How to bridge LM3886s
We covered this before:
http://www.diyaudio.com/forums/showthread.php?threadid=508
The original link:
http://www.national.com/appinfo/audio/files/BPA-200_Application_Note.pdf
We covered this before:
http://www.diyaudio.com/forums/showthread.php?threadid=508
The original link:
http://www.national.com/appinfo/audio/files/BPA-200_Application_Note.pdf
confusion
Perhaphs some of the confusion arrises from the fact that they are called T.I. modules in the Rowland amps.. people think, TI -> Texas Instruments -> ICs. I think it actuallys
stands for Transimpedeance model.
I am not that familiar with the Rowland product line however am saving pennies for a Rowland model 5.
-- Aaron Finley
arnach5@hotmail.com
Perhaphs some of the confusion arrises from the fact that they are called T.I. modules in the Rowland amps.. people think, TI -> Texas Instruments -> ICs. I think it actuallys
stands for Transimpedeance model.
I am not that familiar with the Rowland product line however am saving pennies for a Rowland model 5.
-- Aaron Finley
arnach5@hotmail.com
Rowland and 3886
Here's a link (on Rowland's page) to the parallel-bridged amp using 3886. Nice photos there too.
http://www.jeffrowland.com/review16b.htm
Here's a link (on Rowland's page) to the parallel-bridged amp using 3886. Nice photos there too.
http://www.jeffrowland.com/review16b.htm
. What does this unit sell for? It appears to be more of a bread and butter sort of product.
I wouldn't pay 560.00 for it! It looks like its from Singapore. Even the Soundstream amps were built better than this is. I bet it has a tough time with low impedance loads too. The magazine article only states its output into 8 ohms. The .22 ohm resistirs probably help balance out the resistance so the chips don't fight.
Mark Gulbrandsen
Salt Lake City, UT
Mark Gulbrandsen
Salt Lake City, UT
Here is the link to the JRDG write up about the design.
http://www.jeffrowland.com/Concentra II Tech Discussion.htm
This is a funny line that I copied right from the JRDG write up, "These integrated power output devices, or transistors, despite greater cost in comparison to their more commonly used discrete transistor counterparts, occupy very little circuit “real estate,” dramatically reducing capacitive and dielectric storage effects, as well as simplifying the overall signal path. "
Greater in cost to discreet transistirs?? I don't think so.... How does that happen when they only cost two to three dollars each in quantities?? Its beyond me, unless the cost to select them is way high but I doubt that. Even if it doubles the cost then we're talking about 4 to six dollars each which is still cheap. I'd like to see him construct one of those chips discreetly for three to six dollars. They'd never be able to do it. And while the on board signal path may be short the actual signal path through the I.C. is not in terms if amount of transistors the signal sees. No argument from me on the lower capacitive effects though.
Mark Gulbrandsen
Salt Lake City, UT
http://www.jeffrowland.com/Concentra II Tech Discussion.htm
This is a funny line that I copied right from the JRDG write up, "These integrated power output devices, or transistors, despite greater cost in comparison to their more commonly used discrete transistor counterparts, occupy very little circuit “real estate,” dramatically reducing capacitive and dielectric storage effects, as well as simplifying the overall signal path. "
Greater in cost to discreet transistirs?? I don't think so.... How does that happen when they only cost two to three dollars each in quantities?? Its beyond me, unless the cost to select them is way high but I doubt that. Even if it doubles the cost then we're talking about 4 to six dollars each which is still cheap. I'd like to see him construct one of those chips discreetly for three to six dollars. They'd never be able to do it. And while the on board signal path may be short the actual signal path through the I.C. is not in terms if amount of transistors the signal sees. No argument from me on the lower capacitive effects though.
Mark Gulbrandsen
Salt Lake City, UT
The future product and the latest one will keep using the High power Opamps in the main flame. Look at the new poweramp of JRDG....
And I read the interview of Jeff Rowland at StereoSound(Japan). They will keep going on that way.
Actrally JRDG not only selling you the "opamp", it include the very good case, the very well fine tune at the sound performance and the most important is his name--- Jeff Rowland, right?
And I read the interview of Jeff Rowland at StereoSound(Japan). They will keep going on that way.
Actrally JRDG not only selling you the "opamp", it include the very good case, the very well fine tune at the sound performance and the most important is his name--- Jeff Rowland, right?
Well the post is titled Pass vs. Jeff Rowland if I'm not mistaking. While there may be some very distant similarities as both companies use simple circuits, the Pass designs are clearly the winner in my experience and judgement, both in buying ready made components and in building my own. The Aleph series may well become the one and only classic solid state power amps. There really are no others in the solid state realm that can be considered "classic".
