Toroidy has been recommended more than a few times and used for some Group Buys.
Hi Andrew, you'll know about this. I asked the guy at torroidy about earthing the case of the transformer. Its basically potted in a chromed metal case. He said that because it's double insulated it doesn't need it. I suspect if you mount the transformer sticking out the chassis on display this would be fine. My concern is when mounting on the inside of the chassis. I was under the impression that any metal needs to be earthed so if a wire comes loose and comes into contact with the metal casing of the transformer it wouldn't become live, it would short to ground and presumably trip something as well.
Now to what I actually came here for...
I have given up on some active monitors which need repairing and are going to be sold on so I need something new in my studio.
I'm very happy with my f4 and I think building another of the troels gravesen designs to use in the studio would be fab.
I'm would rather build another f4 but I want to avoid having to use an impasse or similar.
My rme sound card has balanced outputs that can go to +19dBu.this is supposedly 19.5v pp. I'm not sure whether that's on the hot pin or differential between hot and cold. I will need to investigate further.
But either way, would using the rme output balanced into an input transformer to get the balanced swing converted to single end be a suitable solution. I think cinemag make line input transformers capable of handling upto 27dbu.
The alternative is to build an f5 or f5 turbo.
I have given up on some active monitors which need repairing and are going to be sold on so I need something new in my studio.
I'm very happy with my f4 and I think building another of the troels gravesen designs to use in the studio would be fab.
I'm would rather build another f4 but I want to avoid having to use an impasse or similar.
My rme sound card has balanced outputs that can go to +19dBu.this is supposedly 19.5v pp. I'm not sure whether that's on the hot pin or differential between hot and cold. I will need to investigate further.
But either way, would using the rme output balanced into an input transformer to get the balanced swing converted to single end be a suitable solution. I think cinemag make line input transformers capable of handling upto 27dbu.
The alternative is to build an f5 or f5 turbo.
Thanks for the reply, I would actually be doing the opposite. Taking a balanced output from my soundcard then running single ended into the amp so I would be using a single f4 in stereo.
But good to know that theyre ok with a transformer on the input.
This is fine until I get a dedicated dac though as that probably would be line level only. Having said that. By that time I could either build another amp and stick this F4 onto my hifi and either run 2 amps balanced or biamp.
Or,
Build a dac with a suitable output. Which i guess would in essence have an impasse like circuit on the output!
In the mean time I can always get hold of a couple of transformers (theyre always useful) and try it with my current set up.
But good to know that theyre ok with a transformer on the input.
This is fine until I get a dedicated dac though as that probably would be line level only. Having said that. By that time I could either build another amp and stick this F4 onto my hifi and either run 2 amps balanced or biamp.
Or,
Build a dac with a suitable output. Which i guess would in essence have an impasse like circuit on the output!
In the mean time I can always get hold of a couple of transformers (theyre always useful) and try it with my current set up.
RE you question about popping a can over the torroid and grounding the can: this is fine as long as the can does not make electrical contact with the chassis. So, cut a piece of rubber to fit between the can and chassis. If they, the can and chassis, make electrical contact your torroid will get extremely hot because you have created a shorted turn around the toroid. If you use the rubber insulator then its okay to ground the can.
Uriah
Uriah
No.
The can needs to form a turn through the hole and around the toroid, to create that shorted turn.
The can does not pass through the hole, so cannot be part of a shorted turn.
Electrically connecting the can to the chassis/enclosure is not a shorted turn problem.
Drilling a hole through the can and putting a bolt down through it into the hole and thence to the chassis will create a shorted turn when the bolt completes the circuit.
For those who have built 2 F4s....
I am toying with building another f4 for my setup. I am currently using 1 in stereo in to my open baffles and they go plenty loud enough. Im not sure i really need the 100w per side and the damping factor goes down too. (is this even an issue?).
I was wondering what people thought about the bridged vs biamp vs parallel setup.
I am toying with building another f4 for my setup. I am currently using 1 in stereo in to my open baffles and they go plenty loud enough. Im not sure i really need the 100w per side and the damping factor goes down too. (is this even an issue?).
I was wondering what people thought about the bridged vs biamp vs parallel setup.
The transformer can is what it's potted in. There was a nut set into the epoxy at the bottom of it to bolt it to a supplied mounting plate. The bolt doesn't go all the way through. This nut and associated bolt is not connected to the can in anyway. The mounting plated has a thick paint finish on it.