Man cave amp?

Ok well here is the update. I have plugged my phone into the aux at the back of the amp and wired the speaker up to the amp, but on turning things on I find I am only getting sound out of one speaker. So I swapped the speaker leads over and the other speaker works, so then I tried swapping the speakers cables to the remote speaker and still the same sound only from one side. Does anyone have any idea's or is the amp goosed?
 
First off, do the simple stuff first. Make sure the balance control on the amp is set to the mid point. Have a look at any phone settings for balance and bass and treble to see it's not an issue there. Check that the jack plug is seated correctly in the phone socket. Sometimes you can find that the jack socket is slightly recessed which suits some jack plugs but not all.

Next, swap the red and white RCA plugs going to the back of the amp in to the AUX socket. If there's still only sound from one speaker channel then the jack plug and RCA connections is fine. However, if you find that the problem swaps to the other channel, then it could be that you have a duff AUX in. This can be checked by using the Tuner or one of the Tape Playback sets of sockets. The signal is fine going to these sockets; just don't try the Phono socket connection because the signal from your mobile phone will be far too powerful for it.

Another possibility is that the mobile phone requires a 4-pole jack plug because the headphones connection is designed to support an in-line remote control. Where you might use ordinary headphones on a standard 3-pole jack, and they work fine, then that eliminates this as a possible cause.

To decide whether it's an amp or a speaker problem...
Where you find either speaker works but only from say the Left channel on the amp, then it could be a duff channel in the amp. The Remote speakers connection feeds from the same channels as main. Whatever issue there is on Main will be mirrored on Remote.

If you find that one speaker works in either channel, but the other produces nothing, then it's either a speaker fault or a wiring issue.


Duff amp channels are fixable, but for the work involved and cost compared might not be worth it compared to buying a fully-working used amp. Where you're lucky and it's just a dead capacitor, then the cost for the component will be somewhere in the £10 to £20 each region. To be safe, you're better off recapping both channels, so the cost is x2. A hair dryer putting some heat on a dead or dying cap can sometimes be used to temporarily coax the channel back in to life and verify it's just the cap and nothing more serious. Where luck isn't on your side, then the amp's output transistors could have been taken out too. That's a far more involved repair, and with used stereo amps it's not usually worth fixing unless the amp is something of high value.


If this or any other reply was helpful to you, then please do the decent thing and click the T-H-A-N-K-S button. It appears when you hover the mouse pointer near the Quote Multi-quote buttons. This is the proper way to show your thanks for the time and help someone gave you.
 
Hi Lucid
I did check the balance on the amp but I didn't think about the phone possibly having its own balance, thing to try much appreciated.
 
Ok well I managed to get both speakers working when I next plugged my phone in but then if faded out after 5mins so I unplugged it and inserted it again and it started working again and then it just stopped all of a sudden and then 30 seconds later it started up again and then faded out again! not sure what to do next. Another amp?
 
Yep. Another amp is probably the quickest solution.

Stick your old amp on Ebay as a spares or repair sale. The fact that the sound starts but dies could help someone diagnose possible causes and that would increase your chances of it finding a new home. IMO, that's better than it just going to the tip.

Pick up a replacement amp. Refer back to what I wrote back at the beginning of this thread. You're looking for a good solid amp from a reputable brand, and one that draws a decent amount of wattage from the mains so that it has the balls to run those speakers.

I had a quick look at Ebay's completed listings for Hi-Fi amps. These caught my eye.

Yamaha AX-396 £42

Marantz PM4000

Denon PMA250SE - £46

Yamaha AX-330 £37

Harman Kardon PM365 £30

Cambridge Audio Azur 340A £32

Rotel RA935BX £33

ARCAM Alpha 2 £40

Kenwood KA1030

Sony TA-FE330R £33

The above are all what's referred to as 'full size' or 'full width' Hi-Fi products. That's the size width as your existing amp, and it means there's space inside for a proper transformer, some decent sized caps and fairly large heat sinks to dissipate the heat generated. I don't think any of the above require a cooling fan which you'll see on some Technics gear. That's a bit of a red flag to me. It suggests that the amp is under-spec'd and so running harder and getting hotter than passive air cooling can cope with. That's not good for long term reliability.

Gumtree and your local Facebook selling groups are worth keeping an eye on as well. It's probably a bit too far away, but there's an Arcam Alpha 8 for sale on Gumtree in County Durham. The price is a downright dirt cheap £45 for what would have been a very well regarded £700-ish stereo amp back in the early 2000s. It's missing the knob for the audio selector, which I guess is the reason for the low price.


If this or any other reply was helpful to you, then please do the decent thing and click the T-H-A-N-K-S button. It appears when you hover the mouse pointer near the Quote Multi-quote buttons. This is the proper way to show your thanks for the time and help someone gave you.
 
Thanks Lucid

I looked at those amps you listed but they have gone. I am bidding on a technics su.3200 is that suitable do you think?
 
@catlad

Yes, they were all COMPLETED listings. That means the prices were what they sold for. That's a more accurate gauge of actual prices you might expect to pay for the same or similar models when they next come up for auction.

The prices from LIVE listings could still go stratospheric in the closing seconds of the auction. It's pointless then steering you to gear with hours or days to run that might be an attractive price at that point in time, but by the end of the auction the price is double or treble or more. Do you see?

