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 Post subject: HQ-180C audio is muffled
PostPosted: Mar Tue 06, 2018 10:31 pm 
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Joined: Dec Wed 02, 2009 3:55 pm
Posts: 38
I recently acquired a HQ-180 and it's working pretty good.
However when the selectivity switch is in the 3 Kc position the sound is muffled on AM.
When I put it in the 2 Kc position it's much clearer but the sensitivity drops off.
In the 1Kc position the audio is gone. The slot frequency is on zero and works as it should.
I'm using both side bands.
I wonder if this is normal?

Al
K2DYH


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 Post subject: Re: HQ-180C audio is muffled
PostPosted: Mar Tue 06, 2018 10:53 pm 
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Joined: May Tue 16, 2017 3:03 pm
Posts: 152
Location: Potomac, MD 20854
Slot should not be on ZERO (straight up), it should be at -5 or +5 (9 o'clock or 3 o'clock). Also, might just need an alignment, 2 kc should not be "clearer" than 3 kc. Also, this set has an "auto-response" circuit. It tends to muffle audio. Make sure RF gain is not max and play with RF gain or AF gain; might help.

I removed the auto-response on my HQ-180A; it helps but still audio is not great. It is a COMMUNICATIONS receiver, not a stereo receiver.

paul


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 Post subject: Re: HQ-180C audio is muffled
PostPosted: Mar Tue 06, 2018 10:57 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 7445
Location: Minneapolis, MN USA
The HQ 170 and 180 are notorious for poor sounding audio. The IF passband is narrow and the audio amp uses a form of negative feedback that doesn't work as good as it should. 1kc is too narrow for trying to receive AM broadcasts.

Here is an easy mod to change the audio quality.

http://www.amwindow.org/tech/htm/hqaudiomods.htm


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 Post subject: Re: HQ-180C audio is muffled
PostPosted: Mar Tue 06, 2018 11:12 pm 
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Joined: Dec Wed 02, 2009 3:55 pm
Posts: 38
Paul is right, the slot freq is on +5Kc.
What I meant to say is that the vernier tuning is at zero.
Thank you for the correction.

Al


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 Post subject: Re: HQ-180C audio is muffled
PostPosted: Mar Tue 06, 2018 11:29 pm 
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Joined: Jun Sun 19, 2011 2:31 pm
Posts: 5866
From what you describe the 60 Khz. IF alignment is off, the audio bandpass should be better in the 3 Khz. position than the 2 Khz. position. A proper alignment will be the only way to get this receiver working as it should.

The audio won't be HiFi but it shouldn't be horribly muffled with a properly operating HQ-180 receiver.

Neutering the auto response circuitry will help a little but it really doesn't have a huge impact, especially when stations are strong enough not to require that the AF gain is highly advanced.

Rodger WQ9E


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 Post subject: Re: HQ-180C audio is muffled
PostPosted: Mar Wed 07, 2018 1:19 am 
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Joined: May Tue 16, 2017 3:03 pm
Posts: 152
Location: Potomac, MD 20854
rsingl wrote:
Neutering the auto response circuitry will help a little but it really doesn't have a huge impact, especially when stations are strong enough not to require that the AF gain is highly advanced.

Rodger WQ9E


I did the audio mod, and I wish I hadn't. As Rodger said, it did not make much of a difference. I could move it BACK, but why. I saved the parts (I think). But MY HQ-140X has much better sounding audio on AM, but the 180 is such a better receiver I just deal with it.

paul


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 Post subject: Re: HQ-180C audio is muffled
PostPosted: Mar Wed 07, 2018 2:46 am 
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Joined: Oct Fri 09, 2009 9:25 pm
Posts: 281
Location: Cleveland, Ohio
Yes, the HQ-140 will have better audio response....but the 170 and '180 do not sound nearly as bad as you describe, even with the S-100 or S-200 speaker.

