I didnt talk about active IV stage?
.
DAC itself is an specific active element
Who does not like to be loaded with passive reactive component RLC as the transformer does...
I just want the point to complex RLC components loading the DAC output in the case of transfiremer direct at the output of the dac...
.
Why the people use non inductive and low capacitive R for Riv?
To non to load DAC output with reactive components just pure as it can be Resisrive component.
.
After that use simple buffer and after buffer transformer.
cheers.
.
DAC itself is an specific active element
Who does not like to be loaded with passive reactive component RLC as the transformer does...
I just want the point to complex RLC components loading the DAC output in the case of transfiremer direct at the output of the dac...
.
Why the people use non inductive and low capacitive R for Riv?
To non to load DAC output with reactive components just pure as it can be Resisrive component.
.
After that use simple buffer and after buffer transformer.
cheers.
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constant dc current of +2mA for tDA1541A should be compensated with simple R from +5V (or +15V analog) or CCS with JFET to the Iout of DAC.
In that case there will be no I DC component and no Voffest at the output of the dac.
And transfromer can be without the gap.
.
it is the simple, manufactureres cpecified, and there are no reason not to do that...
transformer or not at he end...
.
I didnt said that Bisesik transformers are not good, just opposite i think they are good
just the way is used could be more better.
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Actually I do use such approach like you describing except of the very first stage after DAC.
It looks like that:
DAC->5R>SUT->BUF->SUT->BUF->SUT->BUF.
There is no first BUF before the first SUT due to very low impedance I want.
But I will try to implement the first buffer in Toby's system.
Let's see what will be the impact compared to non-buffered output.
It looks like that:
DAC->5R>SUT->BUF->SUT->BUF->SUT->BUF.
There is no first BUF before the first SUT due to very low impedance I want.
But I will try to implement the first buffer in Toby's system.
I have expiremented with 1541 a lot, including that 2mA dc-offset compensation, including the special coil. In fact using trafos with a very low DCR coils there is simply no hearable and measureble difference with extra compensation circuits. DCR of the primary coil I tried was from 0.5R down to 0.08R - almost identical results.
🤷♀️
it is essential not to have transformer at the dac output.Actually I do use such approach like you describing except of the very first stage after DAC.
It looks like that:
DAC->5R>SUT->BUF->SUT->BUF->SUT->BUF.
There is no first BUF before the first SUT due to very low impedance I want.
But I will try to implement the first buffer in Toby's system.Let's see what will be the impact compared to non-buffered output.
Because of complex reactive load to the DAC output...
(That is why people using NON-inductive, low capacitive RIVs at DAC out, to minimize reactance as load of DAC...)
.
Try like this
DAC > Riv > Buffer > Transformer > Buffer (optionaly)
Riv is specific to each Current output dac requirements.
For TDA1541A and other Idc offset dacs Idc compensation at the output is a must.
because without this buffer will have an offset voltage at the input trefore this will appear at the output
(
Buffer out offset should be set to 0mV DC because of the transformer magnetization.
Also it is good to check moment of turning on/off power supply to the buffer prior to the transformer for DC out. That could be present in short time after on/off...
)
For what? For 80uV offset?..
Magnetization or saturation not an issue for my trafos even within couple of milivolts, not talking about microvolts.
The complex reactive load of the transformer is shunted by the very low constant impedance of the resistor. Buffers acts very similar to the DACs transistors I think at such a very low seen impedance. The very low seen impedance is the key I believe.
What is your practical (not theoretical) circuit, Zoran?
If You use 5ohms Riv to the TDA DAC it will be 10mV offset without the compensation. That is under specified 25mV offset from the datas...
.
BUT why it is so hard to give the dac proper and very very simple current injection at the output?
AND why to inject into the transformer any dc IF it is so easy to get rid of it?
.
That is questionable because in step-up transformers ALL reactances from secondary transferring by square of step-up ratio to the primary... for instance if the step-up ratio is 30 ALL reactive components transfering and adding to the primary side by 900 times
Directly at the Riv and to the DAC Iout.
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What is the specifications of the transformers?
Q from #899
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btw
is there on the topic some PDF about main chrs of transformers?
Primary inductance (open sec. and closed secondary)
Primary Rdc
Secondary inductance
Secondary Rdc
Capacitances
etc...
.
Thanks
Again... DC is DC. It is not AC. Thus DAC see Riv (let it be even 100R), but shunted by the active coil resistance. DCR of the coil is 0.08R. The real offset is not 10mV (5R) or 200mv (100R), but just 2mA*0.08R=0.16mV
Because taking into account what I said,
it is simply USELESS.
Audio is ALWAYS about compromises. If you think that adding extra active circuit without real benefits is a way to get rid, then it is out if my scope.
I have many versions, but some information you asking can be found on my page: ivxformers.com
You are welcome!
