Decware Dynagrid rectifier - theory behind how it works?

[zackthedog]

Not sure what the intended conclusion is posting a photo of a partially-finished prototype.

Prototype, or production model in progress? I honestly don't know. But it's clearly a Sarah. And my point is that 1) it doesn't look very professional and 2) I'm not seeing the advantage of "point-to-point" wiring that sprawls over an excessive amount of real estate. Not to mention $5 volume pots, nylon stand-offs as bolts holding the sockets to the top plate, and cheap ceramic sockets with DIY PCBs soldered to them. If a socket breaks or the pins start loosening, you have to literally rip that assembly apart to replace it, or the least spend a lot of time desoldering the socket pins. Ask me how I know. ;-)

Maybe it is a prototype, or maybe it all gets tidied up in the end, but it looks more like a homebrew than a $5000 amp.

 

[gadget73]

The PCB mount sockets are a little weird.

I have shared tube socket mounting screws with terminal stips, and I guess in some cases it might make sense to share them with a standoff to mount something else. Not being specifically familiar with what the fully assembled unit looks like I'll hold off judgement on that.

 

[zackthedog]

I have shared tube socket mounting screws with terminal stips, and I guess in some cases it might make sense to share them with a standoff to mount something else.

So have I, but using metal nuts and lock washers. Given that a lot of tube enthusiasts regularly swap tubes in and out, I'd be concerned about using nylon as a retainer for those sockets.

 

[Selmerdave]

Prototype, or production model in progress? I honestly don't know. But it's clearly a Sarah. And my point is that 1) it doesn't look very professional and 2) I'm not seeing the advantage of "point-to-point" wiring that sprawls over an excessive amount of real estate. Not to mention $5 volume pots, nylon stand-offs as bolts holding the sockets to the top plate, and cheap ceramic sockets with DIY PCBs soldered to them. If a socket breaks or the pins start loosening, you have to literally rip that assembly apart to replace it, or the least spend a lot of time desoldering the socket pins. Ask me how I know. ;-)

Maybe it is a prototype, or maybe it all gets tidied up in the end, but it looks more like a homebrew than a $5000 amp.

Well, kind of lazy to copy and paste from an Audiogon post though. It's not excessive real estate when the amp is complete. No the standoffs are not a cheap replacement for nuts, there's nothing wrong with an ALPHA volume pot, and if you have a link to the cheap ceramic sockets that you are sure are being used, feel free to post it. This is designed to disparage.

 

[zackthedog]

Well, kind of lazy to copy and paste from an Audiogon post though. It's not excessive real estate when the amp is complete. No the standoffs are not a cheap replacement for nuts, there's nothing wrong with an ALPHA volume pot, and if you have a link to the cheap ceramic sockets that you are sure are being used, feel free to post it. This is designed to disparage.

Yes, my comment was designed to diparage. Yes, I did find that photo and a similar critique on Audiogon, and added my own observations. The little socket PCBs strike me as an especially problematic feature, having experience issues with them myself. In the end, there's nothing wrong with any of these things, but I question the value one is getting for the money one pays, and also, ultimately, the reliability of the build. And a three-year wait in the bargain. Compare the quality of this build to a Dennis Had Inspire 300B. It, too, is point-to-point but strikes me as a far sturdier and tightly coupled design:

 

[Selmerdave]

Yes, my comment was designed to diparage. Yes, I did find that photo and a similar critique on Audiogon, and added my own observations. The little socket PCBs strike me as an especially problematic feature, having experience issues with them myself. In the end, there's nothing wrong with any of these things, but I question the value one is getting for the money one pays, and also, ultimately, the reliability of the build. And a three-year wait in the bargain. Compare the quality of this build to a Dennis Had Inspire 300B. It, too, is point-to-point but strikes me as a far sturdier and tightly coupled design:

View attachment 3637822

Apart from being short a choke, that's very different than this?

 

[zackthedog]

Yes, I see a difference. Here's an even better example:

https://community.klipsch.com/topic/211838-dennis-had-inspire-amps-%E2%80%93%C2%A0what-to-expect/

Firmly-clamped power-supply caps, minimal signal path, indestructible Belton octal sockets, shock-mounted 300B sockets, thick steel chassis. But more to the point, if we want to talk about point-to-point wiring, I think there are better examples out there. Marantz, Leak, McIntosh, even modern manufacturers like Prima Luna. Heck, some of the better-made Chinese amps. By the same token, I'm not convinced it's necessarily a better way to build an amp. But I'm cognizant of the marketing angle.

 

[Selmerdave]

Yes, I see a difference. Here's an even better example:

https://community.klipsch.com/topic/211838-dennis-had-inspire-amps-%E2%80%93%C2%A0what-to-expect/

Firmly-clamped power-supply caps, minimal signal path, indestructible Belton octal sockets, shock-mounted 300B sockets, thick steel chassis. But more to the point, if we want to talk about point-to-point wiring, I think there are better examples out there. Marantz, Leak, McIntosh, even modern manufacturers like Prima Luna. Heck, some of the better-made Chinese amps. By the same token, I'm not convinced it's necessarily a better way to build an amp. But I'm cognizant of the marketing angle.

"Shock-mounted" LOL! He sells that for $6k and still no choke. You're a little short of info on both amps but clearly your comments about the Decware amp are just animus and not based on any actual facts about the actual product.

 

[zackthedog]

"Shock-mounted" LOL! He sells that for $6k and still no choke. You're a little short of info on both amps but clearly your comments about the Decware amp are just animus and not based on any actual facts about the actual product.

"Still no choke"?? That's your criterion? What difference does that make? Plenty of legendary tube amps dispense with tube rectifiers and chokes. And who the hell cares about a choke if the sockets break, or the 300Bs pick up vibrations from the chassis, or the volume pots are cheap and flimsy, or components come loose in shipping? The difference in build quality is patently obvious. Is the Sarah a magical amp that enables one to overlook the build quality? Maybe--I haven't heard one. But based on build quality alone, the Inspire strikes me as a safer investment and a better implementation of point-to-point wiring, if that's what you're looking for.

You're right about one thing--I don't know much about the actual circuit the Sarah uses. I can make a pretty educated guess about the Inspire, since Had tends to use the same basic tube compliment and circuits he employed during his days at Cary. If you're at all familiar with his work there's no secret there. And I have eyes! I can see what's inside and on top of both amps. Plenty of "facts" right there.

 

[BmWr75]

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