I agree with Rodger, your IF chain needs to be aligned. You are probably just a minor tweak or two away from improving (proper can alignment or a little staggering if you want) the radio's performance to where it is as enjoyable as it should be. I move 10-15 different receivers in and out of service regularly but always seem to have the HQ-170 in use. It is very reliable and has quite a 'hot' front end. Good sideband and cw performance albeit not the best sounding AM, these were very good receivers in their respective price classes....

Todd
ka8gef

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 Post subject: Re: HQ-180C audio is muffled
PostPosted: Mar Wed 07, 2018 3:19 am 
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My nicest Hammarlund setup is a HQ-160 with the external HC-10 SSB adapter. The HQ-160 sounds very nice and is basically a HQ-180 without the final IF. When conditions are good I listen directly to the HQ-160 and when conditions are tough the external HC-10 gives it the same selectivity (and product detector) as a HQ-170/180.

Higher performance vintage receivers are more reliant upon proper final IF alignment than lower performance versions and the HQ-180 (and its HQ-170 ham band brother) have very selective final IF sections which work quite well when properly aligned but can range from horribly to useless when out of alignment.

Your HQ-180C is definitely worth spending the time to get it right. I finished up a HQ-180AX over Christmas and have spent quite a bit of time listening to it. It doesn't have the nice audio of my SX-88 in its wide bandwidth but the audio from the Hammarlund isn't horribly muffled or unpleasant.

Rodger WQ9E


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 Post subject: Re: HQ-180C audio is muffled
PostPosted: Mar Wed 07, 2018 4:21 am 
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Joined: Oct Sun 15, 2006 12:57 pm
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Location: Liberty, Missouri
As the others have said, the Hammarlunds are good receivers, but a thorough, and careful, alignment is a must.

My first Hammarlund was a 180A many years ago, and I was really impressed with it's performance when I finished the alignment.

I have since acquired several different models, and think my next is going to be an HQ-110.

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 Post subject: Re: HQ-180C audio is muffled
PostPosted: Mar Wed 07, 2018 5:12 am 
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IT'S HAMMAR TIME


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 Post subject: Re: HQ-180C audio is muffled
PostPosted: Mar Wed 07, 2018 12:36 pm 
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Nice table full of Hammarlunds Norm :)

The HQ-180AX was the last project of 2017, I plan to get to the thankless task of installing new dial cords for the PRO-310 before the end of this year :) It is next up on the bench.

Rodger WQ9E


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 Post subject: Re: HQ-180C audio is muffled
PostPosted: Mar Wed 07, 2018 1:10 pm 
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Location: Liberty, Missouri
Norm;

Nice Family pic Norm, but, no 600?

Rodger;
Nice 310 example, where did you find the manual for it?

The last few offerings from Hammarlund were certainly interesting and significant styling changes for the company, and the SS 215 certainly turned the page electrically, but they were all too little, to late I guess.

Though it doesn't look like it was much of a performer electrically, I really liked the looks of the HQ-200.

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 Post subject: Re: HQ-180C audio is muffled
PostPosted: Mar Wed 07, 2018 1:49 pm 
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Mike,

I got a copy of the manual that was scanned and put on the Hammarlund website. I don't know if the site made it back to full health yet but let me know if you need a PDF of the manual. I also have a PDF of the Hammarlund sales brochure and some notes that Grant Youngman created about the receiver.

The PRO-310 is an oddball design with its "differential tuner" band spread system. It uses a 52 rather than 60 khz. IF and is single conversion on the lower two ranges (below 2.2 Mhz.). The receiver doesn't have a product detector and for SSB the manual suggests tuning in AM mode for maximum strength and then switching on the BFO and adjusting for proper SSB demodulation. Selectivity options are .5, 2, and 4 Khz. so for those who think the HQ-170/180 are too tight for good AM you will feel the same about the PRO-310. It doesn't have the upper/lower/both IF bandpass shifting gymnastics introduced with the HQ-170 IF and with the narrow bandwidth AM is best received tuned to select only the carrier plus one sideband.

The mechanical band spread system via the differential tuner works well but it was a difficult approach to solving a simple problem. Like the HQ-215 it wasn't quite ready for prime time but it is an interesting receiver.

Rodger WQ9E


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