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tube fanatic

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  1. It's easy to fall into the trap of remembering what another system sounds like. Auditory memory is extremely short. There's also the issue of psychoacoustics- I'm sure that you experienced days with your previous reference where it just didn't sound quite as incredible as it may have the day before. Moods and emotions play a role here. Have you ever tried nearfield listening? Doing that allows you to be encompassed by the soundstage- basically, you become part of it. I've listened that way for years and can no longer listen any other way.

  2. The need to be fully immersed in the music to obtain full enjoyment is common. Why else do people spend countless hours and dollars tweaking their systems, or switch to headphones (which, of course, allow total immersion)?

  3. The cheaper the better, but want something substantial and black finish.


    About the cheapest stands you can get, which are amazingly effective, is to use cinderblocks. A plywood top can be easily attached for increased speaker stability, and the entire unit can be draped with your favorite cloth to make a very decorative, room coordinated, unit. The weight and concrete offer terrific acoustic isolation from the floor as well.

  4. I'm sure that this amp will work well. 40 watts/channel is plenty of power unless you plan to listen at ear damaging volume levels. You will also have fun trying it in triode mode. The sound, when used that way, is very different from ultralinear- much smoother through the midrange and high frequency range, but with somewhat softer bass (as you will find out when you listen to it at the dealer). Please post your impressions after getting the amp!

  5. Cayin is another company whose amps have received very favorable reviews. They also provide great value for the cost. Are there any dealers/distributors near you who would allow you to take home an amplifier to audition in your system? I presume that you are not in the US based on the metric room measurement that you provided. Here, some distributors offer a 30 day money back guarantee on equipment purchased. It's a wonderful way to be absolutely sure that what you buy will satisfy your needs.

  6. Modern tube amplifiers are designed to provide a very flat frequency response across the audio band, or even beyond. So, the thinking is that any kind of tone control will detract from the quality of the sound. I'm sure that there is also a cost consideration- implementing sophisticated tone control circuitry definitely adds to the cost of the amplifier. But, with the RF82s, I can't imagine that you should run into any problems which can't be fixed by varying the speaker position slightly, or playing around with various types of sound absorbent materials (like books, carpets, etc.). Best of luck, and please post after you make the changes!

  7. Well, regarding the rectifier tubes, you need to be careful. If the amp uses a standard CRC or CLC filter, switching to the 5R4 could subject the electrolytic caps to a much higher voltage than was intended. The 5AR4 is a cathode type rectifier which tends to warm up somewhat slowly thereby limiting the voltage to the electrolytics. The 5R4, however, being a filament type rectifier, warms up almost instantaneously; this will allow the electrolytics to "see" a much higher voltage until the remaining tubes in the amp warm up and start drawing current. The 5751 can be swapped for the 12AX7; as to which arrangement will sound better, why not just swap them around and draw your own conclusion? Hope this helps you a bit......

  8. Capacitors can affect almost anything in an amplifier depending on where in the circuit they are located- frequency response, hum, noise, voltage, etc. How old an amplifier are you talking about? Assuming you are speaking about a vintage amp, say 30+ years old, the electrolytic caps should be replaced at the very least (keeping in mind that amount of use and operating temperatures may necessitate replacement in much newer amps too). Please be more specific about the amp in question.

  9. Another solution is to go with a passive line stage (basically, a single resistor and a potentiometer) between your source component and the power amplifier. With extremely efficient speakers, like K-horns, it allows them to be driven to ear shattering levels; and many consider the sound quality to surpass that of any preamp since you are eliminating all of the noise generated by another power supply and numerous resistors, capacitors, switches, etc. If you are handy, one can be made for around 20 bucks!

  10. I am fairly nostalgic, I know the things that I collect I like to be "left alone" and I am sure someone somewhere wants the same with this piece. Its 40.00 dollars and near perfect, but I think I will have to pass, it is just to nice to rip apart! If it was like 98% of the consoles I have seen in the past I would have no problem hitting it with a sledge hammer, because some history may be better forgotten, but I think someone will appreciate this in it,s original state.

