10-07-2013, 04:30 PM
Are we definitely speaking of the same Bob?
My experiences have been excellent with him.
RE: tube substitution, there is a time and a place for it. Personally, I recommend them (Guides) if for nothing else than expanding one's knowledge.
And while there are definitely cases where the substitution of a tube can introduce different parameters, there are (my opinion) just as many in which the tube will function in an acceptable manner.
Many subs are not "either, or." Example: you can use a 5R4 in place of a 5Y3, BUT you cannot use a 5Y3 in place of a 5R4. Not that I would waste a 5R4 where a 5Y3 belongs, BUT if I was out of 5Y3s and had a 5R4 sitting in the stash, I would certainly use it until another 5Y3 came along.
In some radios the Manufacturer listed different types of tubes that could be used. Example: The Truetone D-697 on the schematic lists either a 6U7G or 6K7 tube for the RF and IF amp tubes. Another WG set does the same for the rectifier (5Z4 or 5Y3).
My experiences have been excellent with him.
RE: tube substitution, there is a time and a place for it. Personally, I recommend them (Guides) if for nothing else than expanding one's knowledge.
And while there are definitely cases where the substitution of a tube can introduce different parameters, there are (my opinion) just as many in which the tube will function in an acceptable manner.
Many subs are not "either, or." Example: you can use a 5R4 in place of a 5Y3, BUT you cannot use a 5Y3 in place of a 5R4. Not that I would waste a 5R4 where a 5Y3 belongs, BUT if I was out of 5Y3s and had a 5R4 sitting in the stash, I would certainly use it until another 5Y3 came along.
In some radios the Manufacturer listed different types of tubes that could be used. Example: The Truetone D-697 on the schematic lists either a 6U7G or 6K7 tube for the RF and IF amp tubes. Another WG set does the same for the rectifier (5Z4 or 5Y3).
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