hello, I just tested output transformers 15K:150+150ohm for triode line preamplifier and this time really i need help
i frequently use for my amplifiers and preamplifiers transformers,input, interetage SE toPP, SE to SE, DC/noDC,
gapped /no gapped /bifiliar /multylayer/no DC capacitor parafeed coupling/ etc etc ,
each transformer can give good sound and linearity , i pay much attention to respect each general parameter and primary drive current and impedance, secondary load resistor, amplitude swing capacity,and so go on...
but this time i'm very upset so please help me understand if its a real bad transformer : please pay attention to
the non-standard specifications, this its a gapped E-I iron
""105H when the standard is 10 to 30H, primary DCR 1120ohm, when the standard is 100 to 200 ohm etc etc.""
cost to France 328 euro , factory description :
Wide frequency response 15K: 600 ohm tube single-ended pre-amp output transformer, boost transformer, balanced output transformer, output transformer for amp, EI76X45 iron core winding.
Primary inductance about: 105H 100Hz measurement
Secondary inductance about: 5.5H 100Hz measurement
Primary current: 35mA
Secondary current: 70mA
Primary copper resistance: 1120 ohms
Secondary Copper Resistance: 53.6 ohms + 57.7 ohms
Distributed capacitance: 16.3NF 20KHz measurement
Leakage inductance: 26.2mH 1000Hz
Frequency response: 20HZ -- 36KHZ-0.2DB
Volume: 80×68×73mm, weight about 3.16Kg/pair.
The wire package does not use the organic material nylon skeleton, and uses the original cardboard without borders. Like the Shanghai Radio 27 Factory, the output transformer process is layered with layers of paper. The superb hand-winding process ensures that the enameled wire does not collapse. The process is complicated and time-consuming. . The insulating varnish penetrates the entire wire wrap, protecting the wire wrap and the transformer core..
the problem its linearity, with DHT triode 250V30mA currently very linear with 5Kohm SE transformer,
with these 15K result very good from 20Hz to 2Khz ! but -15db @20Khz ,
and no way to get linear output, even if driven by capacitor without DC.
measurement from signal generator its perfect, sweep linear in 150+150ohm resistors.
so its a transformer for transistor preamplifier??? i do not see other way to get thems good working
of course i do not try 6C33C CF capacitor coupled.......
i frequently use for my amplifiers and preamplifiers transformers,input, interetage SE toPP, SE to SE, DC/noDC,
gapped /no gapped /bifiliar /multylayer/no DC capacitor parafeed coupling/ etc etc ,
each transformer can give good sound and linearity , i pay much attention to respect each general parameter and primary drive current and impedance, secondary load resistor, amplitude swing capacity,and so go on...
but this time i'm very upset so please help me understand if its a real bad transformer : please pay attention to
the non-standard specifications, this its a gapped E-I iron
""105H when the standard is 10 to 30H, primary DCR 1120ohm, when the standard is 100 to 200 ohm etc etc.""
cost to France 328 euro , factory description :
Wide frequency response 15K: 600 ohm tube single-ended pre-amp output transformer, boost transformer, balanced output transformer, output transformer for amp, EI76X45 iron core winding.
Primary inductance about: 105H 100Hz measurement
Secondary inductance about: 5.5H 100Hz measurement
Primary current: 35mA
Secondary current: 70mA
Primary copper resistance: 1120 ohms
Secondary Copper Resistance: 53.6 ohms + 57.7 ohms
Distributed capacitance: 16.3NF 20KHz measurement
Leakage inductance: 26.2mH 1000Hz
Frequency response: 20HZ -- 36KHZ-0.2DB
Volume: 80×68×73mm, weight about 3.16Kg/pair.
The wire package does not use the organic material nylon skeleton, and uses the original cardboard without borders. Like the Shanghai Radio 27 Factory, the output transformer process is layered with layers of paper. The superb hand-winding process ensures that the enameled wire does not collapse. The process is complicated and time-consuming. . The insulating varnish penetrates the entire wire wrap, protecting the wire wrap and the transformer core..
the problem its linearity, with DHT triode 250V30mA currently very linear with 5Kohm SE transformer,
with these 15K result very good from 20Hz to 2Khz ! but -15db @20Khz ,
and no way to get linear output, even if driven by capacitor without DC.
measurement from signal generator its perfect, sweep linear in 150+150ohm resistors.
so its a transformer for transistor preamplifier??? i do not see other way to get thems good working
of course i do not try 6C33C CF capacitor coupled.......
