cyclotoine

I am realizing how long it has been since I started a new thread and here I am starting on completely off topic. I know there are some audio gurus on this forum.

I like music and I like cool audio equipment. My set-up is a modest thriftstore purchased Technics mid level consumer reciever from 1976 that is good enough for my old pioneer turntable which I replaced the cartridge and belt on and works swimmingly.. full manual too... no auto return or any of that jazz...

Anyway, I have the issue of one speaker always cutting out or fading and I get all the fuzz when I twiddle the volume or whathaveyou to try and get it back. I know you can take these in for service but being a mechanic of course I want to do it myself.

SO any advice, tips or links would be great. I just starting googling and am having no luck, I have been thinking about how I need to do this for a long time but am just getting around to it now. not having any work these days an all...

Sorry if this OT bothers anyone.

Doohickie

Sounds like a bad crossover. But I'm a mechanical guy, not an electronics geek, so don't quote me on that. I kind of like the idea of finding an old receiver at a thrift store. My uncle had a 1970s-vintage Pioneer receiver that used to blow me away. I wonder how much I could find one for?

This whole C&V lifestyle is starting to scare me....

RobbieTunes

The fuzz/static when changing the volume is a dirty or corroded volume control rheostat.
Turn the receiver off. Grab the volume knob and gently pull it toward you and turn it a bunch of times from full down to full up. Now, push in gently on it and turn it a bunch of times from full down to full up. This will help to scrape/clean off the contacts. Or, you can take cover off the receiver and locate the volume rheostat just behind the front panel, and spray "tuner wash" in there, while turning the volume up/down. It evaporates quickly, available at Radio Shack.

As for the speaker fading in/out, you need to make sure it's the speaker and not the receiver. Do this by switching speakers and see if the same speaker acts up, or the same channel. If it's the channel, first thing to check is the speaker connections on the back of the receiver, then go inside, as that age of receiver may have some wires inside there from the circuit board. If there's nothing wrong that you can see, it's in the channel, and a shop can track it to a single component.

If it's in the speaker, it could be the crossover, yes, or it could just be old and dried wiring inside the speaker. You'd have to go inside the speaker to find it. You can still test it by tapping on the speaker, or rocking it back and forth while it's playing to try and make the problem happen. If you can, it's physical, and easily fixed. If not, it's electronic, and the only electronics in the speaker is likely the crossover, and they are easily replaced.

70's vintage stuff is readily available, cheap, on eBay. Shipping is the main drawback. I could not afford the gear I wanted in the 70's or 80's, though I had some nice stuff from a tour in Japan/Korea. I did pick up a LOT of stuff about 3 years ago, and if you really want killer sound, look at some amp/control amp combos, or integrated amps, from the 80's. The 70's big receivers are still out there, with lots of bells and whistles. I had a Pioneer SX-780 and it was as smooth as any I've ever had. I dig the weighted volume knobs, the smooth rotary/analog tuning, etc.

Now I have a nice reel-reel, a couple cassette decks, a 6-cassette changer, an 8-track recording deck, and a turntable, amps, etc. I still don't own a home CD player.

My wife is glad I switched to bikes.

cb400bill

I started selling hifi gear in back 1978. We offered electronics from Technics, Pioneer, Sansui, Akai and Marantz. We had speakers from JBL, Altec-Lansing, Pioneer, Marantz, and Sansui.

I sold many Pioneer SX-780 receivers. That whole '80 series was nice sounding. Especially the 275 wpc SX-1980.

My Marantz 2265B receiver and Akai GX-M50 cassette deck are long gone but I still use my Pioneer PL-S70 turntable and just recently sold my JBL L166 speakers to a JBL collector.

And yes, it sounds like you have corrosion on your VC. Very common issue.

dannyg1 

Could be output transistors heating up and fading to over-hot. Does it happen quickly, at different time intervals or always after you've been running the amp at a good volume for over a half hour? Are you plugging a CD player into phono in's? Kicking the bass?

BTW: A true CV'er runs tubes and collects vinyl.

cb400bill

Nah.

A current day CV'er runs 70's vintage solid state gear.

Tube gear belongs on CR.

John E

The first step in diagnosing your problem is to connect your left speaker to your right amplifier output, and vice-versa. If the problem stays in the same speaker, I suspect a rubbing or intermittent voice coil or a worn-out suspension (the rubber ring which connects the paper cone to the frame). If the problem is now in the other speaker, then try cleaning not only your volume and balance controls, but also tape monitor and source selector switches. This is what I have to do periodically to repair my bedroom system's ca. 1980 Technics receiver.

There is nothing wrong with vintage audio gear. My main system comprises a 15-year-old 4-box Cambridge Soundworks Ensemble speaker system, a powered Cambridge Soundworks subwoofer, an early 1980s Sony integrated amplifier complete with a convective heat pipe cooling system, an early all-digital DUAL AM/FM tuner from Germany, and, until recently, a first-generation Sony CD player which I finally had to replace with a newer unit.

mishmashmusic

Caig DeOxit contact cleaner in the volume pot might do the trick.

mishmashmusic

Oh, and by the way, here's my current vintage setup:

Marantz 2238B receiver
Philips 312 turntable w/Shure mx97e cart
EPI 100 speakers (refoamed the woofers a few years ago)

I have both a Scott & a Pilot tube amp, both need to be refurbished
I also have a pile of turntables and speakers in reserve

cb400bill

2238b is a very nice receiver. I wish I had still had my 2265B.

