lynn_olson

Responses from lynn_olson

300b lovers
Thanks for the update, Don. Yoder, there was a lot of progress sonically after the first prototypes. What we have now is actually simpler in some ways. We went for a pair of spacious monoblock chassis mostly to simplify assembly, and to improve c... 
Did I just cook my preamp?
Safety advice: do not turn on the questionable electronics until repaired, and get a socket tester for your house. They’re not expensive and are worth getting.  
300b lovers
Yes, Don and I are working on a medium-price (by high-end standards) amplifier, most likely a stereo integrated amp. Not much to say about it now, since it's mostly conceptual at this point. If people are looking for value, I think Spatial may sti... 
Send in the Clowns
Using Science as a fetish object, or a pseudo religion. There's plenty about human perception and consciousness we don't know, and that directly overlaps with measurement technique.  
300b lovers
Certainly a great benefit in a phono preamp where you have to overcome the wall of noise in the very first stage, and yes, cascodes are more linear than pentodes. The EF86 mike-preamp pentode so popular in the Fifties and Sixties is now very expen... 
300b lovers
By the way, there’s a very intelligent discussion of the latest John Curl/Parasound amplifier design here: Parasound Discussion Note they are talking about fully isolated input+driver sections with 117 volt rails. That might sound insanely high ... 
300b lovers
If you’ve been curious the kind of things two designers discuss with other, the previous posts give a simplified example. Sonics, different circuits and what they sound like, and reliability. It's also an example why collaborations between designe... 
300b lovers
One variant we did not try was a center-tapped inductor to load the 6SN7 plates, and direct coupling between the input and driver tubes. That requires a high B+ voltage for the driver, but that’s no problem when the input + driver have their own p... 
300b lovers
It may strike some readers as weird that Don and I are taking a minimalist approach to a PP amplifier, more like a SET than a typical PP. The signal path is simple: Optional SE/Balanced input transformer -> Balanced 6SN7 -> Interstage #1 -&... 
300b lovers
That’s a subtle aspect of feedback theory that is often overlooked. The summing node must be distortionless, and also free of overshoot or slewing artifacts. Applying input signal to a grid, and feedback to the cathode, impresses tube distortion (... 
Spatial Audio Raven Preamp
Happens all the time in the small-production-run solid-state world. Oversights in manufacturing like no heat-conducting paste between transistors and heat sinks, for example. Or a wave solder machine not properly set up for EU-required leadfree so... 
300b lovers
Ralph, you’re the acknowledged OTL expert. How does an OTL amp work without feedback? I’d like to know. The last I checked, tubes designed for series regulator use like the 6080, 6AS7, or the Russian 6C33C have a Zout on the cathode side somewhere... 
Spatial Audio Raven Preamp
Oh it blew a fuse all right. After the output section was completely destroyed, and a massive DC pulse killed the woofer. This was European oligarch-class audio gear from a well-known manufacturer. The manufacturer is still around, twenty years l... 
Spatial Audio Raven Preamp
The anecdote is true, not fictional. I was there and saw it happen. Not surprisingly, the preamp and power amp were all solid-state and were stupendously expensive, in the $100,000 range. As we old-timers know, price does not guarantee quality in... 
300b lovers
To recap, there are different challenges associated with low and mid-frequency distortion vs high frequency distortion. HF distortion is very often caused by nonlinear current delivery into a capacitance, and stray capacitance is everywhere in aud...