How to check a used amplifier?

[Jfs]

I am looking for a used integrated amplifier. What things should I look for when checking out the amp: sound or the physical hardware? any tests, I could get a voltmeter or some other device if not expensive to help.

Joe

 

[PENG]

You can go by hearing (change the volume level and hear for sound quality, audible distortions, noise, transformer hum etc.) to a point, and definitely try to find ways to confirm that it has not been tempered with, such as looking for signs that the enclosure has not been opened. Also, try out every functions including all inputs/outputs etc. When doing your listening test, it may be a good idea to compare it with something that you know you can trust, such as another high quality amp that you know is in perfect condition.

Other than that you can use a good spl meter and use some test tones to check for channel output balance. It is always a good idea to take some measurements with a multi-meter (at least use the voltage range) but that's only if you know what you are doing and preferably are qualified (by virtual of knowledge and experience) to do it.

 

[highfigh]

Connect it to speakers and a source, then listen to something. Use all of the controls and switches- if it works, great, and if the controls or switches are scratchy, make a deal with the seller and if you buy it, clean them. The seller should let you listen for a while, I wouldn't be comfortable with less than an hour or setting up a return period, in the event that it might have an intermittent problem.

If you show up with a bunch of test equipment, it's likely that the seller will tell you to go away.

 

[Jfs]

I am also wondering how an amp that can deliver more current into lower impedances like 4 ohm or dips in speakers operates different than one that can't.

What king of sensitivity for speakers would be good for a 50 or 100 watt amp?
I am looking at a listening area of about 10' distance to speakers. The room is also open behind me. Will be looking for speakers where sound will be more contained for an apartment. I'm assuming this will involve less bass. Trying to find a comprimise of having good sound and not having neighbours complain.

 

[killdozzer]

What king of sensitivity for speakers would be good for a 50 or 100 watt amp?

This is slightly the wrong way around. It's better to start with speakers that are fit to do the job in your listening room and then the amp that is fit to drive them.

I also don't think you should look for speakers with less bass as you can always lower the bass, but if you buy something that proves lacking, you could regret it and perhaps have a difficult time returning if they're second hand.

For some good speakers recomm, you should state your aprox. budget, listening habits (movies / music - which style of music), size of your room...

Solely by the spec. of 50 - 100 watt amp... no can do. Also, amps are usually rated according to the load they'll be handling, so 50 - 100 watt into how many Ohms? But you'll still need to know how power hungry or not will your speakers be. Even the more sensitive speakers might have impedance dipps that ask for a stronger amp.

 

[Johnny2Bad]

I am also wondering how an amp that can deliver more current into lower impedances like 4 ohm or dips in speakers operates different than one that can't.

What king of sensitivity for speakers would be good for a 50 or 100 watt amp?
I am looking at a listening area of about 10' distance to speakers. The room is also open behind me. Will be looking for speakers where sound will be more contained for an apartment. I'm assuming this will involve less bass. Trying to find a comprimise of having good sound and not having neighbours complain.

The difference in low-impedance power delivery, or transient power delivery, is in the power supply.
Amplifiers are voltage amplifiers but to deliver power into low loads or to have reserve power for transients requires current delivery. That comes from the power supply, not the power transistors.

Power Supplies are expensive ... either the supply or the enclosure (which often includes the heat sink) will represent the most expensive part of an audio device, and their weights add to the shipping cost, almost like a tax on the parts cost.

Cutting costs on either or both is very much an area that amplifier designers will focuses on. So it's not unreasonable to expect differences there.

I would just load up some 16/44.1 music files on my smartphone or iPod/music player and bring along a cable with the appropriate interface for the phone/etc and dual RCAs. You might want to bring a second cable with a 3.5mm phone plug as well; one or the other will plug into the gear you are interested in.

Then just play some tunes and see what you think. The advice to work your way through the controls is good advice as well. If the unit has been sitting for a while you may notice some noises when you use the controls. Often these are not serious, but they give you tools to use to bargain down the price, as the seller will be present and hear them as well.

 

[M Code]

I am looking for a used integrated amplifier. What things should I look for when checking out the amp: sound or the physical hardware? any tests, I could get a voltmeter or some other device if not expensive to help.
Joe

Before putting down the $ U better check a few things out. An electrical checkout for feature functions and output is required...
However before going too far, I would ask How old is the amplifier? Even though early integrated amplifiers can be good deal, if older than 10 years U better have confirmation about the power supply's electrolytic filter capacitors.. These capacitors dry out over the years and can short out easily, usually they emit a low frequency hum when starting to deteriorate...

Just my $0.02..

 

[Jfs]

I also don't think you should look for speakers with less bass as you can always lower the bass, but if you buy something that proves lacking, you could regret it and perhaps have a difficult time returning if they're second hand.

