If you are interested and hopefully it might give some insight,
Here's the link to my 1625 amp. It sounds really good to people I know...including an audiophile...but it might sound like chicken dung to other's, even you...who knows?
I'm sure others will criticize it... hey, that's what this forum is for...the encouragement, critiques of peoples work for the sake of sharing knowledge to improve tube audio.
http://www.diyaudio.com/forums/tubes-valves/307321-misty-se-1625-triode-strapped-newest-build.html
You say you have 94db speakers and you are trying to reach 102db. 4Watts gets you to 100db... within range of a SE triode with a 5K OPT.
I'm not sure what will give the lowest distortion... however triode seems to give good sound even with 5k opt's.
I will take even order harmonic distortion with no feedback over odd order...
However, the great thing is... everyone hears differently... so the question is... what do you like?
Build the chassis larger than you think you need...to give yourself space to add tubes, components as you develop it... you can start with triode...if you don't like it, you will have room for tetrode...and even PP if you decide...
No one can really tell you what will sound better...only distortion figures, power and safety can be calculated by math and what people convey on paper/ screen.
Here's the link to my 1625 amp. It sounds really good to people I know...including an audiophile...but it might sound like chicken dung to other's, even you...who knows?
I'm sure others will criticize it... hey, that's what this forum is for...the encouragement, critiques of peoples work for the sake of sharing knowledge to improve tube audio.
http://www.diyaudio.com/forums/tubes-valves/307321-misty-se-1625-triode-strapped-newest-build.html
You say you have 94db speakers and you are trying to reach 102db. 4Watts gets you to 100db... within range of a SE triode with a 5K OPT.
I'm not sure what will give the lowest distortion... however triode seems to give good sound even with 5k opt's.
I will take even order harmonic distortion with no feedback over odd order...
However, the great thing is... everyone hears differently... so the question is... what do you like?
Build the chassis larger than you think you need...to give yourself space to add tubes, components as you develop it... you can start with triode...if you don't like it, you will have room for tetrode...and even PP if you decide...
No one can really tell you what will sound better...only distortion figures, power and safety can be calculated by math and what people convey on paper/ screen.
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Ok,do i use zeners to stabilizie Vg2 then?
Can you please explain that more to me,what value,can you make a drawing. 🙂
None. But the lower is an error order, the less it is audible. The lower is loudness, the lower order and level of distortions is acceptable.
Did a search on RH807 and it seems it all have been done before....and that it should be a pentode driver..therfore I thoght I´d try a 6J51P in pentode mode as driver.maybe thats been done before to.. 🙂
You can. I tried it, but feeding them via an RC filter from B+ sounded better. Zeners sounded grainy and thin, midrange was dead and top end was noisy. Tried quieting them with caps but it did not help much.
Implementing the RC filter: From 350V to 250V we need to drop 100V, at 2.5mA, that is: you need a 40K resistor (I recommend an 1W or 2W KOA Speer carbon film) and a smallish value, high quality plastic cap to ground (10-20uF or so, value not critical - quality matters more). Separate RC filters for each screen.
To most people's hearing H3 messes up the sound much more than H2. Very little H3 is already noticeable and intrusive, while comparatively much higher levels of H2 are usually well tolerated.
H2 makes the sound seem fuller and richer.
H3 makes it seem louder.
H2 dominating over H3 - typical SET sound stereotype
H3 dominating over H2 - typical PP sound stereotype
You can use that. I would suggest a Rubycon, 400V rated. You can go bigger than 10-20uF with the plastics, I would use 100uF, if you can fit it physically.
Or, you can use a small value DC Link cap. In the 20uF range they are pretty compact.
Screen supply is super sensitive, makes a bigger impact on sound than the plate supply. Just think about it: even big changes in plate voltage have absolutely negligible impact on plate current for 807, while the slightest changes in screen voltage have big impact on the plate current. Hence, screen supply (in general, but particularly for 807) is paramount, its regulation and filtering requires more attention than the plate.
In the power supply try to use your best quality parts and save as much space as possible for the screen supply.
Thank you janos,
I try...
I was hoping I would get at least one response 🙂 and a delightful response it is.
Motor run caps if you can fit them in... they are oil filled polypropylene made for high amperage and usually 450VDC
I find 2nd harmonic is more preferred.
the order of harmonics are fairly simple...
I have read that even distortion is full octaves away from the primary. While odd order are half octaves away.
So, if you are playing 1000 htz the following results would be:
Orders of distortions-
2nd = 2Khtz 1 octave
3rd = 3Khtz 1.5 octaves
4th = 4khtz 2 octaves
5th = 5khtz 2.5 octaves
6th = 6khtz 3 octaves
and so on.
So, think of harmony with instruments... a piano playing C and one octave above -C
with be less noticeable than higher F#. Distortion can kinda be thought of like this...
So one will not necessarily be "better" due to everyone's hearing and preferences are different... only generalizations can be made.
IMD modulation, however, is all over the place.
Some prefer distortion to no distortion free amplifiers. Often solid state integrated circuits and test distortion free below the threshold of hearing...yet tubes are often preferred...but I'm staying out of this hornets nest.
the order of harmonics are fairly simple...
I have read that even distortion is full octaves away from the primary. While odd order are half octaves away.
So, if you are playing 1000 htz the following results would be:
Orders of distortions-
2nd = 2Khtz 1 octave
3rd = 3Khtz 1.5 octaves
4th = 4khtz 2 octaves
5th = 5khtz 2.5 octaves
6th = 6khtz 3 octaves
and so on.
So, think of harmony with instruments... a piano playing C and one octave above -C
with be less noticeable than higher F#. Distortion can kinda be thought of like this...
So one will not necessarily be "better" due to everyone's hearing and preferences are different... only generalizations can be made.
IMD modulation, however, is all over the place.
Some prefer distortion to no distortion free amplifiers. Often solid state integrated circuits and test distortion free below the threshold of hearing...yet tubes are often preferred...but I'm staying out of this hornets nest.
I just want to clarify something..
I Definitely don't want to spread myths...
I just know people that preferred speakers and amplifiers with more distortion. It is perceived to make the music sound fuller...with emphasis on perceived. As time went by, they realize the difference.
The main thing is , not everyone prefers "correct" sound.
I'm not saying more about it as I don't want this thread becoming hi-jacked.
I know only one such a guy, but he has impaired hearing, and distortions help him to hear a soundstage.
But all that hypo about "euphonic 2'Nd Order Distortion" is a myth created to explain why when early transistor amps measured low distortions people still preferred tube sound.
So called "tube sound" does not mean presence of some "specific tube distortions", but absence of distortions caused by amps of typical solid state topology. I can show you a "toobey" solid state amp that is free from such distortions, and indeed it sounds "toobey".
However, I can believe that some people do not enjoy the music because they do not understand it, so high intrermods causing porridge instead of an orchestra remain them what "the right tube amp supposed to sound". But they are cargo cult audiophiles. 🙂 Why you should assume that the topic srtarter is the one and hijack his thread? I don't know.
But all that hypo about "euphonic 2'Nd Order Distortion" is a myth created to explain why when early transistor amps measured low distortions people still preferred tube sound.
So called "tube sound" does not mean presence of some "specific tube distortions", but absence of distortions caused by amps of typical solid state topology. I can show you a "toobey" solid state amp that is free from such distortions, and indeed it sounds "toobey".
However, I can believe that some people do not enjoy the music because they do not understand it, so high intrermods causing porridge instead of an orchestra remain them what "the right tube amp supposed to sound". But they are cargo cult audiophiles. 🙂 Why you should assume that the topic srtarter is the one and hijack his thread? I don't know.
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