rowuk
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Post by rowuk on Aug 6, 2014 17:04:38 GMT
Thinking about cables, I often wonder why the hundred of metres of microphone cable in the studio with extremely low level microphones doesn't completely trash sound - more at least than any metre lengths at home could.
Could it possibly be that the microphones cables are biased by the phantom power and that saves the day? Phantom power would be very easy to implement in a home setting - and a hell of a lot cheaper than expensive interconnects........... Maybe USB interconnects/interfaces have to be rethought.
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rowuk
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Post by rowuk on Aug 5, 2014 4:22:14 GMT
I hope that there were no cats in those trees!
Someone could make a real ugly film based on this invention.......
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rowuk
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Post by rowuk on Jul 29, 2014 21:06:33 GMT
A friend of mine in Serbia has a novel solution for getting the high amperage filament voltage required for the heavy duty valves. They start life as quality electronic transformers for halogen lighting. Depending on the brand, they have HF AC at over 30Khz. The second harmonic hum (>60KHz) he reports as not audible and doesn't get through the output transformer. The advantages are very high efficiency and no audible hum - even with 10V valves. Here is a link to the project. You need to scroll down about ¼ way down the page. It only involves rewinding the secondary on the toroid transformer and adding the cap rh-amps.blogspot.de/2014/06/rh813-flagship-project.htmlI have built one of Alexs amplifiers the RH307A Super and it is a solid design, sounds great and works essentially immediately. As he has a whole family of these amplifiers it is easy to mix and match for multiamping. The technical documentation makes DIY really easy!
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rowuk
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Post by rowuk on Jul 26, 2014 14:02:44 GMT
The picture was as close as I could get as I didn't have a hot dog in stock. This is probably closer.....
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rowuk
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Post by rowuk on Jul 25, 2014 16:34:11 GMT
crispy fried onions, relish, cheese, mustard, ketchup - All at the same time:
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rowuk
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Post by rowuk on Jul 23, 2014 18:29:45 GMT
Hi Derek,
I simply tried to reply to your "question" with my experience involving constricted. There are no absolutes in the audio world as we have no interchangeable frame of reference. Not even words necessarily have a common understanding. This is very unfortunate because it is often impossible to discuss anything and be sure that the true intent is conveyed. If I buy a professional oven for baking pizza, it is possible to describe just about everything that it can do to produce a world class pizza. Shit, in the audio world, we can hardly find anyone admitting to using the same interconnects.
My experience with passives was different than yours, that is all that that means. No need to defend your personal experience - I never challenged it.
As far as RG offering advice on good deals, that is most certainly true. And then you find out after you bought it, how much you can rip out and replace. It does keep us busy and out of trouble however.
The longer I deal with audio, the more I discover that better seldom means "more" or "less" of something, rather the synergy with which an entire playback chain is put together and that many of the things that make audio more enjoyable are very explainable when we find a way to discover a common meaning for the "words" that we use.
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rowuk
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Post by rowuk on Jul 22, 2014 21:35:12 GMT
I think that the plus and minus are pretty much equal. The British government is not doing jack shit for manufacturing and there just so many jobs in the financial sector that is screwing manufacturing and jobs even more. Every pence that is used to earn interest instead of support companies that provide jobs is wasted.
Whether the then newly formed Scottish government with the new Queen Martha Stuart would do a better job? Hard to say..................
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rowuk
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Post by rowuk on Jul 19, 2014 21:35:23 GMT
El Al Commercial Airliners It seems that the Israelis are about 10 years ahead of the U.S. in almost every venture and here is one good example. Unbelievable! All El Al Commercial Airliners have this MUSIC. www.youtube.com/embed/uVlERTFVSpo?rel=0 This Is Made In Haifa And All El Al Planes Have It!!!!! If the missiles had valves instead of solid state guidance systems, they would be able to follow the trajectory with only a bit of second harmonics... Thats what sand and feedback get you.........
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rowuk
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Post by rowuk on Jul 19, 2014 10:04:11 GMT
Thanks Alex,
that guy is a pro. Before I came to Germany (1970s) he was on the Smothers Brothers show on television. He also wrote comedy and produced shows. Hardly "new" talent, but a breath of fresh air for the phony casting shows!
I laughed so hard!
