It is very difficult for me to visualize the concept without an image. Would you care to redraw my sch Andrew ?
You've never heard the Magni 3, yet you're concerned about my hearing??
I don't need to see a doctor immediately. I have BOTH amps to evaluate and to listen to...apparently YOU DON'T.
PLEASE go see your Gynecologist ASAP!!
By the way, your typing or grammar skills suck! It should read "I am concerned" not "Iam concerned".
Anyway, I won't be wasting anymore of my time replying to your worthless comments/opinions.
Guys I suggest you stop the subjective fighting thing before it escalates and some moderator takes notice resulting in penalties. I will not intervene as a mod because its a rule we don't moderate in our own threads not to be prejudiced. Each one to his own preferences. Ammel likes very much an apparently class B biased BJT straightforward push pull Schiit pre with an op-amp chip driver. But the guy in the youtube review says Ammel's has glare and compression with a hint of V shaped like quality. Go figure. Others may like the class A SE discrete minimal FET DCG3 because its closer to tubes tone but Alex took out of his rack a real tubes several k$ highly reviewed Japanese preamp and listens with the DCG3. Go figure. In the end science says ABX blind all the properly measuring stuff you got and I guarantee you can't pick them apart. But all people did not just make an O2 and stopped there. Go figure.
> Ammel likes very much an apparently class B biased BJT straightforward push pull pre with an op-amp chip driver.
To be fair, the "Magni 3’s gain stage is an-all-new, fully discrete, high-speed, dc-coupled, current-feedback design,
completely different than the first and second-generation Magnis."
Schiit Magni 3
With 8 BJT's per channel, the claim is believable.
The opamp is probably a servo (TL082 in the Magni 2) or a JFET unity gain buffer at the input after the pot.
It is also supposed to be Class AB.
The power devices (2SA1552 2SC4027) are not particularly linear though.
Something like this perhaps :
Current-feedback operational amplifier - Wikipedia
Lots of negative feedback. Personal taste (as we are of course allowed in the free world).
Cheers,
Patrick
To be fair, the "Magni 3’s gain stage is an-all-new, fully discrete, high-speed, dc-coupled, current-feedback design,
completely different than the first and second-generation Magnis."
Schiit Magni 3
With 8 BJT's per channel, the claim is believable.
The opamp is probably a servo (TL082 in the Magni 2) or a JFET unity gain buffer at the input after the pot.
It is also supposed to be Class AB.
The power devices (2SA1552 2SC4027) are not particularly linear though.
Something like this perhaps :
Current-feedback operational amplifier - Wikipedia
Lots of negative feedback. Personal taste (as we are of course allowed in the free world).
Cheers,
Patrick
20mA (just an example, not that I know) bias is still Class AB, for a headphone amp.
[Review] Schiit Magni 3 and Modi Multibit: The Schiit of Dreams? : headphones
"The Magni 3 is completely different. It was suppose to be the "Class AB upgrade" for the Asgard 3"
Incidentally, I have a lot of respect for people who can design a commercial product for 99USD, fully discrete.
I know I cannot.
Patrick
[Review] Schiit Magni 3 and Modi Multibit: The Schiit of Dreams? : headphones
"The Magni 3 is completely different. It was suppose to be the "Class AB upgrade" for the Asgard 3"
Incidentally, I have a lot of respect for people who can design a commercial product for 99USD, fully discrete.
I know I cannot.
Patrick
Precarious running naked when it must swing for a listed 430mW at 300Ω I would still think.
Such circuitry ideas are not things that DIYers have not experienced though. My first beta tester had a CFA discrete JFET input + BJTs line pre. Based on input and driver stages of CFA power amps like Juma's. And he enthusiastically moved it out to keep the DCG3. His mates asked for copies too. One of them listens to an IRS Gamma well preserved half active loudspeaker system where he compared the preamps and moved to DCG3. So again for taste in sound go figure.
Such circuitry ideas are not things that DIYers have not experienced though. My first beta tester had a CFA discrete JFET input + BJTs line pre. Based on input and driver stages of CFA power amps like Juma's. And he enthusiastically moved it out to keep the DCG3. His mates asked for copies too. One of them listens to an IRS Gamma well preserved half active loudspeaker system where he compared the preamps and moved to DCG3. So again for taste in sound go figure.
the summer channels adds the two signals and send the sum to the next stage.
The two inputs to the summer channel are still separate for normal stereo duty.
The summer is a true ADD function.
But prior to the summer the two channels are still independent.
I revised the sch so to have 100k input impedance.
I am using LME4971 opamps.... are these unity gain stable with -Vin connected to the output ?
Attachments
The Buffers are not adding anything.
I would try a plug board version with just the summer and see how the stereo performs when you make the two connections to the summer.
R3 = 20k will give an output that is 2times the inputs.
if you have a high proportion of bass (at any time) in the stereo signal then you may overload the summer and the next stage. Try reducing R3 to 10k.
