--------------------------------------------------------------------------------tbla said:
tbla
Tell us about your mods; I may want to start on my 20i.
What clock and power supply are you using?
first i installed a lclock xo - BIIIIG difference - a few days later it was replaced by a lclock xo2, the 2 sounds even better.
replaced the 8 nichicon 35V/470uF - which feed the discrete buffer - with elna silmic 63V/470uF.....= better sound.
the op27 and op42 was replaced with opa627 + the 10uF tantal decouple caps was replaced tonight with 25V/100uF elna silmic.
i'm not shure about the opa627 as I/V, it has another character - its darker and more "hifi".....i don't know, but anyway the player now performs very clean and correct, very upbeat and dynamic with excelent focus and spatial cues....the best i have heard so far, and there is still room for improvement like rectifiers and regulators.........🙂
up next is the decouple tants for the 4 x pcm63k, i will replace them with black gate nx hi q 6,3V/22uF.....a total of 16.
btw who has the lowest prices on black gates...?
replaced the 8 nichicon 35V/470uF - which feed the discrete buffer - with elna silmic 63V/470uF.....= better sound.
the op27 and op42 was replaced with opa627 + the 10uF tantal decouple caps was replaced tonight with 25V/100uF elna silmic.
i'm not shure about the opa627 as I/V, it has another character - its darker and more "hifi".....i don't know, but anyway the player now performs very clean and correct, very upbeat and dynamic with excelent focus and spatial cues....the best i have heard so far, and there is still room for improvement like rectifiers and regulators.........🙂
up next is the decouple tants for the 4 x pcm63k, i will replace them with black gate nx hi q 6,3V/22uF.....a total of 16.
btw who has the lowest prices on black gates...?
tbla said:
I told you to use the LM6171 for I/V instead of the OPA627.🙄
Relax, there's a simple thing you can make in 5 minutes and tell us what you think.
Are you still using the 18v PSU on the op-amps?
Put a 2k or 2.2k resistor from the negative psu rail to the output of each OPA627.
Class-A bias at 9 or 8.2ma, respectively.
It works very well usually, but on your circuit, and as I/V, I dunno...
Please try it and listen.
at this state the opa627 doesn't sound bad - not at all, but it has another sound......levinson versus krell...!!!!!
its a matter of taste and many have stated that the opams from analog devices has more snap, slam and are more open sounding.....!
at this moment the opa627 only has 100uF as supply decoupling - i will try to use some film or ceramic too, and report back.
in a few days i will try the lclock xo3.
i will also try preregulated supply for the clock.
its a matter of taste and many have stated that the opams from analog devices has more snap, slam and are more open sounding.....!
at this moment the opa627 only has 100uF as supply decoupling - i will try to use some film or ceramic too, and report back.
in a few days i will try the lclock xo3.
i will also try preregulated supply for the clock.
tbla said:first i installed a lclock xo - BIIIIG difference - a few days later it was replaced by a lclock xo2, the 2 sounds even better.
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Suggest you should try the Tent XO with the XO2 supply or with the ALW regulator; truly ultra low noise.
tbla said:
Try it.
Later you could also try the LM6171 for I/V.
Or, maby even better, an LM6181, without any cap across the feedback resistor.
tbla said:
I have an XO3 too, waiting for an opportunity to be installed.😀
The clock has good regulation on-board, but it benefits from pre-regulation.
I used it on my lclock XO, an LM317 with a big cap for Cadj.
Works very well.
"every" decoupling trick has been tried and there is only a small difference, the opa627 sounds very nice - a bit laidback and soft with good resolution.....but it's not as good as the "original"....so i have ordered 4 new op42......🙂
OPA627
Try the biasing to class-A, as I said.
A simple resistor.
A diferent animal is hidden there.😉
Try the biasing to class-A, as I said.
A simple resistor.
A diferent animal is hidden there.😉
as i see it, bb opamps and ad opamps have there own "house sound"....and it's really a matter of taste.
