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Another Scott tech question in 2-ch forum


T2K

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Playing my Scott 233 today with Chorus II's. Let the thing run playing away while I worked in yard. Came in 3 or 4 times, changed CD's several times, cranked up the volume and everything sounded just fine. After 5 1/2 hours I sat down to listen to some music.

Turned up the volume and heard a loud crackle/pop sound on certain hi notes. It was the right tweeter. Swapped speaker cables. The pop was in the left speaker, on the same notes. The noise is not constant, just on certain notes. Sounds like a tube pop type of sound.

I changed the speaker cables back, the sound was now back in the right channel. I swapped out every right channel tube, including the rectifier, one tube at a time. The pop persisted, same as before. It seemd to stop with the volume control at about #3, any higher and it is back. Could have just been that the sound was not audible at the #3 position or lower. Thought it might be the volume pot but nothing happened when I wiggled it while music was playing.

Any suggestions? Thanks.

Keith

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These types of phonomena are always a concern.

-Source hardware

-Source software

-Old equipment does weird stuff

-do not leave old stuf on unattended

High resolution speakers and amplification are a tough "mirror" to look at.

My origonal Tull "Aqualung" and "Frampton Comes Alive" CDs sound HORRIBLE!

...and sometimes an old resistor gets unhappy for a while.

40 year old stuff is a little quirky; but AWESOME!

Audio Flynn Scott aholic!

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-Old equipment does weird stuff

-do not leave old stuf on unattended

===============

Depending on the hours of use; once or twice a year trip to a tech is good maintainance.

Like carb tweaking in the same era for cars. And setting the points.

Or computers if your family are power users.

My computers need tweaks almost once a month.

Did you try a different input?

Tape or phono?

Sound like you may have reduced the proability of this being a power out put stage issue.

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Swapped out ALL the tubes-new set. Changed speaker wire. Changed interconnects. De-Oxidized the volume pot. Checked bias. Used tape input, same problem. Getting worse now the longer it plays.

Pulled speaker wire and interconnects from the 233 and plugged them right into the 222-C. Everything was lovely. The Chorus II's are mighty sweet sounding speakers. The 233 is still f-ed up though.

Thanks for trying Flynn.

Keith

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...and sometimes an old resistor gets unhappy for a while.

++++++++++++++++++

And sometimes permenantly.

I would send it off to someone for a "bench check".

I keep a couple nice old Denon SS integrateds for when i need to send the Scott off for an examination.

Frustrating to be sure; but normal.

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Going to go thru the drill one more time and then its off to the doctor. Was hoping to have the thing working while I was off so that I could have dbflash over to hear it with the Chorus. The 222-C will have to do (it ain't too shabby).

Yeah, I've got a few back ups too Flynn, but that 233 seemed to be made for the Chorus II's. Maybe my luck will change. 2.gif

Keith

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It is nasty to leave them out of the system when you are hooked.

In the past few years I have heard.

299A

208

130

LK-48

296

222B

As I remember.

The NOS Valves modded LK-48 and the 208 (with Dynaco PAS pre) made great music with my Chorus IIs.

I have not had time with the 296 to tell.

never heard the 233.

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Kieth,

Sounds like a internal problem to me. You've pretty much covered all the bases above the chasis. If this amp rebuilt or still basically factory stock ? If its stock it could be almost anywhere under the chassis and pretty hard to diagnos over the forum.

Craig

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Hey Craig. Happy Easter. The 233 was restored by Ryan a couple months ago. I have probably 40 hours listening invested and the thing has mellowed out in that time. The difference in the output of the 2 is noticeable, not a world of difference, but the difference shows up in the botttom end. That difference being good solid low bass in the 222-C and pounding bass in the 233. The few extra watts help with the Chorus II's.

Ryan gave me a few trouble shooting suggestions and I tried those to no avail. Must be something under the hood. Just grasping at straws here I guess. Seems the 233 will have to take a little vacation while I'm on vacation.

Thanks for the help.

Keith

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----------------

On 4/11/2004 11:39:45 AM Ryan C. Inman wrote:

Hi Keith,

The only parts I didn't replace were the capacitors under the tone control cover, there are a few under there for EQ and Loudness stages, sounds like one decided to go. All though they rarely fail, it does happen. The same caps went on my 222-D when I still had it. If the tubes and control contacts were OK, along with the bias, this could be the only other problem (everything else was replaced). Since it failed so soon, I'll pay 1/2 the shipping for you to send it back.

Have a great Easter

Best Regards,

Ryan

----------------

Hey Ryan! Mighty generous of you. I can't think of anything else to try. I may have missed something, did find and replace one Tele 6U8 borderline good, but I think I've eliminated anything superficial.

At first I thought it may have been the volume pot. It, like all the controls, work like new. As I said earlier I De-Oxited it anyway yesterday. Didn't help. The problem has gotten worse the more I used it. Tried other speakers too. Right channel only, worse on newer more dynamic CD's.

The thing sounds (sounded) great though. It's a keeper for sure. The thought of possibly upgrading the crossovers in my speakers is pretty much history. This thing is smooth, even with the Tele AX7's.

I'll get in touch with you in a couple of days. Stopped using my e-mail because of a suspected virus/parasite. Going to take care of that tomorrow.

Nice avatar BTW. Thanks to all.

Keith

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"The thought of possibly upgrading the crossovers in my speakers is pretty much history."

A shame you won't be at the Arkansas gathering in May. I plan on waking up Stream's (Jesse) RF-7s. I'm sure you would find it enlightening.

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