LolloTheMad

Re: The official G9 help thread
« Reply #2160 on: September 15, 2018, 02:01:19 PM »
Lundahl LL5402, connected as shown in the attached picture to obtain a 2:1 ratio.


gyraf

Re: The official G9 help thread
« Reply #2161 on: September 16, 2018, 09:49:36 AM »
Why not connect it like the original G9 (look at layout) - windings connected series-series?

http://gyraf.dk/gy_pd/g9/g9_pcbs.pdf

If you connect in parallel, you are looking at entirely different inductances to drive, and I'm running this tight already..

Jakob E.
..note to self: don't let Harman run your company..

LolloTheMad

Re: The official G9 help thread
« Reply #2162 on: September 16, 2018, 10:00:44 AM »
Isn't your schematic a series-parallel configuration? The output is connected in parallel and i would get a 4:1 ratio. Am i wrong? I connected parallel-parallel to mantain the 2:1 ratio, but i didn't think it would be that bad for the bandwidth.

gyraf

Re: The official G9 help thread
« Reply #2163 on: September 16, 2018, 11:44:20 AM »
The pcb is known working, small details different from schematic. Like transformer pin numbers and ratios..

Jakob E.
..note to self: don't let Harman run your company..

LolloTheMad

Re: The official G9 help thread
« Reply #2164 on: September 16, 2018, 01:03:28 PM »
Ok, if you think this could be what is causing my issue i'll cut the traces and wire it manually. Thanks alot for the help, Lorenzo

LolloTheMad

Re: The official G9 help thread
« Reply #2165 on: September 16, 2018, 03:46:11 PM »
I connected the output trafo as you suggested and this is the result. It looks pretty good to me. Is this in line with other g9's?
Thanks again, Lorenzo

gyraf

Re: The official G9 help thread
« Reply #2166 on: September 17, 2018, 02:59:19 AM »
-3dB points at 30Hz and 30KHz are definitely in the right area. This was probably it..

Jakob E.
..note to self: don't let Harman run your company..

Re: The official G9 help thread
« Reply #2167 on: September 25, 2018, 01:57:01 PM »
New to this tube DIY but learning a lot. Ive read through a few pages but haven't found this answer, it's probably here some where?

Is there anything special about using the 2 power transformers, would this work with a 250v HT power supply with a 6v heater supply?

LolloTheMad

Re: The official G9 help thread
« Reply #2168 on: October 21, 2018, 05:48:53 AM »
Hello again, just a quick answer to be sure about the wiring.  I connected the LL 1528 input transformer as showed in the picture, is it correct?
Thanks in advance, Lorenzo

tamtamstudio

Re: The official G9 help thread
« Reply #2169 on: October 27, 2018, 08:08:49 AM »
G9 phase issue. I would like to share this issue occurred me in my G9.
Put same sine on signal to left or right channel and reverse phase. Normally I can't see any differences, but with G9, on phase reverse, the signal is higher than normal phase.
 On both channels. I can't explain me what's up.
The sound seems good, but with a strange cut on low-end, could be OEP traffo?
Any suggestion?
thanks in advance, Corrado


patzo

Re: The official G9 help thread
« Reply #2170 on: December 06, 2018, 09:46:24 AM »
Hi . I finished my G9. But I want a little more gain. Now is 53db. I noticed if I  reduce R26 from 47k  to 27k there is more gain. Or can I increase R9 to 150k – is that  going to increase the gain. Which one of this solutions is better. Maybe if I  reduce R26 it will affect lower gain settings but that’s OK for me if it does’t affect something else.

gyraf

Re: The official G9 help thread
« Reply #2171 on: December 06, 2018, 09:57:25 AM »
I don't think you can push more gain without compromizing frequency resoonse..

Jakob E.
..note to self: don't let Harman run your company..

liquidcolor

Re: The official G9 help thread
« Reply #2172 on: February 21, 2019, 11:02:25 AM »
Finished my first G9. About to start on the second. Wonderful sounding unit.

gyraf

Re: The official G9 help thread
« Reply #2173 on: February 21, 2019, 11:31:09 AM »
Darn, it looks good too...!  8)
..note to self: don't let Harman run your company..

TillM

Re: The official G9 help thread
« Reply #2174 on: May 07, 2019, 03:30:59 PM »
When I start building my own studio gear and finding our lovely forum I always think to myself: "Someday, when I've enough experience, maybe I can build the Gyraf G9"

I had always much respect for Tube buildings (and still have).
So it was clear for me, that I first will build some 500-modules and FET-microphones until I start in the tube world.
After some M49 and U47 builds, I finally realized it !
I buy the pcbs two years ago. When I had some resistors or capacitors laying around from other projects, I soldered it to the PCB.
When I find some nice tubes, who fit the G9, I buy them and so.

Last week I placed my last order. A nice case from Frank.
Now it's done. Lundahl Transformers in and out and NOS Phillips 5814a tubes.
Everything works perfect and I'm totally in love with this Pre.
The Led should be purple, but they turned out pink.

Thanks Jakob, for sharing your knowledge to our community and this nice Preamp !

gyraf

Re: The official G9 help thread
« Reply #2175 on: May 08, 2019, 02:23:11 AM »
*like*

can I ask - where did you get the small/pointer knobs?

Jakob E.
..note to self: don't let Harman run your company..

TillM

Re: The official G9 help thread
« Reply #2176 on: May 08, 2019, 04:20:50 AM »

gyraf

Re: The official G9 help thread
« Reply #2177 on: May 08, 2019, 10:13:45 AM »
Nice. We like Mentor...!
..note to self: don't let Harman run your company..


 

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