What's the difference ???

MIDNIGHT

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hey guys :wave:

i was just going over the tubedepot site and i realized how there are SO many different tube types and i don't know what makes each one different.. :eek2:

can anybody differentiate the different tube types please? :wave: (ex. 12AX7, 12AU7, 12AT7, EL, CA, DW, etc etc!!!) :slap:

whoops sorry... got carried away again :rofl:

:D

:hippie:
 

5F6-A

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that'd be reeeaaallllyyyyy long to explain. Why don't you get hold of a book like The tube amp by Aspen Pittman. Really good book and a great entrypoint to the fascinating world of tubes and amps driven by those....
 

GeeJay

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I'm no expert when it come to tubes, but as I understand one of the differences between 12AX, AT, AU is the amount of gain that each valve can deliver. But which is which I don't know.

Good luck in your quest to find the truth about tubes.. :)
 

lp59aholicDon

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I'm no expert when it come to tubes, but as I understand one of the differences between 12AX, AT, AU is the amount of gain that each valve can deliver. But which is which I don't know.

Good luck in your quest to find the truth about tubes.. :)
`12 AX7, reachs gain , overdrive distortion fastest Has Highest gain sensitivity, 12AY nest highest peak stage of gain, 12AX7s High and low end gain sensitive AY7s have a diffrent low end high end gain structure, the 12AU7 Gives the lowest gain break up signature highs and lows , AT7's are also commonly used phase inverters for older Fender Gibson and other tube amps The phase inverter has no real effect on the tonal output and or break up of your amp, its more there as a operational pre amp tube
 

rockinlespaul

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Tube Characteristics and substitutions
Some quick and dirty subs and some tube data such as recommended bias current and appx voltages. These subs are all taken from the Tube Substitution Handbook sold by Antique Electronics Supply. or provided from the net.

A (short) catalog of tubes you are likely to see in a guitar amp:

12AX7[A, WA] and substitutes - preamp and driver tubes
12AT7, 12AU7 and subs, preamp and driver tubes
12AY7 - driver tubes
6EU7 - dual triode used in some older amps for preamp tube
6L6 types - power output tubes, up to 50 watts/pair, a mainstay of Fender
EL34 - Euro power pentodes, up to 50 watts/pair, many Marshalls
6V6 - smaller, lower power cousin of the 6L6, 10-14 watts per pair; used in smaller Fenders
EL84 - fits a 9 pin socket like a 12AX7 but twice as tall; miniature power pentode, good for 12-18 watts per pair; used in smaller Vox amps, and a quad of these drives the Vox AC-30 for 30 watts.
Substitutions:
* means appropriate for parallel filament circuits
# means may not work in all circuits
Preamp and driver tube substitutions:

12AX7 (high gain dual triodes with pinout 9A)
12AD7* 12DT7 7729
12AU7# 5751* B339
12AU7A# 5751WA* B759
12AX7 6057 CV4004
12AX7A 6681 E83CC
12AX7WA 6L13 ECC803
12BZ7* 7025 ECC83
12DF7 7025A M8137
12DM7* 7494
12AU7 (moderately high gain dual triodes with pinout 9A)
12AU7[A,AW,] 6189 7730
12AX7* and subs 6670 ECC186
5814[A,AW]* 6680 ECC802
5963 7316 ECC82
6067 7489 M8136
12AT7 (medium gain dual triodes with pinout 9A)
12AT7[many suffixes] 7492 E81CC
6201 7728 ECC801
6679 A2900 M8162
ECC81 B152 QA2406
12AZ7[A]* B309 QB309
6060 B739
6671 CV4024
12AY7 (low gain dual triodes with pinout 9A)
12AY7(and suffixes) 6072
2082
Power tube substitutions:

6BQ5/EL84 (miniature pentode with pinout 9CV)
6267 7189 EF86
6BQ5 7189A EL84
6BQ5WA 7320 N709
6P15 E84L Z729
6L6 (beam power tube with pinout 7AC)
6L6(many suffixes) 7581(A)
5881 WT6
5932 EL37
EL34/6CA7 (power pentode with pinout 8ET)
EL34 12E13
6CA7 KT77
7D11 KT88
6550 (power pentode with pinout 7S)
6550[A] 7027A#
7D11 KT88
12E13
Cautionary Tubes - these are very hard to find

7591/7591A - legend has it that these otherwise excellent tubes were all bought up by an oriental buyer who toured the USA paying cash for all of them he could find, then disappearing. You are likely to only find used ones or the odd pair in some out of the way place. Dealers will in general not have them. I have personally seen trays full of NOS 7591A's for sale in the Akihabra electronics district in Tokyo, lending some credence to the rumor.
These were used a lot in old Ampegs. They are very small and high gain for their physical size, so there may not be a lot of room in a chassis for a larger replacement. The 5881 will work in some circuits, but has significantly lower transconductance.

Rumor Update: The rumor mill on the net says that the Russians will soon be making 7591's soon. Cross your fingers...

