With first trace cut, first test positive. Streaming a video, sound did not bleed through when I turned it to laptop/DAC input, silent.
Now to try it the other way, with TV playing, stream music from laptop and see if TV bleeds through. Trying now and no bleed through! Oh no...now I'm 150 hr trace cut.
In short, first cut being the deepest, did the trick.
Russellc
Now to try it the other way, with TV playing, stream music from laptop and see if TV bleeds through. Trying now and no bleed through! Oh no...now I'm 150 hr trace cut.
In short, first cut being the deepest, did the trick.
Russellc
during last year i did rewiring of inputs a zillion times in order to get rid of intersource crosstalk. even it´s me, I'm happy that it was not me 
felt a little like little georg in road to wellville
The Road to Wellville[1994] - Little George - YouTube
what's me is that I still have veeery tiny crosstalk to empty inputs when they are dialed in with a unchosen source playing. But this is easyly fixed with shorting plugs, hardgrounding to my understanding, what we just cut. hell, lot to learn.
but i came across the recommendation of making twisted pair cables (with what i actually started but gave it up after 10th time of rewiring), the kynar cables which a real charme to solder instead of multi strain..
so, enjoy preamp, think about new speakers : )
all the best, and special thanks to ZM for getting near Spiegel–nuts with me
stefan
felt a little like little georg in road to wellville
The Road to Wellville[1994] - Little George - YouTube
what's me is that I still have veeery tiny crosstalk to empty inputs when they are dialed in with a unchosen source playing. But this is easyly fixed with shorting plugs, hardgrounding to my understanding, what we just cut. hell, lot to learn.
but i came across the recommendation of making twisted pair cables (with what i actually started but gave it up after 10th time of rewiring), the kynar cables which a real charme to solder instead of multi strain..
so, enjoy preamp, think about new speakers : )
all the best, and special thanks to ZM for getting near Spiegel–nuts with me
stefan
it still sounds good, I hope?
Yup. Sounds fine. when I touched one source interconnect it hummed loudly then stopped. I do believe it's the interconnect, loose or broken ground connection to RCA plug, easily fixed.
Russellc
Howdy,
I retested with a Sharp TV and a lenovo laptop , nothing fancy on either.
I get similar behavior when laptop alone is playing and TV is off. Volume pot has to be > 80% for me to hear. If laptop is off and TV is playing, nothing. I'm using a 100k alps audio taper pot. Unconnected inputs are quiet.
So Rusellc, it isn't you.
I dont think this will bother me
The plus part of this test, analog audio output from TV is great. Laptop is not.
While problem is mild distraction, it is easily remedied in couple of minutes.
One cut and done. I didnt do the cuts around the relays yet as this first one seemed to fix it completely.
Iron Pre now sussed out, will wait for store to be stocked and will try the balanced version. I only have AlephJ that is capable (as is) of taking balanced signal. (For now) Have box for BBA3 mono blocks, but sissysit first.
As single ended, this unit is a great pre amp in 6 db format. I haven't tried 12 dB as 2016 version didnt have jumper pads, and didnt want to torture board further!
Iron Pre will become a popular build. What's not to like? Buffer with Toshibas, relay inputs, shunt regulator and Iron. A very special sounding unit and a great addition to the DIYaudio store selection.
Russellc
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Hum update. Still humming.
I rotated the donut. I removed the donut. I moved wires around (ac, led, board to board ac, grounds). I disconnected grounds briefly. I moved in/out signal wires. I added ground jumper (shouldn’t matter in my build I think). No real difference with any of the above. Other ideas?
I rotated the donut. I removed the donut. I moved wires around (ac, led, board to board ac, grounds). I disconnected grounds briefly. I moved in/out signal wires. I added ground jumper (shouldn’t matter in my build I think). No real difference with any of the above. Other ideas?
Attachments
I couldn't tell. I only used 12db briefly with the F4 and while I did try it also
at 6db, the volume diff made a meaningful comparison difficult.
Well that is positive as to the 12 dB setting, at least it wasnt immediately noticeable. So far, volume/gain is acceptable. I remember Zenmod saying how greedy boys want it all, more gain and so forth, along with no costs to sound quality, so I wondered.
With weeny inputs like smart TV, it is almost full throttle on some speaker/amp combos. Amazing at how weak modern TV sound/signal is. For viewing movies/streaming if I use weeny Roku box instead of TV to source it, even tiny Roku out drives TV.
PC streaming is not a problem, plenty of gain at the 6 dB setting. Phone, not so much requiring full volume and not all that loud even with efficient speakers. The 12 dB might be handy in those cases, but those cases are easily avoidable.
Russellc
With weeny inputs like smart TV, it is almost full throttle on some speaker/amp combos. Amazing at how weak modern TV sound/signal is. For viewing movies/streaming if I use weeny Roku box instead of TV to source it, even tiny Roku out drives TV.
PC streaming is not a problem, plenty of gain at the 6 dB setting. Phone, not so much requiring full volume and not all that loud even with efficient speakers. The 12 dB might be handy in those cases, but those cases are easily avoidable.
Russellc
Still humming.
I added bridge wires from center of pcb ground points. I also played with clip leads at the rca grounds. No difference. I used a shorting rca on an input, that one went dead silent.
Would it make sense to change out twisted pair to shielded cable to RCAs? Or possibly going to 3 mini donuts?
I added bridge wires from center of pcb ground points. I also played with clip leads at the rca grounds. No difference. I used a shorting rca on an input, that one went dead silent.
Would it make sense to change out twisted pair to shielded cable to RCAs? Or possibly going to 3 mini donuts?
Attachments
Do you have a non-AJ amp to try? Random I know...and I'm no grounding expert. AJ and Iron is super nice though—My AJ isn't quiet however. And I've tried a lot of things to make it so....Noise went up a hair with Iron Pre for some reason, and Iron Pre alone was quiet. Inputs shorted—headphones on the outputs—stethoscope style (Don't fire it up with headphones on your ears!).
@Russellc and Dennis re gain settings: We preferred 6db. 12db was fine—seemed better at 6db though—something about "more clarity, less crunch", feelings mostly, but audible we felt. HOWEVER. This was with M2X... Iron + Iron. On my list is to try it with the F5. I'm feeling that could be a winner.
@Russellc and Dennis re gain settings: We preferred 6db. 12db was fine—seemed better at 6db though—something about "more clarity, less crunch", feelings mostly, but audible we felt. HOWEVER. This was with M2X... Iron + Iron. On my list is to try it with the F5. I'm feeling that could be a winner.