Technics SU3200 - it's being sold as vintage. Unless you have a hankering for something that old or you really want to go retro, then I'd steer clear personally.
 
@catlad

...Continued

I'm sure that the Technics is a perfectly reasonable amp. Being a mid-70s model, it's a little before my time of buying Hi-Fi. I recall hearing a mid-70s Pioneer receiver (amp with a tuner) coupled to a very nice Ariston turntable which looked like the spiritual father of the famous 80s Linn Sondek, and hooked up to some KEF Concord III speakers. To my 14-year-old ears it was all a sonic revelation. I never knew that records could sound so good. Then again, the system cost somewhere in the region of £1500+ back in the day when terraced houses were changing hands for £8000, so that puts it in perspective.

Pretty soon after, I began my own Hi-Fi buying journey. Within a year I had a decent turntable, amp and set of speakers that put a huge smile on my face. Total budget under £600. The system belonging to my mate's dad went a bit deeper, and was a tad sweeter with a little more resolution. But it wasn't three times better. Instead of all the toggle switches and dials, my amp had three controls and an On/Off switch. I had volume, source selection, record-out selection and that's it. No tone controls, no subsonic filters or rumble switch, and not even a balance control. It didn't need them, although balance would have been useful on occasions. Everything about purist Hi-Fi in the 80s was all about getting the best sound from the gear rather than providing a whole bunch of toys to fiddle with to 'fix' something in the sound that really wasn't broken. As it turned out, getting rid of all these extra circuits in the signal path was a greater benefit to the music performance of an amp.

If you want something that will sound lovely, then there's an A&R Cambridge ARCAM Alpha amplifier on a buy-it-now for £69. It doesn't look as flash as the Technics, but in a straight fight it has more real power output, and sonically it would kick the bejesus out of any Technics amp at close to the same money. It also has a terrific headphone stage. You could run some really high-end headphones from the socket. Better still, the seller says that the Alpha has been serviced, and it may even be local to you as it's in Rossendale. This is the sort of amp you could partner with today's £1000+ floorstander speakers and a really good streaming front end and blow your socks off. It would likely be better than anything you or your neighbours have experienced unless they're serious Hi-Fi nuts themselves.

Going beyond the Alpha (that's if you want to spend bigger and fancy remote controlled volume) I have a friend in Hazel Grove with a big Yamaha amp that has just epic power reserves. It has been sat in a box since he upgraded(!) to a pre-amp/power amp combination. I have to say though that the Yamaha is huge. It would be like your old amp twice the height and twice the depth. It's a mammoth beast. I think it weighs around 20 Kilos.
 
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Ok well I missed out on the technics due to being out at the local, drinking beer and doing the quiz!
So I have just purchased via the internet the cambridge alpha you recommended.
 
The Technics. Not one to lose sleep over.

A&R Cambridge Alpha: Good. I think you'll be pleased with that. :)

ETA, let us know how you get on with the amp. Would be interesting to hear your views if you can try it with a high quality source.
 
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Hi Lucid

The Amp's arrived but I am waiting for some 4mm sockets for the speaker cable as that's how they plug in on this amp. I also noticed that it doesn't have an aux. port only
disc. tuner. cd. video. tape Which do you think would be most suitable.
 
Inputs
Any of the inputs except 'disc' will work fine. The CD input is designed to take a higher strength signal from (unsurprisingly) CD players. It will accept up to 0.45 V without overloading. The Tuner, Video and Tape-in connections are designed for the lower signal levels from devices that output a bit less signal. The max level is 0.2 volts. The peak-to-peak figures will be double this (0.9V and 0.4V).

When you connect the headphone socket of your phone to one of the inputs on the amp, the voltage coming from the socket will be determined mostly by the volume setting on the phone, and partially by the how much boost and dynamic compression has been thrown at the audio track when it was mastered. Maxed out, the headphone jack from some Android phones can deliver up to 0.8V peak-to-peak. Apple devices with a headphone jack might go louder still at 1V p-p.

I wouldn't recommend running the phone at full volume. This is because the electronics that drive the headphone output will be chucking in a lot of distortion. A safe maximum for sound quality is around 70%. That will get you a decent compromise between the inherent background noise of any circuit and not crashing in to the headphone amp starting to overload. The audio inputs on the ARCAM are much better quality than those of the headphone output of any phone. If there's any limit on sound quality of streamed music, it will be the source file first followed by the quality of the headphone output.

For safety though, I'd go with the CD input when you're getting everything set up. It has the biggest tolerance to overloading. If you find the sound a bit quiet even with the amp on half volume, then try swapping over to either Tuner or Tape.


Speaker connections
The red and the black terminal covers are screw-down shrouds. It should be possible to unscrew each (lefty-loosey, righty-tighty) to reveal the binding post (looks like a piece of a threaded bolt) with a hole through for threading in some bare wire. Screw down the terminal cap to clamp the wire. Make sure none of the bare wire touches any other speaker terminal connections. Trim if required.
 
Well I've got my speakers connected to the new amp , and now I have my phone plugged into the amp.
Spotyfi is working a treat and my man cave now has a great sound! Thanks Iron man & others for their suggestions.
 
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