Go Back   UG Community @ Ultimate-Guitar.Com > Instruments > Guitar Gear & Accessories
User Name  
Password
Search:

Reply
Old 10-05-2012, 10:59 AM   #21
admi62
Registered User
 
Join Date: Oct 2012
very first post and i started an argument. i even impress myself sometimes !
thanks
admi62 is offline   Reply With Quote
Old 10-05-2012, 11:04 AM   #22
Kevin Saale
Talks to empty chairs
 
Kevin Saale's Avatar
 
Join Date: Dec 2007
Location: In a desert, next to a chair
Yeah, we're quite prone to arguing when false info comes up, but you'll learn that in time. Usually we're civilized enough to make sure the TS has the info he sought first though
__________________
I don't give a shit if you listen to me or not.

Quote:
Get three coffins ready.

My mistake, four coffins.
Kevin Saale is offline   Reply With Quote
Old 10-11-2012, 02:03 PM   #23
admi62
Registered User
 
Join Date: Oct 2012
the ruby tubes are in ; now it sounds like a dying duck. i have dialed up all the gains & it is still nowhere near the sound i had before. albeit nowhere near as noisy, either...
admi62 is offline   Reply With Quote
Old 10-11-2012, 02:06 PM   #24
R45VT
Doesn't speak guitar
 
Join Date: Dec 2009
Location: Traffic Town LA
Stop raging for a minute and explain a little more.

You changed your preamp tubes? Now what is your problem?

Edit: what is the writing on your Rubys? That will determine we're it is made.

Also what tubes did you pull out?
__________________
Quote:
Originally Posted by DeathByDestroyr
See, it's important that people clarify when they say "metal", because I pretty much always assume they are a Cannibal Corpse fanboi.

Last edited by R45VT : 10-11-2012 at 02:08 PM.
R45VT is offline   Reply With Quote
Old 10-12-2012, 12:06 PM   #25
admi62
Registered User
 
Join Date: Oct 2012
the tubes I pulled out had nothing written on them except '12AX7A" in red. humming and crackling started recently. they came in the unit when I got it , (1993) so I dont know what they are. would love to find out...

the ruby tubes have J / J on them. the full model # is 12AX7A CZHG

in the ADA manual: the tube spec is : 12AX7A / 7025
after checking out dougstubes.com, they said the JJ CZ HG is the highest output of12AX7A tubes. but my rig has WAY less volume and crunch than before. do they get louder after several playings ?

I guess I need tube buying 101...

Last edited by admi62 : 10-12-2012 at 09:24 PM.
admi62 is offline   Reply With Quote
Old 10-12-2012, 09:34 PM   #26
R45VT
Doesn't speak guitar
 
Join Date: Dec 2009
Location: Traffic Town LA
Swap your old tubes back in to make sure it wasn't a bad tube, if the concern is gone then switch in the new tubes until you find the dud.

I hate to say it but I would assume something wasn put back correctly. Check all wiring.
__________________
Quote:
Originally Posted by DeathByDestroyr
See, it's important that people clarify when they say "metal", because I pretty much always assume they are a Cannibal Corpse fanboi.
R45VT is offline   Reply With Quote
Old 10-12-2012, 11:44 PM   #27
Cathbard
Grumpy Old Tech
 
Cathbard's Avatar
 
Join Date: Oct 2009
Location: Australia
12AX7A? That could be a 7th generation Shuguang. Does it say what country it was made in?



As for the standby switch argument; you're both right and you are both wrong. It's got a lot to do with history.

Originally the standby switch was added to be used as a standby switch, ie to keep the tubes warm during breaks. This is evident because stereos never had a standby switch and some of those were pretty big. It was a guitar amp specific thing. So it wasn't added to provide safer switch on. Those old tube amps were built with enough headroom to cope with the inrush current and if anything the old Fender guitar amps had even more.
The small practice amps like Champs didn't have a standby originally because they weren't made to be used on stage so you didn't need to put the amp on standby. Don't forget, people were used to having to wait for things to warm up at home - everything was like that.

However, over time a few things happened and today is not yesterday.
1. We discovered that leaving the amp on standby does almost as much damage due cathode poisoning as turning the amp on and off does due to thermal work hardening.
2. Manufacturing's focus shifted from reliability and quality towards profit margin as corporatism/consumerism rose to power.
3. People associate the presence of a standby switch with there being tubes inside.

So where does that leave us now?
Well, the standby switch is primarily used as a safe switch on method only. It limits inrush current because you are turning on the heaters and HT separately. Particularly important when you are cutting costs on your power transformers.
Smart people just turn down the volume during breaks; myself I hit the mute button on my MIDI controller. That way there's no thermal work hardening OR cathode poisoning.

There really should be no need for a standby switch any more - thermistors are cheap and more than capable of limiting inrush current. Howver people expect to see a standby switch on a tube amp so standby switches have stayed with us even though their original purpose has proven to be worse than pointless.

