Do you have a link to the schematic you used? I built and am using this very simple tube pre build and I enjoy it very much but then I like a healthy dose of 2nd harmonic. I did change the design a little for just the 12AU7 tube.
4S Universal Preamplifier for 12A*7 Tubes
It does not get much simpler than this circuit.
The heck with boards Russellc. Build point to point from the schematic and have some fun.
My "70 Watts of McIntosh Power" P-P 6550/KT 88 amp is point to point. I much prefer circuit boards for these amps.
Russellc
It would allow you to play with it. That's a real advantage.
Nicoch,
in response to your PM: The arrangement to add a trimpot to the input stage of the M2 looks like the attached.
The snippet is taken from p.2 of the F5Turbo article by Nelson.
Attachments
Hi Generg,
Can you show a picture on how you shield the transformer? My friend is experiencing hum when the PS board or the rectifiers are close to the amp module/Input transformer. Even if just the rectifiers close to the input transformer will cause hum. No hum if we put all the power supply cap bank, rectifiers and power transformer in another case or away from the amp module. We have also noticed that the rectifiers gets quite hot and vibrates, is that normal ?
Thanks
I noticed a 3db increase on my left channel without the star ground. Im going to try running a separate ground from: supply-board-thermistor-ground and see if that lowers it, I also read that shielding the power transformer is better than shielding the input transformer. Overall my un-shielded M2 is buzzing about 6db louder than the F6 on 115db/w drivers.
On Antek transformers their is a shield wire, where is the best place to connect it?
On Antek transformers their is a shield wire, where is the best place to connect it?
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To make it clear:
You want the shield to be connected to a point which has the biggest distance to your audio signal, and also from the audio ground. And this is the ground/earth from the AC mains, where it gets into your amplifier's case. You can put it to the connection, where you grounded your case (so where the ground/mains connects to your case).
A picture does say more like 1000 words (especially if it's not your mother tongue )
You want the shield to be connected to a point which has the biggest distance to your audio signal, and also from the audio ground. And this is the ground/earth from the AC mains, where it gets into your amplifier's case. You can put it to the connection, where you grounded your case (so where the ground/mains connects to your case).
A picture does say more like 1000 words (especially if it's not your mother tongue
)Attachments
Member - @ wdecho has twisted my arm as we have similar speakers and he loves the M2
Have joined & ordered the M2 in group buy scheme from @ teabag
So hopefully in a couple of months I will have the parts delivered and have the M2 amp built
I'm just looking at a self assembly chassis using Conrad heatsinks - Conrad Heatsinks - Products
I could do some nice work with the MF20 double flange heatsinks
You have to start planing early ( so they say )
FR
Have joined & ordered the M2 in group buy scheme from @ teabag
So hopefully in a couple of months I will have the parts delivered and have the M2 amp built
I'm just looking at a self assembly chassis using Conrad heatsinks - Conrad Heatsinks - Products
I could do some nice work with the MF20 double flange heatsinks
You have to start planing early ( so they say )
FR