I've recently acquired a Rivera era 1984 4x10 Fender Concert II and I've been looking at the schematics and trying to become familiar with the circuit and it's peculiarities.
I've seen a couple differences in two schematics that I'm wondering about.
One difference being the negative feedback resistor being marked as 27k vs 82k. I'm wondering if the 27k was a factory mistake that makes for way too much feedback and makes the amp sort of flat and dead sounding. The resistor in mine is an actual 27k upon checking. I'm wondering if 82k seems like a better option? It brings the ratio more in line with Blackface and Dumble ratios. Those being roughly 8/1 and 12/1. My negative feedback is connected to the 8ohm tap.
The other thing that's perplexing me is the switching line connected to the switched sleeve on the inputs. It connects to the Vactrols and what i think are blocking diodes? In one schematic there is only one line running to the inputs and in the other there are two lines running to separate places. I'm wondering about the functionality here and if deleting the low gain input in favor of a Mid pot control would present and potential problems.
The last thing is that the speaker out jacks are connected as such that when an 8ohm extension speaker is connected the switching jack engages the 4ohm tap if I'm not mistaken. The normal speaker jack for the internal speakers is a shorting jack which suggests that I need to have the internal speakers connected in order to use the extension jack. If i were to install a non-shorting jack for the normal internal speaker jack would i effectively end up with the ability to use the external speaker jack as a regular 4ohm output on it's own without the internal speakers connected? I'd like to have that versatility available should i need to connect this amp to a 4ohm cab by itself without the internal speakers.
Thanks for any help or insights, TAG!
Schematics:
https://schematicheaven.net/fenderamps/ ... _ii_83.pdf
http://www.stratopastor.org.uk/strato/a ... iagram.pdf
Fender Concert II questions
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Stevem
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Re: Fender Concert II questions
I have never heard of entity’s called the feedback police anywhere on this planet, so just increase the value of that 27k resistor until you have a smile on your face my friend!
I have some zero ohm 1/2 watt resistors here, I can send you one if not having a resistor there on the fiber board makes you feel uneasy.
I have some zero ohm 1/2 watt resistors here, I can send you one if not having a resistor there on the fiber board makes you feel uneasy.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Fender Concert II questions
I’ll take you up on that resistor! I’ll PM my address hahaStevem wrote: ↑Sat Sep 10, 2022 12:18 am I have never heard of entity’s called the feedback police anywhere on this planet, so just increase the value of that 27k resistor until you have a smile on your face my friend!
I have some zero ohm 1/2 watt resistors here, I can send you one if not having a resistor there on the fiber board makes you feel uneasy.
I guess more specifically I’m wondering if that value or ratio seems odd as I’ve not seen anything around the 4/1 as it present a with a 27k and 6.8k