Three Events this Month with Dan D'Agositno's Momentum
Keep in mind the follow events from this month with Dan D'Agositno (complete overview go to post #32)
HiFi Centre
November 3, 5 – 9 p.m.
RSVP 604 .688 . 5502
578 Seymour Street, Vancouver BC V6B 3J5 Canada
http://www.hificentre.com/Contact-Us.aspx
Music Systems
November 11, 5:30 – 8:30 p.m.
RSVP 786.331.9012
2854 NW 79th Ave, Doral FL 33122
http://www.facebook.com/note.php?note_id=10150242004220881
HiFi House
November 16, 5:30 – 8:30 p.m.
RSVP 302 .655 . 4780
2304 Concord Pike, Wilmington DE 19803
http://www.hifihouse.com/
Keep in mind the follow events from this month with Dan D'Agositno (complete overview go to post #32)
HiFi Centre
November 3, 5 – 9 p.m.
RSVP 604 .688 . 5502
578 Seymour Street, Vancouver BC V6B 3J5 Canada
http://www.hificentre.com/Contact-Us.aspx
Music Systems
November 11, 5:30 – 8:30 p.m.
RSVP 786.331.9012
2854 NW 79th Ave, Doral FL 33122
http://www.facebook.com/note.php?note_id=10150242004220881
HiFi House
November 16, 5:30 – 8:30 p.m.
RSVP 302 .655 . 4780
2304 Concord Pike, Wilmington DE 19803
http://www.hifihouse.com/
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two additional URL's concerning this model:
New Music Forum - NMF • Afficher le sujet - Dan d'Agostino MOMENTUM.
A votre écoute !: Dan D’Agostino ex Krell sort ses griffes, c'est Le Momentum !
New Music Forum - NMF • Afficher le sujet - Dan d'Agostino MOMENTUM.
A votre écoute !: Dan D’Agostino ex Krell sort ses griffes, c'est Le Momentum !
Last event this year with Dan D'Agositno's Momentum near Washington DC
JS Audio http://www.jsaudio.com/
December 3
RSVP 301 .656 .7020
4919 St Elmo Ave., Bethesda MD 20814
http://jsaudio.com/dan-dagostino-master-audio-systems
JS Audio http://www.jsaudio.com/
December 3
RSVP 301 .656 .7020
4919 St Elmo Ave., Bethesda MD 20814
http://jsaudio.com/dan-dagostino-master-audio-systems
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I met with Dan when he was here a few weeks ago my apologies for having no pics nor posting about it here, i had forgotten...
The amp is gorgeous and not as small as pics would lead you to believe. I will not comment on the sound, the room and display setup was not optimal IMO and had issues, so i will refrain from discussing the sound, i would have to hear the amplifier in another environment or after the dealer has made the necessary changes to the room, we plan on going back, for another listen and for what it's worth , the issue i was hearing was not amp related IMO, but more room/ speaker /interactions.
Speakers were Wilson Sasha's , with Boulder electronics (CD/Pre-amp) , Dan in discussion had said , he was limited ( marketing)when at Krell and could not drift too far away from big heavy Class-a type amplifiers that had become krell's forte, this new co allows him a new start to build amplifiers with the changes and designs he always wanted to.
We did discuss the amplifier and he did give some details as to feedback ,et al , but i did not take notes and do not want to misquote the numbers i was given 4 weeks ago.
Sorry ...
The amp is gorgeous and not as small as pics would lead you to believe. I will not comment on the sound, the room and display setup was not optimal IMO and had issues, so i will refrain from discussing the sound, i would have to hear the amplifier in another environment or after the dealer has made the necessary changes to the room, we plan on going back, for another listen and for what it's worth , the issue i was hearing was not amp related IMO, but more room/ speaker /interactions.
Speakers were Wilson Sasha's , with Boulder electronics (CD/Pre-amp) , Dan in discussion had said , he was limited ( marketing)when at Krell and could not drift too far away from big heavy Class-a type amplifiers that had become krell's forte, this new co allows him a new start to build amplifiers with the changes and designs he always wanted to.
We did discuss the amplifier and he did give some details as to feedback ,et al , but i did not take notes and do not want to misquote the numbers i was given 4 weeks ago.
Sorry ...
Two Events this Month with Dan D'Agositno's Momentum
follow events this month:
Aurant Home Theater
Aurant - Gallery
January 20, 2012
RSVP 801 . 467. 591 8
Salt Lake City UT
Innovative Audio Video
Innovative Audio Video
January 25, 2012, 6 – 9 p.m.
RSVP 212 .634 . 4444
150 East 58th Street, NY NY 10155
follow events this month:
Aurant Home Theater
Aurant - Gallery
January 20, 2012
RSVP 801 . 467. 591 8
Salt Lake City UT
Innovative Audio Video
Innovative Audio Video
January 25, 2012, 6 – 9 p.m.
