Thanks for the kind comments on the build...
Case was bought from HiAmplifier Audio Store. Don't know much about them but the order went through without fault.
Case was bought from HiAmplifier Audio Store. Don't know much about them but the order went through without fault.
18v due to the lme49990 and 200ma for the buffers, but will probably get toasty. put some bga sinks on the underside and you might get more, but it current limits at 250ma. the power supply will do more (1.5A limit for the regs), but how much exactly depends on the Vin-Vout and the heatsink size
Last edited:
Hi Davide,
For the PSU:
Max input voltage = 25VDC (capacitor limited)
Max output voltage = 16VDC (capacitor limited)
Max Current = 2.2A (typ) 1.5A (min) 3.4A (max)
Max input to output voltage = 40VDC
All of these things can be increased accordingly by selecting different caps and even different regs if desired. For example, the same PCB with different caps can easily be adjusted to supply up to +/-80VDC with the correct caps and resistor values.
Creepage and clearance on the PCB would suggest not exceeding 100VDC anywhere on the board. You could possibly go higher, but it's a risk.
Always respect the power dissipation on the regs, and opt for larger heatsinks if using them at higher current, or with a lot of voltage drop.
Cheers,
Owen
For the PSU:
Max input voltage = 25VDC (capacitor limited)
Max output voltage = 16VDC (capacitor limited)
Max Current = 2.2A (typ) 1.5A (min) 3.4A (max)
Max input to output voltage = 40VDC
All of these things can be increased accordingly by selecting different caps and even different regs if desired. For example, the same PCB with different caps can easily be adjusted to supply up to +/-80VDC with the correct caps and resistor values.
Creepage and clearance on the PCB would suggest not exceeding 100VDC anywhere on the board. You could possibly go higher, but it's a risk.
Always respect the power dissipation on the regs, and opt for larger heatsinks if using them at higher current, or with a lot of voltage drop.
Cheers,
Owen
All done
Regards
Paul
Hi everyone,
I am a total newb when it comes to 240volt toroids. Everything I have built in my life has been 12 volt or less. (mostly analog synths) So I really have no idea about getting a 240v toroid.
qusp informed me in a PM to look at Anatek (??) toroids and advised the numbers as:
"you should be looking for a transformer with single 230v or dual 115v primaries and dual 15vac ( 15v-0-15v-0 ) and up to 25va (volt amps) so the secondaries should be up to 850mA each." This kinda did my head in, I looked at the webpage for anatek and it was a little too tech speak for me.
As I can see in "Buildnesomething"s pic his toroid has 2 wires each going into the power supply. I am guessing this is what dual secondaries means?
What would help me most I guess is if someone tells me to go "here" and buy this "Part Number" I have techies mates at my work who can help me install the thing safely but getting them away from World of Warcraft is too hard for any further help.
I'm in Australia and 240volts has a dramatic way of telling you "You've done it wrong"
Thanks for any advice and sorry qusp if posting part of your PM is inappropriate.
Well he has 4 wire ends going to the power supply (thats the two secondaries). But your issue is you want a primary for 240V. So you have a choice of a single primary (two wires ends) that go the full length on the primary that match to your 240 mains.
But odds are you aren't going to find one with a 240V single primary. It is smart for a torroid maker to have two 120V primaries (4 wire ends not what is in the photo), this way you Aussies can tie the secondaries together (the middle two primary wires) and have one lone 240V primary (back to 2 wire ends) and we westerners can tie the ends in paralell and have a 120V primary (so one model transformer is a multi-national one). It will make sense when you receive the transformer with the color coded diagram. Though you may find a transformer with a single 240 primary wire (2 ends).
To be safe pick a part number you think is going to work and we can proof-read before you order. Understanding the transformer mains connection is the most important first step of learning the fun hobby of DIY amp building.
