A friend who makes a living servicing electronics once told me the 7591 was better known for causing smoke.
Quite a few years ago a stereo amp, I think HK came my way, the four 7591s were cooked.
Perhaps the JJs are better.
Quite a few years ago a stereo amp, I think HK came my way, the four 7591s were cooked.
Perhaps the JJs are better.
6P25 agree
KT61 - expensive but KT81 is the loctal, rarer maybe cheaper
EL33 - best of all these, really good in triode, cheaper than KT61
EL11 - very nice, similar to EL33 but Y8A socket
EL41 - good but not as good as EL33 in triode - rimlok.
E80L - also good, clean and detailed but not octal of course.
I tried out all these in triode mode as drivers. EL33 and EL11 were best followed by E80L, then the others about equal. All were better than EL84 in triode and also 6V6 in triode.
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A triode strapped 6AV5GA is effectively an indirectly heated 6B4G and less money for now. Of course, it's nothing like an EL84 in an octal package though.
I used them in push pull in a modular amp I sold (320V B+, 60mA, 2k2 Ra-a).
George has some info on his site tubelab.com
I used them in push pull in a modular amp I sold (320V B+, 60mA, 2k2 Ra-a).
George has some info on his site tubelab.com
EL11 as well AL4 yes after EL33
there's more PL33 heater 19 v, but so far only acquired, haven' t heard yet
I remembered, there are more EF55
there's more PL33 heater 19 v, but so far only acquired, haven' t heard yet
I remembered, there are more EF55
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AL4, EL11, EL3N, EL33, EBL1, EBL21 - all the same pentodes (of course besides envelopes, sockets, heaters...)!
Best regards!
Best regards!
Maybe compressing, lower power, low emission, low peak current. Anemic.
Just get a JJ KT77 and be done with it. Better triode curves, twice the power, cheaper, octal.
Or EL34, or EL36 if you like rounded knee distortion/compression.
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Think of vacuum tubes as a tool.
Don't use a screwdriver when what you need is a hammer.
(The but end of the screwdriver can work as a very poor/bad hammer).
Do not design your EL84 or 6V6 amplifier to get as much output power as an EL34 amplifier.
Your Mileage May Vary.
I have used my JJ 7591S tubes for hundreds of hours (I think for more than a thousand hours).
I use them within their maximum ratings.
They are still self biasing to the same current.
They are still low distortion.
They still have the same output power.
The damping factor, without any global feedback, is still the same . . .
And, I am able to sleep at night because I know I do not have to worry about those 7591S tubes going bad.
Don't use a screwdriver when what you need is a hammer.
(The but end of the screwdriver can work as a very poor/bad hammer).
Do not design your EL84 or 6V6 amplifier to get as much output power as an EL34 amplifier.
Your Mileage May Vary.
I have used my JJ 7591S tubes for hundreds of hours (I think for more than a thousand hours).
I use them within their maximum ratings.
They are still self biasing to the same current.
They are still low distortion.
They still have the same output power.
The damping factor, without any global feedback, is still the same . . .
And, I am able to sleep at night because I know I do not have to worry about those 7591S tubes going bad.
The original poster needs to clarify what this design is going to be doing. Head phone Amp?
An EL84 type is going to be pretty anemic in SET mode.
At 19 Watt Pdiss, (7591) there is some range of choices, 7591, 7868, EL506 (rare), 10/6JA5 ($3 EL506), 6P41S, 25HX5, 6GB5, EL36.....
7591 and EL36 are actually Octal (the others are same size, but non Octal bases). (10/6JA5 is bigger, at 1.5" diameter. )
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The original poster is no more, has not answered questions and have not been active. I suggest we let him
continue to sleep.
The OP ( me ) is still here, just have had no time for a proper ( which will be detailed ) response. So sorry.
I will get to it this weekend. I should have been more specific in what I am doing.
Thanks, Crazy Bill
I will get to it this weekend. I should have been more specific in what I am doing.
Thanks, Crazy Bill
EL84 is super easy to drive. Only 13V peak input to full power, or less if you're operating the output stage at lower voltage/higher current.
7591 is probably the closest one can get to an octal version of EL84. A bit harder to drive (but not much), a bit more power output available.
EBL21 looks like a great match for EL84 but octal. Are any available? Whoever suggested that, nice one!
6V6 is often considered close to EL84, but it's more of a baby 6L6, with lower gm than EL84. A bit harder to drive than an EL84.
