gemini86

Re: [BUILD] GIX-51X tube preamp
« Reply #320 on: September 27, 2013, 11:57:13 AM »
Toure, some people are lucky enough/brave enough to just plug it in and start running signal through it. I recommend powering the 24v rail alone and measuring the hv output to make sure it's working properly.
- Rodney

"...you better call Kenny Loggins, 'cause you're in the danger zone."


qmp audio

Re: [BUILD] GIX-51X tube preamp
« Reply #321 on: September 28, 2013, 02:10:48 PM »
are there any wattage specs for the resitors?  i have all 1/4w resisters.   r31 on the pcb is bigger... is 1/4w ok here?

gemini86

Re: [BUILD] GIX-51X tube preamp
« Reply #322 on: September 28, 2013, 06:11:09 PM »
R31 was specced at 2W for the original G9, but I haven't the slightest clue why. It really only needs to be 1/4W.
- Rodney

"...you better call Kenny Loggins, 'cause you're in the danger zone."

bruce0

Re: [BUILD] GIX-51X tube preamp
« Reply #323 on: September 29, 2013, 03:40:06 PM »
 I had the same question , a short in the tube or the ht psu would stress that resistor while it drained the reservoir and smoothing caps but i don't know how to calculate what is appropriate
"it was like heaven on earth, all those transformers" - cj

Toure14

Re: [BUILD] GIX-51X tube preamp
« Reply #324 on: September 30, 2013, 02:08:35 AM »
had my fingers crossed but i got the low whining/hum some have also experienced

Toure14

Re: [BUILD] GIX-51X tube preamp
« Reply #325 on: September 30, 2013, 12:08:36 PM »
Yeah so I tried again this morning and there is noticeable hum seems to die out a little bit with the filter set to 150Hz but it's still there. So do I need that rodney cap or is it the tubes? I ordered my tubes brand new as a matched pair with noise check. So the only thing they couldn't do was burn in. I don't know what burn in noise would sound like so I'm left to assume something is off.

Looking at the schematic am I correct to assume I check the HV Out at the molex connector closest to the tube?

My tubes heat up and nothing is smoking or burnt so kinda drifting at this point... :-\

gemini86

Re: [BUILD] GIX-51X tube preamp
« Reply #326 on: October 01, 2013, 12:46:09 AM »
Yes, the 'Rodney' cap is required to make the converter run smoothly.

- Rodney

"...you better call Kenny Loggins, 'cause you're in the danger zone."

Toure14

Re: [BUILD] GIX-51X tube preamp
« Reply #327 on: October 01, 2013, 01:15:17 AM »
so is that the source of my noise problem? and where do i get the Rodney Cap?

Toure14

Re: [BUILD] GIX-51X tube preamp
« Reply #328 on: October 01, 2013, 07:18:05 PM »
Just thought Id post pictures of my build so I can get some help with this annoying low but present hum. Don't know how to put all the pictures in 1 post so I will take up a few post

Toure14

Re: [BUILD] GIX-51X tube preamp
« Reply #329 on: October 01, 2013, 07:19:09 PM »
Top View


Toure14

Re: [BUILD] GIX-51X tube preamp
« Reply #330 on: October 01, 2013, 07:22:18 PM »
HV board with Cap installed across R503 and R504

Toure14

Re: [BUILD] GIX-51X tube preamp
« Reply #331 on: October 01, 2013, 07:23:52 PM »
I added small spacers so my board wouldn't be grounded to the metal plate

Toure14

Re: [BUILD] GIX-51X tube preamp
« Reply #332 on: October 01, 2013, 07:28:03 PM »
I also can verify that the cart that is accurate although I added WIMA caps where ever I could so Mouser may not have all the WIMAs but TAW Electronics does

100WChris

Re: [BUILD] GIX-51X tube preamp
« Reply #333 on: October 02, 2013, 01:17:56 PM »
Quote
HV board with Cap installed across R503 and R504

put the cap across R503 and R502 as shown in pictures by bruce on side 3 of this thread, reply 45.
Might solve your hum-problem.

Cheers
Chris

Toure14

Re: [BUILD] GIX-51X tube preamp
« Reply #334 on: October 03, 2013, 10:44:21 PM »
Quote
HV board with Cap installed across R503 and R504

put the cap across R503 and R502 as shown in pictures by bruce on side 3 of this thread, reply 45.
Might solve your hum-problem.

Cheers
Chris

This solved it...I think I miss read the instructions...Both Pre's are working now..The Lundahls sound amazing with the RCA tubes I have installed in them. While the OeP sounds good with the Raytheon tubes there is simply not enough gain compared to my other pre's but it has a bunch of character to it. I think I am going to swap the OEP input for an EA2622 from CAPI. should get better results

My WHITE Face and My BLACK Face

gemini86

Re: [BUILD] GIX-51X tube preamp
« Reply #335 on: October 03, 2013, 10:50:27 PM »
I love seeing these finished pics... I like to think that someday, maybe one of these preamps will be used to record a hit in a small independent studio and launch some musician or band into stardom and in some why I will have played a small part in all that.
- Rodney

"...you better call Kenny Loggins, 'cause you're in the danger zone."

Winetree

Re: [BUILD] GIX-51X tube preamp
« Reply #336 on: October 04, 2013, 01:26:52 AM »
K&K Audio, LL1538XL is $300.00 WOW
Doesn't list 5402
Can I find a better deal?

bruce0

Re: [BUILD] GIX-51X tube preamp
« Reply #337 on: October 04, 2013, 01:34:57 AM »
"it was like heaven on earth, all those transformers" - cj

100WChris

Re: [BUILD] GIX-51X tube preamp
« Reply #338 on: October 04, 2013, 08:35:32 AM »
another one  :) still waiting for some tubes.
but even with old tubes i had at hand the pre sounds fantastic!!


frequency-plot with old tubes i had lying around (made with fuzzmeasure).
I was surprised to see a clear bass rolloff, even with filters off



« Last Edit: October 04, 2013, 08:51:05 AM by 100WChris »

Toure14

Re: [BUILD] GIX-51X tube preamp
« Reply #339 on: October 04, 2013, 11:35:40 AM »
another one  :) still waiting for some tubes.
but even with old tubes i had at hand the pre sounds fantastic!!


frequency-plot with old tubes i had lying around (made with fuzzmeasure).
I was surprised to see a clear bass rolloff, even with filters off



How are you able to attach multiple pictures in one post?


 

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