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rowuk
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Post by rowuk on Jul 18, 2014 16:15:57 GMT
Hi Derek,
there are many reasons why components at their basic level can "change" sound. There are also a lot of bogus claims to sell stuff - especially with the concept of "less is more".
I guess the first step is to determine if you hear differences in audio cables. I personally do not believe in esoteric crap, but there are basic rules, laws of physics that explain why resistance, impedance and capacitance change frequency response. There are also schools of thought that say the shielding is a critical issue in todays hi res/high electronic smog environments.
I have been there, tried all sorts of stuff and can claim to hear at least a bit of it.
In my own system, I have recently tried out various pots and switched attenuators (no LDRS tried yet). My system has valve amplifiers located next to the speakers. There are about 5 meters of cable between my sources and the speakers. The difference between a passive attenuator and a fine active buffer/attenuator is very large. I personally believe that capacitance and impedance have the most to do with this phenomenon. With the passive attenuator, the source has to be able to "drive" the cables to the passive, it has to handle the resistance load from the attenuator and then drive the cables to the amplifier (my valve amps are easy to drive with a 330K resistor to ground on an input valve). The biggest difference is putting the buffer AFTER the attenuator. The difference is perceived extension at both ends of the audio spectrum, the reproduction of the "attacks" and "tails" of each note as well as an interesting effect that kind of changes the playback so that a solo piano or chamber orchestra does not sound any smaller than a large symphony orchestra. With less demanding music created in the studio with no acoustic reference, the differences are hardly noticable. Vinyl and digital are equally affected as my output stages of both of those amps are very similar.
I have received quite a few suggestions for improving my cables, changing the attenuator to another more "magic" type, descriptions of a "diode" effect at each solder or contact junction. Funny enough, these suggestions all came from people that do not know me, don't know what I have or have tried, and for the most part only cut and paste the advertising garbage read elsewhere. Maybe there is merit to the arguments, but these people are in no position to help me believe it.
My personal belief is that we need to star ground/shield to the pre amp, we should keep the cables as low impedance and low capacitance as possible. The best interconnects that I have found are made from good quality balanced microphone cable with good solid connectors. This seems to have the best balance between capacitance and impedance. I attach the hot and earth wires at both ends, and the shield at one end that gets connected to the preamp. The cable is not expensive, it holds up for many years before becoming microphonic (unlike many hundreds of dollars worth of Monster cable that I recently tossed for exactly this reason). It is easy to solder and looks nice too.
If one uses a passive attenuator with very short (and good) cables between good sources with solid output stages and a high impedance amp input, there is probably no gain or loss of fidelity.
I am experimenting with "biasing" the cables - having a DC component present on the interconnects- filtered at the amplifier.
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rowuk
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Post by rowuk on Jul 17, 2014 16:01:20 GMT
What, this old thread? Regardless of the language used it's still a bargain and definitely hi-fi. I've just bought a back issue of Hi Fi Critic so I could read their review(s) of the OBH-22. Seems the crtitcs loved it. I do to. If you don't want to call such a device a Pre-Amp then how about 'PVC' or Passive Volume Control? Or 'AARSS' which stands for Attenuator And Remote Source Selector. Derek I like AARSS. Most of the passives that I have heard deserve the name "SignalConstrictor" however............... Just like the big snake, they kind of squeeze off "life".
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rowuk
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Post by rowuk on Jul 16, 2014 15:31:11 GMT
Now you fill the box with fine sand. It is as effective as wax potting but is a hell of a lot easier to modify if and when you get the itch........... That's a neat idea. cheap too!
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rowuk
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Post by rowuk on Jul 14, 2014 22:02:48 GMT
Now you fill the box with fine sand. It is as effective as wax potting but is a hell of a lot easier to modify if and when you get the itch...........
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rowuk
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Post by rowuk on Jul 7, 2014 22:07:01 GMT
On stage with my trumpet and a smile!