My system is pretty much current era gear:

Pioneer Elite A35R integrated amp
Pioneer DVD DV-525 cd/dvd player
Sangean HDT-1 HD Radio tuner
B&W DM603 Series 3 speakers
Pioneer PL-S70 w/ AT LS500 cartidge

markk900

+1 on the contacts.....

My current setup: NAD 3020A with Genesys I speakers (speakers had the bass surrounds replaced after 25 years of use). Both purchased new....Went modern with sound source - only a CD/DVD and computer input now.....Dual Turntable currently on the shelf and vinyl stored away

Have a mid-30's Rogers Tube radio as well - working but in need of a new tube....

Grand Bois

I have the same speaker system. All of the foam surrounds in the satellite speakers have disintegrated and the black paint on the outside of the boxes has turned into a gummy substance that comes of on my hands and has left black marks on the walls. I contacted Cambridge Soundworks and they insisted that the speakers had been subjected to excessive heat. I live by the bay and it rarely gets hot here. I ended up replacing all four satellites with used Bose double cubes from eBay. They sound great with the CS subwoofer.

I have an old Marantz 2285 that has noisy controls and a channel that cuts out. It's caused by corroded contacts. TV tuner spray helps a little for a short time, but it does not solve the problem. It's unusable, but I don't have the heart to get rid of it.

cb400bill

https://www.audiocraftsman.com/

Grand Bois

Thank you for that!

cyclotoine

Thanks everyone!

I'm going to get some contact cleaner And try blowing out the volume and balance knobs.. I guess I used improper terminology because the sound doesn't fade and I rarely turn it up to half, there is lots of airspace around the amp so I don't think it is overheating. It just sort of cuts out and one speaker goes really quiet or I can't even hear it. Often wiggling the volume knob can bring it back momentarily so I've always had a feeling the problem lied there. I'll try swapping channels to make sure it's nto the speakers etc..

jtarver

Build it up as a musical fixie, just don't cut off the braze ons...

balindamood

Val Alstine modified Hafler DH-220 Amp
Yamaha C-1 Pre-amp
Kennwood KT-30 Tuner
Denon DVD-3910

All from trift stores going through Martin-Logan electrostats and a B&W 610 subwoofer all on clearence.

I also have an old Kennwood KR-7600 in the shop.

Rabid Koala

I used to have one of these, bought for $10 at a garage sale in 1973. I replaced several capacitors in it, they were causing the tubes to glow way beyond what was normal. I had a relative that could read (and understand) the schematic, I did the repair. I used that old thing for a number of years before junking it.

Having tubes, it was great to set your feet on top of the unit while it was on. I never had a decent set of speakers for it, but did have a nice set of Koss Pro 4AA headphones.

zacster

I've had my Dynaco ST-70 (highly modded) on all day listening to classic rock. I started the day listening to classical piano on my turntable.

raverson

I picked up this Fisher Studio Standard RS2010 reciever along with the deck and a Dual manual turntable for $15 at auction. It does the job well out in the shop. The Akai, Teac and Technics stuff all stay in the house proper.

And no, that's not my SS# engraved in the front panels.

bcoppola

More digression from the OP, but: Speaking of vintage Pioneer audio gear, check this out:

https://www.silverpioneer.netfirms.com/

I bet there's a similar site devoted to Marantz out there. Used to drool over those beautiful silver fronted Marantz tuners with that cool horizontal tuning wheel.

Up till a few years ago my system was Dynaco I got new in the 70s: Stereo 120 power amp, PAT 4 preamp, and FM 5 tuner. Amp died, eBay'd the tuner & pre. I built the tuner from the kit.

Still have my Thorens TD-160 from then. But I am not an audio C&Ver in general. Have done some DIY though:

https://www.bruce.coppola.name/audio/orionspeak.html

https://www.bruce.coppola.name/audio/amplifiers.html

https://www.bruce.coppola.name/audio/room.html

late

You can also check out...

www.audioasylum.com

Grand Bois

I've got an Elac Miracord 770H record changer built into a teak cabinet in the attic. I probably haven't used it in 20 years.

My Marantz receiver has the cool horizontal tuning wheel, but the face is gold anodized.

I left the Sansui speakers with the 15" woofers hanging on the shop wall when I sold the house. I just didn't want to move them again.

cb400bill

Nice. Great amp for the money.

His name was Henry Kloss.

He founded or co-founded more hifi companies probably than anyone else. Great idea guy. Many many audio products sprang from his mind.

https://en.wikipedia.org/wiki/Henry_Kloss

PhotonDon

Well, NOW you've got me goin'.

Sansui G9000DB monster receiver
Pioneer SG-9500 EQ
Technics sl-1350 'table
JBL L-100 Century


Hey, be careful with the contact cleaner you use. Some types are not friendly to plastics found in many receivers. Caig De-Oxit is the vintage audiofool's friend.

When in doubt, crank it up!!

Don