Aha, so you err towards the vintage rhythmic school. How come and you don't use an Ortofon SPU?
My choice cart. is a Supex 909 which at 0.2mV has just sufficient gain in my current system. I have to retire it due to old age (channel imbalance) and put on the Dyna. The Dyna surprisingly sounded full and very dynamic with the TT/arm setup.
Good idler driven TTs can be magnificent for bass and propulsion. The L 75 is one of the vintage Swiss best. The Dyna probably mated well with the professional style S arm. Many energetic Japanese carts with strong cantilevers don't get controlled best by modern straight and short arms.
I like the L75 because of the PRaT. The bass is very good with this setup even when the phono stage is this new. The interstage cap is only just collected from my post office this morning and inserted barely 4 or 5 hrs ago and the improvement is obvious in the bass region.
The left side is the ground plane. whereas those on the right are my diy load resistors.
Can you do a simple experiment? Put a GSM phone on call and hover it say 10 cm above the main boards. I did that with the PCB version in light aluminum box and it did not buzz at all. I wanna know if its due to the input topology alone or the board layout partially. You having the same topology but in different construction and in wooden box make for a good comparison.
P.S. There can be still catching a buzz due other factors like signal wiring (coax in mine), grounding scheme, other units in the full audio system more susceptible, whatever. But lets do it.
Power the phono down now and do it again to see if something else in the system catches the buzz. Use coax for signal and a metal box to be more RF immune in general.
OK nobody sticks a GSM phone in his phono when listening to records and you can even hear GSM buzzes on air from fully pro compliant international TV networks many times.
That is why I asked because its not easy to avoid. But it did in mine. Then there are noisier phones than others. Its not a controlled experiment but it moved my curiosity it did not catch a buzz on my rig.
OK nobody sticks a GSM phone in his phono when listening to records and you can even hear GSM buzzes on air from fully pro compliant international TV networks many times.
That is why I asked because its not easy to avoid. But it did in mine. Then there are noisier phones than others. Its not a controlled experiment but it moved my curiosity it did not catch a buzz on my rig.
No buzz when the phono is turned off...I do think that those random noise I hear sometime could have come from GSM/TV signal. BTW I haven't put a lid over my phono wooden box (which may help with reducing interference) because of heat issue.
You can make full metal surrounding with fine metal mesh top.😉 That will do for Malaysia and your hot rod shunt regs. Box grounded at PSUs 0 and in electrical continuity for all panels and mesh top. Add TO-92 sinks to the 369s. Change your twisted signal wiring to coax too. See if the bifilar load resistors play a role also. Is the TT interconnect coax?
Your suggestions are all noted with thanks.
It is so far very quiet even in a wooden case without the top plate. I will monitor if the random noise comes from the drift as I am still having 3R0 under K369s.
One other reason for the wooden casing is because I can diy them 😉. It is not easy/cheap to find proper metal casing for my projects here being the other main reason.
It is so far very quiet even in a wooden case without the top plate. I will monitor if the random noise comes from the drift as I am still having 3R0 under K369s.
One other reason for the wooden casing is because I can diy them 😉. It is not easy/cheap to find proper metal casing for my projects here being the other main reason.
Far easier to dress wooden panels with thin metal though.🙂
Start with coax cable as it stands first, just the signal wiring maybe acts as the most important RF antenna now.
Start with coax cable as it stands first, just the signal wiring maybe acts as the most important RF antenna now.
I put up a simple common source 2SK170GR circuit to make some tests. Using arta and a e-mu 0404 I can clearly see the behaviuor that you describe.
Next step: go to the second measurement setup (ears 🙂 )!