I've managed to get a pair of Kari's X-CCS-BOSOZ boards and put them together.
Problem is that the L/R channels don't use any power, after turing the thing on, and off, the power does not drop, and there is no output. Overnight the + rail went from +60 to +54 for example.
Link to schematic.
Link to image of my board
Perhaps I oriented something incorrectly?? the + and - DC inputs? The MOSFETS? The voltage references?
I don't think that there were any errors on Kari's L/R preamp boards (unlike the 2 on the power supply) but I could be wrong.
edit- the power supplies are working, +60V and -8V DC. The 22.1 ohm resistors are under the board so you don't see them. I have no grounds connected to the inputs and outputs, yet (no signals going in or out at this point) figured that the DC power supply ground would be sufficient to get it up and running, and that one is connected.
anyone?
Problem is that the L/R channels don't use any power, after turing the thing on, and off, the power does not drop, and there is no output. Overnight the + rail went from +60 to +54 for example.
Link to schematic.
Link to image of my board
Perhaps I oriented something incorrectly?? the + and - DC inputs? The MOSFETS? The voltage references?
I don't think that there were any errors on Kari's L/R preamp boards (unlike the 2 on the power supply) but I could be wrong.
edit- the power supplies are working, +60V and -8V DC. The 22.1 ohm resistors are under the board so you don't see them. I have no grounds connected to the inputs and outputs, yet (no signals going in or out at this point) figured that the DC power supply ground would be sufficient to get it up and running, and that one is connected.
anyone?
Pretty sight
Do check your wiring again! As far as I know, the boards are supposed to work. Did you swap in/out wires with the ground wires or something like that? I just happened to do that on one channel of a preamp
Take a really close look at all your wiring. I just built the Twisted BosoZ, which is based on Kari's schematic, and it works (wonders!) Good luck Steen
steenoe said:Pretty sight
Steen
Yeah, I checked the wiring. Hmm.....is the silkscreen ok on those boards? anything shown backwards?
I'll take some DC measurements and post results if this can't be solved asap.
Yep, I quote: Important! The diodes on the positive side has a silkscreen error! Just turn the diodes 180degrees and you should be fine.
Also D9 and D10 are connected wrong. Please connect them as the picture here:
I just took a pic of the pic from Kari's homepage
Hope you can see it Luckily enough, I did print it out, when the homepage was still running Here you go Hope this is the answer!Steen
Sorry if this is the problem, I took it for granted, that you knew about it!
Attachments
Darn
Well, I have a pair of Kari's boards too I will try to see if I can solder them up, next week and find the faults, if there are any! At this point I cant offer you better than that I recommend that you check the wiring again, though Could someone please give a link to a working preamp of Kari's?? Please come forward if you know of one! Steen
Maybe the fact that Colombo is not delivering parts from the group buy is not as bad. Otherwise we all will be pulling our hairs.
Sorry Lgreen
I still hope for the parts so I could join you in finding the problem. This whole thing was a problem - long wait for the boards, mistake on boards, no parts... Unfortunate. And I have 6 boards!!!
Sorry Lgreen
I still hope for the parts so I could join you in finding the problem. This whole thing was a problem - long wait for the boards, mistake on boards, no parts... Unfortunate. And I have 6 boards!!!
Hi Guys
Yeah I got mine working just fine. Apart from the diode situation there are also some diodes on the rectifier board the wrong way round. again that is in the thread (" heatsinks for bosoz "I think)
Yeah I used Mikkels input selector board and volume control. Im just putting the finishing work to the case today.... Will post when complete.
regards
dave
Yeah I got mine working just fine. Apart from the diode situation there are also some diodes on the rectifier board the wrong way round. again that is in the thread (" heatsinks for bosoz "I think)
Yeah I used Mikkels input selector board and volume control. Im just putting the finishing work to the case today.... Will post when complete.
regards
dave
working!
Ok, I got it working. Turns out my negative 6.5V power supply was not sufficiently negative to turn the transistors on.
todays changes
- changed the edgemost 3.6v zener diode in negative supplies from 3.6 to 9.1v, unloaded supply is now 10.1 V, loaded is 9.2 V. This is weird, I've got 2 zeners about 3 and 4 v each, plus a 9.1 zener and all i get is 10v out unloaded.
