Gain of +1 is commonly referred to as "unity gain". 😉
Yesss...use the LT1128 as the output opamp. 🙂
Yesss...use the LT1128 as the output opamp. 🙂
one thing I fail to understand is that 2*LT1028AC used to work fine as final buffer...and now either they give a very loud shredding noise or a lot of hiss on the left channel...hummm, did I fry the chips somehow??
I can get some LT1128ACN8 for rather cheap on ebay, 8 EUR a pop including shipping..
ah well, LT1363 is a good guy too..SQ is very good! I'm sick and tired of rolling anyway 😀
I can get some LT1128ACN8 for rather cheap on ebay, 8 EUR a pop including shipping..
ah well, LT1363 is a good guy too..SQ is very good! I'm sick and tired of rolling anyway 😀
Yes, it is! It drove my HD238 (32 ohm) just as well as the AD845KN. 🙂 But you must pay a little attention to its input current...the AD845 being more likely to fit well in a given circuit.
That's a good bet 🙂 and would counterbalance the LT1363's relative brightness well.
yes, I'll look into my options...but IME adding a final buffer always kills the SS of the opamps that are used on the AK4396 output...it will color it to death.
right now I've got a mind blowing SS, OKish trebles, great mids and OK-ish bass response(the AD797B was definitely more bass shy)...sound is actually very balanced.
I could add some op-amps as final buffer, it will give far more bass....but also shrink down and color the SS from the DAC output, this I'm not sure I want.
and I will compare 4*LT1363 to 2*LT1364 to make sure that the much wider center channel is not the fruit of my imagination 😛
I'll also try 6*LT1363, but from what I've heard so far LT1363 doesn't sound too good as final buffer...ppl seem to prefer 2*1364 and 1*1361, I'm expecting some 1360 😉
and tbh, the hiss/loud screaming noises from the LT1028 have kinda scared me...I really don't wanna screw up my beloved headphones 😱
right now I've got a mind blowing SS, OKish trebles, great mids and OK-ish bass response(the AD797B was definitely more bass shy)...sound is actually very balanced.
I could add some op-amps as final buffer, it will give far more bass....but also shrink down and color the SS from the DAC output, this I'm not sure I want.
and I will compare 4*LT1363 to 2*LT1364 to make sure that the much wider center channel is not the fruit of my imagination 😛
I'll also try 6*LT1363, but from what I've heard so far LT1363 doesn't sound too good as final buffer...ppl seem to prefer 2*1364 and 1*1361, I'm expecting some 1360 😉
and tbh, the hiss/loud screaming noises from the LT1028 have kinda scared me...I really don't wanna screw up my beloved headphones 😱
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Adding one more, complementary-sounding opamp stage (such as with LT1363 and LT1128, which are rather complementary both color wise and balance wise) can only help to balance the sound presentation, and will never "color" it. Provided you don't just choose some trash chip 🙂
And in your case the output opamp seems pretty much necessary as it's the one that converts the balanced output of the DAC into single ended...
And in your case the output opamp seems pretty much necessary as it's the one that converts the balanced output of the DAC into single ended...
Which is the typ. impedance to load a rca audio dvd output?
I want not to affect the source. (Vrms 0.38)
I want not to affect the source. (Vrms 0.38)
it will kill the SS for sure, even the 1028 was...but well, it was prolly oscillating to death when it was still working
anyway, bass is great(LT1363/4 sure are bass nodders)...I just bought a Griffin Powermate btw, very cool stuff, I love it!
getting a proper analog pot is a PITA, as it requires steps to be accurate and I hate steps: High Precision Volume Control (HPVC)
and LT1363 just has an amazing SS, far more natural than AD797B I would say...when I watch a cartoon, I can picture the dubbing actors recording in the studio...it seems to capture the original room reverb so accurately! if hell doesn't break loose anytime soon, those four LT1363CN8 will stay there for a while 😛
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What's to explain, he's happy and that's all that matters. Those empty opamp sockets look cool.
Appears that he/she did:
- removed differential/LPF/buffer opamps.
- removed coupling capacitors.
- connected audio transformers to AK4396 DAC differential voltage outputs.
- routed transformer outputs to card's RCA audio output jacks.
In otherwords, transformer provides DC blocking/isolation, impedance matching, and LPF functions.
- guessing output level is lower than stock.
- typical transformer coupled topology. (of "no-opamp" ilk.)
- tradeoff appears to be increased noise and THD. (long signal wires in noisy PC environment.)
Power Section:
- replaced various power filter capacitors with OSCON.
