[BUILD] GIX-51X tube preamp

[mhuss]

Thanks again, Rodney.  This would be a lot easier to troubleshoot  if I had my 51x rack & PS in the same room as my workbench.  :-\

 

[mhuss]

I got a 7-pin XLR for my test jig from JS so I could bring my 51x PS down to the workbench and plug it in. 

On both units, in MIC mode with both gains maxed, I'm getting about 43 dBv gain (~48mv in / ~6v out) from the first grid of V1 (IN-SEC+) to the plate of V2 (OUT-PRI+) . Is this low or in the ballpark?

Thanks...

 

[maq3396]

Having been working on this for some time now but am having issues with it.

When powered on it is initially quiet but over 10 seconds or so this buzz begins.

Buzz tends to oscillate a bit....sounds like it is changing gears!

Volume of the buzz does not change with the position of any of the front panel controls.

It passes audio very well

Redone all solder joints and isopropyl ' ed everything.

Any help would be appreciated as I love the sound of this!

https://soundcloud.com/mac-quantz/voice-170217-1mp3

Thanks
Mac

 

[maq3396]

ok....seems to have resolved by itself!

Left it on overnight and the buzz has completely dissipated

Not the tubes as I tried a different set and they were very quiet as well.

Interesting as it has spent many hours on before!

At any rate I am a happy boy today!

 

[delaystomper]

Hi greetings to everyone ! I know i know im so behind on this project but i just recently joined the 500 series group  just got my rack a few days ago and im looking to build some modules . Im very interested on this gix-51x project , is there any one here that can tell me where to find the pcb's for this unit. I checked the schematic and layout but there is no pcb transfer on it . I know its been here for a while but not all of us were able to jump aboard on it earlier i will  appreciate any help
Thanks

 

[supersonic]

So how about the low frequency response in these ones?  Anyone with OEPs througout?

 

[iturnknobs]

Hello-

Any chance someone has an extra HV converter pcb or the files for it? Fingers crossed.

-Brian

 

[mtw]

I just bought a pair of half finished kits from another DIYer.

The additional bypass cap (the one on the underside of the board) that the seller sent me are too fat to fit between the PCB and the bracket. No problem, I bought some new ones.

I went to Mouser and got 10 of these: Multilayer Ceramic Capacitors MLCC - Leaded RAD 250V 0.1uF X7T 10% LS:5mm

However, they look nothing like the round caps I've seen in others' builds. The specs are same (0.1ufF/ 100nF and 250V rated) but they look more like little bypass caps than the larger "disc" type.

Will these caps I bought work for this build?

 

[choolder]

are there still kits available?

 

[87Gerhard87]

Hi Everyone,

I'm going through the thread and really exited to start with this project.
I just want to make sure and see if the Schematic and BOM on the first page has been updated as the thread went along. As the mods were added and the BOM changed. I am doing my own reading but it will be great if someone can confirm.
I'm thinking of making pcb's from scratch.

Thanks!

 

[gemini86]

Hello everyone-

It's been a long time since I was active here- life has been keeping me busy. I've been trying to make sure these files stay available. Due to Google's security changes, the old links were disabled and I have tried to make sure to update with current links that work. I do not have any time to try to support this project but I wish you all the best in your builds. I think the weakest link is the DC-DC converter, which was my first go with high frequency circuits. There may be off-the-shelf products that would work better than my home-made attempt. I challenge anyone to test some of the units you can get on mouser/etc.

Happy building!