Which amperage of Cree semiconductor?
Are all cheap 1N4007 diodes 1 amp?
What amps of the Cree would you recommend to bridge a 125v-125v, 15MA into 160 VDC?
Cree Semiconductor Rectifying Diodes
I am thinking the 4 amp version for a few dollars more?
Are all cheap 1N4007 diodes 1 amp?
What amps of the Cree would you recommend to bridge a 125v-125v, 15MA into 160 VDC?
Cree Semiconductor Rectifying Diodes
I am thinking the 4 amp version for a few dollars more?
The supplier is having a laugh. Look at the price for a 5c item!
I would use any 400v or higher 1A diode. We are talking mains frequency here so no need for RF diodes.
Bridge Rectifier| Rectifier Diode | Farnell element14 UK
I would use any 400v or higher 1A diode. We are talking mains frequency here so no need for RF diodes.
Bridge Rectifier| Rectifier Diode | Farnell element14 UK
I see you are a member of the "Expensive is better" School.
Then nothing better than using these, which also have all the Vintage Mojo anybody could need:
https://www.youtube.com/watch?v=yjMZ5qtyCUc
tons of cool 30´s SF vibe, and probably what Flash Gordon would have used to charge his Magneto Hydro Dynamic futuristic car batteries.
Then nothing better than using these, which also have all the Vintage Mojo anybody could need:
https://www.youtube.com/watch?v=yjMZ5qtyCUc
tons of cool 30´s SF vibe, and probably what Flash Gordon would have used to charge his Magneto Hydro Dynamic futuristic car batteries.
Here is the schematic :
https://web.archive.org/web/20081227012251/http://www.decware.com/newsite/zkit5.htm
Powering a 12AU7
https://web.archive.org/web/20081227012251/http://www.decware.com/newsite/zkit5.htm
Powering a 12AU7
He used a 33K resistor in a C-L-C to "lose" the 60 volts.
Current draw is 125v-125v at 15ma secondary with whatever a 12AU7 draws.
I am using the Edcor 217 which is 120V-120V at 50 ma.
Hi Corey,
That transformer isn't really specified correctly. The heater winding is running at 100% capacity, so the transformer will run hot and eventually fail. 15 mA is also on the edge for a pair of tubes - depending on their current levels. That is one hot little transformer. I have the feeling the person who designed this is not well versed in how tubes operate. They sure don't know much about power supplies.
So tell us what you have bought already in the way of parts.
Also, 47 uF is the same as 50 uF (think component tolerances), and you don't run a 100V capacitor at 100V, more like a 160V rating for the input capacitor, but I would have specified a 250 V capacitor in case there is no load on the power supply, like when you remove the tube for example. I've been known to use 250 VDC capacitors in all positions on the power rail in supplies similar to this. Cheap insurance. It would be nice if it lasted 20 + years, which go by quickly.
-Chris
Edit: What is the heater winding current? The B+ current rating is fine.
That transformer isn't really specified correctly. The heater winding is running at 100% capacity, so the transformer will run hot and eventually fail. 15 mA is also on the edge for a pair of tubes - depending on their current levels. That is one hot little transformer. I have the feeling the person who designed this is not well versed in how tubes operate. They sure don't know much about power supplies.
So tell us what you have bought already in the way of parts.
Also, 47 uF is the same as 50 uF (think component tolerances), and you don't run a 100V capacitor at 100V, more like a 160V rating for the input capacitor, but I would have specified a 250 V capacitor in case there is no load on the power supply, like when you remove the tube for example. I've been known to use 250 VDC capacitors in all positions on the power rail in supplies similar to this. Cheap insurance. It would be nice if it lasted 20 + years, which go by quickly.
-Chris
Edit: What is the heater winding current? The B+ current rating is fine.
Ya, I think I will just go with a C-R-C.
Like I said before, I have purchased the ZBox in the past and it sounded wonderful, very good. I used it on a custom Eddie Vaughn built 2A3 SET and a pair of Decware HDT speakers(Fostex 206E based)
The sound was warm, smooth, bass was quick and the soundstage never really suffered at all.
When I took the ZBox apart, the build quality was very inferior and used very cheap parts so I think using some good quality caps and an improved bridge will help the matter!
Hi Corey,
Okay, then what is the heater current rating of your transformer?
If money isn't a paramount concern, and reliability is, then I highly recommend you buy a good multimeter and some kind of analog oscilloscope. You also need a soldering station worth between $100 and $200 so you can make reliable solder connections. You need these things as an absolute minimum.
I've trained many technicians over the years, and there are certain minimums that you need to have. These things will continue to pay you back over the 20+ years you own them. So, equipment and some soldering practice 1st. Then, try to assemble this circuit once you know how to figure out is everything is going wrong or right.
