Yes it is bulk of it is discrete except the servo which is an opamp (simply because it is hard to achieve the kind of DC performance you need without an opamp).
We might decide to produce it as a kit after I have a chance to test a couple of part changes. It is probably a couple months off at least before I even build another prototype. The decision to produce it will depend on a number of factors.
We might decide to produce it as a kit after I have a chance to test a couple of part changes. It is probably a couple months off at least before I even build another prototype. The decision to produce it will depend on a number of factors.
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Hahahaha...
Perhaps, I have been doing some research
, also I am about to be testing another nCore amplifier amp build here, and these amps seem to be very finicky about RF at their inputs. I know that technically the filter stages of my current Legato 2 should be removing RF from the output, but testing with my previous nCore build (for someone else) indicated that something bad was getting to the outputs, as the nCores had some very low level (ear to tweeter) rough static-y sounds coming through, which were not present with a different DAC (Opus/IVY III) at the input, or with the input open. A highly textured noise floor has always bothered me, no matter how low in level. I prefer to hear just a nice, smooth, even, white noise hiss indicative of the thermal noise of electronic components.
Also, as mentioned, I have heard some very, very good sounding DACs which coupled their outputs through Lundahls. I know everbody says this (lol), but my set up is pretty dam resolving at this point, if transformers did obscure detail at all, I would be able to note it pretty easily here, so it might be a fun experiment to try them. As Russ mentioned, it might be better to transformer couple the input of the amp (I suspect he means in terms of impedances), but this nCore build is not technically for me at this point, and I would have to add transformers externally on any of my other amps, adding complexity and connections, which I hate!
I'll probably just try no connection to pin 1 at first, unless Santa brings me a couple of $140 Lundahls!
Ah, looking for a taste of the dark side eh Barrows?
Perhaps, I have been doing some research
, also I am about to be testing another nCore amplifier amp build here, and these amps seem to be very finicky about RF at their inputs. I know that technically the filter stages of my current Legato 2 should be removing RF from the output, but testing with my previous nCore build (for someone else) indicated that something bad was getting to the outputs, as the nCores had some very low level (ear to tweeter) rough static-y sounds coming through, which were not present with a different DAC (Opus/IVY III) at the input, or with the input open. A highly textured noise floor has always bothered me, no matter how low in level. I prefer to hear just a nice, smooth, even, white noise hiss indicative of the thermal noise of electronic components.Also, as mentioned, I have heard some very, very good sounding DACs which coupled their outputs through Lundahls. I know everbody says this (lol), but my set up is pretty dam resolving at this point, if transformers did obscure detail at all, I would be able to note it pretty easily here, so it might be a fun experiment to try them. As Russ mentioned, it might be better to transformer couple the input of the amp (I suspect he means in terms of impedances), but this nCore build is not technically for me at this point, and I would have to add transformers externally on any of my other amps, adding complexity and connections, which I hate!
I'll probably just try no connection to pin 1 at first, unless Santa brings me a couple of $140 Lundahls!
Russ...
Now that you have spilled the beans on the forthcoming Counterpoint 3, perhaps you will start an announcement thread on it for discussion? I am assuming this will be a feedback bipolar circuit with low input impedance to suit the ESS 9018, I would like to hear what other people think of it conceptually vs the IVYIII.
Now that you have spilled the beans on the forthcoming Counterpoint 3, perhaps you will start an announcement thread on it for discussion? I am assuming this will be a feedback bipolar circuit with low input impedance to suit the ESS 9018, I would like to hear what other people think of it conceptually vs the IVYIII.
I will start an announcement thread when and if I think its ready for prime time.
It's far more like Legato than IVY-III. In fact it has almost nothing in common with IVY-III except that it converts current to voltage.
It has no global feedback - just a servo that sets the cascode current to get the common mode voltage to 0V.
It is also right now just an experiment.
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Sweet, Russ...
Now you have my attention! Relatively simple circuit with no global feedback, but with a servo. Too bad I just purchased a L3 kit... One can never have too many output stages to try though, thanks for creating another interesting option.
I will start an announcement thread when I think its ready for prime time.
It's far more like Legato than IVY-III. In fact it has almost nothing in common with IVY-III except that it converts current to voltage.
It has no global feedback - just a servo that sets the cascode current to get the common mode voltage to 0V.
Now you have my attention! Relatively simple circuit with no global feedback, but with a servo. Too bad I just purchased a L3 kit... One can never have too many output stages to try though
, thanks for creating another interesting option.
Oh don't worry! I don't see this as better than Legato 3 - only different.
It is not in any way ready to replace Legato 3.1 in fact there is a lot to recommend the Legato 3.1 approach - for one it is much simpler and cheaper.
