Tube Replacement

[rdasilva]

Patulong naman sa mga experts diyan.  

My Marshall amp's pre-amp tubes are 2 x 12AX7/ECC83 as per spec.  Want to have more clean so I'm cosidering replacing them with 12AT7's.  Has anyone had a chance to try this?

Is this safe?  Walang makasagot sa Yupangco eh.  But I'll post this question there also.

Thanks in advance to anyone who can help.

[markflo]

yea you can do that...no damage will be done...12at7's are more known for being in the phase inverter though...they don't sound too good as an actual preamp tube

[abyssinianson]

Patulong naman sa mga experts diyan.  

My Marshall amp's pre-amp tubes are 2 x 12AX7/ECC83 as per spec.  Want to have more clean so I'm cosidering replacing them with 12AT7's.  Has anyone had a chance to try this?

Is this safe?  Walang makasagot sa Yupangco eh.  But I'll post this question there also.

Thanks in advance to anyone who can help.

The ratings are similar and they are compatible but since the circuitry is different for those, your amp will sound different. I worked on a friend's Ampeg guitar amp with obscure 12AX7s variants (they were 5751) which are compatible with the 12AT7s. If you want to preserve the sound of your amp - even though tubes vary in sound between tubes so this is no guarantee in itself - you could opt to get one of the newer Groove tube replacement 12AX7s which are still currently being made. Mullard or Sovtek might still make NOS 12AX7s if you want to go that route but hunting down older model tubes might be hard.

[rdasilva]

thanks for the inputs.  It is apparent that I'm a newbie when it comes to tube amps so I hope you guys don't mind if I shoot some more questions.

markflo >  if they are meant for phase inverters (btw, what are these?), how will they perform in the pre-amp?  when you say they won't sound too good, what sort of sound changes should I expect?

abyssinianson >  I'm looking for more headroom.  the 12ax7's I have in the clean channel break up right away past level 2. So how do I get more of the clean sound?  Which 12ax7's do you recommend?

[abyssinianson]

using the 12AT would give you less headroom since it is a lower rated tube at, I think, 60...you might be better off using something like the 12AY7 which has a higher ceiling to give you more saturation room. i don't know what watt your amp is rated at but i will assume it is at least a 50 watter..if this is the case, the 12AY would work pretty well

[rdasilva]

abyssinianson >  thanks for the suggestion.  you are correct.  my amp is a 50 watter.  i'll try to look for a 12ay7 and test it to see how it sounds.

appreciate the help.  will let you know how it goes.

[extreme16199]

using the 12AT would give you less headroom since it is a lower rated tube at, I think, 60...you might be better off using something like the 12AY7 which has a higher ceiling to give you more saturation room. i don't know what watt your amp is rated at but i will assume it is at least a 50 watter..if this is the case, the 12AY would work pretty well

i beg to differ.  a 12at7 tube will give more headroom before the onset of gain, precisely because it is a lower gain tube.  a 12ay7 will give even more headroom (it has a lower gain factor than a 12at7).  the 12ax7 actually has the most gain among its family.  sequentially, from most gain to the least gain, you have the 12ax7, 5751, 12at7, 12ay7, 12av7, and 12au7.

[abyssinianson]

using the 12AT would give you less headroom since it is a lower rated tube at, I think, 60...you might be better off using something like the 12AY7 which has a higher ceiling to give you more saturation room. i don't know what watt your amp is rated at but i will assume it is at least a 50 watter..if this is the case, the 12AY would work pretty well

i beg to differ.  a 12at7 tube will give more headroom before the onset of gain, precisely because it is a lower gain tube.  a 12ay7 will give even more headroom (it has a lower gain factor than a 12at7).  the 12ax7 actually has the most gain among its family.  sequentially, from most gain to the least gain, you have the 12ax7, 5751, 12at7, 12ay7, 12av7, and 12au7.

good looking out. i made a mistake there. if the amp is a 50 watter and you use the 12AT7 which is rated at around 60, then it will distort much easier than if you were to use a 12ATY7 which is rated much higher - double, I think, cmpared to the 12AT7. I was thinking on the basis of a 100watt amp but erroneously typed 50watt. My sincere apologies for this error.

