Search found 229 matches

by Wolfgang
Fri May 07, 2021 7:41 pm
Forum: Everyones Projects
Topic: 45 SE
Replies: 170
Views: 41393

Re: 45 SE

...use proven engineering principles... THERE IS NO MAGIC. I was kind of hoping that the OPT topic would come up at some point because I am considering to build a 2A3/45 switchable SE amp based on a Loftin-White circuit.Shouldn't the quality of the OPT be #1 on the list if we talk about "prove...
by Wolfgang
Mon Apr 19, 2021 5:00 pm
Forum: Assorted Stuff
Topic: Joseph Crowe
Replies: 19
Views: 7153

Re: Joseph Crowe

And what about cancelling distortion (more or less ) using a SE tube amp and a single moving coil speaker with reversed polarity as described in this article (Why SE tube amps?)? Also explains why speaker systems with active x-overs sound generally better. https://www.audiopax.com/e/Article.html I c...
by Wolfgang
Tue Apr 13, 2021 4:28 pm
Forum: Everyones Projects
Topic: 2P29L Preamp
Replies: 18
Views: 9517

Re: 2P29L Preamp

Interesting approach. Basically some kind of a simple active x-over without the options for adjusting and fine tuning. The Muse volume control adds so many opamps that one could use a good active analog x-over and would get the same impact of solid state (if that's a concern) but with all the option...
by Wolfgang
Tue Apr 06, 2021 5:11 pm
Forum: Speakers
Topic: PERSPEX QUASAR ver 2.0 prototype build
Replies: 324
Views: 127039

Re: PERSPEX QUASAR ver 2.0 prototype build

Cathode bypass cap and output cap changes will create some kind of a shelving filter curve which is not useable for xo purpose. A third option that hasn't been discussed is a simple filter in the NFB line but it's also rather a tone control than a real filter suitable for x-overs. Just another idea ...
by Wolfgang
Mon Mar 15, 2021 6:43 pm
Forum: General Vinyl
Topic: Zenith Errors
Replies: 15
Views: 16166

Re: Zenith Errors

The Fozgometer incorporates a "LogRatioDetector" developed for surround processor steering logic circuits to measure channel separation. The LEDs show which channel is ON, the signal reading of the analog meter shows the amount(voltage?) of the signal. If left and right channel show the sa...
by Wolfgang
Mon Mar 15, 2021 2:53 pm
Forum: General Vinyl
Topic: Zenith Errors
Replies: 15
Views: 16166

Re: Zenith Errors

Testrecord and Fozgometer is the only thing that really worked for me but is completely overprized. The sound improvement was very obvious. Shouldn't be too hard to build the circuit for a fraction of the resale price. https://www.dedicatedaudio.com/products/fosgate-fozgometer-azimuth-range-meter Th...
by Wolfgang
Sat Mar 06, 2021 3:51 pm
Forum: Assorted Stuff
Topic: CCS topologies
Replies: 3
Views: 2520

Re: CCS topologies

But you can’t use a constant current sink on low transconductance valves. Ok, but my question was going in the direction of what difference it makes using a current regulator vs a voltage regulator. And JBroskie uses both together which makes it even more difficult to understand in case it is about...
by Wolfgang
Fri Mar 05, 2021 3:54 pm
Forum: Beginners
Topic: Simple Active Low Pass Filter/Buffer
Replies: 6
Views: 9114

Re: Simple Active Low Pass Filter/Buffer

With miniDSP and measuring equipment the process would be ideally: 1. OB speakers in the final(expected) room position connected to the amps that will be finally used 2. miniDSP connected to the DAC (ideally miniSHARC before PCM DAC with I2s connection, or external unit), first selection of filters ...
by Wolfgang
Wed Mar 03, 2021 3:42 pm
Forum: Assorted Stuff
Topic: CCS topologies
Replies: 3
Views: 2520

CCS topologies

Don't now if "topology" is the right term here. I was wondering if there is any noticeable difference in how it sounds using a voltage regulator vs a current regulator. Or: why would one use all those extra parts for replacing a 10k/2k (elysium) resistor if a TL738 could be used ? JB (2).p...
by Wolfgang
Mon Mar 01, 2021 3:38 pm
Forum: Everyones Projects
Topic: 300B Headphone Amp
Replies: 114
Views: 52204

Re: 300B Headphone Amp

Nice development, Ray. Looking forward to hear more about how both DACs perform in comparison. I am building an OTL headphone amp for my studio(with the 6AS7, no NFB) and was wondering how you got to the two different output impedances (32/600ohms) with the MP circuit. Do you use output transformers...
by Wolfgang
Mon Jan 11, 2021 4:04 pm
Forum: Assorted Stuff
Topic: Reel to reel
Replies: 67
Views: 25160

Re: Reel to reel

Not to be misunderstood: The +2dB were of course the settings for the peak levels not the general recording level.
by Wolfgang
Mon Jan 11, 2021 3:12 pm
Forum: Assorted Stuff
Topic: Reel to reel
Replies: 67
Views: 25160

Re: Reel to reel

No "stupid questions"! An r2r machine looks cool and sounds cool. I had for many years an Akai GX-630DB and it was the highlight of my sound system. I recorded not only my vinyl for having a compilation of my favorite music but also for the sound. High speed at +2dB recording level produce...
by Wolfgang
Fri Jan 01, 2021 6:16 pm
Forum: Speakers
Topic: SLOB project
Replies: 318
Views: 144051

Re: SLOB project

It looks like you are right! I did some more research and found this: “The phase control setting is a bit confusing and the operation is not explained well in the owners manual. The DCX uses the LP filter frequency setting (even if it's "Off") as the reference point for the phase adjustmen...
by Wolfgang
Thu Dec 31, 2020 6:36 pm
Forum: Speakers
Topic: SLOB project
Replies: 318
Views: 144051

Re: SLOB project

I forgot to mention that I used the miniSHARC PEQs only for adjusting the frequency response of the room. I never tried the x-over option which would be a different thing regarding phase shift and filter types.
by Wolfgang
Thu Dec 31, 2020 6:12 pm
Forum: Speakers
Topic: SLOB project
Replies: 318
Views: 144051

Re: SLOB project

Though measuring phase without the right kit is very difficult. Carma 4 for example shows magnitude and phase together. But even just by looking at the magnitude response one would see if there is a dip around the x-over point which would indicate a problem. I don't think the Ultradrive offers FIR ...