Hi Thomas,
I think it is good that you are making transformers, and I, and many others want to hear about that. Was just suggesting you provide a link to your pictures and information, rather than posting it all here..
Some day I may even be a potential client, you just never know.
I ended my business in the early 2000 time frame, but in my limited experience both Tango and Tamura offered performance levels not really available here in the USA - at least at that time.
I no longer have all of the details, but found that the F-5002 in normal use at 60-80mA in my amplifier design met or exceeded all of the performance specifications Tamura provided. Unfortunately at the time I did not have access to an AP, so I had to use my Amber 3501 and did a series of measurements at various plate currents, frequencies and power levels. While I no longer have the data, but I do clearly remember that it easily exceeded its specifications, particularly in regards to primary inductance. (I wasn't too surprised as Tam Radio specifies things very conservatively.)
One of the things I wondered is how you actually measure the performance of your transformers? Do you drive them with a representative source impedance similar to the rp of the tube it is going to be used with, and in addition with a dc current superimposed that equals the operating current? I know you have an AP so that helps quite. When I test I usually use a circuit similar to what will be driving it in the application..
I think it is good that you are making transformers, and I, and many others want to hear about that. Was just suggesting you provide a link to your pictures and information, rather than posting it all here..
Some day I may even be a potential client, you just never know.
I ended my business in the early 2000 time frame, but in my limited experience both Tango and Tamura offered performance levels not really available here in the USA - at least at that time.
I no longer have all of the details, but found that the F-5002 in normal use at 60-80mA in my amplifier design met or exceeded all of the performance specifications Tamura provided. Unfortunately at the time I did not have access to an AP, so I had to use my Amber 3501 and did a series of measurements at various plate currents, frequencies and power levels. While I no longer have the data, but I do clearly remember that it easily exceeded its specifications, particularly in regards to primary inductance. (I wasn't too surprised as Tam Radio specifies things very conservatively.)
One of the things I wondered is how you actually measure the performance of your transformers? Do you drive them with a representative source impedance similar to the rp of the tube it is going to be used with, and in addition with a dc current superimposed that equals the operating current? I know you have an AP so that helps quite. When I test I usually use a circuit similar to what will be driving it in the application..
hi kevin,
very nice to discuss with U in here.
I fully agreed for your comment about 5002.
HF & atmosphere was really very good which compare to normally OPT ( HI-B)
Vocal also smooth too.
5002 is a success product but looks it birth period amorphous production is not in high mature condition. price of core was expensive & crystalline looks still in micro crystalline or super micro crystalline only. Nano crystalline was promoted & mass production on recently time.
5002 was very good. If U use full range speaker. But if u use large size woofer large than 12' inch woofer. LF will little weak.
that's why I combine & test different method for amorphous core & hope the bass maintain fast detail but deeper & less phase shift.
Hashimoto winding method was very good but combine with tango X series winding can improve & air gap mst good fit with thin copper sheet.
this is part of my experience. I really hope can discuss with U too.
thx
thomas
hashimoto method I was reference for this.
very nice to discuss with U in here.
I fully agreed for your comment about 5002.
HF & atmosphere was really very good which compare to normally OPT ( HI-B)
Vocal also smooth too.
5002 is a success product but looks it birth period amorphous production is not in high mature condition. price of core was expensive & crystalline looks still in micro crystalline or super micro crystalline only. Nano crystalline was promoted & mass production on recently time.
5002 was very good. If U use full range speaker. But if u use large size woofer large than 12' inch woofer. LF will little weak.
that's why I combine & test different method for amorphous core & hope the bass maintain fast detail but deeper & less phase shift.
Hashimoto winding method was very good but combine with tango X series winding can improve & air gap mst good fit with thin copper sheet.
this is part of my experience. I really hope can discuss with U too.
thx
thomas
hashimoto method I was reference for this.
An externally hosted image should be here but it was not working when we last tested it.
>>Are they typical?<<
In my experience with amorphous core inductances in measurement applications, rather not.
