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Old 5th April 2017, 07:52 PM   #281
analog_sa is offline analog_sa  Europe
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You are welcome.

Again, not sure if the 9018 performs at its best when the bias voltage is disturbed. Otoh, introducing caps somehow spoils the entire idea of a transformer, doesn't it?
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Old 5th April 2017, 08:18 PM   #282
TioFrancotirador is offline TioFrancotirador  Poland
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Quote:
Originally Posted by analog_sa View Post
You are welcome.

Again, not sure if the 9018 performs at its best when the bias voltage is disturbed. Otoh, introducing caps somehow spoils the entire idea of a transformer, doesn't it?
For me it does unfortunately. I tried different caps for Super V/I and each time I got different sound signature, so for me it does matter. I tried polymer, ESA and copper foil. Copper foil was best in clarity. However now, no cap is best especially in high frequencies. At least this observation works for ak4490.

Call for someone to test Super V/I LL1684 (no cap) with es90x8.

Otoh, I am wonder how Teramoto Finemet transformers handles bias voltage for es90x8 without the cap ...

Last edited by TioFrancotirador; 5th April 2017 at 08:22 PM.
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Old 5th April 2017, 08:41 PM   #283
analog_sa is offline analog_sa  Europe
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A quick scan of the archives indicates the 1.65v is of no importance, or at least i cannot see a valid reason for trying to preserve it, no matter whether current or voltage operation is desired.

So the Teramoto does exactly the same thing as the Lundahl in its place does, only sounds much, much better
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Old 6th April 2017, 10:00 AM   #284
quanghao is offline quanghao  Viet Nam
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Quote:
Originally Posted by kmajjo View Post
Hello Guang Hao,
Sorry , but if i understand well, in this case i have a 4 : 1 transformer and not a 1 : 4 transformer for more gain.
I want to use LL1674 or LL1676 (1 : 2) in your dac converter.

LL1684 = 1:1 / Prim dc = 41 ohm/winding / Second dc : 41 ohm
LL1674 = 1:4 / Prim dc = 33 ohm/winding / Second dc : 605 ohm
LL1676 = 1:2 / Prim dc = 145 ohm/winding / Second dc : 605 ohm

Br
Jacky

HI!

You can use LL1674 in the configuration 1+1 : 4 instead of 1 + 1 : 2

A my friend use this configuration without problems, some modifications on output pcb are necessary to use it!

no need by LL1684, thanks
quanghao
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Old 8th April 2017, 06:12 PM   #285
kmajjo is offline kmajjo  France
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Originally Posted by quanghao View Post
HI!

You can use LL1674 in the configuration 1+1 : 4 instead of 1 + 1 : 2

A my friend use this configuration without problems, some modifications on output pcb are necessary to use it!

no need by LL1684, thanks
quanghao
Hello Guang Hao,
If i am not mistaken , connections are like this with LL1674 :
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Old 8th April 2017, 06:42 PM   #286
TNT is offline TNT  Sweden
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Vishay VAR-Series "naked" 18 ohm parallel to the output, then:
Lundahl LL1941

Trafo must be loaded by a reasonably high impedance (>25k)

Works very well.

//
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__________________
More distortion to the people!

Last edited by TNT; 8th April 2017 at 06:44 PM.
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Old 9th April 2017, 09:05 AM   #287
kmajjo is offline kmajjo  France
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Quote:
Originally Posted by TNT View Post
Vishay VAR-Series "naked" 18 ohm parallel to the output, then:
Lundahl LL1941

Trafo must be loaded by a reasonably high impedance (>25k)

Works very well.

//
Hello,
So , i understand well, ES9018 works in current mode , but output must be very low at the primary and gain partially offset by the output transformer ?
Could you give us some voltage level in this case ?
Br
Jacky
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Old 9th April 2017, 12:03 PM   #288
schultzsch is offline schultzsch  Europe
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The caps and the resistor in the primary side of the transformer as per kmajjo diagram form a low pass filter, this way you wont put subsonic frequencies in the trafo and create distortion

Since amorphous core transformers are very sensitive to dc offsets(if you apply a dc voltage across any of the coils you can magnetize the core and after the transformer will produce distortions) I don`t reccomend that you use in place of this filter a short wire to ground. LL1674 and LL1684 are amorphous core transformers.

There is another thread here where Joe Rasmussen presents some interesting things that you should check.
Buffalo II & transformers
See from post 185 and after.
I am using my es9018 with some LL1684 in the output connected as per diagram C in post 185 in the link above and the combo sound very good.

Regards.
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Old 14th August 2017, 03:23 PM   #289
szczemirek is offline szczemirek  United Kingdom
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Default OUTPUT STAGE WITH LL1684 LUNDAL TRANSFORMER

I'm looking for 👍 Anyone have any spare for sale? Other proposals?
Cheers and thanks 🙏
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Old 15th August 2017, 12:23 AM   #290
szczemirek is offline szczemirek  United Kingdom
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Quang Hao,
Is any possibilities to buy parts of OUTPUT STAGE WITH LL1684 LUNDAHL TRANSFORMER?
Regards
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