Rajeev,
A typical hand wound transformer has an efficiency of 80-90% so with 10% to 20% losses, you might need to go higher than 1:1.5.
People who use Autotansformers (or impedance matching transformers) experience a loss in damping or uncontrolled bass, but they sometimes like the bloom of the midrange. They also experience attenuation of the HF. Basically unless you experiment with it, you will not know if you like the sound or not, it's a toss.
A typical hand wound transformer has an efficiency of 80-90% so with 10% to 20% losses, you might need to go higher than 1:1.5.
People who use Autotansformers (or impedance matching transformers) experience a loss in damping or uncontrolled bass, but they sometimes like the bloom of the midrange. They also experience attenuation of the HF. Basically unless you experiment with it, you will not know if you like the sound or not, it's a toss.
rajeev luthra said:
The other day my mind drifted and i mentioned MacIntosh amplifiers, solid states with output transformers, discussing Arif's mystery Pioneer amplifier.
The 2 Mac models i had the chance of hearing when they were produced long time ago did not sound half bad to me.
Like Arif said, depends on the quality of the transformer.
Power in is power out minus losses, so with voltage out 50% higher current through the output devices will be at least 50 % higher too.
You'd have to check if they'll handle that much, and how big the transformers would be with the kind of power you are talking about and still have good frequency response.
A bonus of using a transformer would be the added protection of the output stage.
You are the winding expert, with what i've seen you do so far it would not surprise me if you were able to make a good output transformer, Rajeev.
Dear Arif & Jacco,
An old leaflet of MacIntosh amplifiers in which the company described
their output transformer with winding diagrams was very useful in
designing my custom made output transformers , I can hardly make out if
there is a transformer in the output , the sound is so good . The advantage
to use a auto transformer is that the transformers power handeling is only
that of the power it is increasing hence the size is much smaller . yes the
devices will handle the extra current I checked that first .
An old leaflet of MacIntosh amplifiers in which the company described
their output transformer with winding diagrams was very useful in
designing my custom made output transformers , I can hardly make out if
there is a transformer in the output , the sound is so good . The advantage
to use a auto transformer is that the transformers power handeling is only
that of the power it is increasing hence the size is much smaller . yes the
devices will handle the extra current I checked that first .
K-Amps
THANKS for the encouragement !!!
Please let me have your comments on post no 267 by Villaw here
http://www.diyaudio.com/forums/showthread.php?s=&threadid=46824&pe
rpage=10&pagenumber=27
very interesting
THANKS for the encouragement !!!
Please let me have your comments on post no 267 by Villaw here
http://www.diyaudio.com/forums/showthread.php?s=&threadid=46824&pe
rpage=10&pagenumber=27
very interesting
Rajeev:
Would you please be so kind as to educate me on why bifilar (or trifilar) windings are sometimes needed.
I mean, do the bifilar windings behave just like one winding, with twice the wire thickness?
Do they behave like two separate inductors in parallel, so half the copper resistance, half the inductance?
Do they behave like two coupled inductors, energy from one gets coupled into the other, then reflected back, then reflected, etc...
Each time I thinks about all the possible ways to treat a bifilar, it's like thinking about infinity, it makes my head spin.
thanks
Would you please be so kind as to educate me on why bifilar (or trifilar) windings are sometimes needed.
I mean, do the bifilar windings behave just like one winding, with twice the wire thickness?
Do they behave like two separate inductors in parallel, so half the copper resistance, half the inductance?
Do they behave like two coupled inductors, energy from one gets coupled into the other, then reflected back, then reflected, etc...
Each time I thinks about all the possible ways to treat a bifilar, it's like thinking about infinity, it makes my head spin.
thanks
Dear Funberry,
Sorry to reply so late ,
some of the advantages of bifilar windings are that ;- 1, the length wire
in two windings will be the same hence the resistance will also be the
same and due to this if there is any voltage drop that will also be the
same , thus making two identical windings .
2, In audio transformers to get minimum losses , it is desirable to get
max signal transfer from one winding to another , for this the windings
should be very close to one another , now if we use several parellel
bifilar windings they will have better signal transfer than only two
primary and secondary windings
Sorry to reply so late ,
some of the advantages of bifilar windings are that ;- 1, the length wire
in two windings will be the same hence the resistance will also be the
same and due to this if there is any voltage drop that will also be the
same , thus making two identical windings .
2, In audio transformers to get minimum losses , it is desirable to get
max signal transfer from one winding to another , for this the windings
should be very close to one another , now if we use several parellel
bifilar windings they will have better signal transfer than only two
primary and secondary windings
Phase 400 Series 1 Trannies?
Anyone out there have any advise for my rebuilding of my PL400 Series One.
