Morning gents,...once more some transformer/psu questions. See pic.
In addition: I assume all the mentioned ground connections are connected to the ground-lifter as stated in the wolverine docs or am I wrong?
In addition: I assume all the mentioned ground connections are connected to the ground-lifter as stated in the wolverine docs or am I wrong?
1. Those are the bleeder resistors. I remember that they are there to discharge the psu large caps.
2. I never used psu snubbers, I don't know.
3. I remember that transformer shield needs to be connected to AC earth ground.
4. That star ground needs to be connected straight to the ground lift-loop breaker.
Gaetano
2. I never used psu snubbers, I don't know.
3. I remember that transformer shield needs to be connected to AC earth ground.
4. That star ground needs to be connected straight to the ground lift-loop breaker.
Gaetano
The bleeder resistors are useless. They would only be practical if a service technician opens the amplifier and then doesn't get a shock when he touches 70V. But you don't make the circuit for service technicans.
@wkloppen I see that you are super keen to get started which is great but you may want to consider just taking
one step at a time. Rome wasn't built in a day as they say.
My advise would be to build and test your wolverine boards first. Focus on getting those working and out of the way.
To test them you just need a basic Dual Voltage power supply or a VariAC and a Lightbulb set up in series to limit the current in case of a fault. Search this thread as its been discussed before.
The image that I attached showing a power supply was just some generic schematic that I found and may not be what you would actually build. Once you have built your Wolverine boards you can investigate some of the other things that you will need to complete your Amplifier.
There are many resources available online and in the DiyAudio store to help with this.
Two great technical resources on power supplies are.
TNT Power Supplies
Elliott Sound Products
one step at a time. Rome wasn't built in a day as they say.
My advise would be to build and test your wolverine boards first. Focus on getting those working and out of the way.
To test them you just need a basic Dual Voltage power supply or a VariAC and a Lightbulb set up in series to limit the current in case of a fault. Search this thread as its been discussed before.
The image that I attached showing a power supply was just some generic schematic that I found and may not be what you would actually build. Once you have built your Wolverine boards you can investigate some of the other things that you will need to complete your Amplifier.
There are many resources available online and in the DiyAudio store to help with this.
Two great technical resources on power supplies are.
TNT Power Supplies
Elliott Sound Products
True, your amplifier boards will drain the Main PSU reservoir capacitors due to their idle current. However if there is a fault with your amplifier where one or more of the rail fuses blow there is a potential safety issue.
I definitely recommend using bleeder resistors.
Yeah I'm keen...and I'm learning and I WILL make the boards first. Can't wait to get started... but I'm taking at least 6 months to complete it making sure to use to proper tools, parts and tests.
This article may help you with grounding the amp and it also includes safety tips:
https://sound-au.com/earthing.htm
https://sound-au.com/earthing.htm
Hello I wanted to ask if it also took you so long until the Ground Lift and T-Ground are delivered. I placed the order last month on the 13th and since the 23rd the package is in Germany. Since I have already paid the customs fees when purchasing I wonder why it takes so long. Have any of you had similar experiences?
Hello Gents,
Ordered the majority at mouser. BOM > EFS3-3 + IPS
NJW0281G and NJW302G at Sinuss
2SC4793 and 2SA1837 at Electro Andijk
Thewre is a couple of resistors where the value is related to the rail-voltage. I've assuemd based on the advice of Omed and the group-buy excel order list info that my rail voltage is 59-volts. The 2 transformers of 500VA have 2 x 42 volt windings. I hope I'm right.
willem
Ordered the majority at mouser. BOM > EFS3-3 + IPS
NJW0281G and NJW302G at Sinuss
2SC4793 and 2SA1837 at Electro Andijk
Thewre is a couple of resistors where the value is related to the rail-voltage. I've assuemd based on the advice of Omed and the group-buy excel order list info that my rail voltage is 59-volts. The 2 transformers of 500VA have 2 x 42 volt windings. I hope I'm right.
willem
Should be close. Depends on the mains voltage relative to the specified primary voltage for the transformer, but the nominal voltage with a bridge rectifier should be around 58 volts or a bit more when unloaded.