[pjrodz]

mga sir, san po ba nakakabili ng replacement tubes for amps dito sa pinas? specifically ECC83 (12AX7)?? salamat!    

[Tarkuz Toccata]

Sa AUDIOPHILE.

Click here.

[fade2black0520]

san po makakabili ng 12AU7 ECC82?tnx

[pjrodz]

thanks! btw, sa dami ng 12AX7 tube models dun, ano ma-recommend nyo? puro sovtek lang ba available dito sa pinas? salamat! ipapasok ko pala sya sa 65watts na marshall

[blue buddha]

Part of the fun is trying all these goodies in a tube amp to see which suits you best. And these are just the preamp tubes!

From The KCA Tubes site:

Preamp Tube Gain and Compatibility Guide

All of the following tubes are interchangeable and may be used anywhere one of the other tubes was originally specified.  The only possible exception is that 12AY7/6072As should be used only in circuits where the plate load resistor is rated for at least one watt.

Key:
•Tube Number
Gain Factor
Comments


•12AX7/12AX7A/7025/ECC83/CV4004
100
The ubiquitous guitar preamp tube

•5751
70
Military 12AX7 with just slightly lower gain than a 12AX7. Less highs too. Great for cleaning up a harsh or overly bright sounding amp channel.

•12AT7/ECC81/E81CC/CV4024
60
Fender reverb driver and phase inverter tube. Sometimes used to replace 12AX7s where lower gain and more note definition/clarity is desired.

•12AY7/6072A
44
First gain stage tube in Fender tweed amps from the 1950s. More of the same effect as the 5751 above. Good for cleaner blues tones. Harp players like these to reduce feedback.

•12AU7A/5963
20
Phase inverter in Vox amps. Sometimes used by harp players to reduce feedback in 12AX7 stages. Also a great substitution in 12AX7 type guitar distortion pedals. Allows for more usable range on the gain controls with less fuzzy/more bluesy distortion.

[Poundcake]

mga sir, san po ba nakakabili ng replacement tubes for amps dito sa pinas? specifically ECC83 (12AX7)?? salamat!    

good luck na paghanap dito bro... i already tried calling the Audiophile main office and dalawa lang yung 12AX7 tubes na stock nila. sa Phasetron naman ganun din, dalawa lang na National 12AX7. the best na siguro is mass-order from abroad, hanap ka ng mga gusto rin umorder para makatipid sa shipping fees and taxes. check out these sites:

http://www.eurotubes.com
http://www.tubedepot.com
http://www.thetubestore.com

OT lang ng konti: mga forumites, baka gusto ninyong gumawa ng mass-order ng tubes, chip-in tayo lahat tapos pa-ship tayo dito. hassle kasi maghanap nito e. game kayo?

[plugzzzz]

thanks! btw, sa dami ng 12AX7 tube models dun, ano ma-recommend nyo? puro sovtek lang ba available dito sa pinas? salamat! ipapasok ko pala sya sa 65watts na marshall

bro im selling 3 x 12ax7 (ElectroHarmonix)Bnew for 800pesos/each baka interesado ka PM mo lang ako.

[Phil]

...or you can go to my suki...the ever popular Doug Preston...www.dougstubes.com

...tell him your setup and what you are looking for ...he will suggest what tubes you need.

[Tarkuz Toccata]

mga sir, san po ba nakakabili ng replacement tubes for amps dito sa pinas? specifically ECC83 (12AX7)?? salamat!    

good luck na paghanap dito bro... i already tried calling the Audiophile main office and dalawa lang yung 12AX7 tubes na stock nila.

subukan niyo din tumawag sa audiophile pioneer tel. 746-2223 at ali mall 913-3557. tamad kasi minsan maghanap yung nasa main office...  

[pjrodz]

salamat mga sir! balitaan ko kayo pag nakabili na ko hehe

[greasykid]

Wala akong naintindihan sa sinabi ni abyss...  Puro si Katherine Heigl lang nakita ko...  

[Phil]

Wala akong naintindihan sa sinabi ni abyss...  Puro si Katherine Heigl lang nakita ko...  

haaay..galing nga ako sa beach....daming ganyan  naka itsy itsy bikini don.....nasusuka na ako sa magagandang blondes.....I wanna see some ugly ones for a change....hehehehe.