In fact... All that scary stories about trafos capacitances, inductances, etc are checkable by a simple bandwidth measuring. The perfect BW for the regular 44.1kHz source should be 110-120kHz without issues with resonances. Not more, not less in perfect scenario. Why? Because you need to apply LPF even with the x16 oversampling, not talking about lower upsampling (BW should be even less). That is why I am referring to the real practice after theory.
Actually You dont have any propper specs at all?
On this address You have only 2 versions with incompleate and not so useful part of standard datas
D60 and D46
So it is not "many" it is just two versions, sorry...
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And It is only partial, and incomplete informations about main parameters?
Why?
It is so easy to measure and state?
.
Tech_data_bis-115751.jpg
only
Rdc, Capacitances and Ratio
?
.
Tech_data.jpg
again only
Rdc, Capacitances and Ratio
...
Theara are no
Primary inductance with secondary short and open (to calculate mutual inductance and coupling factor...)
Secondary inductance
And so...
...
Please
PrimH=0.45H (@1kHz, 1kR, opened sec)
PrimH=3uH (@1kHz, 40R, closed sec)
SecH=112H (1kHz, 1kR)
Only Rdc, Capacitances, Ratio... Yes! As well as input/output impedances, FR response, phase response, Distorion, CMRR...
You are so funny as well
Good
just attach these additional datas to measured model (probably D60 because of the inductance transfer ratio...) and put it on the site.
Was not so hard?
.
Based on this newly measured datas calculate Mutual inductance and Coupling factor.
Add to the datas.
.
Input and output impedances are relative and in the relation with source
does mean almost nothing
.
Others, transfer, phase THD, should be measured with some free software REW etc.
And put the graphs on site.
Not only numbers...
What You expect for people to mark and connecting the points forming graphs on the paper?
.
What is important too:
Run XFRM free without load.
And with different load values to determine damping factor.
Also run XFRM with square signal of 10 to 20KHz to estimate eventual ringing at the edges.
And find best combination with respect of Load optional RC net
.
Finally FFT diagram 1KHz will be welcome too
Because of the harmonics order relation.
(XFORMER in general adding a just bit of 3rd harmonic...)
.
cheers
just attach these additional datas to measured model (probably D60 because of the inductance transfer ratio...) and put it on the site.
Was not so hard?
.
Based on this newly measured datas calculate Mutual inductance and Coupling factor.
Add to the datas.
.
Input and output impedances are relative and in the relation with source
does mean almost nothing
.
Others, transfer, phase THD, should be measured with some free software REW etc.
And put the graphs on site.
Not only numbers...
What You expect for people to mark and connecting the points forming graphs on the paper?
.
What is important too:
Run XFRM free without load.
And with different load values to determine damping factor.
Also run XFRM with square signal of 10 to 20KHz to estimate eventual ringing at the edges.
And find best combination with respect of Load optional RC net
.
Finally FFT diagram 1KHz will be welcome too
Because of the harmonics order relation.
(XFORMER in general adding a just bit of 3rd harmonic...)
.
cheers
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But what is 1Kohm, and 40R?
Measure without any additional load without serial or parallel R in the measuring path.
For these measurements You only need L meter and transformer...
If RLC meter has option for frequency to choose
it will be good to have tha same tests with different Fo
1KHz iz must, maybe 100Hz and 10KHz same set.
If You did not change the username, i am positive that i am not?Zoran, are you sure you're not confusing me with someone else?
It is not 100% accurate, but it can be used for spice modeling...
.
Lp = primary inductance with secondary open
L'p = primary inductance with secondary shorted, leakage inductance
Ls = secondary inductance, primary open
K = coupling factor
M = mutual inductance
.
k = sqrt [1 - (L'p / Lp)]
.
M = k x [sqrt (Lp x Ls)]
.
there are also other methods for measuring then calculating main parameters of xfrm.
cheers
.
Lp = primary inductance with secondary open
L'p = primary inductance with secondary shorted, leakage inductance
Ls = secondary inductance, primary open
K = coupling factor
M = mutual inductance
.
k = sqrt [1 - (L'p / Lp)]
.
M = k x [sqrt (Lp x Ls)]
.
there are also other methods for measuring then calculating main parameters of xfrm.
cheers
Hello
I have just order 2 60mm transformer from Ivan for AD1852 voltage out dac
at this time output dac is done using output capacitors after DAC and then SRPP with 6SN7 tube
the delivery make more 2 months
no problem
when I'll receive their I'll do some measurements and listenin test and I'll report honnestly if the results are so promising
I have just order 2 60mm transformer from Ivan for AD1852 voltage out dac
at this time output dac is done using output capacitors after DAC and then SRPP with 6SN7 tube
the delivery make more 2 months
no problem
when I'll receive their I'll do some measurements and listenin test and I'll report honnestly if the results are so promising