Personally I just can't see paying 5600.00 for an amp that uses I/C outputs. Just does not seem like much effort went forth into the design. And if one studies the actual circuit inside of the power I.C. you will see that it is not quite as beautifully simple as JRDG claims it is and as the Pass designs actually are, which BTW also make use of very short signal paths of low inductance and capacitance. In fact the only capacitance in most of the Pass designs are provided by the characteristics of the mosfet devices used.
Nicely designed cases are really quite easy to do these days with cnc machine tools and can be made in large or small quantities for really unheard of cheap prices. Modern anodizing and metal treatments these days are far better and more available than they were 25 years ago. Thats why you see the beautiful casing that you do on most high end products...its now more available to everyone. IMHO, cases are not really as much of an issue as is how well engineered the heatsinking is.
Mark Gulbrandsen
Salt Lake City, UT
Personally I just can't see paying 5600.00 for an amp that uses I/C outputs. Just does not seem like much effort went forth into the design. And if one studies the actual circuit inside of the power I.C. you will see that it is not quite as beautifully simple as JRDG claims it is and as the Pass designs actually are, which BTW also make use of very short signal paths of low inductance and capacitance. In fact the only capacitance in most of the Pass designs are provided by the characteristics of the mosfet devices used.
Nicely designed cases are really quite easy to do these days with cnc machine tools and can be made in large or small quantities for really unheard of cheap prices. Modern anodizing and metal treatments these days are far better and more available than they were 25 years ago. Thats why you see the beautiful casing that you do on most high end products...its now more available to everyone. IMHO, cases are not really as much of an issue as is how well engineered the heatsinking is.
Mark Gulbrandsen
Salt Lake City, UT
Two quick comments:
1) Any circuit that uses opamps is no longer simple. Simple to assemble, perhaps...but the signal path becomes quite complicated. Just because you're only dropping in one part doesn't mean you're only dropping in one part, if you follow what I'm saying.
2) I've never heard the Pass Labs commercial output, as there's not a dealer anywhere near me. However, I have heard the Aleph 2s that I built (with the caveat that they may or may not be equivalent to the commercial version), and I own some of Nelson's Threshold amps. I have heard Rowland gear, but have never owned any. Given that I've heard them on different systems, I prefer Nelson's sonic signature to Rowland's. The Rowland I've heard tends to sound very delicate, very nice, at low volumes but fails utterly when asked to produce dynamics. It becomes congested and completely loses any of the charm it had at low volumes. Nelson's designs have always seemed to me to be more cut from the same cloth at all levels. The Threshold S-500 is a fair-sized hunk of amp whose main failing is a tendency towards a bit of grain in the upper midrange and treble. (This doesn't bother me a bit, as I'm using them for lower frequencies.) The Aleph 2s have a very warm, tube-like sound. They are the equal of the tube amps I built in every way except for detail retrieval; I vacillated on this for a while, debating which was the better sound and finally came down in favor of the tubes, but it was a close call, and the Alephs are cheaper to build (though no cooler to operate...). Both the Thresholds and the Alephs maintain their composure at higher volumes.
Grey
1) Any circuit that uses opamps is no longer simple. Simple to assemble, perhaps...but the signal path becomes quite complicated. Just because you're only dropping in one part doesn't mean you're only dropping in one part, if you follow what I'm saying.
2) I've never heard the Pass Labs commercial output, as there's not a dealer anywhere near me. However, I have heard the Aleph 2s that I built (with the caveat that they may or may not be equivalent to the commercial version), and I own some of Nelson's Threshold amps. I have heard Rowland gear, but have never owned any. Given that I've heard them on different systems, I prefer Nelson's sonic signature to Rowland's. The Rowland I've heard tends to sound very delicate, very nice, at low volumes but fails utterly when asked to produce dynamics. It becomes congested and completely loses any of the charm it had at low volumes. Nelson's designs have always seemed to me to be more cut from the same cloth at all levels. The Threshold S-500 is a fair-sized hunk of amp whose main failing is a tendency towards a bit of grain in the upper midrange and treble. (This doesn't bother me a bit, as I'm using them for lower frequencies.) The Aleph 2s have a very warm, tube-like sound. They are the equal of the tube amps I built in every way except for detail retrieval; I vacillated on this for a while, debating which was the better sound and finally came down in favor of the tubes, but it was a close call, and the Alephs are cheaper to build (though no cooler to operate...). Both the Thresholds and the Alephs maintain their composure at higher volumes.
Grey
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