Advent receiver

thetube0a3 · 2nd February 2010, 08:45 PM

Hey guys,

I have an Advent receiver I replaced the output transistors on a few years back. The power amp is quiet and works fine. But.

The preamp has always had a high level of hiss since I received the unit a few years ago. Is there a common cause of this in these preamps? I know its the preamp because I can disconnect it from the power amp via the RCA jacks on the back and drive another power amp with it. The noise I am talking about is from AUX input not just the phono stage.

I'd like to use the preamp in it with a chipamp im building but the noise will drive me crazy.

Also, the tuner has terrible sensitivity, any common problems on this as well?

woody · 2nd February 2010, 09:12 PM

I bought one of those new way back when. I found that most of that hiss came from
the poor quality power supply caps. If I were solving this problem today I would either replace the power supply caps with better ones or bypass them with a pair
of 470uf low esr caps. What I did do back in 1979? was bypass the power supply caps with a pair of 47uf tantalums in parallel with a pair of 15uf tantalums this cut
the hiss about 8db.

thetube0a3 · 2nd February 2010, 10:49 PM

Really?!?
Power supply filters can actually cause high frequency noise? Interesting.

If its that simple i'll just swap them out with new ones + bypass them with some .01's.

CBS240 · 12:26 AM

Well, when you think of all the components of a large electrolytic, you have the capacitance, a resistance, and the fact that the foil 'plates' are rolled up into a coil produces inductance. This is why they are generally bi-passed with small metal film caps.

Also they absorb moisture and decompose over time and do need to be replaced periodically.

Ed LaFontaine · 3rd February 2010, 01:24 AM

Keep talkin' guys.

I have the 12V model I bought new. It accumulated mileage in a 1971 Ford Maverick....playing through Polk Audio mini-monitors.

Jeez, I'm feelin' old. Gotta go sulk...

planet10 · 3rd February 2010, 01:57 AM

Ed,

That is a rare & valuable one. Between Chris & i we have 3 of the AC model (2 in need of attention). Sold a ton of them too (until the apperance of the NAD 3020/7020)/ I love the Scott-style tuning vernier.

dave

thetube0a3 · 3rd February 2010, 02:04 AM

I wish I knew what was wrong with the tuner. The only thing I am aware of being physically wrong is one of the ferrites is cracked in one of the coils. Perhaps way out of tune, but its broken up and its not moving. If anyone has spare parts, I could use em.
The tuner works, its just very weak. And I seem to remember excess noise when receiving a stereo signal, even a strong one, Perhaps all related to less then perfect filter cans?

I doubt thats causing the sensitivty issue tho. The coil with the cracked core is the one right infront of the tuner on the right side of the tuning cap.

gain-wire · 02:53 AM

Hi people. I started to get intrigued by this post when I didn't see the model number... And when I heard "dc version". Is this the kind receiver you are talking about?
http://cgi.ebay.com/Vintage-ADVENT-M...item3efc8f1d1c

planet10 · 3rd February 2010, 04:10 AM

Yes. Advent 300.

dave

planet10 · 3rd February 2010, 04:19 AM

Here is a better pic than that in the eBay advert

dave

2nd February 2010, 08:45 PM	#1
thetube0a3 diyAudio Member Join Date: May 2008	Advent receiver Hey guys, I have an Advent receiver I replaced the output transistors on a few years back. The power amp is quiet and works fine. But. The preamp has always had a high level of hiss since I received the unit a few years ago. Is there a common cause of this in these preamps? I know its the preamp because I can disconnect it from the power amp via the RCA jacks on the back and drive another power amp with it. The noise I am talking about is from AUX input not just the phono stage. I'd like to use the preamp in it with a chipamp im building but the noise will drive me crazy. Also, the tuner has terrible sensitivity, any common problems on this as well?

3rd February 2010, 12:24 AM	#4
CBS240 diyAudio Member Join Date: Aug 2005 Location: K-town	Well, when you think of all the components of a large electrolytic, you have the capacitance, a resistance, and the fact that the foil 'plates' are rolled up into a coil produces inductance. This is why they are generally bi-passed with small metal film caps. Also they absorb moisture and decompose over time and do need to be replaced periodically. __________________ All the trouble I've ever been in started out as fun...... Last edited by CBS240; 3rd February 2010 at 12:26 AM.

3rd February 2010, 01:24 AM	#5
Ed LaFontaine ...truth seeker... diyAudio Member Join Date: Feb 2004 Location: where the Appalachians rise from the Blue Grass	Keep talkin' guys. I have the 12V model I bought new. It accumulated mileage in a 1971 Ford Maverick....playing through Polk Audio mini-monitors. Jeez, I'm feelin' old. Gotta go sulk... __________________ ...call me Ed...Special Ed... EnABL kit http://www.diyaudio.com/forums/swap-meet/119852-enabl-kit.html DCB1 parts http://www.diyaudio.com/forums/swap-...ml#post2361098

3rd February 2010, 01:57 AM	#6
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	Ed, That is a rare & valuable one. Between Chris & i we have 3 of the AC model (2 in need of attention). Sold a ton of them too (until the apperance of the NAD 3020/7020)/ I love the Scott-style tuning vernier. dave __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

3rd February 2010, 02:52 AM	#8
gain-wire diyAudio Member Join Date: Nov 2004 Location: NCR	Hi people. I started to get intrigued by this post when I didn't see the model number... And when I heard "dc version". Is this the kind receiver you are talking about? http://cgi.ebay.com/Vintage-ADVENT-M...item3efc8f1d1c __________________ Trans-directional-servo-logamp non-zerocrossing autogain compressing thingamajig Last edited by gain-wire; 3rd February 2010 at 02:53 AM. Reason: corrected hyperlink


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2nd February 2010, 09:12 PM	#2
woody diyAudio Member Join Date: Jan 2002 Location: Tyrone Ga. U.S.A.	I bought one of those new way back when. I found that most of that hiss came from the poor quality power supply caps. If I were solving this problem today I would either replace the power supply caps with better ones or bypass them with a pair of 470uf low esr caps. What I did do back in 1979? was bypass the power supply caps with a pair of 47uf tantalums in parallel with a pair of 15uf tantalums this cut the hiss about 8db.

2nd February 2010, 10:49 PM	#3
thetube0a3 diyAudio Member Join Date: May 2008	Really?!? Power supply filters can actually cause high frequency noise? Interesting. If its that simple i'll just swap them out with new ones + bypass them with some .01's.

3rd February 2010, 02:04 AM	#7
thetube0a3 diyAudio Member Join Date: May 2008	I wish I knew what was wrong with the tuner. The only thing I am aware of being physically wrong is one of the ferrites is cracked in one of the coils. Perhaps way out of tune, but its broken up and its not moving. If anyone has spare parts, I could use em. The tuner works, its just very weak. And I seem to remember excess noise when receiving a stereo signal, even a strong one, Perhaps all related to less then perfect filter cans? I doubt thats causing the sensitivty issue tho. The coil with the cracked core is the one right infront of the tuner on the right side of the tuning cap.

3rd February 2010, 04:10 AM	#9
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	Yes. Advent 300. dave __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

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