[GROUP BUY] G9 in 51X format (CLOSED, ALL STOCK GONE)

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gemini86 said:
PCBs, faceplates and metal have all been ordered. Will keep you all updated on the status of our stuff.
hey, I missed this post.  Good news!

 
I'll make sure to send yours out ASAP, since I know you have time constraints. They're in production now, scheduled to ship out on the 24th. Shipping shouldn't be much more than a week.
 
Gemini:

I want to thank you (on behalf of all of us readers and participants, lest this turn too gooey) for your prompt and clear communication, and incredible schedule.  You are moving REALLY fast on this (take a look at some of the other feelers and even some white market threads (with no offense intended) and you will see that often the month changes on the thread before anything happens ... sometimes the YEAR! )

You on the other hand are a machine!  On your thread... sometimes the day doesn't change!  It is very exciting, and I really appreciate it. Shipping out the the day before christmas is sort of amazing, and while appreciated, don't burn yourself out.

Thanks for doing it.

Bruce
 
Thanks for the kind words. I know i was a no show for a while when i was having dc converter issues, as well as personal issues, but i felt bad for keeping everyone in the dark. Development takes a long time, and a lot of money. I wanted this project to be clean and the layout correct the first time. My 9k2 pcbs are a good example of rushing it and dealing with the consequences.

I see now that my earlier post could be easily misunderstood. The pcbs will ship from fabrication on the 24th. I'll likely get them after Christmas.

I'm already starting work on my next project. Trying to keep it under wraps until i have more set in stone. Just a hint; pentode based classic.
 
Hi Rodney,

it is no problem for me! I know it and i gladness to read when the end is near  :)

Regards

PS. if you have time, can you check the BOM that I posted?
 
gemini86 said:
I'm already starting work on my next project. Trying to keep it under wraps until i have more set in stone. Just a hint; pentode based classic.
51X as well?  If so I might have to keep on the 51X wagon a bit longer and will need metal for my G9s!  cheers!
 
Nice work - great project. This reminds of something I've been thinking about trying, though:

Wouldn't it be handy to use maybe 48VAC (24VAC might also be plenty) connected to the 51X 24VDC pins, instead of the usual +-VDC higher rails, in order to experiment with tube stuff in general, and on-board regulation and would allow doublers and triplers and whatever for higher anode voltages?

The only thing I'm concerned about at first blush is possible noise coupled/induced elsewhere. Obviously, the normal 51X boards wouldn't work in it, but I could see splitting a backplane for half real 51X, then half special tube side, with two different supplies.

I could see potential for higher current applications like even maybe modular guitar amps, monitor amps, etc., assuming no noise issues and current handling of the backplane traces was there. Hmmm - do Tonelux already do something like this? (sorry, thinking out loud here)

Oh - I plan to order a couple of these boards shortly - thanks.

Frank
Area8




 
Hi there. Take a closer look and see that the b+ voltages are already at around 240v. The boost converter that generates this voltage is much much more efficient than a Trippler/Quadrupler could ever be. This module is designed to go in a 51x rack.
 
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Wouldn't it be handy to use maybe 48VAC (24VAC might also be plenty) connected to the 51X 24VDC pins, instead of the usual +-VDC higher rails, in order to experiment with tube stuff in general, and on-board regulation and would allow doublers and triplers and whatever for higher anode voltages?

there's a tested working prototype built with boards ordered , let us know if you get something working though
 
Hi, and thanks for the replies... I might not have made myself very clear, for which I apologize -

Firstly, Gemini, I wasn't making any commentary on your current design for the current 51x std, which I find excellent, and realize that you already have high B+ after conversion, so I wasn't implying by any means that you didn't - looks like an excellent solution.

My idea, which I've kicked around since I first received my 51X chassis, was to use AC voltage on the 24V pins, in order to more easily support on-board triplers and such, for general tube work (not related to your current board, and didn't mean to hijack - you just reminded me), including potentially things other than our traditional recording gear. I think it might be a good, flexible way to support lots of different voltages without resorting to DC-DC converters and such, and hopefully lowering the cost. My biggest concern is the likelihood of AC coupling of 50/60Hz.
And yes, I realize that current gets cut in half every time you double voltage. Supply enough current (not that a couple of plates generally take that much to begin with), and no problem.

Anyway, just an idea for now, but I'm thinking about splitting my 11-slot backplane to try it sometime (after I finish about 12 other projects), or just try it on a jig (like Igor's) first.

And now back to your originally scheduled program...

Cheers,
Frank
Area8
 
BTW - I like the little MAX1771 you used - nice converter at a good price. Looks like an excellent boost circuit, overall.

Frank
 
Yeah, the separate connection would have to be kludged somehow, and need to use a separate supply with the AC. The backplane would need to be split (physically cut traces between two halves) in this case... or you could use a 51X chassis as-is, but use a different supply with the AC on it, not the usual one. I used to cut computer backplanes all the time as part of a normal installation of "mini-computers" back in the day, so I know it isn't particularly hard to do. (There can be termination issues, though we aren't dealing with high-frequency data or RF here, just (relatively) low freq AF and some voltages.)

Please don't go trying this based on my idea, unless you really know what you are doing and you are ready for some serious testing for noise, and any Murphy factors I haven't considered yet - I haven't tried it yet. It could well turn out to be a really bad idea; I've had my share of them over the years (and a few winners, too).

When I get around to trying this, I'll breadboard something and use Igor's "Rackit" jig first to connect everything to just one slot... that won't tell me anything about noise or crosstalk to other slots over a backplane or anything, but it will let me get something working first. It'll be awhile.

Unless you are really adventurous, please stick to this fine G9 board. Please.

Cheers,
Frank
Area8
 
I still don't understand why you would want a voltage multiplier with all of it's losses in heat and diode drop, not to mention adding a huge ac signal right there at a very audible 60Hz, over a high efficiency boost converter. The converter can be tailored to suite whatever voltage you want, from 48v to 400v. If you're going to put AC voltage in the rack, put 120V in there so you can have small transformers in board. This would then be a totally different type of rack, and more like the old telefunken/siemens series of modules, which is not a bad thing at all. But then, why not do it based on a DIN rack, something more widely used for non specialized purposes, therefor cheaper and readily available.
 
Hi Rodney,

Hey, what's the status on delivery of the stuff?, forgive me if i missed it. BTW, thanx for doing this cool project for us, I'm really looking forward to building my pair.
 
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