EL33 is a nice suggestion. Very easy to drive, but less output power than an EL84. http://www.r-type.org/pdfs/el33.pdf
EL11 looks great but where do you find the socket?
EL34 is a bit harder to drive. Figure about 30V to 35V peak input to full power. Also requires significantly more heater power.
6AV5GA-triode is about as difficult to drive as a 6L6 or a KT88 (or a 2A3 or a 6B4G, of course). Figure 40V to 50V peak input to full power.
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7591 is probably the closest one can get to an octal version of EL84. A bit harder to drive (but not much), a bit more power output available.
EBL21 looks like a great match for EL84 but octal. Are any available? Whoever suggested that, nice one!
6V6 is often considered close to EL84, but it's more of a baby 6L6, with lower gm than EL84. A bit harder to drive than an EL84.
EL33 is a nice suggestion. Very easy to drive, but less output power than an EL84. http://www.r-type.org/pdfs/el33.pdf
EL11 looks great but where do you find the socket?
EL34 is a bit harder to drive. Figure about 30V to 35V peak input to full power. Also requires significantly more heater power.
6AV5GA-triode is about as difficult to drive as a 6L6 or a KT88 (or a 2A3 or a 6B4G, of course). Figure 40V to 50V peak input to full power.
--
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Hello all,
First, many thanks for your responses. Much appreciated.
I'll give you the condensed version of how I got here.
Purchased a Decware outfit back in 2004 ( ? ).
SE84CSEX, ZSLA1 Sig, and a pr of HDT speakers.
I have no formal training, but my father was an EE for Perkin-Elmer so the need to tinker is in my genes.
After reading all I could on the forum, I of course got the urge to mod the amp and see where it could go. Eli D and Eddie Vaughn were a great help in getting a newb like myself to safely navigate the many mods that I eventually did to the amp. To the point where it really was no longer a Decware product, except for the stock OPTs which eventually got swapped out.
After swapping IT coupling for the RC coupling in the stock amp, I could not ( for various reasons ) get it quiet. So I took it apart intending to rebuild it on a larger chassis.
Then a full Stax set-up fell into my lap and I stopped listening to speakers. The amp is still in pieces in my garage. I haven't listened to speakers for at least 7-8 yrs, but I will again. So:
The plan is to take the parts I have from playing around back then ( all high end stuff. Electraprint PS iron, chokes, IT, Transcendar OPT, every fabled resisstor going ( Shinkoh, Riken, Kiwame, etc., ASC motor run caps, Rusky pio PS caps and more ) and build the ultimate version of that amp ( or similar ) But before I actually started I wanted to make sure the EL84/SV83 choice was not easily surpassed by something my present OPT could use.
The OPT is a Transcendar that was one of the five they built as the prototype for Eddie Vaughn's Carina. 5K primary, 4/8 ohm secondary with 43 % UL tap. So I could utilize a 2A3 or a type 45. But since it will still be used to drive headphones most of the time, DC filaments are mandatory. Meaning Coleman regs. I'm a little apprehensive about that as this will be my first scratch build and the added complexity is a bit daunting. But if you guys can convince me that a DHT will trounce an EL84/SV83, I'll go that route. Don't want to spend the money as I have everything here staying with an el84 type.
So, what do you think. Stick with EL84, one of the other tubes offered up here ( Eli D has been preaching the 6v6 tubes to me for a long time. Maybe I should listen ! ), or go with a DHT.
as always, thanks in advance for any advice.
Cheers, Crazy Bill the Eel Killer
First, many thanks for your responses. Much appreciated.
I'll give you the condensed version of how I got here.
Purchased a Decware outfit back in 2004 ( ? ).
SE84CSEX, ZSLA1 Sig, and a pr of HDT speakers.
I have no formal training, but my father was an EE for Perkin-Elmer so the need to tinker is in my genes.
After reading all I could on the forum, I of course got the urge to mod the amp and see where it could go. Eli D and Eddie Vaughn were a great help in getting a newb like myself to safely navigate the many mods that I eventually did to the amp. To the point where it really was no longer a Decware product, except for the stock OPTs which eventually got swapped out.
After swapping IT coupling for the RC coupling in the stock amp, I could not ( for various reasons ) get it quiet. So I took it apart intending to rebuild it on a larger chassis.
