[ARC5] SCR-274N side tone level?

[Brian Clarke]

Hello Dave,

I have a MC-385 available if you’re interested.

You didn’t say how you connected the potentiometer. From your description, it sounds like you put the pot in series. A far better placement is as a volume control, that is, in shunt across the audio feed to the intercom line.

73 de Brian, VK2GCE.

 

From: arc5-bounces at mailman.qth.net [mailto:arc5-bounces at mailman.qth.net] On Behalf Of Michael Hanz
Sent: Sunday, 10 February 2019 3:49 AM
To: Dave Kirk; arc5 at mailman.qth.net
Subject: Re: [ARC5] SCR-274N side tone level?

 

Table 8 in the manual says the sidetone voltage on CW is 7-9 volts into 4,000 ohms.  Are you using low impedance earphones?  If you are, you might try an MC-385* headset adapter to lower the volume.   Or, you might check to see if you have a low impedance tap on the sidetone transformer, T-50, in your modulator.  Here's the note on the tap:



Or, you could just put an appropriate resistor in series with the jack to your headphones...:-)

 - Mike  KC4TOS

On 2/9/2019 10:52 AM, Dave Kirk via ARC5 wrote:

I run a stock SCR-274N setup with a BC-456 modulator not sure if this is normal, but the side tone in CW, and phone is ear piercing I can't even wear my headphones its so loud. Is there a simple way to lower the level? So far I haven't seen in the manual any mention of level adjustment. Guess I understand why its loud the radio dude needed to be able to hear the radio during flight, but dang this is ridiculous.

 

Dave

 

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