I would try a plug board version with just the summer and see how the stereo performs when you make the two connections to the summer.
R3 = 20k will give an output that is 2times the inputs.
if you have a high proportion of bass (at any time) in the stereo signal then you may overload the summer and the next stage. Try reducing R3 to 10k.
As good as the DCG3 sounds, I've recently had to retire my example by throwing it into the trash since it simply can not compete with the Schiit Magni 3 for sound quality as a HA or as line stage preamp.
Yes, the Magni 3 costs a little more, but there's no comparison in sound quality.
I want to give out a big ole' thanks to Salas for all his help answering my questions and for the design.
Just a reminder to guys on this forum...always be open to newer and better options, even if they are commercial offerings.
Now, let's bust out the moonshine and soldering iron and build something else!
Sorry for continuing this OT subject but I feel compelled to share my findings of the M3 vs other designs around here. Note that for me, the DCG3 costs more than M3, at least my build did including PSU and such. The fact the your M3 costs more than your DCG3 might be part of the reason it doesn't sound as good. The M3 is a marvelous piece of engineering and amazing value for $99 retail. Made in the USA too. It is very powerful too - over a watt capable into 30 ohms (but the distortion looks crazy at such drive levels). I use it to compare to my Class A amps and although it sounds very good - in direct AB comparisons, level matched, and with high resolution sources, and material, there is a very audible difference.
The sound stage and depth of the stereo image is not as good as a low or zero global feedback Class A amp. If one only had the M3, one might be very happy, but comparing it with some of the world class design around here - no comparison. The measurements show that the M3 is a very low THD amp, yes. But what is the harmonic profile like? It is dominant third order with lots of higher order stuff that is odd order. Although very low, they are contributing to an unnatural sound. Having lots of global feedback to drive the THD low also makes the sound stage and sense of engagement not as good. Don't get me wrong - for $99 it is an unbelievable value and one wonders how it is possible to make a discrete DC coupled CFA amp for that much.
Here is the FFT for 2.0Vpp into 50ohms for the M3:
Compare that to the DCG3, or Aksa Lender HPA and you will see the beauty of SE Class A designs. Here is FFT of Aksa Lender HPA at same condition (3.5x higher THD but look at the profile is now H2 dominant with only some H3 and nothing else):
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You've never heard the Magni 3, yet you're concerned about my hearing??
I don't need to see a doctor immediately. I have BOTH amps to evaluate and to listen to...apparently YOU DON'T.
PLEASE go see your Gynecologist ASAP!!
By the way, your typing or grammar skills suck! It should read "I am concerned" not "Iam concerned".
Anyway, I won't be wasting anymore of my time replying to your worthless comments/opinions.
Chill out. It was a joke. Everyone has the right to like what they like. I have no ill will towards Schitt or your hearing abilities. Carry on. If anything, I was just trying to defend Salas' amp which I quite enjoy in perhaps a heavy-handed way.
But one thing...I've seen on multiple posts where you don't like something so you say you "throw it in the trash" or something to that effect. In fact, multiple projects I've built you have "thrown in the trash" like garbage.
It's quite unkind to the people here like Salas who are trying to get a project out there (for free) and giving away good info and advice. If you don't like it, you don't like it. That's fine. In fact you can say you don't like it. That's cool too.
But don't discourage people from building who may like it by saying it's garbage (your words, not mine). think of all the people who are excited to build this amp and then read your words? These words can be powerful when people are deciding what to build...
but the transformer input impedance is about 13.5Kohm so isnt that less?
what is the input impedance of DCG3 pre?
Hello
I will like to tell a little about my experience with the Salas pre--
in my setup it do not funktion very good ...it plays super varm and delight,,with a very strong bass ,,,but i could use more bite and soul in the upper area,,this i have in my 4P1L tube pre...
there is nothing wrong with the wide an Depth in the Salas
maybe it is the mosfet there play to soft and not totally open in the upper area..
i know other setup where this Salas pre will work totally perfekt..but my setup plays a little on the dark side,,,so it is not perfekt match
in all other area it is a great preamp..no noise and hum
i will try to sell it ..and hope it come to a place where it will match perfekt
just now i play only with my volume pot,,,not perfekt, but more off the sound i like
hope you understand something off what i try to tell,,hard in English
Best Bjarne
I will like to tell a little about my experience with the Salas pre--
in my setup it do not funktion very good ...it plays super varm and delight,,with a very strong bass ,,,but i could use more bite and soul in the upper area,,this i have in my 4P1L tube pre...
there is nothing wrong with the wide an Depth in the Salas
maybe it is the mosfet there play to soft and not totally open in the upper area..
i know other setup where this Salas pre will work totally perfekt..but my setup plays a little on the dark side,,,so it is not perfekt match
in all other area it is a great preamp..no noise and hum
i will try to sell it ..and hope it come to a place where it will match perfekt
just now i play only with my volume pot,,,not perfekt, but more off the sound i like
hope you understand something off what i try to tell,,hard in English
Best Bjarne