7199 - combination pentode/triode used as a one-tube voltage amp/phase inverter/driver for a pair of output tubes in some Ampeg amplifiers Note: These were once popular, but are now getting rarer and more expensive. There are a number of other pentode/triodes that can be substituted, but the pinouts are different and this will require require rewiring the socket for the tube. Examples are the 6AN8 and the 6U8. There is a Russian tube that is labeled 7199 which may work, although this is new.
7027/7027A - this is a high power tube similar to a 6550. The supply of these is very poor.
7189/7189A - a higher power/voltage version of the 6BQ5/EL84. Hard to find. A stock 6BQ5/EL84 may work if the power and voltage conditions in the amp are not right out at the limits of the tube design.


--------------------------------------------------------------------------------
From the GEO home page...
 

lp59aholicDon

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Tube Characteristics and substitutions
Some quick and dirty subs and some tube data such as recommended bias current and appx voltages. These subs are all taken from the Tube Substitution Handbook sold by Antique Electronics Supply. or provided from the net.

A (short) catalog of tubes you are likely to see in a guitar amp:

12AX7[A, WA] and substitutes - preamp and driver tubes
12AT7, 12AU7 and subs, preamp and driver tubes
12AY7 - driver tubes
6EU7 - dual triode used in some older amps for preamp tube
6L6 types - power output tubes, up to 50 watts/pair, a mainstay of Fender
EL34 - Euro power pentodes, up to 50 watts/pair, many Marshalls
6V6 - smaller, lower power cousin of the 6L6, 10-14 watts per pair; used in smaller Fenders
EL84 - fits a 9 pin socket like a 12AX7 but twice as tall; miniature power pentode, good for 12-18 watts per pair; used in smaller Vox amps, and a quad of these drives the Vox AC-30 for 30 watts.
Substitutions:
* means appropriate for parallel filament circuits
# means may not work in all circuits
Preamp and driver tube substitutions:

12AX7 (high gain dual triodes with pinout 9A)
12AD7* 12DT7 7729
12AU7# 5751* B339
12AU7A# 5751WA* B759
12AX7 6057 CV4004
12AX7A 6681 E83CC
12AX7WA 6L13 ECC803
12BZ7* 7025 ECC83
12DF7 7025A M8137
12DM7* 7494
12AU7 (moderately high gain dual triodes with pinout 9A)
12AU7[A,AW,] 6189 7730
12AX7* and subs 6670 ECC186
5814[A,AW]* 6680 ECC802
5963 7316 ECC82
6067 7489 M8136
12AT7 (medium gain dual triodes with pinout 9A)
12AT7[many suffixes] 7492 E81CC
6201 7728 ECC801
6679 A2900 M8162
ECC81 B152 QA2406
12AZ7[A]* B309 QB309
6060 B739
6671 CV4024
12AY7 (low gain dual triodes with pinout 9A)
12AY7(and suffixes) 6072
2082
Power tube substitutions:

6BQ5/EL84 (miniature pentode with pinout 9CV)
6267 7189 EF86
6BQ5 7189A EL84
6BQ5WA 7320 N709
6P15 E84L Z729
6L6 (beam power tube with pinout 7AC)
6L6(many suffixes) 7581(A)
5881 WT6
5932 EL37
EL34/6CA7 (power pentode with pinout 8ET)
EL34 12E13
6CA7 KT77
7D11 KT88
6550 (power pentode with pinout 7S)
6550[A] 7027A#
7D11 KT88
12E13
Cautionary Tubes - these are very hard to find

7591/7591A - legend has it that these otherwise excellent tubes were all bought up by an oriental buyer who toured the USA paying cash for all of them he could find, then disappearing. You are likely to only find used ones or the odd pair in some out of the way place. Dealers will in general not have them. I have personally seen trays full of NOS 7591A's for sale in the Akihabra electronics district in Tokyo, lending some credence to the rumor.
These were used a lot in old Ampegs. They are very small and high gain for their physical size, so there may not be a lot of room in a chassis for a larger replacement. The 5881 will work in some circuits, but has significantly lower transconductance.

Rumor Update: The rumor mill on the net says that the Russians will soon be making 7591's soon. Cross your fingers...

7199 - combination pentode/triode used as a one-tube voltage amp/phase inverter/driver for a pair of output tubes in some Ampeg amplifiers Note: These were once popular, but are now getting rarer and more expensive. There are a number of other pentode/triodes that can be substituted, but the pinouts are different and this will require require rewiring the socket for the tube. Examples are the 6AN8 and the 6U8. There is a Russian tube that is labeled 7199 which may work, although this is new.
7027/7027A - this is a high power tube similar to a 6550. The supply of these is very poor.
7189/7189A - a higher power/voltage version of the 6BQ5/EL84. Hard to find. A stock 6BQ5/EL84 may work if the power and voltage conditions in the amp are not right out at the limits of the tube design.

--------------------------------------------------------------------------------
From the GEO home page...
ROcking, Great post though I gotta hold soem question bout power output tube specs, since I had several amps that were wattage rated higher with pairs and quads , like the Deluxe Reverb is a 22 watt amp using 6v6's Crate Stealth is a 50 watt combo using the same tubes , 5881's can safely be pushed to 60 watts
 

rockinlespaul

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ROcking, Great post though I gotta hold soem question bout power output tube specs, since I had several amps that were wattage rated higher with pairs and quads , like the Deluxe Reverb is a 22 watt amp using 6v6's Crate Stealth is a 50 watt combo using the same tubes , 5881's can safely be pushed to 60 watts
Yeah, I agree. I just saw this on the net and figured I'd throw it out there...
 


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