AC heaters are fine, and that's the way I design most tube circuits. Just bias them up to +30 to 40 VDC and you won't pick up much hum noise from the heaters. To high a capacitance in the HV section can generate a buzz at 120 Hz that you might mistake for AC hum.
-Chris
Okay, then what is the heater current rating of your transformer?
If money isn't a paramount concern, and reliability is, then I highly recommend you buy a good multimeter and some kind of analog oscilloscope. You also need a soldering station worth between $100 and $200 so you can make reliable solder connections. You need these things as an absolute minimum.
I've trained many technicians over the years, and there are certain minimums that you need to have. These things will continue to pay you back over the 20+ years you own them. So, equipment and some soldering practice 1st. Then, try to assemble this circuit once you know how to figure out is everything is going wrong or right.
AC heaters are fine, and that's the way I design most tube circuits. Just bias them up to +30 to 40 VDC and you won't pick up much hum noise from the heaters. To high a capacitance in the HV section can generate a buzz at 120 Hz that you might mistake for AC hum.
-Chris
12.6V (6.3-0-6.3) at 1A center tapped. This knowledge was gained without the use of cannabis.
It only has one tube wired for 12.6V heater voltage at which it draws 0.15A. When rectifying heater voltage to DC it will be somewhat underdimensioned and it will have too high DC voltage so a regulator must be used in that case. The designer uses a 15 Ohm resistor in series to keep heater voltage at 10V AC !
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Ya, I've got a nice Fluke multi-meter at the farm I am going to use.
I read a thread about the ZBox hum and the simple fix was grounding pin 9. The entire system was floating! :
Forums - zbox hum killer mod
" the box was quiet on a 4WPC amp, but got noisy on a 30WPC amp, and made more noise on a 50WPC amp, 130WPC amp, 160wpc amp, 250WPC amp, and 380WPC amp. *Didn't matter of SS or tube . *I poked around the internet and found a few folks with the same problem and some of them did a photo shoot that involved re-bundling wires and other mods. *None of which worked. *Ultimately someone on the DIYAUDIO forum had me check pin 9 to see if it was grounded. *Pin 9 is center tap for the filiments which were powered by AC in the zbox. *Grounding the center tap was proposed to provide the AC heater circut a DC ground reference. *Key point was to make sure there was no other grounds at play in the AC heater circut of the zBox. *I checked the circut end to end and confirmed that the circut had a totally floating AC circut with no grounds. *I connected pin 9 to ground and was amazed how quiet the box became. *Dead quiet no matter what amp I used and no matter what the sound level was. *I sent a few emails out to get feed back as to why this mod should not be done, and thus far, did not get anything back. *Not sure if this mod would work if you already tried the mod to use two 100ohm resisters, one on each leg of the heater circut. *I stayed away from the two 100 ohm resister mod becuase the current draw of that mod would be .1 of an amp and it looks like the zBox heater circut only has .3 of an amp available. *so that was a no go. *The grounding of pin 9 did not increase current requirements at all. *Make sure you ground pin 9 and not pin 1."
The last post in the Hum ZBox thread seems important to. There seems to be (2) options to fix the inherent ZBox hum problem :
1) - Ground pin 9.
2) - a couple 100 ohm resistor on each heater leg :
"In this circuit, are pins 4 and five connected together? *Would someone please explain the STOCK, un-modified heater wiring in the Z- box? *I'mmassuming that pins 4/5 are tied together with pin 9 providing the other connection point for a parallel supply. *If only pin 9 is grounded, there may be mild imbalance between to two sections of the filament supply. *The 100 ohm resistors, which do not carry heavy current in this case, are thus connected between pins 4/5 to ground for one resistor, and from pin 9 to ground for the other. However, these might be wired in series, with pins 4 and 5 only used. *That's what I'm interested in learning because it determines how hum reduction is employed."
I think I am just going to go ahead and ground pin 9 right off the bat. Sure, it would be nice to know the exact reason why the ZBox is noisy, yet, I just want the darn thing to be quiet!
Corey
1) - Ground pin 9.
2) - a couple 100 ohm resistor on each heater leg :
"In this circuit, are pins 4 and five connected together? *Would someone please explain the STOCK, un-modified heater wiring in the Z- box? *I'mmassuming that pins 4/5 are tied together with pin 9 providing the other connection point for a parallel supply. *If only pin 9 is grounded, there may be mild imbalance between to two sections of the filament supply. *The 100 ohm resistors, which do not carry heavy current in this case, are thus connected between pins 4/5 to ground for one resistor, and from pin 9 to ground for the other. However, these might be wired in series, with pins 4 and 5 only used. *That's what I'm interested in learning because it determines how hum reduction is employed."
I think I am just going to go ahead and ground pin 9 right off the bat. Sure, it would be nice to know the exact reason why the ZBox is noisy, yet, I just want the darn thing to be quiet!
Corey
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