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grounded grid

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It is an interesting comparison if only to see how great the triode strapped EL34 is.  ;D 

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  • Just like Carbon we built. Same box, same PS. Relay=120s. Separated filament transformer.      

  • Another Grounded Grid lives.  Have been listening to it for about a week. Powered by the same GRHV/GRLV PSU I use to power my KGSSHV, Carbon and Blue Hawaii. 400VDC rails and 20mA plate current.

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You will be put in charge of the plugs when the mafia starts to make headphones...  :)  ;D 

11 hours ago, kevin gilmore said:

staxmale5.jpg

Neutrik male pins, right?

Can they be bought somewhere? Don't like to slaughter good XLR connectors to get them.

You need to slaughter innocent XLR's to get them... 

I can get them cheaply. Let me know if you need.

They are something like these:

 

20150815_220602_zpssneduxse.jpg

Edited by chinsettawong

Nice connectors. I really like the color of the male.

Help appreciated. PM sent.

18 hours ago, kevin gilmore said:

seriously, ray has turned into a real sleezeball...

How do you tell?

Edited by guzziguy

On 2/17/2016 at 3:38 PM, JoaMat said:

Life is short. Would T2 accept EML 20B-V4 tall base?

IMG_1442.thumb.JPG.3263ce77ca71846b4cc99

Yes, she does! For how long?

is the el60 a viable replacement?  how do you wire the adapters?

EL60 is said to have the same characteristics as EL34 but it has 9 pin socket. The adapters are bought via eBay and quality seems OK. IMO EL60s are very good sounding tubes.

But not cheaper than EL34 !

Sold rk50. Got money enough for tubes, bottle of single malt and flower to wife.

49 minutes ago, JoaMat said:

Sold rk50. Got money enough for tubes, bottle of single malt and flower to wife.

it's spelled "flour" - probably a good idea to keep the wife occupied

technically this also means that the dht could be a sub for the el34 in the tube version of the circlotron right?

 

this is such a dangerous discovery

  • 3 weeks later...

Have listen to the DHT carbon style for three weeks now. It’s bloody good – think I like it more than the T2. Below is a draft of how a smd version of DHT might look.

56dddc0d20f74_DHT-3DVisualization.thumb.56dddc12b69fc_DHT-3DVisualization1.thumb

 

Edited by JoaMat

I love what you bring to this sport!  Nice job Joachim :D

Pick a lead.

IMG_1446.thumb.JPG.830d6671926a858076192

Ordered transformers for DHT filament. Not sure the brain was involved.

  • 1 month later...

Left channel is a GG. Followed Kevin’s schematic. Intention is to use Emission Labs DHT, didn’t dare to test it with DHT so it’s populated with some modern less expensive EL34. Right channel is an old Blue Hawaii. The combination of BH and GG works terrific.

IMG_1476.jpgIMG_1479.jpg

Is there any problem with that schematic? @congo5 reported KG's version won't work.

I haven't got it to work right, can't be much, a part choice of mine? or something really simple..

I occasionally do real stupid stuff and don't see it.

so far 3 boards and same result, low bandwidth (under 1khz)

Will revisit after finishing some other projects... (June?)

Had two resistors wrong......... Now it works

Edited by congo5

As I posted earlier I rebuilt a Blue Hawaii to GG. And now this new one. I can only say that Kevin’s GG works very well.

I’ve the opto servo on the board, didn’t flip (or, did flipped it, depends on ones perspective) the opto coupler when mowing it to the other side of board. After correcting the connections to opto coupler the servo still doesn’t work. Have to find the reason for failure. The opto servo should work, shouldn’t it?

Edited by JoaMat

While speaking servos. The small board between tubes on Blue Hawaii (right channel) is a servo a la T2 (picture a few posts up). Did built it after Kerry suggested that one maybe should do it simple when we tried different servos some year ago. That servo works great.

 

Edited by JoaMat

Regarding the opto servo. Eventually I spotted the fault. Transistor mounted the wrong way. Now servo working and it works very nice.

Really like the opto coupler. Many thanks Kevin.

Nice. I want to squeeze this project in next. Glad you got the servo working :)

  • 2 weeks later...

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. 

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