The Ultimate DIY Part 2 ? The KGITSOJC

[alexd15z6]

Clear - thanks a lot Kevin .

 

With respect 

Alex

[kevin gilmore]

actually we should rename this thread KGITSOCH

because this input section is virtually the kx-r with a few mods

that make it even lower distortion, lower noise, and faster.

No feedback of any kind.  Should be doing a test run of boards very soon

 

http://gilmore.chem.northwestern.edu/ubaltobal2.jpg

Edited May 15, 2014 by kevin gilmore

[kevin gilmore]

http://gilmore.chem.northwestern.edu/ubaltobal.jpg

rest of the parts on monday

Edited May 30, 2014 by kevin gilmore

[nopants]

does eBay sell zchannel devices? I am not seeing them when I look them up at RadioShack

[kevin gilmore]

nopants you are fucking idiot. birgir and I spend hundreds of hours on this stuff

and you make a stupid joke. not funny

input board complete and works perfect. thd less than the base of my ancient test gear

(<.002% thd, and absolutely flat)

picture later.

[nopants]

I apologize, I wasn't undermining your effort in any way

[kevin gilmore]

http://gilmore.chem.northwestern.edu/ubaltobal1.jpg

[Kerry]

Looking good.

Have you had a chance to test this yet?

[kevin gilmore]

I have tested it, listened to it, works great.

offset is 1.5mv

 

going to swap out the opa445 for op27 and then remove

the offset pots. and probably add a pot on the pnp current

source to do a final trim.

 

input impedance with the bipolars is 10k.

replace them with the jfets and it works better

[kevin gilmore]

should be final rev's of these two boards

 

unbalanced/balanced to balanced

http://gilmore.chem.northwestern.edu/ubaltobald3.zip

 

ss dynalo balanced

 

http://gilmore.chem.northwestern.edu/kgdynalobal5.zip

[kevin gilmore]

http://gilmore.chem.northwestern.edu/dsc_0585.jpg

http://gilmore.chem.northwestern.edu/dsc_0586.jpg

 

on +/-15v power supplies maximum output is 16 volts peak to peak balanced into 50 ohms

on +/-20v power supplies maximum output is 22 volts peak to peak balanced into 50 ohms

Edited June 20, 2014 by kevin gilmore

[Algar_emi]

Hi. I'm very interested in a group buy for this preamp. Keep me posted. Thanks

SB

[Algar_emi]

Can I find the power supply you used in one of the posts, or it was not posted yet? Thanks

SB

[mypasswordis]

Input JFETs just came in the mail. Most of them look real, there are a couple 2sk170s that have funky looking printing on them that I'm not sure about. Will measure IDSS later. 

 

Finally the project can move forward! Actually, I still need to get a few more things. Just ordered the amp and PS cases yesterday, and am about to put in a final mouser order for some other parts. I'm going to be out of town this weekend but should have the attenuator boards and Multi Amp up and running fairly soon, and breadboarding the ubal to bal and phono boards will shortly follow.

[nopants]

So the poverty version of the KGITSOJC would be the ubal to bal (stuffed with jfets) driving the dynalo boards? And I guess a switch between pre and headphone outs?

 

I'm curious about this dynamic piece of equipment, but Iv'e only got k401s and some random onkyo I found lying around. 

[mypasswordis]

If you're interested, have the KG or similar digital attenuator boards, and are willing to wait a couple more months (really sorry about that, I'm pretty busy these days and don't have enough time to do much except sleep by the time I get home), I'll hopefully have finished the microprocessor and touchscreen code, and the android app code to implement in the KGITSOCH so you can build the full version. I aim to finish soldering most if not all the amp hardware this weekend but not sure about the next time I'll have some free time. My Nexus 4 should be getting the Lollipop update sometime next week and I think I'm planning on getting the Nexus 6 anyway (verdict still out on whether or not it's too big) so I can use them to test the app.

 

The only dynamic headphones I still have are a couple of vintage orthos.

[kevin gilmore]

i've started working on the 4dsystems 3.2 inch touch lcd again. I think its the right

answer whether you use it standalone, hooked to a arduino, or raspbery pi, beagleboard etc.

 

still looking for an easy solution that combines this display with a wifi enabled web page

controller. (yep i'm lazy)

 

will publish the 4dsystems standalone code when i have time to test it.

[kevin gilmore]

volume and balance now working with the real attenuators

http://gilmore.chem.northwestern.edu/dsc_0626.jpg

 

something else could be used to feed the serial port with

an infrared or web based controller.

[G600]

Any finished system here ?

I also would like to know if mpsa are OK for the ubal to bal boards ?

And what is the proper way to use them with dynalo mk2 ?

Thanks

[mtoc]

i ve bought several so called new old stock mpsw06 from ebay and waiting for the jfet version...

[purrinn]

Hello, what're these things?

[G600]

LEDs

[starcat]

Hey Kevin, is there a new continuation thread to this somewhere, or did you just stopped this project? Hope you are well. 

[starcat]

No pictures, not even posts anymore... c'mon guys, don't be shy and show off your work 🙂

Edited June 28, 2021 by starcat

[TC1980]

Hi

Could somebody help me out please? I have started building the KGITSOJC, got the boards and the components. What resistor value should I use for resistors labed RF on the silkscreen? For the power supply I'm building GRLV, is it okay to use +/-15V or should I use +/-20V? I have a suitable transformer for 15V output already, but I can get a new one if it is better to use 20V rails.