2N3055

I also agree that the Black Gate and other "high end" electrolytic capacitors are a total waste of money. Regardless of their cost, they are still electrolytic capacitors, and are constructed in the same basic manner as any other electrolytic capacitor. Electrolytics are mainly used for power supply filtering applications. It does not matter if they have lower ESR or dissipation ratings, their sole purpose is to filter ripple. A BG 50 uF capacitor and 50 uF Sprague Atom both have a reactance of 27 Ohms when coupled to a full-wave rectification circuit. The electrical values do not change because the BG cap is more expensive, the Sprague capacitor does it's job equally well, both caps in this example function identically. No audible change is to be detected. The BG costs 10 times more than the Atom, so why spend more? Because a manufacturer claims superior performance? But what performance? The Atom cap will likely out last the BG cap also. Personally, I'd much prefer to use a quality, time-tested brand like Sprague Atom. This high end parts crap didn't happen in the 60's when tubes were in wide spread use. The only reason why the Black Gates are selling now is because of a few gullable people who think if it costs more, it must be better. If these Black Gate capacitors exsisted in the 60's, the company would've went under charging prices like this. The only position in an amplifier where these BG's may be audible is in a bypass circuit, such as a tube cathode. But the possibility of being able to detect a sound difference between the BG and a conventional capacitor would be highly unlikely. The only real advantage of the lower ESR capacitor is at higher frequencies, and they are well above 20,000 Hz (the end of the audio spectrum)

---------------- On 9/1/2004 3:09:14 PM InventiveAudio.com wrote: True but the EL34 is a true Pentode tube which can also run in Triode. ---------------- Yes, but if you wire an EL34 to run as a Triode in an amplifier that was designed for pentode operation, the output impedance of the Triode wired EL34's will be much less than if they were wired for Pentode operation. The output transformer primary impedance would no longer match the load. This would result in a severe drop in output power, not to mention the drop from the pentode to triode conversion. The only way to overcome such an impedance mismatch would be to connect the speaker to the next highest impedance (8 Ohm speaker to 16 Ohm tap, etc.)

---------------- On 8/31/2004 10:05:09 PM jt1stcav wrote: No problem, Erik. Everyone's experiences make for great reading, and in my limited knowledge, I also believe that changing driver and power tubes would probably make more sonic sense then the rectifier (not that it wouldn't also make a difference). But I still have a problem figuring out which GZ-series (if any) would be a best matchup for my amp, and I'm too chicken$hit to try for fear of frying the amp's innards! I did write to Edmund about my little dilemma, but as of yet I haven't received any response...Guess e-mail to Hong Kong is just as slow as the slow boat he uses to ship his gear over to these shores)! ---------------- jt, You can use any tube with the 5T or 5L pinout with the exception of the 5AU4. With your amplifier, the only real thing to watch out for is the filament current rating of the power transformer (which, in this case, is 3A 5V). The 5AR4, 5U4, 5V4, 5Y3 and GZ equals can all be used without causing any damage. While switching between different types, there will be some voltage output variations, but nothing significant. For instance, compare the 5AR4 to the 5U4. Both will supply rated current without a problem, but the 5U4 drops slightly more voltage. The drop of the 5U4 is approx 50V, while the drop on the 5AR4 is approx 30V. A 20V difference in a tube rectified supply feeding tube stages is peanuts. You are not likely going to hear a difference. The 20V difference is truly insignificant. Even two 5U4's made by the same manufacturer will not have identical voltage drops, there is a tolerance of 30% between identical types. Trying other types that have the same pinout and suitable current handling ratings is just fine. Rectifier tubes have such a wide tolerance that calibrating an amplifier to use a single type with a specified voltage output is impractical. If the tube used in calibration were replaced with another brand, or even the same brand, the voltage output value would have a variation up to 30% from the design center value.