. In the U.S. you have a year from from first disclosure to file.


That said, it's still up to the discretion of the inventor as to disclosure of the invention prior to publication of the patent application. You may not want to give your competitors a head start on work-arounds. Also, people may simply ignore the patent. The inventor may not have the means to enforce the patent - it costs money, and lots of it. So why give them an early start? Also, at the time of application the inventor is obligated to disclose the best way to realize the invention. After that, the invention may evolve and become better. Even if the improvements are patentable, the inventor may chose to maintain them as a trade secret, instead of disclosing them in a patent.

Sheldon
 
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