grounded grid

[JoaMat]

Last few days I’ve had some annoying noise from one channel of my Grounded Grid. After a few hours on surgery table I found this three small resistors….

…..obviously I missed solder them on both ends. I’ve used the amplifier like this for almost four weeks before the noise started.

[guzziguy]

It needed 50 hours to burn in.

[JoaMat]

...fifty free hours, then

[nopants]

For the 4 tubes, is there really benefit to go unregulated PS or even regulated PS? Because I wanted to do two-box design and buckle the heater wire with others to use a single connector. I suspect AC 60hz noise will affect others. Heater for el34 needs 6.3V/1.5A each. So I will aim for about 10A for the PS. Also, the heaters are sitting at -450V, so the PS should be floated?

I wanted to go tiny and simple. For single regulator, I could only find MIC29712WT, which is only 7.5A max. 

I use ac heaters for everything without problems. maybe if it was in the input stage, but this isn't a megatron/t2

[JimL]

I used AC heaters in my SRX Plus and it is dead quiet.

[Kerry]

On ‎5‎/‎12‎/‎2016 at 10:44 AM, JoaMat said:

Last few days I’ve had some annoying noise from one channel of my Grounded Grid. After a few hours on surgery table I found this three small resistors….

…..obviously I missed solder them on both ends. I’ve used the amplifier like this for almost four weeks before the noise started.

I'm glad you found this. Not easy to spot.

[MLA]

Quick check before ordering a new batch; anyone with a pair of GG boards to spare from the GB?

[sorenb]

2 hours ago, MLA said:

Quick check before ordering a new batch; anyone with a pair of GG boards to spare from the GB?

there wasn't interest enough to do the GG boards back then ... and non has expressed interest so far ..I'm interested in some sets though

@eggil ? 
 

[G600]

I do too

[chinsettawong]

Count me in too.

[sorenb]

fill in your order here 

[MLA]

Cool!

I'll put in my number tonight, seems I can't edit the spreadsheat via phone on the road...

Done.

Edited July 23, 2016 by MLA

[UFN]

Can't access the sheet for some reason but please put me down for 1 pair of boards @sorenb

 

//UFN

[sorenb]

Ground Grid Group Buy closed, the sheet is view only by now

Edited July 24, 2016 by sorenb

[Arthrimus]

Well that was quick. I was hoping to get in for 1 set of boards for a build way down the road @sorenb

[sorenb]

@Arthrimus

Turned out that @congo5 had some boards he wanted to depart from and those are now distributed.

Let me open another round and include Carbon boards, HV PSU and GR LV.
Have got quite a few request for more Carbon boards, so we might probe if there are still interest.
Will open a new thread in an hour or so...

[Arthrimus]

Does the carbon/grounded grid REQUIRE two separate +/-15V supplies or is that just overkill for the sake of overkill. Basically I want to know if a Blue Hawaii power supply would work for the GG?

EDIT: I'm an idiot. I've been seeing a lot of carbons with the split GR LV boards and mistaking it as a pair of +/-15v supplies. I need to pay closer attention to this stuff. 

Edited July 31, 2016 by Arthrimus

[Kerry]

The Blue Hawaii PS will work fine with the grounded grid. The requirements for the +/-15V supply are identical.

Edited July 25, 2016 by Kerry

[palchiu]

On 2016/1/3 at 4:30 AM, kevin gilmore said:

About 300 ohms is the right number, don't know if that's total or just the tail resistor. Less ohms in the pot and most in the resistor is what we are aiming for.

zener needs to change to 18v

Dear KG,

I'm working Ground Grid's BOM,  Zener should be 18V or stay 12V that label on board?

Thank you!

 

[joehpj]

Is there any update on GG boards? There's only one version on KG's server, so I assume it's the final production version?

Edited July 25, 2016 by joehpj

[nopants]

is there any info on the reliability of eml tubes? kevin alluded to it in another thread but all I can find via Google is that all eml tubes have loose bases.

@joamat how have the v4's been treating you?

[Arthrimus]

In keeping with my long running penchant for putting the cart before the horse, today I whipped up a logo for the Grounded Grid that I hope to build sometime in the next year. If anybody likes it, feel free to use it.

 

Edited July 31, 2016 by Arthrimus

[DefQon]

6 hours ago, nopants said:

is there any info on the reliability of eml tubes? kevin alluded to it in another thread but all I can find via Google is that all eml tubes have loose bases.

@joamat how have the v4's been treating you?

I've had various EML tubes over the past few years which I avoid now due to QC and reliability issues they've had. My 300B's arc'd on first power up and after few hours of use and the construction inside is shit if you're concerned about looks but its really more than just looks that's the problem. One of my 300B's was missing the middle spigot and all of them had loose bases. Elrog and EML I both avoid. 

[JoaMat]

So far, got them in February this year, the EML 20B-V4 have treated me well. But I don’t think I know enough to judge their overall quality and reliability.

[joehpj]

http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=577DCA0C77

This is GG BOM I made for one board. Please check.

Please note: Need 1 pair of 2sk170 or LSK389, which is NOT included in BOM. 

grid resistor changed from 470R to 10K. I asked Kevin he replied there shouldn't be difference and higher value would be safer when the tubes fail. (T2 use 22K)

servo op changed from op27 to TL081 simply because latter is cheaper.

mounting kit, IC socket,pins, tube socket NOT included.

Zener changed to 18V.

Edited August 5, 2016 by joehpj