Eico HF-89A question. Does someone have a schematic of the Eico HF-89a? My specific need is to know the value and location the low value capacitor that is attatched to the grid of V 2 and V 3. What is the location of the other end of this capacitor and the value?
0.25 microfarad/400V. You can use 0.33u, which will probably be easier to source. It goes between grid and ground.
I should have been more clear. Sorry
Tubes V 2 and V3 are a dual tube - 6SN7. I am asking about the grid for the first tube - pin #1.
Tubes V 2 and V3 are a dual tube - 6SN7. I am asking about the grid for the first tube - pin #1.
Right. Pin 1 is bypassed to ground via that 0.25uF cap. Pin 1 is also connected to pin 4 via a 1M resistor.
V2 is Channel 1, V3 is channel 2. The other sections of those tubes (grid pin 4) are direct coupled to the input tube plate.
V2 is Channel 1, V3 is channel 2. The other sections of those tubes (grid pin 4) are direct coupled to the input tube plate.
Yes, but ----
Sorry, I am not asking about the 0.25 mf capacitor.
The capacitor I am asking about is a change brought
about when EICO changed vendors of the output
transformer. The HF-87 and first version of the HF-89
had a 750uuf placed across one half of the transformer
primary to deal with phase shift in the transformer. This
capacitor was replaced in the HF-89a. According to
old posts in the EICO Yahoo group. The new "fix" was
a "low value capacitor at the input of the 6SN7. The
amp I recently purchased does not have this capacitor
but I think I can see where it was cut off of pins 1
of each 6SN7. If someone has a 89A schematic, I
need to know the value and location of this capacitor.
Again, I am not asking about the 0.25 mf capacitor you
describe. I feel the cap. would somehow be connected
to pin four or five of V4 and V5. Thanks for your help.
Sorry, I am not asking about the 0.25 mf capacitor.
The capacitor I am asking about is a change brought
about when EICO changed vendors of the output
transformer. The HF-87 and first version of the HF-89
had a 750uuf placed across one half of the transformer
primary to deal with phase shift in the transformer. This
capacitor was replaced in the HF-89a. According to
old posts in the EICO Yahoo group. The new "fix" was
a "low value capacitor at the input of the 6SN7. The
amp I recently purchased does not have this capacitor
but I think I can see where it was cut off of pins 1
of each 6SN7. If someone has a 89A schematic, I
need to know the value and location of this capacitor.
Again, I am not asking about the 0.25 mf capacitor you
describe. I feel the cap. would somehow be connected
to pin four or five of V4 and V5. Thanks for your help.
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