By turning down the bass would this be just ajusting the tone control on the amp?

For some good speakers recomm, you should state your aprox. budget, listening habits (movies / music - which style of music), size of your room...

Thinking of speakers hopefully within $1000.
I am looking for speakers for a stereo amp.
I listen to rock, folk: led zeppelin, john Fogerty, Bruce Springsteen, Neil Young. Like electrical as well as acoustic music. I also am getting into classical & Jazz. For movies I like westerns, drama, some action. I am living in a basement suite: living area is 14'x15' and goes into a kitchen and dining area about 7' wide and 17' long. Listening area about 9' away from speakers.

Solely by the spec. of 50 - 100 watt amp... no can do. Also, amps are usually rated according to the load they'll be handling, so 50 - 100 watt into how many Ohms? But you'll still need to know how power hungry or not will your speakers be. Even the more sensitive speakers might have impedance dipps that ask for a stronger amp.

Plan on buying 8 ohm speakers, but I realize that speaker impedance can fluctuate over frequencies. I'm tryng to get an idea of what I will need for speakers and how much power of an amp that will be needed. If I buy speakers first I don't want to get something that will need a huge amplifier, that is why I thought I would get an amplifier first. I know even less about speakers so will have to do some research about designs and what I want. I assume that takiing into account impedance it would be better to get an amp that could put out more current than higher wattage. What is good performance that I can expect for current into lower impedance from budget hi fi?

 

[Jfs]

I would just load up some 16/44.1 music files on my smartphone or iPod/music player and bring along a cable with the appropriate interface for the phone/etc and dual RCAs. You might want to bring a second cable with a 3.5mm phone plug as well; one or the other will plug into the gear you are interested in.

For portable I have a sansa cllip+
Also have an adapter: 3.5mm (can plug this into player) with dual rca phone plugs. Would this be adequate?
Have a 3.5mm to 3.5mm plug

 

[Jfs]

Before putting down the $ U better check a few things out. An electrical checkout for feature functions and output is required...
However before going too far, I would ask How old is the amplifier? Even though early integrated amplifiers can be good deal, if older than 10 years U better have confirmation about the power supply's electrolytic filter capacitors.. These capacitors dry out over the years and can short out easily, usually they emit a low frequency hum when starting to deteriorate...

Just my $0.02..

What would be good for electrical check?
For the capacitors how should this be tested?

 

[M Code]

What would be good for electrical check?
For the capacitors how should this be tested?

An electrical check would be to hook up teh amplifier and check all of its inputs and controls. Regarding the power supply capacitors, again age is crucial.. If the amplifier is >10 years old, and if used in a high humidity location this tends to accelerate their detoriation.

To know precisely, the amplifier needs to be bench tested for certain internal power supply voltages, but if not available just an audible listening test will give U some indication. Listen for any hum levels.. Note that the power supply capacitors are the 1 component that can go bad with age... Replacements are generally available, but service bench labor to replace can be expensive.

In the end, it really depends on the selling price, some times these are found @ low prices and other times the seller thinks the amplifier is gold making it overpriced. Note that I have several valuable, vintage amplifiers and still prefer their sonic performance over some of the later audio components. I have (3) different systems, 1 being a dedicated vintage stereo audio system I use just to play vinyl but I do have a high-end CD player connected and often compare between vinyl and CD. The market value of the vintage components in this system is just under $10,000. But being in the audio business for >35 years, developing, sourcing, and marketing products for some of the leading audio brands has provided me with great access to these products.

Just my $0.02..

 

[Bucknekked]

What would be good for electrical check?
For the capacitors how should this be tested?

jfs

looking at this thread from top to bottom, a couple of things stand out. Looking at a used integrated amp is an OK idea if you know something about what you're evaluating. Saying things like "you can get a meter" if you need to just doesn't go well with "what would be a good electrical check and how do you check capacitors"?

This shows that you're probably not up to testing an integrated amp yourself from an electrical health point of view. The best thing that could happen is nobody or nothing gets hurt. Most of the rest of the possibilities aren't so good.

If you have your heart set on a used amp, find a local shop that can test it for you and give you either a bill of health or an estimate to rebuild those components that need it. If you can't see the amp or get it for testing ahead of time, you have some serious decisions to make.

Many people think, incorrectly, that an integrated amp will somehow deliver a better musical sound than an AVR. Its just not the case. There are a ton of AVRs out there, new and used, at just about any price point that may serve your needs without repairs or sticking your fingers where they may become unhappy.

You didn't mention a budget or price point. But, even on a budget, there's a lot of used gear that will get the job done without too much financial risk. You have good tastes in music (loved your list of artists) and some good speakers (the SVS). You should be able to get hooked up with some amplification without too much struggle.