It has ben suggested to me that I replace replace everyone of the 12 power trannies, originally PL909's (some burnt) with MJ15024 or 2199XX or 150XX.
I feel the MJ15024 might be good, but I'm really not sure about any possibility at this point. Any advice from any one out there on any of these choices?
Frank Marsi
frankmarsi@verizon.net
Anyone out there have any advise for my rebuilding of my PL400 Series One.
It has ben suggested to me that I replace replace everyone of the 12 power trannies, originally PL909's (some burnt) with MJ15024 or 2199XX or 150XX.
I feel the MJ15024 might be good, but I'm really not sure about any possibility at this point. Any advice from any one out there on any of these choices?
Frank Marsi
frankmarsi@verizon.net
Hi,
Once I've compared them, in a normal Lin-topology class AB/B amplifier, drivers were MJE15030/31.
After a few hours of listening tests the 2SC5200/2SA1943 came out as the winner.
Bias was readjusted with signal generator and o'scope after switching to 2sc/2sa from mjl, then I tried them with the same bias adjusted - 50mA with the 2sc/sa and the mjl too.
But I think it't a really subjective thing. But after listening a few music style for me 2sc/2sa pair was noticable better. Clearer, more transparent sound. Better sound.
But of course the difference was not so big when I compared TIP35C/36C vs. 2SC5200/2SA1943
I would suggest you to compare them, exciting test.
Once I've compared them, in a normal Lin-topology class AB/B amplifier, drivers were MJE15030/31.
After a few hours of listening tests the 2SC5200/2SA1943 came out as the winner.
Bias was readjusted with signal generator and o'scope after switching to 2sc/2sa from mjl, then I tried them with the same bias adjusted - 50mA with the 2sc/sa and the mjl too.
But I think it't a really subjective thing. But after listening a few music style for me 2sc/2sa pair was noticable better. Clearer, more transparent sound. Better sound.
But of course the difference was not so big when I compared TIP35C/36C vs. 2SC5200/2SA1943
I would suggest you to compare them, exciting test.
"Anyone out there have any advise for my rebuilding of my PL400 Series One.
It has ben suggested to me that I replace replace everyone of the 12 power trannies, originally PL909's (some burnt) with MJ15024 or 2199XX or 150XX.
I feel the MJ15024 might be good, but I'm really not sure about any possibility at this point. Any advice from any one out there on any of these choices?"
Use only MJ15024, and replace them all. Anything else may require an expert tech to stop the amp from oscillating, and replacement of the outputs (again) as they will have been damaged from the oscillation.
It has ben suggested to me that I replace replace everyone of the 12 power trannies, originally PL909's (some burnt) with MJ15024 or 2199XX or 150XX.
I feel the MJ15024 might be good, but I'm really not sure about any possibility at this point. Any advice from any one out there on any of these choices?"
Use only MJ15024, and replace them all. Anything else may require an expert tech to stop the amp from oscillating, and replacement of the outputs (again) as they will have been damaged from the oscillation.
PMA said:
Me too! I've found them performing much better then the MJ15003/4 or the MJ15022/23/24/24 pairs.
The TO-3 version MJ21193/4/5/6 are very nice devices too, but I prefer the plastic cased MJLs because of the easier mounting.
For PA MJ21193/4 or MJ21195/6 are the winners for me. High SOA, good gain and Ft parameters, excellent thermal capacity.
For Hi-Fi I rather use 2SC5200/2SA1943, or the plastic MJL21193/94.
Bad thing but a lot fake 5200/1943 comes out to the market... Grrr... I reallly, I say really hate this fake-problem...
MJ/MJL devices are mostly genuine here in my country.
Hi djk,
Either one should be okay. Either one may oscillate, so I might prefer the MJ2119X types as it is a little slower (but holds it's gain up longer).
Hi blap0220,
The one true way to figure out which one is better is to do the following. Try each in the output configuration you like (EF or CFP) and use an oscillator to drive them. Use a bias network of course. Measure the THD and also look at the residual. The ones with the lower distortion would be the better ones. Feedback will make differences harder to see and you are after the THD level from each uncorrected.
-Chris
Either one should be okay. Either one may oscillate, so I might prefer the MJ2119X types as it is a little slower (but holds it's gain up longer).
Hi blap0220,
The one true way to figure out which one is better is to do the following. Try each in the output configuration you like (EF or CFP) and use an oscillator to drive them. Use a bias network of course. Measure the THD and also look at the residual. The ones with the lower distortion would be the better ones. Feedback will make differences harder to see and you are after the THD level from each uncorrected.
-Chris
I would also give a vote for MJ15024 / MJ15025
TO3 and temp coefficient 0.7 C/W makes them specially suited
for hot, hot Class A
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