What I want to start doing on amps that aren't faithful clones of the originals is to dispense with the standby switch and replace it with a thermistor and a mute button. Some amps are starting to go down the thermistor path, I'm pretty sure that the Excelsior is built that way (somebody correct me if I'm wrong please). If it isn't the Excelsior I know I saw one in some new amp recently.

TL/DR version
The standby switch is there mainly because people expect to see one on a tube amp. Using it as it was originally designed is dumb. The only useful purpose it provides is to make switch on easier on the transformer, a job that could be done easily by a device that costs less than the switch.
__________________
Gilchrist custom guitar
Yamaha SBG500
Telecaster
Randall RM100
Abbey Harmonic II
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Marshall 1960A
Boss GT-100


Cathbard Amplification

Last edited by Cathbard : 10-12-2012 at 11:52 PM.
Cathbard is offline   Reply With Quote
Old 10-13-2012, 12:07 AM   #28
311ZOSOVHJH
G G & A - B A B Y
 
311ZOSOVHJH's Avatar
 
Join Date: Mar 2008
Location: Offline
Quote:
Originally Posted by R45VT
Swap your old tubes back in to make sure it wasn't a bad tube, if the concern is gone then switch in the new tubes until you find the dud.

I hate to say it but I would assume something wasn put back correctly. Check all wiring.

+1
Listen to this man.
__________________
311ZOSOVHJH is offline   Reply With Quote
Old 10-13-2012, 12:10 AM   #29
Cathbard
Grumpy Old Tech
 
Cathbard's Avatar
 
Join Date: Oct 2009
Location: Australia
Quote:
Originally Posted by R45VT
Swap your old tubes back in to make sure it wasn't a bad tube, if the concern is gone then switch in the new tubes until you find the dud.

I hate to say it but I would assume something wasn put back correctly. Check all wiring.

And yes, this. It's smart to identify the dodgey tubes when you do a full retube. There's no reason to throw away perfectly good tubes, you keep the best ones as spares. All preamp tubes don't fail at once unless hit by lightning - and then tubes will be the least of your worries.
__________________
Gilchrist custom guitar
Yamaha SBG500
Telecaster
Randall RM100
Abbey Harmonic II
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Marshall 1960A
Boss GT-100


Cathbard Amplification
Cathbard is offline   Reply With Quote
Old 10-13-2012, 10:47 AM   #30
Beezerk
Registered User
 
Join Date: Apr 2010
Any thoughts on the Sovtek 12AXWB?
Supposed to have a bottom end "hump" however I've also read Sovtek are hit and miss.
Beezerk is offline   Reply With Quote
Old 10-13-2012, 11:02 AM   #31
Cathbard
Grumpy Old Tech
 
Cathbard's Avatar
 
Join Date: Oct 2009
Location: Australia
The only Sovtek worth buying is the 12AX7LPS. Those short plate WB's are garbage.

If I were you I'd be putting a JJ ECC803 in there.
__________________
Gilchrist custom guitar
Yamaha SBG500
Telecaster
Randall RM100
Abbey Harmonic II
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Marshall 1960A
Boss GT-100


Cathbard Amplification
Cathbard is offline   Reply With Quote
Old 10-13-2012, 11:24 AM   #32
admi62
Registered User
 
Join Date: Oct 2012
thanks much for the advice.
i did put the old ones back in yesterday for comparison - the hum & noise were awful.
the rubies are so quiet i can probably go without the noise gate.
i cranked up both overdrives to 10 & dialed in some distortion on my fx unit (something i have not had to do in nearly 20 yrs i've owned the rig) & its starting to get there.
admi62 is offline   Reply With Quote
Old 10-13-2012, 11:27 AM   #33
Cathbard
Grumpy Old Tech
 
Cathbard's Avatar
 
Join Date: Oct 2009
Location: Australia
The JJ ECC803 is a low noise tube with a lot of character. From what you've been saying you'll love it. That Ruby is a JJ ECC83S. If you think that's quiet, wait until you hear the ECC803.
__________________
Gilchrist custom guitar
Yamaha SBG500
Telecaster
Randall RM100
Abbey Harmonic II
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Marshall 1960A
Boss GT-100


Cathbard Amplification
Cathbard is offline   Reply With Quote
Old 10-13-2012, 08:08 PM   #34
admi62
Registered User
 
Join Date: Oct 2012
more weirdness : today, i decided to try the one at a time swap. i put an original tube in the back position, and left the ruby in front. the result was fairly pleasing, and not real noisy. i then shut down and swapped positions with the tubes. i can only describe the noise as sounding like a vacuum cleaner a couple rooms away. i swapped the other original for that one, same sound plus worse low end hum. i swapped positions with these tubes, and the result was similar to my first sound. with both rubies in, it sounded like a sheet had been put over the cabinet in comparison to sounds 1 & 4. with both originals in, it screams noise like bloody hell.
someone with a degree in tubeology can probably explain the physics involved here, but i am truly stumped by this.
admi62 is offline   Reply With Quote
Old 10-13-2012, 10:38 PM   #35
311ZOSOVHJH
G G & A - B A B Y
 
