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Tubes Asylum Questions about tubes and gear that glows. FAQ |
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Tubes Asylum Questions about tubes and gear that glows. FAQ |
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In Reply to: RE: DB110G (Bogen) 1950s. posted by ivan_terrible on April 20, 2024 at 06:23:51:
Using pentodes instead of 6V6 beam tetrodes.
Not to give too much the game away here are the PDD2/UBL7x instead of 6V6.
As you can see, there is a fair difference in height.
You can also see, again so as not to give the game away...
The Loctal valve has the same construction exactly as the EL60 which was used as the first EL34- which became octal with the steel ring base.
Suffice to say the valve below right is a MINIATURE EL60/EL34 OK?
The gain of the PDD2/UBL7x at 9.5 mA/V is almost the same as the 11.0 mA/V EL37 which preceded the EL60, so the drive requirements are about 3x lower than the 6V6.
This means a considerable reduction in distortion in the AF amp/driver
It was quite a lot of work desoldering the octal sockets and replacing them with good s/h Mcmurdo loctal ones.
When I do this next time I use NEW Mcmurdo.
The NOS 6V6 were rated at 14W.
After seating the loctals properly they JUST clear the original Bogen cage
Next stage came to checking various things before messing with bias settings.
Now the pair of them installed
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Follow Ups
- RE: DB110G (Bogen) 1950s. - ivan_terrible 01:09:17 04/21/24 (1)
- RE: DB110G (Bogen) 1950s. - ivan_terrible 06:03:16 04/21/24 (0)
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