a few concerns with my latest aquisition (sp extreme)

[crappyjones123]

so i received this amp yesterday and i plugged it in last night in the following order.

1. put bendix 6080 tubes all the way in the back 2 sockets.

2. put the sylvania 6sn7 tube in the front. noticed that the metal base was slightly loose and could be moved a wee bit.

3. attached the necessary cables and then turned it on with the headphone plugged in.

4. listened to music.

the gear loop is very simple and as follows.

lenovo laptop (line out) - mini - rca cable - sp extreme - hd 650s.

problem that only occurred last night

if i even tap the amp lightly with my fingernail it sounds like it would if i were inside a tube and someone were tapping the glass. its kinda high pitched and something akin to the noise made when your ears are ringing in a game right after you get flashbanged (cant hear anything else but the loud ringing noise). this noise however is not loud, nor overbearing anything else. with no music it is very prominent though.

is this just the hum associated with tube amps that other people were talking about?

problem that occurred last night

after 2 hours of listening to the amp (from the time i plugged it into the power) the left channel started making a LOT of noise. audible enough to drown out the entire music in the left channel. it sounded as if one were holding a plastic bag outside the window while driving. dont know how else to describe it but that i think is the most accurate description i can think of. sounds almost exactly like it. i turned off the amp and left it be for a few minutes. turned the amp on again and the same thing - lots of noise a few seconds after i turned on the amp.

i turned off the amp and went to bed too scared to do anything else.

just got up and tried another 6sn7 gt tube instead of the sylvania and no noise in the left channel so far.

the amp did get exceptionally hot to the touch after 2 hours of use. i know that tube amps are supposed to run hot but i just wanted to make sure it couldnt have been the cause of the noise.

listening to john lee hooker right now and everything sounds good. was it just a driver tube or could it be something with the amp. id rather not open it up and have a look inside unless i absolutely must.

amp sounds marvelous otherwise.

ps. i tried reading up on the topic last night but only found one thread regarding noise in the left channel in a darkvoice but the owner said it was intermittent. kept coming and going every few days or so. id rather have the amp be working in good condition considering it did cost a lot (to me).

[JBLoudG20]

Welcome to the world of tubes.

The first problem is most likely microphonics. Tube dampers can help, but you may just have to replace it.

The second problem sounds like a dying tube.

The joys of tube amp ownership

[Salt Peanuts]

The first problem sounds like microphonic tubes. Something like this may help. Herbie's Audio Lab: Tube Dampers

The second problem may be a bad tube - try leaving it on for couple of hours with the current tubes to see if it happens again.

EDIT - Jay beat me to it. My ISP is sloooow today.

[Torpedo]

IME tube dampers help a little with tubes that are very slightly microphonic, and in some tube models, change sound when there's no microphony at all, but once you have a tube converting a finger tap in clear audible "thump" they're completely useless. Replace those tubes, hopefully the same one being microphonic is the one about dying and causing the rest of problems.

[pompon]

NEVER tap on hot tube .. you will damage them ... the filament is almost in fusion ...

For the "plastic bag" sound ... I heard that 2 times but my 5998 was cold ... after 5 min warm-up, was ok.

I read LD6 with 6080 come very hot .. they use fan.

My Dragon with 6080 come hot too but I can hold my hand without problem on the amp.

For the hiss ... try another input tube .. it's probably a bad tube ...

[Icarium]

Another problem might be the laptop. Barf. I mean I know you had a beta22 that probably was also revealing of its flaws, but I have a Lenovo and even with the lineout the sound quality is hideously shitty and had a high amount of floor noise hiss with every amp I've ever tried.

[n_maher]

NEVER tap on hot tube .. you will damage them ... the filament is almost in fusion ...

You do realize that just about every tube tester manual will tell you to tap the tube as you test it for shorts, right?

From the sounds of it this was all due to a wonky input tube.

One more thing CJ, it's not a good idea to power cycle a tube amp like you did. It's very hard on both the power supply and the tubes. If you have to shut the amp off I'd plan on waiting a half hour or so before turning it on. That's one more thing to add to the list of "The Joys of Tube Amp Ownership".

Edited November 22, 2008 by n_maher

[crappyjones123]

i wasnt tapping the tubes. i was tapping the case and i could hear the ringing sound. too scared to do anything to the tubes.

[Icarium]

Yeah singlepower amps are kinda microphonic. Can definitely hear a ping when you tap the sides of any of their amps that I've ever owned.. except for the SS-1.

