Magnavox 175 Transformer Upgrade?
- Thread starter nikon f
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Lavane
Lunatic Member
They aren't that bad. I've had two 175's. But unless your going to use 4 ohm speakers the output will be less. I have seen some build where they used Edcore output transformers with 8 ohm taps. The 15 watt Edcore GXSE series might be a good choise. They're not as physically large or as expensive as the 25W or larger transdormers. I used some GXSE 10 watt 5K/8 in a 5wpc amp build and they sound good. The frequency responce rolls off at 40hz, but there isn't much lower than that anyway. I have speakers I like that roll off at 40hz.
I guess it really comes down to how much you want to spend on the transformers.
I guess it really comes down to how much you want to spend on the transformers.
More can be had from the stock, but even more can be had with better. Agree it depends how much you want to spend, but either way I'd have a look at the Magnavox 8800 thread since it covers some things that apply to the 175 that will get the most out of what you have already, and set the stage for better transformers if you want to go that route later.
Lavane
Lunatic Member
True. When I bought those Edcore OPT's around 8 or 9 years ago they were $43 each. They've at leased doubled in price since then.
I have a set of MPS transformers on a 6L6 amp I built, it came out quite well. I'd buy from them again. If they don't have exactly what you're after listed, send an email and they will wind you whatever you want.
The only mild criticism I can offer is that the two aren't perfectly identical. One ended up with a slightly different cap somewhere to get them matched up better. Its not a massive difference, but enough that the square waves were obviously different with the same part. Offhand I don't remember what the values were but I think the phase cap on one ended up the next value up or down from the other channel and at that point it was close enough to the same.
The only mild criticism I can offer is that the two aren't perfectly identical. One ended up with a slightly different cap somewhere to get them matched up better. Its not a massive difference, but enough that the square waves were obviously different with the same part. Offhand I don't remember what the values were but I think the phase cap on one ended up the next value up or down from the other channel and at that point it was close enough to the same.
Check out the Magnavox 169 thread that gadget73 and wparks helped walk me through the OPT replacement after I broke one. Well it really turned into a total rewire.
I used MPS in those monoblocks. The square waves looked identical in that pair. I only have maybe 5 hours on them but I'm happy so far.
I used MPS in those monoblocks. The square waves looked identical in that pair. I only have maybe 5 hours on them but I'm happy so far.
I think mine were a custom config, so its possible there is a bit more variance vs something that has been wound multiple times and perfected. What I needed for space reasons was the smaller 20 watt core but at an impedance he usually winds on the next size larger frame.
I wasn't planning on it, once I got the first channel dialed in I copied it on the other side and it wasn't the same. Some futzing back and forth, eventually swapping transformers confirmed it wasn't something I missed so I just tweaked the tuning per-channel so it matched up and called it a day. I don't even know if I made notes on the schematic showing where the difference is. Sometimes mfg would do little things to match channels because of layout-induced differences.
