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Maynard re “ So, in the S-85 schematic there is no coupling at all from the plate of V1 to the grid of V2.” Well??? Maybe So, in the S-85 schematic there is no obvious coupling at all from the

Greetings to the Group: I tried to take some photos using my digital microscope, but unless you want a close-up of a rivet in the band switch, the magnification is too high and the field of view is

Hi Jacques, I just received 1.5 cents from you. Your proposal may well be, but how do you explain the difference the switch setting makes? Sent: Saturday, February 15, 2025 5:57 PM To:

Tom I’m glad I have company on that. Because the switch makes the difference and is before the 6V6s, I tend to think it is up there. Perhaps put a sizable cap on each grid to see if the switch

Richard , I am getting confused. you spoke of the antenna stage, I don’t see difference you mentioned between the 40B and the 85. The next wording must be part of the mixer tuning. On the bama

My two cents: If the 120Hz “hum” is still heard when the 6SC7 tube is removed, that could be that the output stage is not balanced current wise. Meaning: if one of the 6V6 is way less polarized

“When it comes to the switch area, that schematic is spinning my head” Glad it is not just me…… ? I have not had time to get back to this, maybe tonight. I believe it is in the 6V6 area

Hi, Richard, The S-40B also has the same R26/C29 network that passes plate current from V1. The significant difference between the schematics of the S-85 and the S-40B is that the S-85 has no C62. So,

Hi Jim Re paragraph 1: I would not be surprised about the talking, but can that cause 120 cycle hum? Re paragraph 2: I agree, and there must be lots of return currents from B+ running to and thru the

I looked at both (S-40B and S-85) schematics again. The antenna stage is different. The S-85 has a broad band plate load R-26, C-29 rather than a tuned circuit. The coupling appears to come through

Yes, C38 in the schematics of both the S-85 and the S-40B is a gimmick for coupling the BFO. I wrote "CW oscillator" but should have written "BFO." 73, Maynard W6PAP

I will have to look at both schematics again but think there is a "gimmick" in one or both for coupling the BFO. -- Richard Knoppow Los Angeles WB6KBL SKCC 19998

DonMore likely that the filter inductor and the tone inductor are talking to each other.? I don't know exactly where they are located on the chassis but I have noticed that high power Peavey 8 ohm to

Maynard, if we shift to the S-40B for a second, I also was disturbed by C62 which would try to pass band 4 30MC signals, bypassing the tanks. My guess was that the tanks must overpower C62. Even if

Maynard, good to know that they show a gimmick like this But that leaves the that ongoing v1-v2 coupling question more mysterious. Sent: Saturday, February 15, 2025 11:57 AM To:

Maynard, FYI

It seemed to me to begin with that C62, or an equivalent gimmick, ought to couple the signal adequately but that its value might not be very important. But if C62 is very low reactance, the

Hi, Emanuele, There is a gimmick in the S-85 schematic and parts list, C38, that has a capacitance of 2 mmfd (pF). It should, ideally, be a twisted assembly just about 10 percent shorter than is

Hi, Richard, Yes, that's exactly as it is in the S-40B, in the schematic and in the receiver. It's C62, a 2.2 pF cap (2.2 mmf in the S-40B parts list). But the S-85 lacks that cap, in the S-85

Very interesting Maynard. I am not sure I am seeing this straight but it appears that there is an RC load on the RF tube coupled via the 2.2 uF cap to the tuned circuit of the mixer grid. Should