BUT i just found out why the player had better focus and pinpoint perspective with the ad op42.....you see each op42 has a trimpot connected, and i thought it was for offset trimming,.
but after a closer examination of the pcb, i now see that this pot is connected in series with the I/V resistor........in other words, it is there to make it possible to trim all 4 lines to the exact same value (right +/- and left +/-)....very interesting, i don't recall to have seen this on any other player.
all the 4 trimpots have been touched and the opa627 is still in place, therefor i need to finetune it again.....how...?
🙂
BUT i just found out why the player had better focus and pinpoint perspective with the ad op42.....you see each op42 has a trimpot connected, and i thought it was for offset trimming,.
but after a closer examination of the pcb, i now see that this pot is connected in series with the I/V resistor........in other words, it is there to make it possible to trim all 4 lines to the exact same value (right +/- and left +/-)....very interesting, i don't recall to have seen this on any other player.
all the 4 trimpots have been touched and the opa627 is still in place, therefor i need to finetune it again.....how...?
🙂
What value are those trim pots?
In series with the I/V resistors?
Matched resistors would do the same, removing that trimmer may have advantages.
Do you know the original resistance value they had before touching them?
In series with the I/V resistors?
Matched resistors would do the same, removing that trimmer may have advantages.
Do you know the original resistance value they had before touching them?
these are 1k pots and i don't know the original values - and it's 4 different values - and yes, a fixed value would be best......the I/V is also 1k......i was thinking that recording a 1k tone would do the trick - adjusting while playing....?
So, there's parallel dacs.
It seams like independent I/V stages too.
Maby at the factory they adjust each pot on each I/V stage independently, measuring for minimum THD?
Does it have a cap across it?
If it does, the cap is across the resistor, the pot or both?
Variable filter?🙄
It seams like independent I/V stages too.
Maby at the factory they adjust each pot on each I/V stage independently, measuring for minimum THD?
Does it have a cap across it?
If it does, the cap is across the resistor, the pot or both?
Variable filter?🙄
no, 2 for each channel - fully balanced (not seudo) and 4 I/V opa's + 4 discrete filter/buffer lines....it's done right.
and there is a 30 picoF silvered mica across the resistor/pot.
i have recorded a 1Khz tone and adjusted the 4 pots - now we're are getting somewhere.
back to normal - total pinpoint again...best i ever heard.
FMAK - just an advice, don't mess with those pots....both dac and I/V opa....and don't change the op42's.
but get the best clock + supply...and you are in for a treat.....🙂
FMAK - just an advice, don't mess with those pots....both dac and I/V opa....and don't change the op42's.
but get the best clock + supply...and you are in for a treat.....🙂 [/B][/QUOTE]
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tbla
Thanks; I wouldn't have anyway 'cause I don't like the sound of the 627s.
I seem to remeber that the pcm63s were difficult to implement. The pots may be to optimise linearity to below -100dB.
What did you do with the test tone? It may be worth measuring linearity as low as possible perhaps using a very good FFT.
but get the best clock + supply...and you are in for a treat.....🙂 [/B][/QUOTE]
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tbla
Thanks; I wouldn't have anyway 'cause I don't like the sound of the 627s.
I seem to remeber that the pcm63s were difficult to implement. The pots may be to optimise linearity to below -100dB.
What did you do with the test tone? It may be worth measuring linearity as low as possible perhaps using a very good FFT.
Dear all,
Last month I was testing the best Op-amp use in my DAC.
(My Twin TDA1541a non-oversampling VER.II)
I was lucky because I can test the performance between AD844, 811 & OPA627 in same time. In my opinions & personal taste. I choose OPA627. so....... I decided used opa627or 2604 be the standard parts of my factory completed TDA1541a DAC (Non-oversampling VER.II). Besides, I test different rank of OPA627 that I can continous purchase & use in my DAC.
Test result: OPA627AM metal can made in USA is the best. secondary is BP, the rear is AP.
So................ OPA627AP or OPA2604AP will use in my DAC later.
OPA627BP & AM will be optional offer to diyers!!!!!!! Hope they will like it.