311ZOSOVHJH's Avatar
 
Join Date: Mar 2008
Location: Offline
Master Cathbard should be up and reporting for duty soon


I'm at a loss. Did you try plugging guitar into the FX return?
__________________
311ZOSOVHJH is offline   Reply With Quote
Old 10-13-2012, 11:29 PM   #36
Cathbard
Grumpy Old Tech
 
Cathbard's Avatar
 
Join Date: Oct 2009
Location: Australia
Your description is a little vague but it sounds like you only have one decent tube amongst the bunch. The first tube in the chain is the one where a noisy tube will have the most detrimental effect. I don't know which one that is on those. Check the manual, it will be the one they call V1.
Buy yourself at least one JJ ECC803 and stick it in V1. Then roll through your other tubes until you find the best one. Now you know what's what and can make an informed decision.

Personally, I'd buy two ECC803's and see what you like most out of two 803's or an Ecc803 and an ECC83S. The ECC83S is a marginally darker sounding tube than the ECC803. In anything but a combo the go is to start with all ECC803 and then try an ECC83S in different places, taking notice of what it changes about the sound. Then from that you can add in as many ECC83S tubes as suits your taste. If an amp is very icepicky then running all ECC83S may be the way to go; if it's boomy, all ECC803.

This is the process you go through even if you have a collection of NOS tubes. You start with a known set of tubes and roll each position with your candidates. It can be a long process in an amp that has a lot of tubes but in your case the truth table is mercifully small.





Oh and Kevin, with a tube rectifier you don't get any HT until the heater in the rectifier gets the cathode firing. In effect they act as a timed turn on and in electronics times the delay is friggin huge. Standby switches are a waste of bloody time on an amp with a tube rectifier.
The problem with SS rectifiers is that as soon as you hit the power the heaters turn on - at exactly the same time as the HT capacitors start to charge.
Add to that that you no longer have a severely restricted reservoir cap size like a tube. So of course you're gonna throw bigger caps in there aren't you? And they do.
So your inrush current is going to be substantially larger aint it? It's being hamerred from all sides. Simultaneous coil energising and bigger caps. You gotta watch yourself.
__________________
Gilchrist custom guitar
Yamaha SBG500
Telecaster
Randall RM100
Abbey Harmonic II
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Marshall 1960A
Boss GT-100


Cathbard Amplification

Last edited by Cathbard : 10-14-2012 at 12:03 AM.
Cathbard is offline   Reply With Quote
Old 10-14-2012, 12:03 AM   #37
Kevin Saale
Talks to empty chairs
 
Kevin Saale's Avatar
 
Join Date: Dec 2007
Location: In a desert, next to a chair
Yeah, but like you said, thermoresistors are cheap and a well made amp with an SS rectifier should have some sort of inrush limiting circuit to protect the amp from people who don't know how to use a standby switch.
__________________
I don't give a shit if you listen to me or not.

Quote:
Get three coffins ready.

My mistake, four coffins.
Kevin Saale is offline   Reply With Quote
Old 10-14-2012, 12:08 AM   #38
R45VT
Doesn't speak guitar
 
Join Date: Dec 2009
Location: Traffic Town LA
TS- please start over from the beginning and try to make sense.

Why did you want to retube?

What happened after you installed the new tubes that you don't like?

Thanks!
__________________
Quote:
Originally Posted by DeathByDestroyr
See, it's important that people clarify when they say "metal", because I pretty much always assume they are a Cannibal Corpse fanboi.
R45VT is offline   Reply With Quote
Old 10-14-2012, 12:16 AM   #39
Cathbard
Grumpy Old Tech
 
Cathbard's Avatar
 
Join Date: Oct 2009
Location: Australia
Agreed, Kevin. Just because the amp is designed around ancient devices doesn't mean that we should be living in the dark ages.
Standby switches are a dumb way to mute the amp and thermistors are cheap. Seriously, wtf?


TS a truth table would be handy - so two columns, one for each valve position. In each row show which tube is in where and beside it write the test result.

Edit: sorry that's three columns aint it?
__________________
Gilchrist custom guitar
Yamaha SBG500
Telecaster
Randall RM100
Abbey Harmonic II
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Marshall 1960A
Boss GT-100


Cathbard Amplification

Last edited by Cathbard : 10-14-2012 at 12:18 AM.
Cathbard is offline   Reply With Quote
Old 10-14-2012, 12:19 AM   #40
Kevin Saale
Talks to empty chairs
 
Kevin Saale's Avatar
 
Join Date: Dec 2007
Location: In a desert, next to a chair
Yeah, like you said, it all comes down to it being expected.
__________________
I don't give a shit if you listen to me or not.

Quote:
Get three coffins ready.

My mistake, four coffins.
Kevin Saale is offline   Reply With Quote
Reply


Thread Tools Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



All times are GMT -4. The time now is 12:26 AM.

Forum Archives / About / Terms of Use / Advertise / Contact / Ultimate-Guitar.Com © 2014
Powered by: vBulletin Version 3.0.9
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.