low watt amp cause of distortion?

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gbcweber
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low watt amp cause of distortion?

Post by gbcweber » 19 Jul 2019 07:29

I've about had it with trying to get a consistently good sound from my turntable!
I have a Denon DP 11F for which I splurged (at least for me) and bought an Ortofon 2M bronze cartridge last October. This was an attempt an attempt to get rid of inner track distortion which has always bugged me. I do believe I hear an improvement in those tracks with the finer stylus. It was installed by the merchant who also performed adjustments at the time. A second set of adjustments were done because of my dissatisfaction and I was pleased with the sound for a while. This current distortion is across all tracks and seems to be most noticeable with piano. Thinking my old record cleaning fluid was leaving a residue which was being collected by the stylus, I bought new fluid which is not supposed to leave a residue. I also tried washing it clean with water. My brush is a good quality Discwasher from the days when they were made well. I bought new stylus cleaning fluid to be used with a Discwasher microfiber(?) brush. (The last time I took my TT in, I had the merchant check the stylus. He said it was clean and showed no signs of trauma.) I bought an Onzow gel cleaner, but it doesn't fit under my tonearm and cartridge, but I can use it if I really push up on the tonearm and sneak it under. I checked wire connections to the cartridge. I increased the tracking force a little without improvement. (I went up to 2.) I can't think of anything else to try with the TT and attachments themselves.
Now I'm wondering if my Harmon Cardon A-401 amp. with only 20 Watts per channel is just not enough power for the new cartridge. I have no idea if this is a legitimate thought or not. Like I said, there were brief periods where I thought my LPs were sounding pretty good. My speakers are large Advents I purchased new in 1978. I'm quite happy with how my CDs are sounding with this equipment. Any thoughts would be appreciated. I'm willing to upgrade as long as I can get some good performance from this cartridge. Thanks.

Sunwire
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Re: low watt amp cause of distortion?

Post by Sunwire » 19 Jul 2019 08:34

How far are you turning the volume knob?
12:00? 1:00?

Solist
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Re: low watt amp cause of distortion?

Post by Solist » 19 Jul 2019 10:14

The Large advents are supposedly 89.5db sensitivity. That should be enough in a normal size room in Europe, but you Americans have bigger rooms in general. The problem is that they are 4ohm speakers.

Your amp produces 20w into 8 ohms. As far as I know, you should avoid using 4ohm speakers with a 8ohm amp, especially if its low watt. Speakers are constantly trying to get more power than the amp can produce. This will cause the amp to overheat and possibly cause distortion.

Ideally you should have the volume on your amp turned at about 10, maybe 11 o clock to get the desired volume you usually listen to. That way the amp has enough headroom if any spikes in music occur.

The cause of the distortion could also be that the phono input is not of the best quality. Vintage amplifiers rarely have good phono inputs. Try and borrow a separate phono preamp if possible.

The cause of distortion could also be improper anti skate.

cafe latte
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Re: low watt amp cause of distortion?

Post by cafe latte » 19 Jul 2019 11:03

I sold a really nice 25wpc valve amp as I was getting distortion with realistic volumes admittedly in a big room, but speakers were efficient. Nothing beats cubic inches as the car nuts say.
Chris

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Re: low watt amp cause of distortion?

Post by tlscapital » 19 Jul 2019 11:42

Like with many things, once one had it good, the same one will seek the as good and/or better. There's only once a 'first time' and the quest in such exhilarating "feeling" is often desired consciously or not. This is for the psychology subjective explanation side of things.

Now as for the amplification side of things; one explanation might be the distortion 'starting' point. Amplifier manufacturers take for references the first 15 to 20% of the maximum power for reference in performance as there the measurable specifications are less prone to distortions.

Meaning that over that initial "entry" power ratio, distortions in the amplification starts to appear. With the improvement I gained successively through my tweaks, I have learn to appreciate better my playback time with some volume power like I love. But the distortions became more noticeable as well...

So I understood that 'as is', momentary in the office room where my phono gear is set, I am about fine with my amp volume knob set at 50% all the time. Higher/louder than that distortions truly appears and I find the overall presentation rather messy then. As long as I am in that small acoustically challenged office room; it's fine !

But the day I'll move in my dedicated music room/basement that is twice as big and fully dampened, I'll need more power/juice to have an overall satisfactory playback listening time. Although it's only recently that I manage to achieve such sound presentation, I had to look out all over again for a bigger amp and speakers for that future project.

Thus requiring a more powerful amp and speakers. There it is often recommended to find matching speakers in specifications. The sensibility of these for example is to be balanced with the power of the amp. But the amp (and preamp as well mind you) sonic characteristics should also be taken into account in that regard. And there tests and trials only will show.

Higher efficiency speakers (90+ dB) are generally matched with low power amp (+/- 20 W) and vice versa. Your 'large' Advent speakers are 89 dB (of the 'low' efficiency kind) running 8 Ohms and your Harman Kardon A401 amp 20 W ('low' power kind) evenly down to 8 Ohms. Meaning you need to drive your amp 'high' to squeeze out painfully some 'juice' out your speakers...

MostlyHarmless
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Re: low watt amp cause of distortion?

Post by MostlyHarmless » 19 Jul 2019 13:55

Reading the original post, I suspect the issue is not the amp's wattage, since you report that levels are acceptable playing CDs. Review the entire turntable-cable-preamp-amp chain.