RSVP 212 .634 . 4444
150 East 58th Street, NY NY 10155
wonder who he hired to do the design...
_-_-bear
And this?
http://4.bp.blogspot.com/--V7DMgFJrkE/Tp8Z9N4QpaI/AAAAAAAACnI/zVRAwUVgHPI/s1600/DAgostino2_600.jpg
Hey, that's a great start, I guess but who first figured out how to do that with that particular preamp?
"In the interview Dan talks about a low feedback design with only 8-10 dB overall feedback, but more around the output devices that need heavier feedback to perform well...sounds a bit like two split feedback loops."
From what I have read, Dan's Momentum amp does not have global feedback from the output to the input, but it does have (patented) nested feedback over the input stages plus (large amounts of) error correction feedback on the output stage.
The Momentum design goal appears to focus on isolating output noise from the high sensitivity diff input. To me, this is the most interesting discussion point.
1) The reverse currents from high inductance speaker voice coils can affect the sound if they are fed back to the high gain differential input stage.
2) All Krell amp schematics I have seen use MOSFETs for the first output driver stage, with the goal of isolating the speaker's reverse currents from the gain stages. I do not know if the Momentum design includes this voltage-to-current isolation. John Curl's amps also use a MOSFET output driver for this same isolation goal.
3) RFI noise, especially from digital Wi-Fi networks and in-home local networks, can get picked up on the speaker interconnect cables and fed back to the high gain differential input stage.
4) Nested feedback over the high frequency, low capacitance input stages is more accurate than global feedback that goes around the 24-pair output stage. Very little noise gets injected into the intput stage loops.
Bob Cordell and Doug Self favor designing stable circuits to which you add large amounts of global feedback.
Charles Hansen(Ayre) favors designing very simple but stable circuits with no global feedback.
The Momentum is Dan's statement of absolute Solid State audio truth.
From what I have read, Dan's Momentum amp does not have global feedback from the output to the input, but it does have (patented) nested feedback over the input stages plus (large amounts of) error correction feedback on the output stage.
The Momentum design goal appears to focus on isolating output noise from the high sensitivity diff input. To me, this is the most interesting discussion point.
1) The reverse currents from high inductance speaker voice coils can affect the sound if they are fed back to the high gain differential input stage.
2) All Krell amp schematics I have seen use MOSFETs for the first output driver stage, with the goal of isolating the speaker's reverse currents from the gain stages. I do not know if the Momentum design includes this voltage-to-current isolation. John Curl's amps also use a MOSFET output driver for this same isolation goal.
3) RFI noise, especially from digital Wi-Fi networks and in-home local networks, can get picked up on the speaker interconnect cables and fed back to the high gain differential input stage.
4) Nested feedback over the high frequency, low capacitance input stages is more accurate than global feedback that goes around the 24-pair output stage. Very little noise gets injected into the intput stage loops.
Bob Cordell and Doug Self favor designing stable circuits to which you add large amounts of global feedback.
Charles Hansen(Ayre) favors designing very simple but stable circuits with no global feedback.
The Momentum is Dan's statement of absolute Solid State audio truth.
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Looking at pictures of the chassis design, I would say that it is very immune to any radiated RF and the only ingress would be through connectors, but one can apply very successful filtering by means of feed-through capacitors and inductor to attenuate and avoid RFI to get into the circuits.
I am not convinced about the statement that even split up negative feed-back loops eliminate noise ingress from the output stage, in fact it will enhance it, if the same noise is not present on the input of the differential stage.
This may just sales hype
I am not convinced about the statement that even split up negative feed-back loops eliminate noise ingress from the output stage, in fact it will enhance it, if the same noise is not present on the input of the differential stage.
This may just sales hype
Speaking about several hundreds of MHz and units of GHz (RFI cell phone range), any input differential stage is completely ineffective. Even feedthrough filtering may be ineffective, if the product is not intended and designed/built for GHz range, which is never the case in audio, regardless Names.
Can any expert in output error correction circuits describe how to improve the basic circuit in the attached schematic for 12 pairs of 60Mhz Sanken output transistors? The Spice simulation shows 0.015% THD for 300 watts into an 8 ohm load.
What is the best output error correction circuit for 12 pairs of 60Mhz power transistors?
As a reference, a fully symmetrical design with global negative feedback using the same output transistors simulates at 0.00008% THD for 300 watts into 8 ohms.
What is the best output error correction circuit for 12 pairs of 60Mhz power transistors?
As a reference, a fully symmetrical design with global negative feedback using the same output transistors simulates at 0.00008% THD for 300 watts into 8 ohms.
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