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Tube amp for Cornwall III


Thuper

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What do you mean by noise? Can you hear it from your listening position? They are sensitive speakers and finding an amp with no noise whatsoever with your ear to the speaker is virtually impossible. If it's noisy from a distance there might be something wrong with the amp. Some are certainly more quiet than others however.

Are you looking for an integrated amp? Monoblocs? What's your price range, room size, musical tastes?

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I have some Luxman MB3045 which are dead quiet even when turned up all the way. But you'll be hard pressed to find any of these that haven't been modified to use KT88 (or something else) as the original 8045G has been out of production for at least 25 years - very expensive when you do find them.

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What do you mean by noise? Can you hear it from your listening position? They are sensitive speakers and finding an amp with no noise whatsoever with your ear to the speaker is virtually impossible. If it's noisy from a distance there might be something wrong with the amp. Some are certainly more quiet than others however.

Are you looking for an integrated amp? Monoblocs? What's your price range, room size, musical tastes?

By noise I mean a weak whispering sound, and yes! I do hear it from my listening position. But only between tracks. It does not affect the music.

I haven't made up my mind of what kind of amp, as long as it has tubes[;)] I'm not going back to SS amps! Price? My limit for now is $3500. My room is 4x4m. My music taste? Allmost anything, but opera and symphonicorchestra. I like Radka Toneff, and I like Metallica. I listens to John Fogarty and to AC/DC. I think the music of Chet Baker is good, and I enjoy Joe Satriani's music... And Pat Methany of course and Stevie Ray Vaughan...

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This a pretty loaded question since there could be so many different reasons for the buzz or humming noise you hear coming out of your loudspeakers. I don't think KT88s are necessarily noisy tubes, but since your tube amp has dual power modes, maybe something in the pentode stage's circuitry is causing the noise (like maybe a bad capacitor or resistor...I don't know). Or maybe it's the beginning stage of a failing tube? Wish I was an expert in the field of electronics, but I'm not. Then again, maybe it's not your amp at all that's causing the noise...maybe one of your interconnects isn't making proper contact or the RCA jacks on your equipment are corroded...or even your power cords crossed over your interconnects are causing the hum. I would assume no amplifier is perfectly quiet, but some may cause more noise than other. Plus, efficient Klipsch loudspeakers always bring out even the most subtle of noises from any system (I have a very faint buzz from my RB-75/300B SET amp setup that you can only hear when your ears are pressed up against the horn tweeters; I can't hear it at all from my listening chair).

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Thuper I guess the real question is do you like the sound of your current amp because a tube amp in good condition shouldn't be making that level of noise. As Jim mentioned, I would remove and then reinstall all your connections, speaker wire etc. I would also try it with another cd player. If you have a dvd player in the house try that. Then remove all the tubes that can be swapped and change their positions. It could easily be a bad or noisy tube.

Not familiar with your amp. Is it an integrated, and if no,t are you using a preamp or running it straight line through your cd player? In my opinion, some small tubes in preamps, especially 6DJ8's are prone to noise, and a straight line setup can also do the same thing.

What I and others are getting at is if you like your current setup, fixing that first before spending a lot of money makes much more sense.

Of course if you follow our advice and save yourself $3500 we'll be expecting a payment of at least half that amount.[:D]

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My amp is a integrated one, and yes, I love the sound of it! It has 2x 12AT7PhillipsMiniwatt, D-getter halo, 1947 production, and 2x12AU7A RCA ClearTop D-getter halo, 1960's in the line stage, and 4x Shuguang KT88 as output tubes. On my previous speakers I couldn't hear that noise. but they wheren't this sensitive... only 91dB. I had to move the setup when I bought the Cornwall's, and the cables are just lying in a mix for the moment. I shall buy a bench tomorrow to place my setup on. and tidy up in the cable mess... perhaps it will help...

I'll let you know!

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Swap out tubes one at a time until you find the noisy one(s). I find noisy tubes to be the main cause. High efficient horns will bring out the best and worst in a tube. FAST. Even excellent testing tubes can be noisy. I see/hear it all the time. I usually find the noisy tubes in my preamp. Most tube amps are totally quiet if in good condition. I do get some "white noise" through my horns when running SS gear. I can even hear a lot of it at idle.

Harry

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My amp is a integrated one, and yes, I love the sound of it! It has 2x 12AT7PhillipsMiniwatt, D-getter halo, 1947 production, and 2x12AU7A RCA ClearTop D-getter halo, 1960's in the line stage, and 4x Shuguang KT88 as output tubes. On my previous speakers I couldn't hear that noise. but they wheren't this sensitive... only 91dB. I had to move the setup when I bought the Cornwall's, and the cables are just lying in a mix for the moment. I shall buy a bench tomorrow to place my setup on. and tidy up in the cable mess... perhaps it will help...