I was happy for that because..................... my friend offer a very good price to me. I can maintain Ver.II dac to diyer in good price.
pls see the photos.
thx
thomas
Last month I was testing the best Op-amp use in my DAC.
(My Twin TDA1541a non-oversampling VER.II)
I was lucky because I can test the performance between AD844, 811 & OPA627 in same time. In my opinions & personal taste. I choose OPA627. so....... I decided used opa627or 2604 be the standard parts of my factory completed TDA1541a DAC (Non-oversampling VER.II). Besides, I test different rank of OPA627 that I can continous purchase & use in my DAC.
Test result: OPA627AM metal can made in USA is the best. secondary is BP, the rear is AP.
So................ OPA627AP or OPA2604AP will use in my DAC later.
OPA627BP & AM will be optional offer to diyers!!!!!!! Hope they will like it.
I was happy for that because..................... my friend offer a very good price to me. I can maintain Ver.II dac to diyer in good price.
pls see the photos.
thx
thomas
Attachments
Another concealed marketing postage of
DIYAudio's commercial man.
It seems I can't read a thread here, where (s)he posts a message with non-information.
Sorry for this non-informative postage. As you see you get infected by that what you go about with (at least that is valid for me).
On topic.
Within my PMD100 and Balance AD1865 DAC, the LM6181 (bypassed with Cerafina caps), was in all aspects better than the opa627BP's. I used the AD8066 as output buffer, adn ALW-regulators (that is Jung-type reg). The aspects are:
- dynamics,
- details of a tone (drum base kicks are supported by the mids and hights, the same counts for the tones of a bass string)
-phase -correctness
This does not mean other opamps aren't good, but within my configuration the LM6181 performs the best.
Regards Henk
DIYAudio's commercial man.
It seems I can't read a thread here, where (s)he posts a message with non-information.
Sorry for this non-informative postage. As you see you get infected by that what you go about with (at least that is valid for me).
On topic.
Within my PMD100 and Balance AD1865 DAC, the LM6181 (bypassed with Cerafina caps), was in all aspects better than the opa627BP's. I used the AD8066 as output buffer, adn ALW-regulators (that is Jung-type reg). The aspects are:
- dynamics,
- details of a tone (drum base kicks are supported by the mids and hights, the same counts for the tones of a bass string)
-phase -correctness
This does not mean other opamps aren't good, but within my configuration the LM6181 performs the best.
Regards Henk
Dear Elso Kwak,
I was PM to U already. Pls check.
BTW, is the metal can still seperate AM & BM????
I trust AM will be better because metal can is Made in USA. AP & BP is made in Taiwan. As the different periods of making about TDA1541a. I trust early in overseas will better. So way I collect Netherland & belgium factory made only.
PCM 63P on my hand also be same. J,K,K2 was made in Japan.
Later is Made in Taiwan. Pls see the different between them.
Now on my hand is AM, let me ask my friend that can get BM or not!!!!
Hope I can get it.
thx
thomas
I was PM to U already. Pls check.
BTW, is the metal can still seperate AM & BM????
I trust AM will be better because metal can is Made in USA. AP & BP is made in Taiwan. As the different periods of making about TDA1541a. I trust early in overseas will better. So way I collect Netherland & belgium factory made only.
PCM 63P on my hand also be same. J,K,K2 was made in Japan.
Later is Made in Taiwan. Pls see the different between them.
Now on my hand is AM, let me ask my friend that can get BM or not!!!!
Hope I can get it.
thx
thomas
Attachments
Sorry Thomas, you still don't get it. The higher grade is the B-grade (beeeeeee). This is obvious from the datasheet.tube-lover said:
Actually specs for metal can are exactly the same as for the DIL package.
Now if for some mysterious reason the metal can is better for audio the B-grade (metal can) will even be more better...
But I understand from you posting that you only offer the A-grade in the metal can, right?
The plastic DIL B-grade I am using are made in the Phlippines but the bag says Taiwan.
Thanks for your mail.