- replaced onboard 5vdc voltage regulator(s) (for AK4396 DAC) with external shunt regulator.
Amplimo TM20 Signal Transformer:
- 30Hz - 25000Hz
- price: approx $114.00 USD
- removed differential/LPF/buffer opamps.
- removed coupling capacitors.
- connected audio transformers to AK4396 DAC differential voltage outputs.
- routed transformer outputs to card's RCA audio output jacks.
In otherwords, transformer provides DC blocking/isolation, impedance matching, and LPF functions.
- guessing output level is lower than stock.
- typical transformer coupled topology. (of "no-opamp" ilk.)
- tradeoff appears to be increased noise and THD. (long signal wires in noisy PC environment.)
Power Section:
- replaced various power filter capacitors with OSCON.
- replaced onboard 5vdc voltage regulator(s) (for AK4396 DAC) with external shunt regulator.
Amplimo TM20 Signal Transformer:
- 30Hz - 25000Hz
- price: approx $114.00 USD
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I bought me a very cheap (on offer @ 19.90€) "Sansui DV1200" DVD player, whose sound (after burn in & connected with the always dependable VDH The Bay C5 interconnect) I definitely like, for its warmth and fluidity, although it certainly doesn't do anything extraordinary.. It looks like a perfect base for some modding, though 🙂
I will need to open it and see what DAC it has (provided it's even an independent DAC chip) to decide whether to use (most probably) OPA1642 or LME49725. 🙂 Secondly, I guess I'll change coupling caps, and perhaps some power supply caps too.
I like the amount of goodness you can buy today for 20€. 😎
I will need to open it and see what DAC it has (provided it's even an independent DAC chip) to decide whether to use (most probably) OPA1642 or LME49725. 🙂 Secondly, I guess I'll change coupling caps, and perhaps some power supply caps too.
I like the amount of goodness you can buy today for 20€. 😎
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ok thanks for the explanations!
so you can replace op-amps by pricey transformers huh
he's usually using Burson op-amps and already tried pretty much every op-amp in the book, I'd trust his judgment
I have seen data from some small integrated amplifiers, fed at low voltage. the Max, tda, ... tpy
Are there any integrated amplifier that can be used as a headphone amp for hd595, with high audio quality (above all). Or is it better to go directly to operational amplifiers for this application.
The supply voltage would prefer that high, I have 22/0/22V in the transformer.
Are there any integrated amplifier that can be used as a headphone amp for hd595, with high audio quality (above all). Or is it better to go directly to operational amplifiers for this application.
The supply voltage would prefer that high, I have 22/0/22V in the transformer.
And this? Welcome to Audiophilechina 🙂
Anyway the HD595 was driven well by opamps directly in my experience. I remember it sounding really good driven by the LT1361 (or two single LT1360). The OPA132 (singles tend to be a better choice for this) is a good candidate as well. If you try the LT1360/1, pay attention to DC offset 🙂
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And... I just bought the parts (some 105°C electrolytics) to fix my "Xenos 1HA-EPC" headphone amp.
As for the opamps, I'd already soldered an LT1358 in the stage that drives the transistor buffer; and this will remain. And I'll use the OPA1642 as the input and gain stage. I'm sure they'll pair well 😉
That way I'll manage to try this OPA1642 that I'm curious about, and sooner than I would have in the said DVD. 😎
As for the opamps, I'd already soldered an LT1358 in the stage that drives the transistor buffer; and this will remain. And I'll use the OPA1642 as the input and gain stage. I'm sure they'll pair well 😉
That way I'll manage to try this OPA1642 that I'm curious about, and sooner than I would have in the said DVD. 😎
I have an old headphone amplifier circuit that employs the rc4558 dil-8, with a dc decoupling capacitors in and out. Gain 6. Could I use it with a more modern dual ao, what would you advise me?
I had given up using it because, from reading this forum, had figured that would work best to build a new circuit with two opa1611, and although more work (and money) might be worthwhile to design and build. (In order to improve the quality of sound.) The source I want to use is high quality and i want to make the best of it.
Furthermore, no stone seen your note on the Yulong a1000, which ultimately is based on another dual, the OPA2134 + bc377 at very reasonable prices. You just have to ask ...and paid.
I had given up using it because, from reading this forum, had figured that would work best to build a new circuit with two opa1611, and although more work (and money) might be worthwhile to design and build. (In order to improve the quality of sound.) The source I want to use is high quality and i want to make the best of it.
Furthermore, no stone seen your note on the Yulong a1000, which ultimately is based on another dual, the OPA2134 + bc377 at very reasonable prices. You just have to ask ...and paid.