https://rpaudio.estranky.sk/fotoalbum/mbl-6010-preamplifier/
Fantastic preamplifier. Excellent sound. With LM6171
Fantastic preamplifier. Excellent sound. With LM6171
That's a difficult call to make because different ohmmeters will source different tests currents, and since junctions of transistors, rather than just resistances are involved, voltage drops will vary in a nonlinear fashion with applied test current. That will make for unpredictable and different readings amongst the different meters used to make them.
@kozard @egellings
There is no need to worry about AD797. I have tried both assembled and Chinese bare boards populated by original ICs, I also have tried swapping the ICs. No difference at all.
There is somewhere in this thread a post by @scott wurcer, a member with first hand knowledge, who knows that AD797 has some features that can't be replaced with some other rebranded IC..
This board seems to be generic but good design that boasts with the 'stolen' famous name. However, very good indeed. I'm not impressed by trade marks but measurements.
There is no need to worry about AD797. I have tried both assembled and Chinese bare boards populated by original ICs, I also have tried swapping the ICs. No difference at all.
There is somewhere in this thread a post by @scott wurcer, a member with first hand knowledge, who knows that AD797 has some features that can't be replaced with some other rebranded IC..
This board seems to be generic but good design that boasts with the 'stolen' famous name. However, very good indeed. I'm not impressed by trade marks but measurements.
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If you are looking at building a fantastic op-amp based preamp you should seriously consider the Douglas Self Preamp that you can find right here in DIYA. I would argue SOTA still to this day. You can end up with something that could be sold on the market for thousands. Boards, enclosures, Front and Back panels all exist for it
Great idea, but I've never heard about it.
Could you please provide a link?
Dennis Colin wrote an article in a construction-oriented audio magazine similar to The Audio Amateur, if not that magazine, about a phono stage he designed called the LP-797. It used a very low noise dual JFET with both transistors paralleled (LSK489 or some similar type-number; don't remember exactly) bootstrapped by an AD797 to remove miller effect and to linearize its performance. That stage implemented the HF roll-off of the RIAA curve passively. This drove another AD797 set up as a straight gain stage with a switch to select one of 3 possible gains, and that stage drove another AD797 that implemented the bass boost using feedback. I built one and can say that it is accurate as far as EQ conformance goes (better than 0.5dB everywhere), is dead silent, and it's just not there; you hear just the music, without a trace of the preamp's presence. Highly recommended!
if i am not wrong the 6010d is a line stage only ?
If i understand well the design is like this input buffer stage > volume pot > output stage ?
i wonder how much buffering the inputs is important Has anyone tried to by-pass them ?
many great line stages do not buffer the inputs before the volume control
are any measurements available ?
If i understand well the design is like this input buffer stage > volume pot > output stage ?
i wonder how much buffering the inputs is important Has anyone tried to by-pass them ?
many great line stages do not buffer the inputs before the volume control
are any measurements available ?
I used an AD797 for the main line level gain stage in this preamp
https://www.ovationhifidelity.com/product/model-1501/
I can attest to it being a fantastic opamp and good reason for it to be found in some of the best gear around.
(Despite ppm level distortion spec’d and ultra low noise, it didn’t stop a tube loving reviewer from asking me ‘did you use an opamp?’. I replied ‘yes, an AD797’ hoping he’d recognize the value in that, but instead he replied ‘I thought you did. I couldn’t help but hear the opamp haze that veiled the music’. They had already opened the preamp up to photograph the innards 🤦♂️. Utter rubbish and why I especially dislike the British hifi press - self-annointed money grubbing charlatans End of rant. )
https://www.ovationhifidelity.com/product/model-1501/
I can attest to it being a fantastic opamp and good reason for it to be found in some of the best gear around.
(Despite ppm level distortion spec’d and ultra low noise, it didn’t stop a tube loving reviewer from asking me ‘did you use an opamp?’. I replied ‘yes, an AD797’ hoping he’d recognize the value in that, but instead he replied ‘I thought you did. I couldn’t help but hear the opamp haze that veiled the music’. They had already opened the preamp up to photograph the innards 🤦♂️. Utter rubbish and why I especially dislike the British hifi press - self-annointed money grubbing charlatans End of rant. )
Is was an LSK389. I used a similar scheme with the JFETs in this preamp (links will take you to the audioXpress article)
https://hifisonix.com/projects/x-altra-phono-eq-preamp/