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


 

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