I've generally been very satisfied with the excess inventory / NOS devices I've purchased from Unicorn Electronics in Aliquippa, PA, USA. Their price on 2N3055 is quite low.
I also recommend you train your fingers to ALWAYS type octopart.com when you are looking for semiconductor devices. Always.
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I also recommend you train your fingers to ALWAYS type octopart.com when you are looking for semiconductor devices. Always.
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Yeah, you possibly need 10 ohm base resistors on Ft 2 mhz up parts in place of 1970's 2n3055 which were 200 khz. This helps reduce chance of oscillation. Depends on the layout whether your circuit will oscillate or not . Designs using homotaxial slow parts were not checked for oscillation with 2 mhz parts.
I've got MJ15003 equivalents in my 1966 design amp, NTE60. It doesn't oscillate but I put 10 ohm resistors in the base line to burn out in case of O.T. failure, which turned out to be exactly the right thing to do. According to Mooly. Some people have run sims on a similar circuit (Leak delta 70) and saw the faster O.T.'s improves high freq intermodulation distortion a lot. I say mine doesn't sound as bad as the reviews from the time claim. With an idle bias current control add on circuit to keep idle current above 20 ma cold and silent.
I've got MJ15003 equivalents in my 1966 design amp, NTE60. It doesn't oscillate but I put 10 ohm resistors in the base line to burn out in case of O.T. failure, which turned out to be exactly the right thing to do. According to Mooly. Some people have run sims on a similar circuit (Leak delta 70) and saw the faster O.T.'s improves high freq intermodulation distortion a lot. I say mine doesn't sound as bad as the reviews from the time claim. With an idle bias current control add on circuit to keep idle current above 20 ma cold and silent.
We can now find several Ebay type kits, some built and tested too, that have, for example, 15MHz 2SD1047 parts instead of 2N3055 TO3 transistors. I haven't completed any JLH builds with them myself yet but friends tell me of the sound quality which is much improved using these TO3P transistors. No sign of instability on the 'scope that I could see there and no other changes implemented either, regardless of whether the transistors are actually fakes or not.
+1 on 15003. Switched from 3055 to 15003 and definitely noted sound improvement. No oscillation problems and did not alter anything in the circuit.
However, my old Motorola 3055s did not sound bad and they have a relax, little slow but warm sound as well. I would describe as antique sound and its comfortable to listen to.
However, my old Motorola 3055s did not sound bad and they have a relax, little slow but warm sound as well. I would describe as antique sound and its comfortable to listen to.
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