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Vintage threads from the first ten years
Fender reverb changes
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 9/16/1997 10:17 AM |
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Steve Keay |
Fender reverb changes Anyone have any idea why the previous owner of this Princeton Reverb I have would have of changed the cathode res for the reverb feed tube to a 470 ohm and removed the cap??? Is this a known mod?? Any ideas??? TIA, Steve K |
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| 9/16/1997 12:39 PM |
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| J Fletcher | I understand that it's hard on that tube to have that low a value cathode resistor.Standard value would be 2200 ohms bypassed by 25microfarads.You probably knew that. |
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| 9/16/1997 12:47 PM |
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| Steve Keay |
I did notice the reverb was pretty intense before I started poking around. But I usually keep it pretty low so I didn't really notice anything unusual about it. Think I'll put the correct components back and see the difference... Thanks for the info... Steve K |
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| 9/16/1997 4:10 PM |
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| Charles |
>>I understand that it's hard on that tube to have that low a value cathode resistor.<< It appears that someone was trying to goose the gain a bit. Considering the voltage it gets fed, it's a wonder it lasted at all, except maybe because it was in a Princeton. In a Super, or Pro or Twin (etc) I could imagine smoking the tube very quickly... |
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| 9/19/1997 8:39 PM |
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| Gary |
I've seen resistors used in that position that ranged from 470 to 2200ohms. I have a deluxe reverb that has a 470 there. It is a bit low, but if you look at the ratings for a 12AT7( the RCA tube manual lists it as 2.5watts plate dissapation per triode) my deluxe is at 3.8 watts for both sections combined. Of course the plate voltage(~400v) exceeds the listed spec of 300v but I've seen this exceeded on every Fender reverb circuit I ever looked at. The main thing for me is how it sounds and that high current 12AT7, to my ears, sounds good. Regards, Gary |
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| 9/22/1997 6:07 AM |
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| Steve Keay |
Thanks for that info Gary,, I put the correct values back and I'm not happy with the sound of the reverb now so plan to do some experimenting... Thank again, Steve K |
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