Further to my comments regarding volume control and transformer volume control (TVC). I like to add that I have the same TVC as in the Bent Audio passive box, but as built-in in my tubed phono stage, custom made by Kevin Carter of K&K Audio. I don't have a linestage. In my phono stage, I have a set of output for vinyl and another set for CD. The output for CDP goes directly to the TVC, so it's like a passive linestage without gain. Eventhough I don't listen to CD, I have this CD output just in case I get a CDP later. I have tried a CDP in this set up, it has more than enough gain. Most CDP have output of 2 volts. For my phono stage, it has 65dB gain, my cartridge is the Koetsu Rosewood Signiture with 0.6 dB and I have more than enough gain. Let me tell you, the dynamics is unbelievable with TVC. Standard volume control is resistor based, which suppresses high frequencies, bass and dynamics, TVC dosen't do that at all. I have numerous phono stages in the last 20 years and this is the best of them all.
Won't preamps become obsolete?
I'm in the market for a new preamp because I want to upgrade from my Conrad Johnson PV10A. I listen mostly to vinyl but some CD and hopefully SACD some day so I need a preamp to integrate sources. As I look at the used preamp ads on A'gon, however, I notice more and more people saying that they are selling their preamp because they are going directly from a cd player with volume control into an amp. As vinyl wanes (never with me!) will the preamp follow suit or become more oriented towards integrating home theatre digital video and audio sources?
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I don't think so. The reason are several fold, of which two are: 1) Separating the first stage from the following stages relieves the problem of frequency dependent feedback through the power supply. This lessens sonic interactions between stages, resulting in better, more lively, sound quality. 2) Hum and noise are reduced without compromising the integrity of the design. Steve SAS Audio Labs |
Sounds like the preamp, or for that matter the amp or speaker (possibly the extra ICs), doesn't have flat frequency response. (If the preamp is capacitively coupled, the input impedance (Z) of the amp may be too low.) In otherwards, it is possible that one is compensating, sonically, for the other component(s). Steve SAS Audio Labs |
Blptwp...What is a TVC? I am guessing that it is a multitap audio transformer. I don't understand your comment about superiority vs a resistor divider. It was a great step forward when interstage transformers went away, and here you are puting a transformer back into the circuit! Transformers have limited frequency response, and if they include core material (like iron) they create distortion. Power amp output transformers have extra windings applied to grids of the output tubes as many dB feedback to correct these transformer deficiencies. |
Eldartford, You are correct in assuming that a TVC is a multitap audio xformer. If done correctly they provide excellent sound today. Xformer technology has come a long way since the days you remember & really excellent sound can be had at a reasonable price. Personally I have heard a very inexpensive passive TVC from Antique Sound Labs (when I was in Atlanta listening to single driver speakers. You did make a post on that thread - it's the last one) & it was quite impressive. Basically, it had no sound! Plus, there was really no loss of high freq. content that I could tell in the 3-4 hrs I listened to that system. I believe that ASL wind their own xformers in-house (China). Other TVCs made by Stevens & Billington are supposed to be excellent. You can check the freq. response of the same at their website: http://www.stevens-billington.co.uk/page102.htm I know that it is each to his own but do not under-estimate the sonic performance of a TVC until you have actually heard one! Stellar sonic results are very much possible today. You'll be surprised. I also know that these days a # of tube amps (both manuf & DIY) use a lot of coupling xformers in them with excellent results. I *think* Art Audio is one such brand & there is a highly regarded DIY personality (Art Loetsch?) who uses coupling xformers in his designs. IMHO. FWIW. |
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