bias splitter resistors
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bluesguitar
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bias splitter resistors
I replaced my 220k bias splitter resistors on a 67' Super Reverb. Later I discovered that the old ones had a gold (5%) tolerance band, and the new ones have a silver (10%) band. Is this a big deal? Is there any reason for concern?
Re: bias splitter resistors
I think this is a case of, A) measure the voltage to make sure you're still in spec (or measure the resistors before you put them in the circuit!), and B) if it sounds good, it is good.
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bluesguitar
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Re: bias splitter resistors
I measured them before installation, and they were at the top edge of the 10% tolerance (239k). The amp plays fine. I'm just wondering why fender designated 5% tolerance?xtian wrote:I think this is a case of, A) measure the voltage to make sure you're still in spec (or measure the resistors before you put them in the circuit!), and B) if it sounds good, it is good.
Re: bias splitter resistors
it was what they had on hand at the time of populating the boards.
I've seen all sorts of "things" in Fender amps.
The thought process was simply closer is better and better means less chance of failure.
As long as you have metered the components you should be fine for years to come. If at any point it bothers you replace it with a 1%
I've seen all sorts of "things" in Fender amps.
The thought process was simply closer is better and better means less chance of failure.
As long as you have metered the components you should be fine for years to come. If at any point it bothers you replace it with a 1%
My Daughter Build Stone Henge
Re: bias splitter resistors
They also specified 5% for the PI plate loads. 5% was a pretty tight tolerance for consumer gear in those days. If they used 10% and got one grid leak at 242K, the other at 198K and plate loads at 76K and 110K, the push and pull sides of the PA would have been way out of whack. 5% was the best they could do to keep things acceptably close.bluesguitar wrote:I'm just wondering why fender designated 5% tolerance?
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Re: bias splitter resistors
I just opened a twin to work at a couple days ago and was surprised (not really) to find that only the volume pots were correct, and I think the bass pots. The rest of the pots were half or double what the spec shows. Fender amp inspections give me the balls to use whatever I have on hand to try out whatever I want. Thatsafact.selloutrr wrote:it was what they had on hand at the time of populating the boards.
I've seen all sorts of "things" in Fender amps.
The thought process was simply closer is better and better means less chance of failure.
As long as you have metered the components you should be fine for years to come. If at any point it bothers you replace it with a 1%
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
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bluesguitar
- Posts: 98
- Joined: Wed Feb 15, 2012 2:17 am
Re: bias splitter resistors
Thanks to all for your comments. I feel more at ease and will leave the new resistors in. 