Hi Everyone,
I want to add a thermostat that will shut down amp if over 75 degree. I do not feel safe bringing AC close to heatsinks.
Can I place thermostat between Secondary AC and bridge rectifier. What happens if only half the PSU is working?
I am using single bridge rectifier to generate +/-. I am thinking of connecting thermostat on the + side of PSU.
I want to add a thermostat that will shut down amp if over 75 degree. I do not feel safe bringing AC close to heatsinks.
Can I place thermostat between Secondary AC and bridge rectifier. What happens if only half the PSU is working?
I am using single bridge rectifier to generate +/-. I am thinking of connecting thermostat on the + side of PSU.
no, too much current on that side, and you'll hardly find thermoswitch capable to conduct it, and switching just one rail of two is big nono
thermoswitch carrying mains AC voltage - arrangement used for eons
just take care of proper insulation and that's it
or resort to aux mains switching circuit, where thermoswitch will handle low voltage, governing said circuit
relay based thingie or whatever
Hi everyone, I've read through all 109 pages and I could not seem to find an answer to the following questions and I'm hopeful that someone may be able to assist. The application I have in mind is not what would appear to be the primary objectives of most of the queries and responses so far: I am hoping to use the PCB to build a tube amp power supply and incorporate Tent Labs Mini MECs in lieu of one of R1 through R4 and R5 through R8.
1) Hole/Via diameter for R1 through R8 dropping resistors. The P0.47W-3BK-ND spec sheet indicates that the lead diameter is 0.8mm. The Tent Labs MEC has a lead diameter of 1.0mm. I'm hoping to determine if the hole/Via is large enough to accommodate a 1.0mm lead.
2) Lead spacing for R1 through R8 on the PCB. The P0.47W-3BK-ND spec sheet indicates a body length of 15mm and the build guide appears to have the leads of these resistors bent very close to the body which implies a lead spacing of around 16mm. The Tent Labs MEC has lead spacing of 14mm. I'm reasonably confident that I can make them fit with some manipulation of the PCB lead spacing is in the 16mm (or hopefully a little less) range.
For reference and to ease potential anxiety of responders, I have no intention of using caps in the thousands of microfarad range as would appear to be the dominant usage case. I'm looking at something along the lines of 220uF-MEC-220uF for my application.
While I could continue my current practice of lashing something up on perf board, I'd like to give these well designed and applicable PCBs a shot if possible.
Thanks in advance for any assistance that is offered.
cheers,
Bill
1) Hole/Via diameter for R1 through R8 dropping resistors. The P0.47W-3BK-ND spec sheet indicates that the lead diameter is 0.8mm. The Tent Labs MEC has a lead diameter of 1.0mm. I'm hoping to determine if the hole/Via is large enough to accommodate a 1.0mm lead.
2) Lead spacing for R1 through R8 on the PCB. The P0.47W-3BK-ND spec sheet indicates a body length of 15mm and the build guide appears to have the leads of these resistors bent very close to the body which implies a lead spacing of around 16mm. The Tent Labs MEC has lead spacing of 14mm. I'm reasonably confident that I can make them fit with some manipulation of the PCB lead spacing is in the 16mm (or hopefully a little less) range.
For reference and to ease potential anxiety of responders, I have no intention of using caps in the thousands of microfarad range as would appear to be the dominant usage case. I'm looking at something along the lines of 220uF-MEC-220uF for my application.
While I could continue my current practice of lashing something up on perf board, I'd like to give these well designed and applicable PCBs a shot if possible.
Thanks in advance for any assistance that is offered.
cheers,
Bill
Hi,
About the snubber circuit on the PSU (for an Aleph J),
Which solution is better between building the snubber circuit or use monolithic bridge rectifiers, instead of building our own discrete rectifier section ?
Thank you.
About the snubber circuit on the PSU (for an Aleph J),
Which solution is better between building the snubber circuit or use monolithic bridge rectifiers, instead of building our own discrete rectifier section ?
Thank you.
Neither choice really relates to the snubber, I don't believe. The snubber is primarily dependent on what power transformer you choose. Some say... that you may not need a snubber if you choose 'soft recovery' diodes... b/c the ringing on the transformer will not be as strong or not at all, but I am not smart enough to know if that is correct.
My reasons for monolithic vs. discrete.
Use monolithic bridges because (in general) they take up less space, and they are easy. The builders creating the guide you linked chose to use monolithic bridges and omit the snubber (my guess) because it is intended for new builders. Many people use a snubber with monolithic bridges.
Some people use the discrete diodes b/c they have a preference of diode type that they cannot get in a monolithic rectifier package. They may prefer the performance characteristics of a certain diode.
Better... depends on you.
If you're new, I'd follow the guide. You can always change to discrete diodes and/or add a snubber later. Then you can decide if you can hear a difference.
My reasons for monolithic vs. discrete.
Use monolithic bridges because (in general) they take up less space, and they are easy. The builders creating the guide you linked chose to use monolithic bridges and omit the snubber (my guess) because it is intended for new builders. Many people use a snubber with monolithic bridges.
Some people use the discrete diodes b/c they have a preference of diode type that they cannot get in a monolithic rectifier package. They may prefer the performance characteristics of a certain diode.
Better... depends on you.
If you're new, I'd follow the guide. You can always change to discrete diodes and/or add a snubber later. Then you can decide if you can hear a difference.
Thx.
If I choose the snubber way, what kind of capacitor should I take, it's not specified in the BOM : this ones ?
Cx 10nF
Cs 150nF
I choose for toroidy 500VA/2x18V 240V
"Torroidy 500VA, 240V primary, dual 18V secondaries
I hesitate...
If I choose the snubber way, what kind of capacitor should I take, it's not specified in the BOM : this ones ?
Cx 10nF
Cs 150nF
I choose for toroidy 500VA/2x18V 240V
"Torroidy 500VA, 240V primary, dual 18V secondaries
I hesitate...
Rectifier snubbers are good, and can be used with either diode packages. If using the discrete diodes on the PSU board, you want radial lead capacitors that fit the PCB.
Also worth noting, the resistor is what’s actually doing the snubbing, has anybody measured a similar Toroidy in the thread “Quasimido results”?
Also worth noting, the resistor is what’s actually doing the snubbing, has anybody measured a similar Toroidy in the thread “Quasimido results”?
Any Issue with mounting one cap bank PCB over the other? I am using monolithic diode bridges. How would you tie the grounds together?
I am building monoblocks. So it will be the positive rail over the negative rail or vice versa.
?? I’m not following… are you thinking about splitting a single PSU board and stacking the two halves to save room? That will also be no issue. As for tying the grounds together, you’ll need some wire to connect the “top” board to the “bottom” one.
Yes, that is what I am doing. Have height available, but not the width. I am building tall amps with an interior space of 300mm x 150mm.
Ok, that makes sense. I’d get standoffs 10mm or so taller than your capacitors for the in-between spacers.
Take V+ and V- from their respective outputs, and tie your grounds together with a couple pieces of wire between the two layers on the diode side if possible.
Make all GND connections to the amplifier from just one of the boards, it won’t matter which.
Take V+ and V- from their respective outputs, and tie your grounds together with a couple pieces of wire between the two layers on the diode side if possible.
Make all GND connections to the amplifier from just one of the boards, it won’t matter which.