Asr Posted April 27, 2009 Report Share Posted April 27, 2009 There are two ZDs listed for sale that are available right now! New & Used Stuff I inquired if both were from the 2009 run and Craig confirmed that they are. I kinda want a ZD now but if I actually go for one (not really sure yet), I think I'll be going for a new one with the impedance switch... Quote Link to comment Share on other sites More sharing options...
jp11801 Posted April 28, 2009 Report Share Posted April 28, 2009 once you go BA you never go back:p I love the ZD but the BA is just sooo much better. I know its a grand more but that is why god blessed you with 2 kidneys one for you and one for ebay Quote Link to comment Share on other sites More sharing options...
Augsburger Posted April 28, 2009 Report Share Posted April 28, 2009 once you go BA you never go back:p I love the ZD but the BA is just sooo much better. I know its a grand more but that is why god blessed you with 2 kidneys one for you and one for ebay Well looking at your last few purchases *galabier* cough, I guess you have no kidneys left. Quote Link to comment Share on other sites More sharing options...
jp11801 Posted April 28, 2009 Report Share Posted April 28, 2009 I'm using a mr coffee filter at the moment Quote Link to comment Share on other sites More sharing options...
Dusty Chalk Posted April 28, 2009 Report Share Posted April 28, 2009 You should try something organic. Or recycled. Or both. Quote Link to comment Share on other sites More sharing options...
grawk Posted April 28, 2009 Report Share Posted April 28, 2009 I find cardboard on an end grain works Quote Link to comment Share on other sites More sharing options...
Asher Posted May 3, 2009 Author Report Share Posted May 3, 2009 I'm going to go ahead and give you 24hrs to ponder that remark. My bad about being a sarcastic asshat... Quote Link to comment Share on other sites More sharing options...
n_maher Posted May 3, 2009 Report Share Posted May 3, 2009 My bad about being a sarcastic asshat... Well, this is a step in the right direction. Welcome back. Quote Link to comment Share on other sites More sharing options...
luvdunhill Posted May 3, 2009 Report Share Posted May 3, 2009 My bad about being a sarcastic asshat... Asshat is rather generous. We reserve the term jagbag for situations like this. Quote Link to comment Share on other sites More sharing options...
Hopstretch Posted May 26, 2009 Report Share Posted May 26, 2009 Some quick questions for my technically-minded friends. So how would one likely implement a high/low impedance control on an OTL amp like this? And how much of a performance advantage is it actually likely to afford with low-impedance headphones over the stock configuration? At the NY meet, I thought the stock Zana sounded very good with HP-1s, though I know the combo wouldn't necessarily be considered a great match on paper. Ah theng kyew. Quote Link to comment Share on other sites More sharing options...
n_maher Posted May 26, 2009 Report Share Posted May 26, 2009 Typically (and I don't know the Zana topology specifically) the only thing that could be done easily would be to run each output through different sized coupling caps. The high-ohm output requires a smaller cap to achieve uniform frequency response so typically builders/designers use high-quality film caps here, for the low-ohm output the cap size can need to be 10x as large (uF wise) and therefore it's simply not practical or affordable to use a film cap so what is often done is to use a film/electrolytic couple in parallel. Could be that the low-ohm switch just adds the electrolytic in parallel with the cap used on the high-ohm output. Hard telling not knowing. In a more complex world it might be possible to alter a portion of the circuit to allow the tubes to more efficiently drive the low-impedance load but doing so via a switch wouldn't sit well with me. Quote Link to comment Share on other sites More sharing options...
recstar24 Posted May 27, 2009 Report Share Posted May 27, 2009 Some quick questions for my technically-minded friends. So how would one likely implement a high/low impedance control on an OTL amp like this? And how much of a performance advantage is it actually likely to afford with low-impedance headphones over the stock configuration? At the NY meet, I thought the stock Zana sounded very good with HP-1s, though I know the combo wouldn't necessarily be considered a great match on paper. Ah theng kyew. I asked Craig about it, basically I asked if whether the switch somehow increases the feedback a bit so that it brings the output resistance lower, and he said "That's about it". Last time I checked, the 6C33C-B is biased for a plate resistance of about 90 ohms, and with a little bit of feedback, he brings it to 12 ohms output in stock configuration. So I would imagine the easiest way to implement a lower impedance through a switch would be just having that switch either have a different bias setting for the 6C33CB so the plate resistance is a bit lower, either increasing the feedback level, or maybe a combo of both. Quote Link to comment Share on other sites More sharing options...
screaming oranges Posted May 28, 2009 Report Share Posted May 28, 2009 Multiple input switch. I like that. Wish more manufacturers did that. Quote Link to comment Share on other sites More sharing options...
n_maher Posted May 28, 2009 Report Share Posted May 28, 2009 Multiple input switch. I like that. Wish more manufacturers did that. Lots do on their full sized gear, which in particular are you wishing did? Quote Link to comment Share on other sites More sharing options...
HeadphoneAddict Posted May 28, 2009 Report Share Posted May 28, 2009 My WA6 has an impedance switch - not sure how it works on that amp (whether a multi-tap transformer, or some other trick). Quote Link to comment Share on other sites More sharing options...
spritzer Posted May 28, 2009 Report Share Posted May 28, 2009 The Woo6 has output transformers so you are switching between multiple taps. Quote Link to comment Share on other sites More sharing options...
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