Primary voltage here in the netherlands is pretty stable at 228 VOLTS....at least when I measured it a few times a couple of years ago (ie: same house). I'll be using 2 rectifiers 1 per rail per channel is the idea.
w.
w.
I will contact DHL on Monday. Has been in customs for almost 2 weeks. Didn't even get a notification that something is wrong with the fees.
Thanks for the answers
Thanks for the answers
DHL has a very bad habit of not delivering unless customs fees are paid online or by phone first. Sometimes they won't even contact you to let you know, it just sits there in the warehouse. Probably best to call with the tracking# or there is a payment portal you can use if you google it.
Hello all - I performed an initial power-on of my boards today and hit what appears to be a pretty serious issue. Voltage across R111A and R111B is around 10V. PD+ voltage is around 7V and ND- is at -7V. LEDs D10 and D11 do not light - there is around 1.5V is across them. All other LEDs light and dim bulb tester dims as expected when powered on. Both sides are doing this so I believe I made a component mistake rather than a soldering issue, but I've triple checked everything. All of the pots are set to the proper starting values. I assume my problem is the IPS feeding too much voltage to the output stage. Anyone have any ideas as to what component(s) could be the culprit that I could hone in on?
Okay. Here is how you figure out your voltages before you connect anything - reality may be slightly different 😎.
The transformer is specified with an RMS input voltage - typically 230 for the single or series primary in your area, but it could be as low as 220 or as high as 240. Assume the spec is for 230 volts. You say that you get 228 from the outlet. Thus the input voltage is 228/230 = 99.13%. So your RMS output voltage will be 42 x .9913 = 41.63 volts RMS. For a sinusoid, the peak voltage is sqrt(2) x RMS = 58.88 volts. However, this is usually specified at the rated transformer load, which is your case is 500VA.. Now is when things get a bit more complicated. There is something called the transformer regulation factor, which tells you how much the voltage varies from no load to full load. For the 500VA transformers, the specs I've seen are generally in the 4-7% range, with 5% being typical.
So now we can compute the no load peak output voltage as 1.05 times the loaded peak or approximately 61.82 volts.
Now we need to deal with the diodes in the bridge. I looked up the specifications for a Taiwan Semiconductor 40A 400V bridge rectifier. The typical forward voltage curve shows the diodes starting to conduct around .6 Volts, and having a forward voltage of 1.1 volts at 40 amps. In the one bridge per rail configuration, there are always two diodes in the conducting path, so the minimum voltage drop across the diodes is about 1.2 volts. This gives an absolute peak across the capacitors of 60.62 volts, when the load is the normal 1 ma give or take from the capacitor leakage. The full-load voltage will be well under that, as the charging currents are very high and narrow pulses. If the pulses are 40 amps, then the output voltage across the caps will peak around 59.82 volts. Throw in some ohmic and flux leakage losses, and this is close enough to expect 59 volts nominal. You will not be running under no load conditions once the bias is set. The actual voltage will not matter that much, as most of the voltage dependent resistors are for LED voltages and just need to be in the ball park to ensure that the LEDs do not have too much current through them.
I don't think that your main capacitors and other rail capacitors should be 63 volts, although they would probably work (for a while, at least). There is too much chance of the voltage going over 63 volts if the mains change. Your power may be stable, but there are all sorts of noise and even long term or periodic drift in the mains supply depending on what other people are doing in the neighborhood. We have a lot of solar, and the mains are 124-128 or so during the day and a bit under 120 at night. If you use 80 volt caps for the rail bypass/storage then you should be good.
Make sure that j103 is installed and no output transistors are installed. Verify that R2 and R9 are the same value. Make sure that your input is shorted. Check the position of R25 and the offset voltage from it and also check the CCS values. Make sure that Q104 is in the circuit, although it may not be on the heat sink or output transistor. Check the bias voltage pot (R109) to see if the voltage changes when you turn it. Check the values of the Bias divider resistors and also that the value of Rcc is correct based on the Hfe and that it got installed. Make sure that J101 and J102 are installed. Check the solder jumpers in the NFB trace.