    For forty dollars buy it and find a place for it!!! More than likely, someone will buy it, throw away the amp/speakers, and use it for something ridiculous...............

  11. It depends on how nostalgic you are! As a restorer of antique radios, vintage audio equipment, etc, I'd certainly leave it intact to preserve the history. However, it may be possible to arrange switching which will allow you to play the amp either through the existing speakers, or through the Cornwalls. I don't remember what kind of inputs the amp has, but it may also be possible to connect your CD player to an auxiliary high level input so you can use it for that as well. How much is the asking price, and are there any knowledgeable audio folks in your area who can assist you?

  12. If the price is right, I'd grab it, particularly if it is playing. With Cornwalls, you can't go wrong with almost any decent tube amplifier. If memory serves, the RP91 is the same as the RP90 which used a nice push-pull output stage with 6CM6 tubes (electrically the same as 6V6s). Power output is probably in the range of 10wpc which is plenty.

  13. Well, looking at the pix, it is a very basic emissions type tester which is of limited value. Yes, it will tell you if the tube is working, and will let you compare tubes of the same type to see which has more "output." You would probably get more information by just putting the tube into a working amplifier and using your ears to judge whether it is good. The other question is whether this tester is operating or not, and whether it is properly calibrated. Buying a tester without having its calibration instructions is chancy. If not properly set, a tube with poor emission may show as "good" on the meter, or vice versa. $75 seems a bit high for a unit of this type.

  14. To determine exactly how much power is needed you will have to determine the maximum sound pressure level you desire at your listening position. The easiest way to do that is with a sound pressure level meter (Radio Shack used to make a nice one for around 50 bucks- not sure if they still have them). Once you have that, you can determine the power needed. Your speakers can each produce approximately (approx, because the output will vary with frequency) 102db at a distance of one meter with one watt of power applied. The level at, say, 10 feet will be lower. But, with that in mind, you can still extrapolate somewhat by considering that you need to double the power for each 3db increase in output from the speaker. So, for 105db, you need 2 watts, etc. Considering that the auditory pain threshold is, if my old memory serves me, around 120db, you could achieve that with around 64 watts. But, we're talking about each speaker providing that level of output. So, in stereo, with both speakers driven, the power requirement per channel is far less. Also, don't compare the Palladiums to the RF-7s as they are not as efficient and will require more power for a given sound pressure level. So, I hope this helps you a bit. The bottom line, as mentioned before, is that you have more than enough power.

  15. Unless your RF-7s are in an enormous room which is filled with all kinds of heavy sound absorbing materials like rugs, curtains, hundreds of books, etc, 5 watts/channel would be more than enough! With the amount of power that your receiver provides you could create sound pressure levels that would break your eardrums before you would run out of "steam." Don't even give it a thought!!! 2.83 volts is equivalent to 1 watt into 8 ohms.

  16. Well, I know that my opinion will start a raging controversy, but what the heck! Stick with the cheap stuff. For interconnects that are relatively short, say less than 3 feet, it probably doesn't matter what you use as long as they make a good electrical connection to the jacks. Put a little De-Oxit on the plug center pin, and on the outside of the jacks, and you should be in good shape. Since the cheap interconnects may not be as well shielded as some of the more expensive ones, be sure to keep them away from your AC power cords to avoid any potential coupling which could induce some hum/noise in a worst-case scenario.

  17. The offending glass was a Sovtek 5AR4. I have ordered a pair of Groove Tubes off Amazon as they were the ones that were immediately available with 2 day delivery.

    So, do I plug both in? Can I swap left tube into the right socket and power up with left empty to check rest of electronics first?

    What is best way to proceed?

    You can power up just the one channel. However, depending on the power supply design, the decreased current draw from running only one channel can cause the voltages to be elevated. So, while it shouldn't hurt anything to try it briefly, I'd not run it for too long without knowing if the tubes are being subjected to an overvoltage situation.

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