I'll let you know!

Man am I jealous! Nice tubes!

By all means eliminate the obvious by cleaning up the mess with the cords. Try to separate the power lines from everything else. Twist the rca connectors a few times before re-setting them to clean the contact surfaces.

Sadly, at those ages, one of the small tubes is probably bad. See if you are getting more noise from one speaker than the other. You have to get up close to each speaker to figure this out. Chances are that one side will have a louder noise than the other. Swap those small tubes and see if the noise follows before you deal with the power tubes.

Actually figuring out stuff like can be kinda fun. Sorta like detective work. So get out your smoking pipe and spyglass and get to work!

"Holmes!"

"Yes Watkins?"

"It's the hounds! The hounds are loose upon the moor!"

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If you want a completely silent amp, the Quicksilver Horn Monos are for you.

This answer could lie at the heart of the matter. Most amps by themselves are completely quiet if there's nothing wrong with them. You are probably hearing PREAMP noise unless you disconnected it from the amp before listening. It's magnified to audibility by the speaker's high efficiency. Yes, by all means pursue noisy tubes, but be sure to focus on the preamp, too.

The reason the Horn Mono is so quiet is not just because the amp is quiet by itself -- it's because its gain is so low that it doesn't raise preamp noise to the threshold of audibility. I have always looked for low gain amps because of this issue with high-efficiency speakers. The gain of my current monoblocs was reduced by the manufacturer at my request.

I gather that integrated amps like Scotts and Fishers are silent because they control these gain issues internally.

Larry

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I have some experience here. We have Cornwall IIIs, and they are quiet (slightest hiss with your ear to the speakers) with no source input, and full gain on the preamp. As I recall, here is the system with tube details.....

Preamp - Bottlehead Foreplay 3 with Telefunken 12AU7s

Amp - Dennis Had 'Superamp' running 6DJ8 (BB)/EL84 (BB) driving 6CA7 (GE) in push-pull (class A)

Plenty of power, and also very quiet. Oh, and I have a pair of SVS subs (25-31 PC-Plus) trying to keep up with the Cornwalls.

Jim

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My amp is a integrated one, and yes, I love the sound of it! It has 2x 12AT7PhillipsMiniwatt, D-getter halo, 1947 production, and 2x12AU7A RCA ClearTop D-getter halo, 1960's in the line stage, and 4x Shuguang KT88 as output tubes. On my previous speakers I couldn't hear that noise. but they wheren't this sensitive... only 91dB. I had to move the setup when I bought the Cornwall's, and the cables are just lying in a mix for the moment. I shall buy a bench tomorrow to place my setup on. and tidy up in the cable mess... perhaps it will help...

I'll let you know!

Man am I jealous! Nice tubes!

By all means eliminate the obvious by cleaning up the mess with the cords. Try to separate the power lines from everything else. Twist the rca connectors a few times before re-setting them to clean the contact surfaces.

Sadly, at those ages, one of the small tubes is probably bad. See if you are getting more noise from one speaker than the other. You have to get up close to each speaker to figure this out. Chances are that one side will have a louder noise than the other. Swap those small tubes and see if the noise follows before you deal with the power tubes.

Actually figuring out stuff like can be kinda fun. Sorta like detective work. So get out your smoking pipe and spyglass and get to work!

"Holmes!"

"Yes Watkins?"

"It's the hounds! The hounds are loose upon the moor!"

Well... Now I've fixed the cable mess, and tried to swap the small tubes, but with no result.

I'm not sure of how long my KT88's are used... Will one or more of these tubes start to make noise when it's worn out?

Posted Image

PhillipsMiniwatt 12AT7 D-getter halo, 1947 production in action[:D]

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Well... Now I've fixed the cable mess, and tried to swap the small tubes, but with no result.

I'm not sure of how long my KT88's are used... Will one or more of these tubes start to make noise when it's worn out?

Stop everything and lets do this methodically.

Step one. Unhook the preamp from the amp and turn the volume control on the amplifier all the way down. Report back what noise you have in both Triode and Pentode mode with nothing attached to the amplifier but the speakers.

Craig

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Stop everything and lets do this methodically.

Step one. Unhook the preamp from the amp and turn the volume control on the amplifier all the way down. Report back what noise you have in both Triode and Pentode mode with nothing attached to the amplifier but the speakers.

Craig

Ok!

But my amp is an integrated one...

With nothing but speakers attached I have a kind of hiss sound in Pentode mode, even from my listening position. And almost nothing in Triode. If I put my ear in the midrange horn I can hear a wery weak hum...(that is in Triode mode)

Frode

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