开云体育

6SC7, sorry. Thanks for the input, yes more poking is needed. Hopefully later tody. Tom Sent: Sunday, February 16, 2025 12:08 AM To: [email protected] Subject: Re: [HallicraftersRadios]

The B+ goes to the plate of the first audio through R-37, when the Bass switch is in the IN position (as shown on the schematic) the choke is bypassed, the B+ to the plate through R-37, when the

Richard, we agree about the switch position labels on the schematic being reversed. Sent: Sunday, February 16, 2025 5:00 AM To: [email protected] Subject: Re: [HallicraftersRadios] SX-28A

I am curious about that switch. I would interpret IN as meaning the bass was boosted but the switch shows it the other way. Also the frequency response chart shows the bass boosted with switch "IN".

TomWhen R33, the audio gain control, is set for minimum volume, do you still hear the 120 cycle hum regardless of S10, the Bass IN / OUT switch position?? If you still hear hum then the source of the

Do you mean the 6SA7 or 6SC7? The 6SC7 is the dual triode that acts as the first audio and phase splitter. Pulling that leaves the 6V6's active. CH-2, the bass boost resonator, connects from the grid

Hi Jacques, last reply tonight Ok Ill try. I guess I must be getting cranky! I followed this case more or less since Emanuele posted it, so be kind if I misunderstood anything about. I remember that

Bob, Some of us are not bean counters, but want to know now things work and don’t work, and give them some love too. You can go back to Stephah Gray in about 1750 who found out electric fluid moves

Hi Don, I followed this case more or less since Emanuele posted it, so be kind if I misunderstood anything about. I remember that Emanuele complained about a complete loss of sensitivity in the lower

Oops! In my note number 2 I should have said "... except for C62." Thanks for catching that, Don. 73, Maynard W6PAP

Tom, as you are able to measure it, what is the ripple across C48 and across C44 when the bass switch is “IN” ? What is not normal is to have more “hum” when the bass switch is “OUT”

I rebuilt my SX-28a about 10 years ago including pulling the RF deck out etc. I have never experienced a hum with the bass switch in either position. [email protected]> wrote:

It seems that the way to look at this switch is that in one position the plate load is provided by the choke while in the other the load is switched to R37, and as an aside the choke gets shorted ?

I feel that the guy that had the original post many moons ago was correct. Get rid of it. The job of any good bench technician is to be able to recognize a dog and move on, not beat a $40 radio to

Maynard , I’m gonna mess-up your fine writing! .. Sorry. If there is stray coupling transferring signals at the top end of each band, we might expect that it would see lower loss at the higher

Richard, When the bass switch is “in” it boosts the bass. Going by the schematic it shows that it shorts the choke / cap. Audibly it definitely boosts the bass, I need to confirm the wiring of the

I unscrewed CH2 from the chassis and let it float, no change. Sent: Saturday, February 15, 2025 8:07 PM To: [email protected] Subject: Re: [HallicraftersRadios] SX-28A Hum Ok, tried two

Richard, yes it is hard to describe what is actually a drawing on paper. Perhaps you don’t have anything to copy what you see. Here, I am using

Hi, Don, If there is stray coupling transferring signals at the top end of each band, we might expect that it would see lower loss at the higher frequencies, and that is what is happening, it seems.

Ok, tried two different 6V6’s, no change. On the plates of the 6V6’s there is 6.8Vrms of 120hz ripple. If I remove the 6v6’s it drops to 4.7Vrms and the hum is no longer audible (as expected).