I see Legato 3.1 as some of my best work. I personally have it in my current reference system. It is not going anywhere either.
In any case - counterpoint III not even close to finished yet. I just wanted to give a little window into the workshop.
It is not in any way ready to replace Legato 3.1 in fact there is a lot to recommend the Legato 3.1 approach - for one it is much simpler and cheaper.
I see Legato 3.1 as some of my best work. I personally have it in my current reference system. It is not going anywhere either.
In any case - counterpoint III not even close to finished yet. I just wanted to give a little window into the workshop.
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Yes that's a good point Brian!
it has some rather "not-cheap" (precision voltage divider - big thin film resistors - etc) parts.
In testing I found some mild - but undesirable thermal characteristics which I will resolve with sets of dual (and maybe quad - but not likely) transistors. That will also probably add a bit to the cost.
it has some rather "not-cheap" (precision voltage divider - big thin film resistors - etc) parts.
In testing I found some mild - but undesirable thermal characteristics which I will resolve with sets of dual (and maybe quad - but not likely) transistors. That will also probably add a bit to the cost.
Hi Brian, Russ,
We really do respect what you are doing here but is this not a thread about Legato 3, DC offset discussion
I don't see any value added to discuss the dc offset on the legato3 by your comments although I may be wrong. It appears more like marketing vaporware of a product to market which never appears.
just my personal 2 cents worth.
regards.
We really do respect what you are doing here but is this not a thread about Legato 3, DC offset discussion
I don't see any value added to discuss the dc offset on the legato3 by your comments although I may be wrong. It appears more like marketing vaporware of a product to market which never appears.
just my personal 2 cents worth.
regards.
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One of the really critical design elements of the Legato 3.1 is it's simplicity. That is one of the reasons why it is so special. It is very much like the D1 in that regard (with the same need to AC couple in some cases) except that instead of a FET it uses a hybrid CFP based approach with paralleled devices.
Legato 3.1 adds some nice touches like nulling both balanced and SE offset and BAL/SE conversion and buffering. I would say it is one of our most popular modules, and for very good reason. We leave it up to the builder to choose the coupling path best suited to their system. For some DC coupling is optimal (any truly fully differential amp), for others AC coupling is ideal - via caps or via transformer. This is an age old design choice - and many superb audio stages have employed both forms of AC coupling.
Cheers!
Russ
Legato 3.1 adds some nice touches like nulling both balanced and SE offset and BAL/SE conversion and buffering. I would say it is one of our most popular modules, and for very good reason. We leave it up to the builder to choose the coupling path best suited to their system. For some DC coupling is optimal (any truly fully differential amp), for others AC coupling is ideal - via caps or via transformer. This is an age old design choice - and many superb audio stages have employed both forms of AC coupling.
Cheers!
Russ
AS the OP
I have no problem with some discussion of the Counterpoint III here, especially as it is a discrete output stage (OK, mostly discrete) with a solution for all DC issues. If the Counterpoint III sees the light of day it will be something to give a try and listen to. I have no problem with it being more expensive, in fact, I hope that really good resistors are chosen despite price, because many SMD resistors can sound pretty bad, and replacing them is not all that fun, and I am guessing that it wouldl be a good idea to use 0.1% tolerance parts rather than try and match them...
I do hope to hear from folks using the Legato 3 with different amps, and different solutions for how they are dealing with the DC. I would especially like to hear from some people who are not connecting the G to pin 1 at all at the output of the DAC, and how this is working for them with a given amplifier.
I have no problem with some discussion of the Counterpoint III here, especially as it is a discrete output stage (OK, mostly discrete) with a solution for all DC issues. If the Counterpoint III sees the light of day it will be something to give a try and listen to. I have no problem with it being more expensive, in fact, I hope that really good resistors are chosen despite price, because many SMD resistors can sound pretty bad, and replacing them is not all that fun, and I am guessing that it wouldl be a good idea to use 0.1% tolerance parts rather than try and match them...
I do hope to hear from folks using the Legato 3 with different amps, and different solutions for how they are dealing with the DC. I would especially like to hear from some people who are not connecting the G to pin 1 at all at the output of the DAC, and how this is working for them with a given amplifier.
I agree it would be good to get some feedback from other Legato users on how they use the module with their amps.
In discussing that it would be good to note the topology of the target amp.
Is it SE? Fully differential? Two bridge tied amps per channel?
Really though the discussion around how to AC couple (caps vs trafo) will come down to personal preference. It is fine to hear about that as well.
In discussing that it would be good to note the topology of the target amp.
Is it SE? Fully differential? Two bridge tied amps per channel?
Really though the discussion around how to AC couple (caps vs trafo) will come down to personal preference. It is fine to hear about that as well.
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