It’s FREAKIN’ silent!
YES!
Going to hook up my “good” speakers and my main amp and see how it fares.
Plus, I can put the nice power supply caps back in, I was worried they were the cause of the noise.
Thank You!!!
YES!
Going to hook up my “good” speakers and my main amp and see how it fares.
Plus, I can put the nice power supply caps back in, I was worried they were the cause of the noise.
Thank You!!!
Thank you!
These things, when they don’t work, are a confidence crusher.
So grateful for the generosity of those who know so much more than me on these forums!
These things, when they don’t work, are a confidence crusher.
So grateful for the generosity of those who know so much more than me on these forums!
Here is my attempt at a SP-14 in-process. I used Aliexpress Relay input selector and CPU board with remote, and a small 5v switching supply. The other board is a VU meter driver that I haven't sorted yet. Very quiet for me, I love it with my VTA ST-120 Tube amp....
Very nice!
I just tried the pre with some more efficient speakers, and the hum is way more noticeable. I’ve been listening to speakers that are about a 3ohm load (likely less), and under 80dB efficient. Put a pair of Coral Holey Baskets (in a Solo 103 enclosure) into my system, and the hum went up a lot.
Think I’m going to drag the Cornwalls out and set them up when I’m listening for hum…
I just tried the pre with some more efficient speakers, and the hum is way more noticeable. I’ve been listening to speakers that are about a 3ohm load (likely less), and under 80dB efficient. Put a pair of Coral Holey Baskets (in a Solo 103 enclosure) into my system, and the hum went up a lot.
Think I’m going to drag the Cornwalls out and set them up when I’m listening for hum…
As far as I can see it is an Aikido schematic. I was making an Aikido preamp long time ago, and it had too much voltage gain, so with that comes noise and hum. It was solved using negative feedback, the gain was adjusted to about 10db (3x). It sounds even better that way. I am currently using the Aikido cathode follower, no gain - no pain.
For the maximum PSRR (lowest hum), R10/R11 should be selected according to the tubes used. There are calculations and calculated values for many tubes at Broskie's website.
The B+ regulator seems to me to be some kind of improvisation, maybe that is the cause of the hum, and maybe it is due to the grounding of the device. R22 seems to be too large (1k5), the factory recommends 240ohm (if it is LM317). Instead of everything, I would put the TL783C and modify the connections a bit.
Last edited:
Going to have a look in my stash for a 1.0uf… IF I can’t find one, off to Parts Connexion I go…
Will be looking at right channel grounding, and will be dragging the Cornwalls up so I can hear all the mess 🙂
Will be looking at right channel grounding, and will be dragging the Cornwalls up so I can hear all the mess 🙂
Right channel
Left Channel
I’m using the DIYAydio VFet amp, which as a slight hiss, but I am attributing that to line noise in the house. But it is really quiet. I’m using a pair of Fe126En drivers which are in a Voigt pipe for these measurements.
Left Channel
I’m using the DIYAydio VFet amp, which as a slight hiss, but I am attributing that to line noise in the house. But it is really quiet. I’m using a pair of Fe126En drivers which are in a Voigt pipe for these measurements.
I built an Aikido on a wood wrap chassis and it had noise like you mentioned. Grounding the bodies of the volume pot and input selector solved it. You did the same when you grounded the metal plates on which they are mounted.
enjoy,
John
enjoy,
John