- added 39K 1/4W resistor (positive) and 2K (negative) to ground at output of power supplies to dissipate/load power supplies when power is turned off.
measurements-
- Positive CRC filter in operation drops 93.3V to 88.8 V.
- Positive regulator outputs 60.1V from 88.8 V, runs at +44 degrees C in free air.
Looks like its working for now anyway. got a few things to do but will post pictures.
FYI, the + rail just doesn't drop when you disconnect power, so I think its very important to have a bleed resistor somewhere on the + supply.
Ok, I got it working. Turns out my negative 6.5V power supply was not sufficiently negative to turn the transistors on.
todays changes
- changed the edgemost 3.6v zener diode in negative supplies from 3.6 to 9.1v, unloaded supply is now 10.1 V, loaded is 9.2 V. This is weird, I've got 2 zeners about 3 and 4 v each, plus a 9.1 zener and all i get is 10v out unloaded.
- added 39K 1/4W resistor (positive) and 2K (negative) to ground at output of power supplies to dissipate/load power supplies when power is turned off.
measurements-
- Positive CRC filter in operation drops 93.3V to 88.8 V.
- Positive regulator outputs 60.1V from 88.8 V, runs at +44 degrees C in free air.
Looks like its working for now anyway. got a few things to do but will post pictures.
FYI, the + rail just doesn't drop when you disconnect power, so I think its very important to have a bleed resistor somewhere on the + supply.
Re: lgreen
I used CRC = 2200 - 47R - 2200 in for positive; CRC = 4700 - .5R - 4700 in the negative supply.
Here is a large hires picture of the power supply. Counting everything there are 8 regulated power supplies in there.
I have no idea why the boards are sized for 4700 uF capacitors but that's overkill. Then again, this design uses 5 MOSFETs per channel instead of the 2 in the original, so maybe you need more?? But think about the fact that the original supply was supposed to be for 2 channels, so by using separate boards for each channel you are effecively already doubling the capacitance.
Essentially, I'm not an expert on this but I'd feel ok with 1000 uF if I had dual mono boards (1 supply for 1 channel).
I listened to it for about 20 minutes late late last night-- is it me or is the gain on this less than with the bosoz?
Anyone know what the gain is?
SteveA said:
I used CRC = 2200 - 47R - 2200 in for positive; CRC = 4700 - .5R - 4700 in the negative supply.
Here is a large hires picture of the power supply. Counting everything there are 8 regulated power supplies in there.
I have no idea why the boards are sized for 4700 uF capacitors but that's overkill. Then again, this design uses 5 MOSFETs per channel instead of the 2 in the original, so maybe you need more?? But think about the fact that the original supply was supposed to be for 2 channels, so by using separate boards for each channel you are effecively already doubling the capacitance.
Essentially, I'm not an expert on this but I'd feel ok with 1000 uF if I had dual mono boards (1 supply for 1 channel).
I listened to it for about 20 minutes late late last night-- is it me or is the gain on this less than with the bosoz?
Anyone know what the gain is?
Re: transformer(s)
two different answers
I used a plitron 60-0-60 wired in parallel for each + rail and another transformer with multiple secondaries for the negative rails.
I don't recommend this, as 60-0-60 is a little too high for the voltages you need.
I cannot see why people dont start a stampeded to buy out all of these surplus transformers at Parts Express $29.68
quote:
One transformer is sufficient for dual mono supplies. Its a no brainer.
SteveA said:
two different answers
I used a plitron 60-0-60 wired in parallel for each + rail and another transformer with multiple secondaries for the negative rails.
I don't recommend this, as 60-0-60 is a little too high for the voltages you need.
I cannot see why people dont start a stampeded to buy out all of these surplus transformers at Parts Express $29.68
quote:
An externally hosted image should be here but it was not working when we last tested it.
One transformer is sufficient for dual mono supplies. Its a no brainer.
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