| meanman1964 |
I need a simple regulated sym. powersupply with an output of 20VDC to 90DCV (variable)and the current must be 10A RMS and 20A MAX.
Something like from www.thel.de |
|
|
| I_Forgot |
Regulated 90V at 10 or 20A is NOT going to be simple or cheap.
I_F |
|
|
| meanman1964 |
| I think I'm gonna buy the one from Thel it cost 237 USD.See image but without the caps. |
|
|
| I_Forgot |
Don't forget to set aside some money for BIG heatsinks, a BIG power transformer, and a big chassis to hold it all. It might be cheaper to buy a surplus lab type supply...
I_F |
|
|
| meanman1964 |
| This is a special powersupply for amplifiers |
|
|
| paulb |
| I looked at that website and could not find the supply you are describing. Are you sure about the specs? Why do you need a variable voltage, over such a wide range, for an amplifier? |
|
|
| meanman1964 |
| quote: | Originally posted by paulb
I looked at that website and could not find the supply you are describing. Are you sure about the specs? Why do you need a variable voltage, over such a wide range, for an amplifier? |
When you have a toroid of let us say 2x60VAC and you want to build an amplifier that only needs 2x25VDC you can use this regulator without changing the toroid.And another thing is you don't need a large bank of caps maybe half the amount.If you want I can make a translation for you because its in German
http://www.thel-audioworld.de/module/spr/spr10.htm |
|
|
| AndrewT |
| quote: | Originally posted by meanman1964
When you have a toroid of let us say 2x60VAC and you want to build an amplifier that only needs 2x25VDC you can use this regulator without changing the toroid.And another thing is you don't need a large bank of caps maybe half the amount.If you want I can make a translation for you because its in German
http://www.thel-audioworld.de/module/spr/spr10.htm |
that's odd logic for amp testing.
20Adc from 60Vac needs 2400VA per winding. That means you are planning a 5kVA transformer for a variable supply. In my opinion, bonkers to go down this route. |
|
|
| I_Forgot |
The regulator has to dissipate whatever power the amp doesn't use. If you have a 60VAC transformer the caps will charge to about 80VDC or so. IF you are going to set the regulator for 25VDC out, the regulator will be dropping 80-25 = 55V. At 10A, the regulator will be dissipating 55V x 10A = 550W. That's one side of a bipolar power supply. Double that figure for a bipolar supply. It looks pretty bad...
However, an amp with a 25V bipolar supply (50V rail to rail) can put out a maximum of 18Vrms. 18V into a 4 Ohm load drives a little over 4.5 A through the speaker, each side of the supply contributes 2.25A, so it isn't quite as bad a the numbers above make it look, but you're still going to have to dissipate over 200W and that takes a BIG heatsink or a sort of big heatsink with a fan.
If you're building one amp, then get/build a PS to meet the required specs of that amp. It will be much smaller and cheaper.
If you plan to build and test a lot of different amps at different power levels then it makes sense to use a variable supply, in which case you want to built it up so it is capable of driving anything you connect to it- use huge heatsinks with fans.
Is regulation necessary?
I_F |
|
|
| meanman1964 |
| The main reason for this supply is that I want to use it for power up different amplifiers without buying toroids for each amp. |
|
|
| paulb |
Oh. You should consider using a variable autotransformer, also called a variac. This will avoid the problem of trying to dissipate a lot of heat. Also, there is really no need for a regulated supply for testing amplifiers.
So, variac -> toroid -> bridge -> Caps. |
|
|
| meanman1964 |
| The regulator you could buy at Thel Audio is designed special for audioamplifiers.They also say that toroids and a bank of caps always sound better than a regulated supply.Pure theoretical a stabilised supply is better but with several impulses you get overshooting.Their solution is by building regulator that isn' so exact.They tolerate a voltage drop of 40mV/Amp.And because the regulator has big output-impedanz you could use big caps and so you have a big stable impulse voltage.That's the main goal. |
|
|
| Fanuc |
Hello,
Can you decipher any of the specifications of the regulator.?
Does it have DC offset protection ?
Noise, PSRR, etc
Thanks
Kevin |
|
|
| meanman1964 |
| quote: | Originally posted by Fanuc
Hello,
Can you decipher any of the specifications of the regulator.?
Does it have DC offset protection ?
Noise, PSRR, etc
Thanks
Kevin |
Hi Kevin,
Here are some specs:Input voltage 100VDC-Regulated outputvoltage 10V to 90VDC-Outputcurrent 10A RMS and 20A Max
Electronic energy dissipation delimitation-Short circuit proof
For a symmetrical operating voltage you need a positive and negative regulator. |
|
|
|