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rowuk
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Post by rowuk on Jul 7, 2014 16:24:53 GMT
Well, "pre" amp could simply mean "before" the amp too. That would fit in any case. In any other market they would be proud to call buffers: buffers, attenuators: attenuators and devices with GAIN: amps One of the biggest challenges in audio is a common language. We still do not have words to describe "sound" or how a technology applies to "sound". Because there are a great deal of challenged people dealing with audio from a manufacturing, reselling and customer standpoint, all seem to be content with words like "better", "neutral", "transparent", "microdynamics", "high res", "black", "detailed", "grainy", "weight" and further non-descript garbage. I guess we cannot expect more from those who don't practice fidelity in any sense of the word. Pimp my cables! A couple of holes in the cover, then we add 2 valves (plus a couple of power supply bits) and now we have a REAL preamp! Hi Robin It seems rather silly to call a buffer with a little less than UNITY gain, or an attenuator with switched inputs a pre-amplifier, although some may try to justify the term as it is before the amplifier. If you are interested, we may soon see the Class A/HA/Preamp project revisited, with PCBs becoming available from a rather knowledgeable U.S.A. member. This could also depend on whether enough members are still interested in this project. Regards Alex
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rowuk
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Post by rowuk on Jul 6, 2014 14:01:12 GMT
A couple of holes in the cover, then we add 2 valves (plus a couple of power supply bits) and now we have a REAL preamp!
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rowuk
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Post by rowuk on Jul 6, 2014 13:56:28 GMT
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rowuk
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Post by rowuk on Jul 6, 2014 13:32:58 GMT
I don't know about better than your other things, but I built this and it is definitely better than anything that I have ever had: rh-amps.blogspot.de/2013/09/rh-307a-v2-super.htmlWhat I notice most is "space" around the instruments and the size of the performing ensemble. Small chamber music, jazz club settings or solo works sound "intimate", major symphonic music sounds huge. Better means that I never zap around to listen to something else. I remain attentive for the whole work being played. I do not use playlists anymore, I want the package that the composer originally intended. Alex (Kitic) has a whole family of valve amps and is very outspoken about what they do and why - exactly what I was looking for. He is very responsive to "sensible" correspondence by E'mail.
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rowuk
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Post by rowuk on Mar 29, 2014 20:57:29 GMT
www.mh-audio.nl/spk_calc.aspThis would get you going.................. My thoughts are that a parallel woofer down deep where it goes into resonance reduces the impedance and allows a decent amp to provide more current. Doubling the surface area of the woofer increases the "woof" reducing distortion at the same time. <150Hz keeps the midrange tidy. Of course you could build a second cabinet with the volume of the first and wire it in parallel (with the big coil) and get the same effect.
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rowuk
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Post by rowuk on Mar 29, 2014 20:34:42 GMT
2014 is here to get major parts of my stereo "good looking". 2013 got a lot of projects started, I still have a 6 channel tube amplifier power supply "open" with 520V, 380V and 250V DC just waiting for cats paws or a dogs tail...... I need to get it closed up so that my wife can "dust it" without fear of death by electrocution. I also have a new phono preamp on the drawing board as well as a buffer stage for the preamp. Then there will be some experimentation with cables.
At the same time, I am experimenting with speaker positioning to see if there is an even better place. If there is any time left this year, my daughter wants some special speakers.......
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rowuk
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Post by rowuk on Mar 29, 2014 19:42:29 GMT
I have had great luck in doubling the cabinet size and adding the second woofer with a 6db/8va crossover (one coil) around 150Hz (15 mH for 8 ohms).
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rowuk
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Post by rowuk on Mar 29, 2014 19:27:20 GMT
I have a MacMini as my digital music source on the main system. I am a Macintosh kind of guy that enjoys the results more than the path to get there. iTunes has its share of sonic warts and I have found a way to solve a major portion of them. It is a software package called BitPerfect and it is a breath of fresh air! bitperfectsound.blogspot.deOne of the biggest problems that iTunes has is that it does not change the sampling rate, it simply resamples and reduces the quality to audiophool level. BitPerfect changes the sampling rate to the original or a 2 or 4x upsample of the original. There is no 48khz resample of redbook CD 44.1 tracks. This would be enough, but they also supply a resampling algorithm that I consider to be a big step up from CoreAudio. On my system it works as advertised and the two issues that I had were promptly solved by their helpline. What is the difference in sound: High quality tracks retain their "detail". Resampling artifacts like smaller soundstage, lost trailing room info, phony etched imaging are GONE. When listening to high sampling rate mp3/AAC tracks, the 2x or 4x upsampling feature seems to make them much less annoying at least with my Focusrite DAC. The listening area has grown - the sweet spot seems MUCH bigger. Even listening from the next room (my office for instance) shows a positive difference.
