Deleted
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Post by Deleted on Jul 2, 2008 7:09:47 GMT
Robin
I have consistently found that increasing the bandwidth of a high quality amplifier/preamplifer to WAY past the -3dB at perhaps 100KHZ, does result in an improvement in resolution and naturalness of sound, even from DTV. I have also noticed a move in DiyAudio as well, in the solid state forums, to a far higher -3dB point in amplifier input filters as well. Detail in a high quality SS amplifier should not sound etched. It should sound natural. Crossover distortion can contribute to an etched sound, as it brings the noise floor close to that of the low level detail, and also tends to make low level natural ambience sound very grainy.
Alex
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Post by dejanm on Jul 2, 2008 8:52:05 GMT
XTRProfI bought S&B trans from: www.bentaudio.comThey costed at that time (~1 year ago) about $500 for a pair. The problem is though that Music First Audio (it is a daughter company of S&B) closed this distribution channel. They do not deliver their tranns any more to Bent Audio. Therefore, I am not sure that it is possible to buy them there. Or anywhere else ... But you may send a mail to Bent Audio - maybe they have some left ... These trans do have 24 steps and every step contains attenuation of 2 dB. With strong sources this is not optimal, because you can still hear a bit of music even when it is set to 0. But that is basically all that I can say against these trans ... There is also a silver version, which is rather expencive (it was: ~ $1.000). I had the opportunity to hear that one as well and it is really a top product. Unbelievable detail, musicality and transparency ... Everything is there ... Concerning other parts: I bought Shalco switches also from Bent Audio. You can see prices on his web site. The first idea was to make this preamp as real passive - without power supply. But then, for some other reasons, I decided to use relays for internal switching (Omrons). If you go this way, then you do not need so good and expencieve switches - something cheaper will do the business as well.
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XTRProf
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Post by XTRProf on Jul 2, 2008 19:44:50 GMT
XTRProfI bought S&B trans from: www.bentaudio.comThey costed at that time (~1 year ago) about $500 for a pair. The problem is though that Music First Audio (it is a daughter company of S&B) closed this distribution channel. They do not deliver their tranns any more to Bent Audio. Therefore, I am not sure that it is possible to buy them there. Or anywhere else ... But you may send a mail to Bent Audio - maybe they have some left ... These trans do have 24 steps and every step contains attenuation of 2 dB. With strong sources this is not optimal, because you can still hear a bit of music even when it is set to 0. But that is basically all that I can say against these trans ... There is also a silver version, which is rather expencive (it was: ~ $1.000). I had the opportunity to hear that one as well and it is really a top product. Unbelievable detail, musicality and transparency ... Everything is there ... Concerning other parts: I bought Shalco switches also from Bent Audio. You can see prices on his web site. The first idea was to make this preamp as real passive - without power supply. But then, for some other reasons, I decided to use relays for internal switching (Omrons). If you go this way, then you do not need so good and expencieve switches - something cheaper will do the business as well. Thanks very much. The silver trans as used in the latest Music First TVC will be excellent as it was reviewed by Hifi News in top category of around 18/20 or 19/20 (can't remember the exact rating) sometime back. Nevermind, now I have more options and I can search for maybe cheaper alternatives from those transformer companies. Regarding you using relays, I don't know, but that will be putting additional items into the product. Being purist, KISS will be better as now there is additional DC PS that can affect the sound. I will do it in a completely passive way, without PS, when I have the time and fund. Also regarding there still having sound with the volume all the way to 0, the 48db (24 x 2) attenuation is not enough as most passive pots like the form of DACT will give at least 60db attenuation. For your case, you can still put a relay or high quality appropriate resistor like Vishay foil to eliminate or reduce much further that problem. The relay way, of course, will cut off the signal when the volume pot is at 0. You know something like muting. |
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XTRProf
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Post by XTRProf on Jul 2, 2008 19:49:33 GMT
XTRProf That is a copout !  We both know that transformers of that type rarely even get to -3dB at 70KHZ.  See if you can obtain a wider bandwidth type for your next ancient technology project ! Well, if you are game, you can sue Audio Research in America for false claim and win handsomely if true. Then you will have more than enough doe for an Esoteric transport and your other SS projects.  Btw, transformer don't add additonal noise being passive whereas active does. |
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Deleted
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Post by Deleted on Jul 2, 2008 21:40:18 GMT
No ? They just "ring"
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Post by dejanm on Jul 3, 2008 5:35:30 GMT
XTRProfI know about that muting idea. It has one drawback -> it adds another switch in the signal path and I already have too many of them (I have a rather complex input/output configuration). That is the reason why I am not going for it ... By the way - try Sowther trannies. Brian Sowther is building exactly what is needed with 0, +6 and +12 dB gain. The price is also much better than S&B. I never though tried them so I cannot tell you much about how they sound ... but having in mind the reputation of Sowther trannies - it should be worth trying ...
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XTRProf
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Post by XTRProf on Jul 3, 2008 10:55:36 GMT
By the way - try Sowther trannies. Brian Sowther is building exactly what is needed with 0, +6 and +12 dB gain. The price is also much better than S&B. I never though tried them so I cannot tell you much about how they sound ... but having in mind the reputation of Sowther trannies - it should be worth trying ... Excellent recommendation! Now I have even more options. That's what truly great forum is all about. Sharing in the spirit of advancing further the state of understanding of a topic and in this case the art and science of hifi. |
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XTRProf
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Pssst ! Got any spare capacitors ?
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Post by XTRProf on Jul 10, 2008 12:44:25 GMT
Some frequency respopnse there for a attenuator trans  |
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Will
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Post by Will on Sept 14, 2008 13:45:58 GMT
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Post by sometrolls2 on Sept 14, 2008 23:25:43 GMT
There is probably an Ebay business to be had as a distributor of that stuff.
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insomniac
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Post by insomniac on Sept 15, 2008 0:35:43 GMT
Nice links Wilbur.
I see they do a neat looking low jitter clock module and a SA-3 Headphone amplifier amongst other things.
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Post by sometrolls2 on Sept 19, 2008 19:42:20 GMT
During September its 3 OPAs for the price of 2, you'd need to buy a pair of the original model and then get the latest one free. With extension leads and delivery it comes in at £15 each.
From Burson 2 modules with delivery and no cable is £80
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We both know that transformers of that type rarely even get to -3dB at 70KHZ. 
See if you can obtain a wider bandwidth type for your next ancient technology project !
