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EL34 SE ultralinear schematic

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#41
You can also protect the volume control with a capacitor on the input to the first tube but the grid must have a resistor to Gnd.

Some don't like a capacitor on the input..
In the link to the thread the circuits were modified quite a lot.

Anyway I'll shut up again.. 😀

Regards
M. Gregg
 
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#42
M Gregg said:
You can use EL34 in triode and "True triode".

The power is lower in Triode.

A few things to try..

I would probably put a 1K on G2 if you are going to switch.

NB on the circuit diagram its not a good idea to have the grid of the first tube dependant on the volume control wiper for a ground connection. Put a 1Meg or 470K from the grid to ground. you could also get grid current that will damage the volume control try a 10K in series with the grid from the volume control (100K).

Change anode resistor on the SL7 to 150K and try it again.
Without FB I guess you will have loads of 2nd harmonic..

The other thread..
http://www.diyaudio.com/forums/tubes-valves/179200-any-thoughts-circuit.html

Regards
M. Gregg
Click to expand...
Is it better to put 1K then 100R on G2 with triode and UL tap.
 
#43
celestar32 said:
Is it better to put 1K then 100R on G2 with triode and UL tap.
Click to expand...

You could use 220 Ohm the idea is to stop grid current and instability.
Try both..😀

Here is some food for thought:
http://www.audiofaidate.org/uploaded/plovati/PyeMozart10.JPG

The power supply on the PYE will not work on your amp<<the circuit has hum rejection built in ...without it, it hums like crazy 😀.
You can use a choke this will effect the sound and you can choke bypass to improve this..
Anyway back to your build..

Regards
M. Gregg
 
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#50
The EL34 will run with as little as 100 volts on the plate, but it runs best in ultra-linear mode, be it push pull or SE with around 400 - 450 volts on the plate. I find that distortion is very low, the tubes are happy and the amp sounds nice and smooth with good definition. The EL34 is my favorite output tube. I've been working with it since I was a kid in the 60's. I have used it in low voltage circuits (under 250 volts on the plate) but I keep going back to around 400 volts on the plate to get that beautiful EL34 sound. Also keep going back to Ultra-Linear circuits. The EL34 got it's reputation as a stellar hifi performer in circuits like the Mullard 5-20, the Dynaco Mark IV and ST70 and of course the HH Scott, Marantz and Fisher amps that used it. I have actually converted everything from American made Quick Sliver amps ( using the horrible 8417 output tube) to Chinese made amps using 6550's to use EL34's and in all cases the amps sounded better to my ears as well as my audiophile friend's ears. Even my later model Sunn 200S, that had 6550 output tubes, ended up sounding better with the EL34. This is just my opinion, but I consider the EL34 THE best audio tube ever produced. The Dutch Phillips company really had their stuff together when they designed that baby back in the 50's.
 
#51
seta1 said:
The EL34 will run with as little as 100 volts on the plate, but it runs best in ultra-linear mode, be it push pull or SE with around 400 - 450 volts on the plate. I find that distortion is very low, the tubes are happy and the amp sounds nice and smooth with good definition. The EL34 is my favorite output tube. I've been working with it since I was a kid in the 60's. I have used it in low voltage circuits (under 250 volts on the plate) but I keep going back to around 400 volts on the plate to get that beautiful EL34 sound. Also keep going back to Ultra-Linear circuits. The EL34 got it's reputation as a stellar hifi performer in circuits like the Mullard 5-20, the Dynaco Mark IV and ST70 and of course the HH Scott, Marantz and Fisher amps that used it. I have actually converted everything from American made Quick Sliver amps ( using the horrible 8417 output tube) to Chinese made amps using 6550's to use EL34's and in all cases the amps sounded better to my ears as well as my audiophile friend's ears. Even my later model Sunn 200S, that had 6550 output tubes, ended up sounding better with the EL34. This is just my opinion, but I consider the EL34 THE best audio tube ever produced. The Dutch Phillips company really had their stuff together when they designed that baby back in the 50's.
Click to expand...
I like this EL34 tubes and it was really a good audiophile tubes. It was a pity we can get those tubes cheap nowadays.
 
#52
Best EL34 I have ever used was the old Amperex Bugle Boy, made by Phillips. Best modern tube and close in sound tot he Amperex is the SED, but Svetlana has stopped making tubes, well audio tubes anyway. Bummer. I have a few quads of them still and plan to stop into this one place that still has some and buy a couple more quads. I have a LOT of amps that use the EL34 so that is one tube I like to keep on hand. Electroharmonix and J/J still produce them as do the Chinese. Tube quality coming out of China has really improved over the past ten years. But no one makes a modern production EL34 that sounds as good as the SED. Cheap is relative. Yea, SED are around $130 for a quad, but Electroharmonix are around $70 for a matched quad which is not bad. Heck I had to replace the output transistors in an old McIntosh 2205 and it cost me as much as a quad of El34's. Some output transistors are now getting as expensive as output tubes.. Go figure.
 
#53
EL34 Distortion

Seta1, the remarks you made about lower distortion in UL mode are confounding. If you look at the tube charts, the lines are clearly more parallel when the EL34 is operated in triode mode, which suggests that the distortion is lower. I don't understand why you say that the distortion is lower in UL mode. Maybe you are using your amp at its ragged edge and you need the little more power it provides in UL mode?

I have old JJ EL34 tubes, have you tried those and how do they compare to others that you have used.

Retsel
 
#54
more than four amp are running with this schematic, the sound is very good, in the last amp I substitute the cathode resistor 6sl7 for red led at 1,7v the sound is litle bit better..