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rowuk
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Post by rowuk on Mar 29, 2014 18:48:43 GMT
Why this specific horn? Because it integrates well with the woofer/midrange, has the softness, clarity and presentation that in the context of my stereo creates the sound that I look for. I have had magnetostats, electrostats, full range drivers, multi way speaker systems. The changes have always been one at a time after identifying something that I was not completely content with. Many alternatives only lasted a couple of days, others years. Human voices, acoustic instruments, chamber music, symphony orchestras all have the "tone", "geometry" and cohesiveness that I enjoy. That is not to say that I am finished - there is just nothing currently that changing anything in my speakers could solve. The biggest advantage to high efficiency is that we have great control over the "sound" produced by each driver. It is not voodoo or magic - or distortion. Even changing the connection between the 8 and 16 ohm taps for a specific driver brings subtle nuances that can manipulate the final "big" result. It is "easier" to get a couple of watts optimised than trying to integrate more power than I could ever use. Burning off power in the crossover seems to be a pretty stupid way to get balance - especially with the increased difficulty of getting the most out of the driver. There is nothing "diffuse" about a properly integrated horn. There is also nothing "direct" about a properly integrated tweeter - regardless of technology. Granted, plugging the EMIT into a 200 watt solid state amplifier crossed over at 5K would change its usability in my context - that is why I do not do it. The horn has about 60° coverage in the frequency band that I use it in. The EMIT is used over 12K and has "more" coverage than that - which I specifically want. I am using a 6dB/8va crossover so the transition to the EMIT is very gentle without any noticable problems. In fact exactly the opposite is true - the presentation of that last octave stays remarkably out of the way. Pro audio horns that are digitally managed are not designed for reproduction of smallest musical details. They need to control directivity and to get some semblance of "flat" frequency response, they do not invest in getting the horn or driver sonically right - they simply equalize what they consider to be problems out. It is like a professional photographer spending a lot of time getting the lighting and mood for a shoot correct versus using Photoshop to "compensate" for lack of attention to detail. The artifacts are similar between the two disciplines, and they both have their "markets". Just for info, I have built a RH307 Super designed by Alex Kitic. This uses an old pentode as a pentode and gets remarkable results. About 9 watts of power, it needs a little over a volt to get that power. The remarkable thing since I finished it, I am listening to complete works instead of single movements or zapping around. I consider this to be a very welcome aspect of the stereo as a whole. Draw me into the music - don't bounce from one spectacular aspect to the next. Here is the link: rh-amps.blogspot.de/2013_09_01_archive.html
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rowuk
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Post by rowuk on Mar 29, 2014 18:16:59 GMT
I have spent more time on this and have given up. Digital can delay cleanly but not filter. Period.
Even a digital 6dB crossover really trashes the sound compared to a line level capacitor. What sounded best was the crossovers over 24dB/8va. Best was still not really "good". My MiniDSP is now a tool for experimenting. It is really easy to model a crossover and then build it analog and get the rest of the sound back.
I will say that there are many audiophiles that can't hear the difference and I definitely don't get into discussions. It is like talking about women, religion or good wine. Without a common description for the important stuff, we always end up wondering why we even talk about this stuff.
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rowuk
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Post by rowuk on Jan 2, 2014 22:36:12 GMT
RFT = Radio-Funk-Technik - Kombinat
Funk is the german word for radio transmission Kombinat is a state owned business
I found RFT E88 tubes. Scroll down to the bottom of this page and you will get references to all known E88 family tubes with lots of pictures. Google translate should be enough. If you have a special problem PM me and I will try and find time to translate,
RFT did a lot of OEM business for the name brands all over the world. Here is an example of only the EL34 output pentodes:
EDICRON EL 34 Telefunken TFK EL 34 ULTRON EL 34 ITT LORENZ EL 34 CALVERT (England) EL 34 NATIONAL ELECTRONIC EL 34 / 6 CA 7, Made in Germany Valvo EL 34 AEG EL 34 Siemens EL 34 WF EL 34 DICRON USA EL 34 WESTINGHOUSE USA EL 34 RIVERA USA EL 34 Sylvania-EL34 MAZDA (FRANCE) EL 34 Groove Tube EL 34 SB-ELECTRONIC (England) EL 34
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