"The Wire" Ultra-High Performance Headphone Amplifier - PCB's

[Wolfsin]

Originally Posted by CaféNoir

In any case, make sure that the upper bolt of the transformer doesn't make contact with the top panel.

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 :-(

[opc]

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

[qusp]

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

[null object]

Originally Posted by N-Brock

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

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!

[BuildMeSomething]

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

[Wolfsin]

Originally Posted by BuildMeSomething

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!

[CaféNoir]

Originally Posted by BuildMeSomething

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?

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.

[hochopeper]

@buildmesomething, it won't help your hum problem but I'd usually put heatshrink over the terminals at rear of the iec socket ... saves you accidentally bumping a live terminal while poking around!

[qusp]

are the signal inputs isolated from the case?

[tommy thong]

hi Owen,
i will take 2 pcs of bal-se pcb, thank's tommy