Then a full Stax set-up fell into my lap and I stopped listening to speakers. The amp is still in pieces in my garage. I haven't listened to speakers for at least 7-8 yrs, but I will again. So:
The plan is to take the parts I have from playing around back then ( all high end stuff. Electraprint PS iron, chokes, IT, Transcendar OPT, every fabled resisstor going ( Shinkoh, Riken, Kiwame, etc., ASC motor run caps, Rusky pio PS caps and more ) and build the ultimate version of that amp ( or similar ) But before I actually started I wanted to make sure the EL84/SV83 choice was not easily surpassed by something my present OPT could use.
The OPT is a Transcendar that was one of the five they built as the prototype for Eddie Vaughn's Carina. 5K primary, 4/8 ohm secondary with 43 % UL tap. So I could utilize a 2A3 or a type 45. But since it will still be used to drive headphones most of the time, DC filaments are mandatory. Meaning Coleman regs. I'm a little apprehensive about that as this will be my first scratch build and the added complexity is a bit daunting. But if you guys can convince me that a DHT will trounce an EL84/SV83, I'll go that route. Don't want to spend the money as I have everything here staying with an el84 type.
So, what do you think. Stick with EL84, one of the other tubes offered up here ( Eli D has been preaching the 6v6 tubes to me for a long time. Maybe I should listen ! ), or go with a DHT.
as always, thanks in advance for any advice.
Cheers, Crazy Bill the Eel Killer
Is this new amplifier design going to run Stax headphones, what impedance are they, and how much power do they need?
Or will the new amplifier run efficient loudspeakers?
What is the DC current rating of the Transcendar 5k output transformers?
Or will the new amplifier run efficient loudspeakers?
What is the DC current rating of the Transcendar 5k output transformers?
Negative on running the Stax headphones. They are stats' and require a dedicated electrostatic headphone amplifier. I have a Woo Audio WES to fill that bill.
It will be powering my Decware HDT ( single full range driver using a Fostex driver ). High enough sensitivity to where I never approach full volume. And I'm a classic rock guy who plays fairly loud.
It will also power various dynamic cans with impedance ratings from 25 to 300 ohms. I usually put a 12 ohm wirewound across the BP to bring the impedance seen by the amp down and flatten it some. Works very well.
FWIW, this will not be a new design. It will be loosely based upon the Decware SE84 series. I bought all of these parts to build the ultimate version of that amp years ago but never got around to it ). It will be one of the following:
1). If I choose either the 6922 or 6n1p for the driver stage, it will be IT coupled to the EL84/SV83 ( or one of the alternatives offered here )
2).If I choose a triode strapped EF86 ( CCS loaded ), it will be cap coupled to the EL84 ( this was a favorite configuration of Eddie Vaughn )
I decided I should investigate whether there was a better alternative to the EL84/SV83 utilizing the Transcendar OPT. I can't tell you the ma rating as I didn't buy them from Transcendar, but from EV's associate who was involved in the early stages of getting the Carina off the ground. I never received that info.
that said, years ago I went on the Transcendar site and compared my OPT to available units. It appeared ( and I'm going by memory here as the Trancendar site is down ) the it was rated for 60 ma and 10 watts. But that's just a guesstimate.
Thanks for all the help.
Cheers, Crazy Bill
It will be powering my Decware HDT ( single full range driver using a Fostex driver ). High enough sensitivity to where I never approach full volume. And I'm a classic rock guy who plays fairly loud.
It will also power various dynamic cans with impedance ratings from 25 to 300 ohms. I usually put a 12 ohm wirewound across the BP to bring the impedance seen by the amp down and flatten it some. Works very well.
FWIW, this will not be a new design. It will be loosely based upon the Decware SE84 series. I bought all of these parts to build the ultimate version of that amp years ago but never got around to it ). It will be one of the following:
1). If I choose either the 6922 or 6n1p for the driver stage, it will be IT coupled to the EL84/SV83 ( or one of the alternatives offered here )
2).If I choose a triode strapped EF86 ( CCS loaded ), it will be cap coupled to the EL84 ( this was a favorite configuration of Eddie Vaughn )
I decided I should investigate whether there was a better alternative to the EL84/SV83 utilizing the Transcendar OPT. I can't tell you the ma rating as I didn't buy them from Transcendar, but from EV's associate who was involved in the early stages of getting the Carina off the ground. I never received that info.
that said, years ago I went on the Transcendar site and compared my OPT to available units. It appeared ( and I'm going by memory here as the Trancendar site is down ) the it was rated for 60 ma and 10 watts. But that's just a guesstimate.
Thanks for all the help.
Cheers, Crazy Bill