Hello All,
Today i rearranged the insides of my dcb1...im trying to do one thing at a time, so that i can find out what the problem is...
So today i unbolted the small toroid transformer from the chassis, and stuck it in the bottom right corner behind the large toroid.
Switched on and...Still got the buzz and hum...BUT...the hum in the right speaker has gone about half as quiet as it was before...left speaker is exactly the same...Buzz seems to have altered...a higher frequency pitch is the only way i can explain it.
I will try the large transformer next.
Alon
Today i rearranged the insides of my dcb1...im trying to do one thing at a time, so that i can find out what the problem is...
So today i unbolted the small toroid transformer from the chassis, and stuck it in the bottom right corner behind the large toroid.
An externally hosted image should be here but it was not working when we last tested it.
Switched on and...Still got the buzz and hum...BUT...the hum in the right speaker has gone about half as quiet as it was before...left speaker is exactly the same...Buzz seems to have altered...a higher frequency pitch is the only way i can explain it.
I will try the large transformer next.
Alon
Thanks Salas, i will try that...not sure the case is high enough though...but if it works then i will have to think about either getting a new case...or changing to a different transformer that will fit...maybe a r-core...glad some progress has been made...but confused as to why the hum has only gone quieter in one speaker??
Alon
Alon
Hi Alon
Maybe this coud help you too:
http://www.diyaudio.com/forums/pass-labs/172446-transformer-screen.html#post2282529
Cheers
Maybe this coud help you too:
http://www.diyaudio.com/forums/pass-labs/172446-transformer-screen.html#post2282529
Cheers
Was it the one related to the input feed to Optivol, to the right as we watch the picture?
That is the one that was nearer to the mains AC primary pair when was running diagonally then.
I see too much mains wiring and no shielded signal wiring. If a part of your buzz is still field related as by now half was in one channel, those things have to be taken care of. I would push the Tx back right and perpendicular if possible, but the AC looms can be as offensive. Should be trimmed given the slack created after Tx relocation. Or tucked along the metal corners.
I see too much mains wiring and no shielded signal wiring. If a part of your buzz is still field related as by now half was in one channel, those things have to be taken care of. I would push the Tx back right and perpendicular if possible, but the AC looms can be as offensive. Should be trimmed given the slack created after Tx relocation. Or tucked along the metal corners.
These hum / buzz problems can be tough sometimes. I guess if it were mine I would get it "back to basics" if I had to, in order to squash the noise. Then add the complexity back in slowly, one step at time. Something bothers me about how the audio ground is arranged with that Lightspeed board. I think I would try something like woodturner-fran suggested. Disconnect the audio ground wires from the input RCA jacks to the Lightspeed board. Connect the two input RCA grounds together right there, at the RCA's. Flip the Lightspeed over and connect the 4 LDR audio grounds all together with very short wires, like an "X". Run a single wire from that center point to the RCA ground point we just made.
Now for connecting the ground of this Lightspeed, to the DCB1. Take the ground wire at the input of the DCB1 (center one of course), and try connecting it to the center of the "X". Or try running it to the RCA jack ground point. See what it likes. Try running a "bus" from the input RCA grounds to the output RCA grounds, better or worse? So, just some expermentation here.
Still noisy? What about running the Lightspeed on battery power... Lose the fan..... disconnect the extension rod from the pot.... What does that do? Quiet yet? And get those transformers all the way to the right, AC wires tucked right along the edge. AC inlet earth ground definitely needs to connect directly to chassis. My own preamp has no connection between signal ground and the chassis / earth ground point next to the AC inlet. Probably shame on me but it's silent. My Lightspeed is p2p hard wired, with the LDR's situated around a central ground run between the input and output connectors on that vero board. Just so that these audio grounds get "all the attention".
I'm sorry if I've said something dum here, it's late and I'm tired...
Now for connecting the ground of this Lightspeed, to the DCB1. Take the ground wire at the input of the DCB1 (center one of course), and try connecting it to the center of the "X". Or try running it to the RCA jack ground point. See what it likes. Try running a "bus" from the input RCA grounds to the output RCA grounds, better or worse? So, just some expermentation here.
Still noisy? What about running the Lightspeed on battery power... Lose the fan..... disconnect the extension rod from the pot.... What does that do? Quiet yet? And get those transformers all the way to the right, AC wires tucked right along the edge. AC inlet earth ground definitely needs to connect directly to chassis. My own preamp has no connection between signal ground and the chassis / earth ground point next to the AC inlet. Probably shame on me but it's silent. My Lightspeed is p2p hard wired, with the LDR's situated around a central ground run between the input and output connectors on that vero board. Just so that these audio grounds get "all the attention".
I'm sorry if I've said something dum here, it's late and I'm tired...
Hi,
I am helping a local member to build a case and wire the "Hypnotize" version by crt. The board came to me populated. I will be changing the input wiring, the output wiring, and replacing the pot with a ladder attenuater. I will remount the IRFP Mosfets onto the bottom plate of the case.
Would someone be so kind as to post links to the schematic of the hypnotize board and the BOM? Thanks.
Attached are a couple of pictures of the mock-up. The interior dividers displayed as aluminum will be copper. This will be an effort to shield the attenuator and separate the transformer and board from each other.
I am helping a local member to build a case and wire the "Hypnotize" version by crt. The board came to me populated. I will be changing the input wiring, the output wiring, and replacing the pot with a ladder attenuater. I will remount the IRFP Mosfets onto the bottom plate of the case.
Would someone be so kind as to post links to the schematic of the hypnotize board and the BOM? Thanks.
Attached are a couple of pictures of the mock-up. The interior dividers displayed as aluminum will be copper. This will be an effort to shield the attenuator and separate the transformer and board from each other.
Attachments
For the circuit look in the very first pages. You are actually holding a live BOM by having an assembled unit but here is the link. http://www.diyaudio.com/forums/grou...led-b1-buffer-shunt-psus-140.html#post1959250
but here is the link. http://www.diyaudio.com/forums/grou...led-b1-buffer-shunt-psus-140.html#post1959250Thank you all, for your suggestions with my hum problem...I am going away on holiday to Cornwall tomorrow and so wont be able to try the suggestions out for a while...but i didnt want people thinking i wasn't grateful...today i moved the large toroid to the right and vertically mounted it, also vertically mounted the small toroid, and i also tuck in the ac primary's into the metal grooves in the chassis all using Blu Tac
The Hum, on the right speaker has almost disapeared, very very quite now...move the ear 6 inches from the speaker and the hum cant be heard. The hum on the left speaker has also got quieter, but not as quite as the right speaker...Buzz remains the same on both speakers.
Well im off on holiday see you all in a week.
Alon
An externally hosted image should be here but it was not working when we last tested it.
The Hum, on the right speaker has almost disapeared, very very quite now...move the ear 6 inches from the speaker and the hum cant be heard. The hum on the left speaker has also got quieter, but not as quite as the right speaker...Buzz remains the same on both speakers.
Well im off on holiday
see you all in a week.Alon