Your heatsinks are all wrong.
At low current ie 10R (60mA) nothing will cook, but if you are HOTRODDING you will need to reorientate your heatsinks.
At low current ie 10R (60mA) nothing will cook, but if you are HOTRODDING you will need to reorientate your heatsinks.
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One other thing to check is that you haven't got any hairline shorts around the B1 buffer section.
OK my PCB was homebrew but I had minute shorts around the relay. That is why I decided to use the Salas Shunt Reg on its own with a regular B1 PCB.
OK my PCB was homebrew but I had minute shorts around the relay. That is why I decided to use the Salas Shunt Reg on its own with a regular B1 PCB.
For the (L) offset the problem can be a dead JFET or wrongly matched by much in the right hand horizontal pair on the pic.
The output offset depends on what you feed into the DCB1 and on what the operating Id is, in comparison to the measured Idss of the amplifying jFET. It does not depend on the PSU voltages. It does not depend on the LED voltages. It does not depend on the CCS current.
Why have you braided your cable pairs/triplets for high inductance?
Twisting for low inductance, is much preferred for attenuating interference.
Why have you braided your cable pairs/triplets for high inductance?
Twisting for low inductance, is much preferred for attenuating interference.
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Thank you for your answers and for your recommendations.
At first I will remove it out of the case (I didn´t expect problems ...) and will check and measure all the things you mentioned.
@Salas
I disconnected the heatsinks cause I thought it effects something.
I know they are oversized and will remove them.
Andreas
At first I will remove it out of the case (I didn´t expect problems ...) and will check and measure all the things you mentioned.
@Salas
I disconnected the heatsinks cause I thought it effects something.
I know they are oversized and will remove them.
Andreas
I changed the JFET you mentioned.
Now I measure R -0,8 mV and L -1,7 mV DC offset.
It's better but good enough?
Andreas
Its very good. Are the supply voltages still alright? Check that you got 1.5-2VDC drop on the current set resistors too. Then you are good to play.
I measured 1.6VDC and it´s connected to Symasyms and sounds good at "Plastic Speakers" in the celler.
I have to finish the front plate and than it moves to my second setup which is DCB1, Symasym, Pearl (my first is ONO, Aleph P1.7, Aleph J 🙂.
I will post some pictures later.
Thank you very much for your help!
Andreas
I have to finish the front plate and than it moves to my second setup which is DCB1, Symasym, Pearl (my first is ONO, Aleph P1.7, Aleph J 🙂.
I will post some pictures later.
Thank you very much for your help!
Andreas
Andreas, good, shows 160mA if with 10R set resistor then. You are welcome, we will read your further news.
finished my DCB1
Finished my DCB1. Enclosure is a BUD box painted with a ceramic, semi-gloss engine paint from O'reillys. Knob is anodized champaign from parts-connexion. Heat sinks are from a local electronics salvage outfit. Internal wiring is 26awg silver 99.99% (not five 9s thank you 🙄). Antek 50va shielded unit. Current resistors are MP930s mounted off-board on 220 heatsinks.Power switch is a switch/fuse/IEC combo.
If it looks overbuilt, it is. Haven't measured current but it is dissapating some real power. But, who cares, because it sounds great. Rail voltages are very close and offset is very low.
I was using a pot or direct out from my BDP-95 but the DCB1 is a sonic blockbuster in comparison. Which in reality, is just due to a much better impedence match and now we aren't "throwing volume away". In short, it's an amazing non-sounding sounding piece of audio equipment. I'm definitely hearing things in tracks I haven't heard before, and that saying a lot because I listen a lot, my wife wouldn't agree, though.😀
I'll probably do a Makore front and lid. The only problem that I have is some hum, so I need to fix that. Otherwise it's a winner and I'm not easy to please at all when it comes to audio gear.
Cheers!
Finished my DCB1. Enclosure is a BUD box painted with a ceramic, semi-gloss engine paint from O'reillys. Knob is anodized champaign from parts-connexion. Heat sinks are from a local electronics salvage outfit. Internal wiring is 26awg silver 99.99% (not five 9s thank you 🙄). Antek 50va shielded unit. Current resistors are MP930s mounted off-board on 220 heatsinks.Power switch is a switch/fuse/IEC combo.
If it looks overbuilt, it is. Haven't measured current but it is dissapating some real power. But, who cares, because it sounds great. Rail voltages are very close and offset is very low.
I was using a pot or direct out from my BDP-95 but the DCB1 is a sonic blockbuster in comparison. Which in reality, is just due to a much better impedence match and now we aren't "throwing volume away". In short, it's an amazing non-sounding sounding piece of audio equipment. I'm definitely hearing things in tracks I haven't heard before, and that saying a lot because I listen a lot, my wife wouldn't agree, though.😀
I'll probably do a Makore front and lid. The only problem that I have is some hum, so I need to fix that. Otherwise it's a winner and I'm not easy to please at all when it comes to audio gear.
Cheers!
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Happy that you are happy.🙂
Still this is a simpler one, a Hypno, not a Mez. Regarding your hum, see about dressing closer together and distancing those trafo wires a bit further from the unshielded signal runs. Rotate the toroid a bit. It may be beneficial if your hum ain't due to a system ground loop.
Still this is a simpler one, a Hypno, not a Mez. Regarding your hum, see about dressing closer together and distancing those trafo wires a bit further from the unshielded signal runs. Rotate the toroid a bit. It may be beneficial if your hum ain't due to a system ground loop.
C'mon, any DCB1 porn is good for this thread!
I'll try that. Need to see if I can measure AC anywhere in the case and maybe ground pot case.
😉
I'm supremely impressed with the way the thing doesn't sonicaly subtract from the source. When it comes to audio, I'm like a nasty food critic, and man does this thing taste good. 😀
It did, thanks. Right now my son is watching cartoons on that rig so I can't play with it. However, I've still got some probably unrelated amp hum that I need to deal with. I'm talking about very quit hum, but still, hum. I need to take my MM and look for AC in the enclosure (s).
Eventually, I'm going to attach a stepper motor to a stepped attenuator (a double entendre?) and have remote volume control. Otherwise it just need some woodworking and it'll be done.