Attachments
Last edited:
What is the source impedance of your signal generator? Maybe you wrote it, but not quite clear to me.
It is presented as a tube preamplifier output transformer.
It seems to be poor winding scheme with resonance peak @20kHz.
You could do a measurement with the transformer wired as an autoformer (the secondary in series with the primary) in a parafeed set up.
It seems to be poor winding scheme with resonance peak @20kHz.
You could do a measurement with the transformer wired as an autoformer (the secondary in series with the primary) in a parafeed set up.
yes tanks, 10 minutes for result, i can photo of oscilloscope from sweep generator or rhode schwarz audio analyser,
the TP for measure its at capacitor - transformer link , ?
the TP for measure its at capacitor - transformer link , ?
16.3 nF and 26.2 mH means you have the first resonance at 7.7 KHz and then all the others. Not a surprise if FR is bad. Not much you can do about that, I think.
45 plase you pay attention 16.3NF @ 20KHz and 26.2mH @ 1000Hz
of course this do not change , its a bad transformer, much costly!
I took the bait
of course this do not change , its a bad transformer, much costly!
I took the bait
Than it will probably not work with transistors either. But 45 already calculated the problem.
As a start, I would take every quoted parameter with a grain of salt and start measuring on my own.
yes but for measuring you should buy first, not easy
, i should say some others transformers from china are very good,
but you can not now in advance so at last its not cheap
but also others european made transformers are very bad and much costly
taths way often hammond its a choice, if you now how to use thems.
look a 850QA input transformer, very nice
, i should say some others transformers from china are very good,
but you can not now in advance so at last its not cheap
but also others european made transformers are very bad and much costly
taths way often hammond its a choice, if you now how to use thems.
look a 850QA input transformer, very nice
That doesn’t tell me anything about the impedances the primaries and secondary see, or how they are connected. If you want help better make it easy for people and show a circuit. Most people don’t have time to trawl through a wall of text.
The way parameters are quoted hints me that the manufacturer is not to be trusted. Unfortunately I'm on travel and cannot elaborate my answer.
16nF is an extremely high capacitance value for such transformer, where I would expect it to be in the 500-1500pF range worst case. I suspect it has been measured like a capacitor, which is wrong and unrealistic.
16nF is an extremely high capacitance value for such transformer, where I would expect it to be in the 500-1500pF range worst case. I suspect it has been measured like a capacitor, which is wrong and unrealistic.
daanve you showed how to measure without DC taths great tanks, 45 you only need specs, superb tanks
one other 10K:600ohm gapped transformer, not so bad, medium quality , sound nice,
if i check linearity manually i get -2dB @ 20Hz, -1dB @30Hz, then 0db till 15KHz -1db and 24KHz @ -2 db
the oscilloscope generator sweep look linear, see photo
but the analyser show resonance 2K5 Hz and very poor linearity
and your methode no DC confirm
wath to tink?
just crossed you 50AE , good to now great
one other 10K:600ohm gapped transformer, not so bad, medium quality , sound nice,
if i check linearity manually i get -2dB @ 20Hz, -1dB @30Hz, then 0db till 15KHz -1db and 24KHz @ -2 db
the oscilloscope generator sweep look linear, see photo
but the analyser show resonance 2K5 Hz and very poor linearity
and your methode no DC confirm
wath to tink?
just crossed you 50AE , good to now great
Attachments
Did you do a self test of the analyzer to make sure it is linear enough?
Also:
What source resistance are using?
Are you grounding the secondary on both measurement conditions?
Do you respect polarities on both measurements?
Also:
What source resistance are using?
Are you grounding the secondary on both measurement conditions?
Do you respect polarities on both measurements?
yes up350 calibrate few working hours ago , the triode its mazda 802, no datasheet but require 5Kohm or less
t-his itsone other transformer 10K:600ohm good sounding
the xxx718.jpg show the noDC measurement like daanve ask show 2k5 peack
probe X10 tap where the primary is connected to the secondary,
so in ordre triode plate - secondary winding connected in serie with primary (TP) -ground
t-his itsone other transformer 10K:600ohm good sounding
the xxx718.jpg show the noDC measurement like daanve ask show 2k5 peack
probe X10 tap where the primary is connected to the secondary,
so in ordre triode plate - secondary winding connected in serie with primary (TP) -ground
