My first tube experience with my Cornwalls - need feedback please.

[markw]

Monday, I purchased a Stromberg-Carlson ASR-333 Stereo amp.

today was the first day I had a chance to play. Here's what happened:

I put in my Staccato CD (Quick aside about the CD- It's a CD that was put out by Audio Magazine in Germany. It starts with a wide range of different instruments, then goes through some different sounds (shattering glass, ringing church bells and telephones), then other recordings of nature and machinery, and things like applause, then absolute silence, and finally white noise and test tones at 1Khz; quite a handy CD for testing equipment)

And listened...

Then I played the same through my old carver amp.

Here's what I finally came up with:

The good: Tremendously smooth: The rinnging church bells didn't have a 'clangey' sound. Very good.

The bad: There is a noticeable hum that increases with the loudness control (adjusting the gain has no effect) It was obviously more noticeable when there was no musiacal sound, but it seemed (could be my imagination) that the hum actually dropped when there was music.

This may be on the same lines, but particularly at low volumes, it sounded sort of muffled, as if a heavy sheet had been placed over the speakers. and to duplicate the highs of my other amps, I had to really crank the treble. As the volume increased, it gained clarity, but like I said, you had more hum.

Also, ther is a loud popping when I turn it off. (I attached to a switched outlet to avoid unnecessary pops)

Now granted, it only paid 57 bucks for it, and it has one mismatched tube, and has not been tested as far as I know.

My question is this: are these issue more likely the result of a bad amp, or just bad parts. In other words, do you think this amp can be made to shine?

As this is my first time listening to tubes, I don't really know what sounds are inherent and which ones shouldn't be there.

That's my story - I'm stickin' to it.

[Randy Bey]

hum level is an issue with tube amps. Some are dead quiet, some are not. If it's an old unit, then tubes are suspect. Also caps go bad and need replacing.

The cornie is a high efficiency speaker so any hum level will be audible. It should disappear completely when the music starts.

[NOSValves]

mtwwmw,

If indeed the amp in its current state pleases you in the sound department and also is of cosmetics that you can live with then its worth getting fixed up. With the $57 investment you surely are not going to end up with a major investment but the thing is with it being a obscure not sought after model it will never command a high resale price so the only reason to sink money into it is to enjoy it yourself.

The hum is a problem that almost surely can dissapear with a proper rebuild. You have a amp there that is stock full of 40 year old stale parts. The hum could be a number of things but most likely nothing that can not be fixed.

Craig

Randy,

Hum is a issue with tube amps but with my experience only with tube amps in need of repair and at volumes that are above normal use. I have never had a amp I couldn't get pretty much humless after rebuilding it at volumes anyone uses one at. Its really not a issue. His hum is surely from being 40 years old and in need of a rebuild.

[TBrennan]

Ain't bells supposed to sound clangy?

[artto]

I was thinking the same thing Tom.

I'd like to put my two cents at this point since I often use both solid state & tubes. While many of you may not like solid state amps like Crown, here's the real deal on hum & noise comparison with tubes: Hum & noise seem to almost always MEASURE better in solid state amps. The listening experience is something else. With ANY of my Crown power amps (D60, D150 or PSA2) turned all the way up (all preceding sources muted or switched out), hum/hiss is clearly audible pretty much anywhere in the room (albeit, its a very quiet room). Hook up the Luxman MB3045 tube amps, same scenario, you can put your ear right up to the tweeter or midrange horn (Khorn) & its DEAD SILENT. Fascinating when you consider that any of the above Crown amps actually measure greater than 20Db less noise than the Lux units. Makes you wonder what they're actually measuring!

I'd also like to add that the Crown amps, while made to withstand the rigors or professional touring & 24/7 use for years on end, also have some physical (or mechanical) hum from the power supply transformer which is also not present on my tube amps. All the amps are somewhat the same vintage. And its been years since the tube amps last had their tubes changed.

[markw]

OK, so Clangy was a bad choice of words, but it was a harsh, fatiguing clang as opposed to a ring.

Craig,

here's the thing... since it is my first tube amp experience. I don't know if the sound pleases me. There are parts that sound astounding, and then others not so much. And I don't know what kind of changes will be required to produce desired results.

For example... If the hum is removed, will the aforementioned blanket be lifted? or is that sound a part of the amp?

Thanks,

Mark

[sunnysal]

mark, I am not an expert but I have owned some old electornics and, as a rule, I think you have to plan to swap out most original capacitors, perhaps some resistors and certainly one or more of the tubes is suspect. you could get a set of new tubes from sovtek or svetlana and while they may not sound as good as the best nOS stuff out there, they will give you the best image of how you amp should sound without spending a fortune. send this somewhere (or do it yourself if you are handy) and freshen it up with new caps and tubes. then see where you are. tony

[markw]

Tony, thanks for the idea. I'll try to combine two of my favorite things - music and fiddling around with stuff. I'm not a stranger to a soldering iron, but its been quite a while since I've read a schematic. I figure best case - I end up with a great amp (I can even drop it into a new box) and worst case, I learn alot about the inner workings of a tube amp.

Craig, can you give me a few pointers on what do as far as what I should try check/replace first? I'd be happy to give you the business. I found the schematic glued to the inside. I figure if the design is sound, it should follow that with quality parts it could be a pretty nice amp?