Soloist and tlscapital have provided thoughtful advice. I have a few quibbles - the old Large Advents are 8ohm speakers, I've several vintage amps with pretty fair onboard preamps. Certainly yours could be faulty - I've no experience with it. Time to do some methodical investigation. Go slow, change one thing at a time. Patience will identify the source of the issue.

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Re: low watt amp cause of distortion?

Post by Legrace » 19 Jul 2019 14:54

Per mfgr information's for DP-11F:

"The straight, light weight tonearm extracts the maximum performance from high-compliance cartridges."

2M Bronze is far from high compliance. Proper compliance matching is essential for obtaining optimal results.

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Re: low watt amp cause of distortion?

Post by tlscapital » 19 Jul 2019 17:30

Legrace wrote:
19 Jul 2019 14:54
Per mfgr information's for DP-11F:

"The straight, light weight tonearm extracts the maximum performance from high-compliance cartridges."

2M Bronze is far from high compliance. Proper compliance matching is essential for obtaining optimal results.
Yes evidently you are right there. Totally forgot to underline that in my post. Although this would likely only "impair" the cartridge performance and not so much HF distortions I believe. But yes, I also believe that the 2M's benefit much more from medium to entry heavy effective mass tonearm.

And that DP-11F tonearm counterweight system is unlikely able to cope with some extra effective mass on the headshell side if ever he would want to experiment that.

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Re: low watt amp cause of distortion?

Post by musicmn » 19 Jul 2019 18:37

Hi gbcweber, here's my two cents worth, I currently own a pair of The Large Advent speakers with the Masonite ring on the woofers that the foam surround attaches to. I also have owned three other pair of Large Advent speakers that did not have the Masonite ring and they are 8 ohm speakers. My pair say 8 ohm right on the back where the speaker jacks are. The pair I currently have are being driven a Pioneer SX 550 that clipped out @ 28 watts per channel after rebuild. My Advents sound great with this set up and I have no issue driving them at any volume. Nor do I have any distortion from them while playing records or CD's. And your 20 watt per channel H&K amp should also not have any issue with driving them. My guess goes along with the other posters that the 2M bronze cartridge does not work with the tonearm on the Denon turntable you are using. I have read a lot of posts on this site over the years about people having distortion issues from their turntables while playing a record. 9 times out of 10 it's usually and alignment issue but it can also be caused by a mismatched cartridge to tonearm. In a lot of these posts people like yourself have bought a Ortofon 2M cartridge of some type only to have distortion issues with it. If you can add some mass to the head shell of the tonearm but again you may not be able to adjust the counter weight enough to get the correct tracking force. If this turns out to be the case then the only option is to by a different cartridge that better matches that DP11f's tonearm. I hope this helps

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Re: low watt amp cause of distortion?

Post by josephazannieri » 19 Jul 2019 19:12

Yo gbcweber:

Lots of people are making excellent suggestions about your distortion at high volumes complaint. But even so, I have a suggestion to add. My suggestion would be to play another source, such as a CD player, tuner, or a cassette deck through the amp and see if you get the same distortion at the same high volume. If you do, then the amp is either insufficient to drive the speakers to the volume you want, or it needs servicing. You may also have some difficulty in the phono preamp stages, but usually if the phono preamp is bad, it's REALLY bad, like it's dead on one or both channels. Using another source will tell the tale.

And good luck from the old trouble isolator,

Joe Z.

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Re: low watt amp cause of distortion?

Post by Legrace » 19 Jul 2019 21:18

OP already indicated he is happy with CD sound.
I'm quite happy with how my CDs are sounding with this equipment
To be expected, OP has nice equipment. Whereas analog dissatisfaction is a common complaint. It has many causes,in this instance poor component matching seems likely.

lenjack
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Re: low watt amp cause of distortion?

Post by lenjack » 19 Jul 2019 22:16

It's definitely a turntable/cartridge issue. I suspect the stylus is bad, (worn), regardless of what the dealer told you.

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Re: low watt amp cause of distortion?

Post by jdjohn » 19 Jul 2019 23:16

gbcweber wrote:
19 Jul 2019 07:29
I bought new stylus cleaning fluid to be used with a Discwasher microfiber(?) brush. (The last time I took my TT in, I had the merchant check the stylus. He said it was clean and showed no signs of trauma.) I bought an Onzow gel cleaner, but it doesn't fit under my tonearm and cartridge, but I can use it if I really push up on the tonearm and sneak it under.
A microfiber stylus brush? I'm still suspicious of the stylus collecting gunk or lint. I have found that a 40X loupe is very helpful in doing quick checks of stylii.

Also, how's the VTA? Is the tonearm riding parallel to the surface of the record?

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Re: low watt amp cause of distortion?

Post by KentT » 20 Jul 2019 23:09

45 watts/channel to 150 watts/channel for the Advents are best. They like power, being acoustic suspension. They're 8 ohm and a reasonably easy load. 20 watts/channel is underpowered for them.

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Re: low watt amp cause of distortion?

Post by lenjack » 20 Jul 2019 23:25

They should still sound OK at reasonable levels. Advent made a 15 watt receiver for them, which did a fine job. Ask me how i know.

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