[crappyjones123]

is there a manual for new owners of tube amps anywhere nate? or a list of do's and dont's. wouldnt want to do something out of ignorance.

[pompon]

Avoid leave your amp without headphone attached.

Avoid change IC when your amp is on.

Avoid change tubes when they hot.

It's just ideal situation.

I never turn-off my amp before doing headphone swap.

When I do, I try to not let amp without headphone too long.

[aardvark baguette]

I used to leave my amp on overnight and even while I was at work, essentially never turning it off, but no longer do that in case of power outages, the kind where the power goes off and on several times within a few minutes.

Lately I turn it off when I go to bed and turn it on the next day when I get home from work around 5pm or so.

[crappyjones123]

well weekdays im on campus from 9am till 8pm. so my only listening gets done after 9pm until 12am. i dont think id want to leave them running the entire day just for the 3 hours of use at night. if reason or experience states otherwise, please let me know.

thanks for all your responses.

[riceboy]

Hey CJ. Sorry about the bad input tube you used. As I mentioned earlier in a PM I didn't try all the tubes , but I did like the 6080s and the 2c51 tube as the gain tube or the ECC32 is great as well. Let us know if anything else arises as I would like to know if you do experience any problems. Enjoy your new amp .

Thanks everyone for helping CJ out .

[crappyjones123]

apparently the beta isnt working for the guy i sold it to. no sound in the right channel. fedex says that i have to have a receipt of purchase of the amp from a vendor (their policy doesnt cover diy junk) for them to process the claim. since the amp was built by nate (not a big name vendor) i cant produce a receipt. in the very likely event that fedex doesnt give me back the money i insured the amp for, the sp extreme will be back on sale after its very short 5 hour stay with me.

this fucking blows.

[Salt Peanuts]

That sucks, CJ. I hope it works out for you.

[asebastian0]

They should accept a paypal receipt. Also most online vendors simply send an html/text form as a receipt. Like so::

ITEM //// Cost

b22/3ch /// xxx.xx

xx.xx tax/fees

xxxx.xx TOTAL

You will be receiving your amp shortly, thanks for ordering!

EDIT: That did not post well without spaces, oh well.

[pompon]

If no physical dmg, you can't do a claim IMO.

[n_maher]

apparently the beta isnt working for the guy i sold it to. no sound in the right channel. fedex says that i have to have a receipt of purchase of the amp from a vendor (their policy doesnt cover diy junk) for them to process the claim. since the amp was built by nate (not a big name vendor) i cant produce a receipt. in the very likely event that fedex doesnt give me back the money i insured the amp for, the sp extreme will be back on sale after its very short 5 hour stay with me.

this fucking blows.

CJ, I've produced a receipt before good enough to satisfy Canada Post, we can certainly try with FedEx too. It'll just have to wait till monday when I'm back in the office so I can access the forms I've created for Nugget Audio. You're not screwed yet, and also as with anything that I built I'll try to repair it. If it's a simple fix all that will be asked for is the shipping costs, I'd say it's likely that it would be a simple fix. Where and who did you sell it to, please have them shoot me a PM at Head-Fi.

[riceboy]

Nate to the rescue .

I'm sorry to hear about this recent turn of events. I'm sure/hoping that everything will turn out okay.

[Torpedo]

Maybe Nate can assist with some sort of receipt of his work and parts value. Good luck CJ

Ooopss I missed a lot of replies that came before this one. Glad to see Nate coming to the rescue

[crappyjones123]

nate, i sent you the pm's that the gentleman sent me on headfi. i forwarded them on headfi to you.

just called fedex. they said that they can have the amp picked up, "inspected" and then shipped back to me on their own. i wouldnt have to pay for this option. i dont know how the actual purchase price for the amp is going to be settled. so lets say fedex sends the amp back to me, the guy already paid me (well he paid laine and i dont want him going around doing any paypal nonsense with laine) so am i obligated to pay him back or what.

i have a take home test due monday that i need to work on for now but this whole thing is retarded.

[n_maher]

CJ,

I'll have a look at the PM's on Head-Fi and then I'll send you a PM here or there. We'll figure out what to do for a receipt and also how best to handle the repairs.

[Dusty Chalk]

I agree with what's already been concluded: microphonicity (?word) and bad or dying tube. The only additional piece of information/opinion I'd offer is that bad tubes can sometimes be confused for a bad connection (tube to socket), but that usually results in a bad tube anyway. So progold and deoxit. Even if you end up replacing the tube, it's good to make sure you have a good connection.

[Rob N]

If you got a crackling sound with that input tube it could just be bad contacts between the tube pins and socket