EL34SE.jpg
 
#55
Retsel said:
Seta1, the remarks you made about lower distortion in UL mode are confounding. If you look at the tube charts, the lines are clearly more parallel when the EL34 is operated in triode mode, which suggests that the distortion is lower. I don't understand why you say that the distortion is lower in UL mode. Maybe you are using your amp at its ragged edge and you need the little more power it provides in UL mode?

I have old JJ EL34 tubes, have you tried those and how do they compare to others that you have used.

Retsel
Click to expand...

I don't know what sources you used to show triode mode with less distortion then UL mode, but every manual I have as well as actual tests in UL mode verses triode connected shows UL to have less overall distortion. Now, this is obviously dependent on circuit and the output transformer and where the UL tap is. I have actually built many EL34 amps over the years, some triode connected, some pentode and others UL and the UL amps were not only more pleasing to the ear, they tested better using a scope, distortion analyzer and a square wave as well as sine wave generator. Personally I do not like using pentodes in SE. I much prefer real triodes like the 300B or 2A3. If I need more power I just parallel tubes like the 2A3 or 300B. One of my amps uses two 2A3's in parallel in each channel and delivers around 8 watts before starting to clip. That amp is a joy to listen to through a pair of Belle Klipsch speakers.
My SE pentode amps are actually guitar amps and in that application, I am looking for distortion. For my hifi use, I use push pull EL34's in cathode biased ultra-linear. The push pull ultra linear amps just plain sound the best to me and many of my audiophile friends agree. But, as with anything audio, you need to let your own ears decide. I do use my 2A3 triode amps a lot and enjoy their sound as well. Both sets of amps are great in that they can be cranked up pretty loud and played for long periods without inducing ear fatigue. That is the real test of any amp. Can you stand listening to it for long periods without finding yourself reaching to turn the volume down.
I know many are totally taken with the idea of triode connecting pentodes and nothing I say or show via a scope or what ever device will change their mind. Hey, what ever works for your ears is what you should go with.. Myself, i just plain like tube amps. But, I have always had my best luck when I use a tube in a way it was designed to be used. The EL34 was originally designed for high end audio in a push pull ultra-linear type circuit. That's where it has always shined the brightest. That opinion was echoed in several 1950's publications with editorials on the subject of the EL34.
I had to work on a Cary integrated amp using 6550 output tubes a couple weeks ago. It had the usual Cary triode / UL switch. So I decided to do a little A/B testing between Triode and UL. There were four of us listening. Two could not tell the difference between triode and ultra-linear, and two of us found that the amp was tighter and the music more alive and accurate in Ultra Linear mode where as triode mode sounded slightly veiled with looser, less accurate bass. Now this amp used the 6550, and not the EL34, but the point here is that no one said the amp sounded better in triode mode and some could not even tell the difference. My suggestion would be to install a switch that allows you to switch between Ultra Linear and Triode mode. That would allow you some flexibility. If you don't like one mode, you just leave the switch in the other mode position.
 
#56
seta1 said:
I don't know what sources you used to show triode mode with less distortion then UL mode, but every manual I have as well as actual tests in UL mode verses triode connected shows UL to have less overall distortion. Now, this is obviously dependent on circuit and the output transformer and where the UL tap is. I have actually built many EL34 amps over the years, some triode connected, some pentode and others UL and the UL amps were not only more pleasing to the ear, they tested better using a scope, distortion analyzer and a square wave as well as sine wave generator. Personally I do not like using pentodes in SE. I much prefer real triodes like the 300B or 2A3. If I need more power I just parallel tubes like the 2A3 or 300B. One of my amps uses two 2A3's in parallel in each channel and delivers around 8 watts before starting to clip. That amp is a joy to listen to through a pair of Belle Klipsch speakers.
My SE pentode amps are actually guitar amps and in that application, I am looking for distortion. For my hifi use, I use push pull EL34's in cathode biased ultra-linear. The push pull ultra linear amps just plain sound the best to me and many of my audiophile friends agree. But, as with anything audio, you need to let your own ears decide. I do use my 2A3 triode amps a lot and enjoy their sound as well. Both sets of amps are great in that they can be cranked up pretty loud and played for long periods without inducing ear fatigue. That is the real test of any amp. Can you stand listening to it for long periods without finding yourself reaching to turn the volume down.
I know many are totally taken with the idea of triode connecting pentodes and nothing I say or show via a scope or what ever device will change their mind. Hey, what ever works for your ears is what you should go with.. Myself, i just plain like tube amps. But, I have always had my best luck when I use a tube in a way it was designed to be used. The EL34 was originally designed for high end audio in a push pull ultra-linear type circuit. That's where it has always shined the brightest. That opinion was echoed in several 1950's publications with editorials on the subject of the EL34.
I had to work on a Cary integrated amp using 6550 output tubes a couple weeks ago. It had the usual Cary triode / UL switch. So I decided to do a little A/B testing between Triode and UL. There were four of us listening. Two could not tell the difference between triode and ultra-linear, and two of us found that the amp was tighter and the music more alive and accurate in Ultra Linear mode where as triode mode sounded slightly veiled with looser, less accurate bass. Now this amp used the 6550, and not the EL34, but the point here is that no one said the amp sounded better in triode mode and some could not even tell the difference. My suggestion would be to install a switch that allows you to switch between Ultra Linear and Triode mode. That would allow you some flexibility. If you don't like one mode, you just leave the switch in the other mode position.
Click to expand...
I have to agree with you that pentodes in SE cannot compared to triode mode. That's why some built their amp with a switch between triode and UL. It all depend on the individual listening preference.
 
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