Usually such changes point towards flawed manufacturing or handling process of the cores themselves, creating the necessity to "reset" them magnetically - just the same way one has to "reset" the magnetic properties of permalloy/mu-metal after mechanically forming (bending, cutting, pressing, drilling, ...) it by annealing it in a hydrogen atmosphere...
Regards,
mb-de
===
In my experience with amorphous core inductances in measurement applications, rather not.
Usually such changes point towards flawed manufacturing or handling process of the cores themselves, creating the necessity to "reset" them magnetically - just the same way one has to "reset" the magnetic properties of permalloy/mu-metal after mechanically forming (bending, cutting, pressing, drilling, ...) it by annealing it in a hydrogen atmosphere...
Regards,
mb-de
===
Properly used, I prefer the James JS-6123HS (settin 3,5 kOhms to 8 Ohms).
This will hold up to a Tango XE-20S in similar settings.
Both do not stand a chance against the Tango X30-3,5S (better overall balance) or X-3,5S (way superior in the low frequency regime, no surprise, if you take the core size into consideration).
In check, all of these loose - for my ear AND for my testkit - against the Tamura F7002 (again unsed 3,5k:8R)... cleaner, dryer, more controlled, more low level detail...
That one gets a run for its money from the Lundahl LL1623AM-PP in parafeed (used with setting 3k or 5,6k:8R), if you happen to find a good 120..300 Hy choke which has a good frequency response and will have to stand 80 mA DC (160 mA peak) without saturation, and in must be very wide-band.
Best regards,
mb-de
===
Lest we forget, another source of excellent OPTs are those from O'netics. The company's designer, Bud Purvine (BudP) is also a member of diyAudio. There are several very well known amp designers that have used and recommended these.
Disclaimer: I consider Bud a friend, so I may be biased, but I believe that his transformers are right up there with the very best.
Best Regards,
TerryO
Disclaimer: I consider Bud a friend, so I may be biased, but I believe that his transformers are right up there with the very best.
Best Regards,
TerryO
Me too. Bud's transformers are my 1st choice whenever i'm buying OPTs. Fortunately Bud's entry level are very good, and very reasonable. His higher level OPTs get pricey -- and i bet pretty scarier extrapolating from the cheap ones.
dave
My only 300B SE amp I built used the One Electron UBT-2. Driver was a SV83 in pentode mode. The overall sound was very fast, detailed and snappy. Alas, there wasn't enough power for rock n' roll with the speakers I was using.
I've also built SE2A3 amps using the (now I'm dating myself) old Audio Note "Experimenter" transformers. These were small core trannies but did a decent job with low power.
There was also my EL156/6550/KT88 SEUL monoblocs that used Hammond 1627SEA transformers. These transformers are BIG and can really make some decent bass. One of my favorite amplifiers ever, though I would be curious to hear some different iron in there.
I've also built SE2A3 amps using the (now I'm dating myself) old Audio Note "Experimenter" transformers. These were small core trannies but did a decent job with low power.
There was also my EL156/6550/KT88 SEUL monoblocs that used Hammond 1627SEA transformers. These transformers are BIG and can really make some decent bass. One of my favorite amplifiers ever, though I would be curious to hear some different iron in there.
kstagger: I am intrigued by your comment: There was also my EL156/6550/KT88 SEUL monoblocs that used Hammond 1627SEA transformers. These transformers are BIG and can really make some decent bass. One of my favorite amplifiers ever, though I would be curious to hear some different iron in there. I too built a SEUL with Hammond 1627SE output and it too is my favourite amplifier ever.
Cheers,
Dave
Cheers,
Dave
His car is red, but a modest 2-door GM (at least 15 years old). He essentially lives on the coast (as do i).
dave
15 years old? Practically a new car.
My car (the one Canadian Customs loves to search!) is 22 years old and has 474,000 miles on it. I know a couple of guys that are still (or were, having passed away) driving the first car they ever bought 40 to 50+ years ago.
The Cascadians love to get their money's worth out their cars!
Best Regards,
TerryO
The following link can help to choose the opt:
http://www.diyparadiso.com/lundahl/fiches_transfos_final2.pdf
http://www.diyparadiso.com/lundahl/fiches_transfos_final2.pdf
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