One other thing, as a first time builder never cut/strip the transformer wires, they have an enamal under the insulation that no beginner should ever have to deal with
Last edited:
@null object - since you're in Aus Harbuch is a local transformer manufacturer that you could try. Their website is - Manufacturer of toroidal TRANSFORMERS-Home page
They have a guide on selection for ordering here - http://harbuch.com.au/doc/OrderingGuideJun09.pdf
They have a guide on selection for ordering here - http://harbuch.com.au/doc/OrderingGuideJun09.pdf
Last edited:
Here are two transformers from antek that would work for you.
They both have dual primaries and dual secondaries.
Antek - AN-0115
Antek - AN-0215
The only difference between the two is VA rating and physical size.
-Nelson
Wolfsin is still scratching his head on that bit of advice
@Buildmesomething Sorry you took me seriously. I always stuff cases with the result that electronics get used (as well as abused by pets) because in the end they will noy fit. The BAL-BAL has required input wires to be resoldered already, twice :-(
CaféNoir is referring to a "Short Turn" scenario where a retention bolt through a transformer contacts the case at both the top and the bottom. This effectively makes a single electrically shorted path through the core of the transformer, and can cause large amounts of current to flow through that turn, which may saturate the core and stress the primary winding of the transformer.
Cheers,
Owen
Cheers,
Owen
BTW opc check this out now just need to get them to read that first post. ive asked if it will be made available retrospectively and reported my LPUHP parts GB thread to see if the feature can be enabled. i'll let you know if you have to do the same. the short of it for those reading here, is that the first post and only the first post will be editable indefinitely by the thread starter from now on, to allow them to be updated over time for GB,s build threads, project threads, research threads etc. maybe someone heard my high pitched squealing?
cheers mods!! and from what i understand Andrew T was instrumental in suggesting it; so thanks Andrew!!
indeed shorted turns can be nasty indeed!! glad to have never experienced one (have you Owen?) you can create one simply by bolting the transformer down with the mounting kit without using the rubber isolation pads
cheers mods!! and from what i understand Andrew T was instrumental in suggesting it; so thanks Andrew!!
indeed shorted turns can be nasty indeed!! glad to have never experienced one (have you Owen?) you can create one simply by bolting the transformer down with the mounting kit without using the rubber isolation pads
Ok I went with the AN-0115 it was mentioned in the is thread way back.
When it comes time to finish the build I'll hit everyone up for how to wire it. It does seem a little more straight forward after the gret posts here.
Again thanks for being undertsanding to the newb. I am not that young and have learnt lots of lifes lessons but I dropped out of electronics shortly after I realised I was completly stupid.
I am good at other things!
Hi, I've got a slight problem with a touch of Hum... I presume it's a grounding issue but not sure what to do about it or where to place a ground to the case if that's required. Both inputs and output are isolated from the case, only the volume pot [Alps RK27] is in direct contact with the front panel [this is probably the cause]. Do I need to fully isolate the pot or make a ground connection somewhere?
Any thoughts/solutions v.welome
@wolfsin, I read the post as you intended but went with a more serious reply. No harm done, no feelings hurt
Any thoughts/solutions v.welome
@wolfsin, I read the post as you intended but went with a more serious reply. No harm done, no feelings hurt
I've got a slight problem with a touch of Hum...
@wolfsin, I read the post as you intended but went with a more serious reply. No harm done, no feelings hurt
I get that early in December but it is nearly always gone by the second week in January
Serious is good! That bit on short turns was really good for me as I was just about to commit that error.One thing that frequently goes unstated re balanced interconnect: hum is something one does, no longer an affliction that must be brought under control!
Have you connected the body of the potentiometer to signal ground with a small piece of wire? If not, try it.
If you still have hum, try disconnecting the earth (be careful!). If it does help, you should probably install a ground loop breaker between signal ground and chassis ground.
If there are still no improvements, probably the wiring is in cause: try to shield the transformer, or rethink the layout:
Make the input wiring as short as possible (maybe by installing an extension shaft to put the potentiometer near the rear rca plugs), and as far from the transformer as possible.