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astromaddie's Achievements


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  1. Thanks for confirming, spritzer. I had a feeling, the description was focused on a lot of fairly flowery technical language— the only part that sounded potentially interesting was the "special bias supply".
  2. I've gotten it in my head that I'd like to try crafting a closed-back mod for either my L700 or 007A, a la the CES-A1 official "mod" for the 002/003. Has anyone attempted this before? I only found a Thingiverse file for a L300 back replacement making it closed, but giving no room for air or anything to dampen audial reflections. I'm thinking I'd want a shape like the 4070 with a multi-layered web of material to dampen the sound, that way I could create a 4070-like shell without needing all the insulation that made the 4070 so heavy.
  3. The Fidelix Staccato There seems to be a Japanese maker of high-end audio equipment that makes his own Stax driver. Looks very cleanly-made, but I don't know how much of this is a unique build versus knowledge already known in the Western Stax community. I'm particularly interested in hearing the DIY group's thoughts on the simplified schematic he's posted. Is this anything unique/interesting? Or just a rehash of existing designs?
  4. Does anyone know much about the T1W? There’s one for sale locally and I’m wondering if it’s worth trading up my T1S for it. I’ve been putting together a CCS circuit board, but haven’t installed it in the T1S yet. The preamp output is certainly interesting, but I’m most intrigued by the variable bias output— and wondering if it would have any benefit for my 007A, especially after the CCS mod?
  5. So, from reading your SRX Plus diagrams, it looks like the pro bias line could be created by adding a few zener diodes to reach the 580V bias-- is that right or am I over-simplifying things? (This is still new for me.) I'm asking because, if I converted this, I'd probably just convert the normal bias jack into a pro bias. As for what I meant by ROI, I didn't mean cost-based ROI (since the CCS mod is cheap enough, as you said) but I was asking under the pretense that I couldn't convert my SRX to Pro bias, so I thought the CCS in the SRX with Normal bias may not be worth it. Though, I do think my particular SRX amp is pretty powerful, as it noticeably sounds better than my stock T1S. How do I determine the power supply voltage? That would be coming from the Tango transformer block, depending on which input/output terminals are being used, right?
  6. Nice idea, James! The only issue concern I have is that the SRX only has Normal-bias outputs. I actually just picked up a 007A (still coming in the mail) so I'm not sure I'd get the same kind of ROI from the CCS mod on the SRX as I would from the T1S. Am I on the right track with that thinking, or would the normal-bias SRX (+ CCS) still be powerful enough? Also, thanks for the explanation earlier regarding the 10M90S/DN2540 cascode combo. That's interesting, nice optimisation using the B- supply!
  7. I think that's got me interested in modifying this to be more like your SRX-Plus, though I realise I'll be keeping it normal biased. Which brings me to my next question, after doing a lot of research.. Curious, Pirx, where did you get this schematic? I was comparing it with Jim's published schematic from the 2015 issues of AudioXchange and noticed a few differences... like the use of a 10M90S instead of a DN2540, and some other resistors are different (102ohm vs 250ohm, 1k vs 500, etc) -- plus the addition on the left taps into the -340V power supply with a 220k resistor. Can you help me understand these additions/modifications? Also, @mwl168, that is a beautiful build!!
  8. Makes sense. I wasn't sure if it would effect the overall output on extreme frequencies, or fine-control between frequencies. Hey Jim, thanks. I actually just got components in to put together the CCS mod. I was holding off on replying here until I got hold of your articles from AudioXpress in Nov/Dec 2015, for the SRX Plus, and I just started reading them. Do you think I'd have better returns putting the CCS mod into this SRX or the T1S I also have and will be recapping? I've been doing a lot of electrical studying and am really trying to wrap my head around everything conceptually here.
  9. That’s what I figured, thanks! The amp arrived the other day and, wow, it sounds really good. I think I need to recap my T1S much more than I realised, because the sound on that is all wonky compared to this— peaky upper mids, way diminished bass. For the time being though, what actually is the downside of using Normal bias outputs with Pro Stax (particularly lambdas)? I noticed a rolled off treble and more smoothness, but I assume that’s moreso because of the tubes rather than the Normal bias— or is it?
  10. Thanks @spritzer! That’s cool to hear, I’ve read good things about the SRX— how difficult would it be to modify it for Pro bias? (or not worth the added effort?)
  11. I see, thanks for pointing that out @Pirx — can you go into more detail for someone with less circuitry experience? Is this something I should fix? Also @Craig Sawyers thats good to hear! Sounds like that bodes well that this will be a worthwhile, interesting purchase at least. I’m wondering how it’ll pair with my L700, or if I should just keep it with my SR3.
  12. Hi, been lurking for a while but finally signed up! Quick background on my gear: I'm in the Stax ecosystem with an L700(Mk1), SR-3, and an SRM-003. I also have a D10 and T1S, the latter of which was on a shelf unused in the original box for 25 years or so and last year I bought it. I'm still planning to recap it and upgrade it with the constant current mod, but that's to come soon. In the meanwhile, I came across a curiosity online, a homemade normal-bias tube amp. No real info provided, but it was a reasonable price so I took the shot in the dark, and I don't have the electronics knowledge to grok what I'm looking at. Can anyone more educated help me?
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