You could try the direct coupled Loftin-White 2A3 amp at the fi primer here
I have built this and it does sound pretty good. I used 6B4G though. Only problem is the power transformer-you need quite a high B+... The EZ 2A3 at www.angela.com sounds pretty good to me too and can be made with whatever power transformer is lying around.
The output transformers make the biggest difference. The Hammond 125ESE are ok to start with, but get better iron and you won't look back.
I have built this and it does sound pretty good. I used 6B4G though. Only problem is the power transformer-you need quite a high B+... The EZ 2A3 at www.angela.com sounds pretty good to me too and can be made with whatever power transformer is lying around.
The output transformers make the biggest difference. The Hammond 125ESE are ok to start with, but get better iron and you won't look back.
Raj
i built a 5842 ccs into a fixed bias 2a3 parafeed 2.8k:8 sound not to bad. The layout is available at my website. I think components values are not yet included yet. At the moment using a 6j9 as the input stage.
you mean the whole amp being dht? or just the output stage?
i built a 5842 ccs into a fixed bias 2a3 parafeed 2.8k:8 sound not to bad. The layout is available at my website. I think components values are not yet included yet. At the moment using a 6j9 as the input stage.
you could mod the 300b to include the kt88. output trans should be the same. just the biasing points are different . B+ of 420 and -42 sounded good for me into a 2.5K:8 trans
HI everyone, thanks for the replies,
I don't quite know the individual charecteristics of tubes one would typically see in SE amplifiers, but here goes,
Frank if you think an otl SE can sound good and getting rid of the output cap is a complex issue, then I'll go with the cap....
I'd like it to be class A biased
As quite a few of you may know I've recently built the cd enhancer II with 3a5's, there's just something so fluid and musical about the sound.
As it happens I'm now looking for simple single ended design that has undescribable fluidity, harmonic texture and 'air' (have I hust described the perfect amplifier?)
I'm very open minded (apart from the SE bit ofcourse), and upon more serious thinking an otl would help keep costs down... But I'll still consider opt's as well......
With regards to DHT's, going on what I've personally heard, yes I would prefer that the signal is amplified using these type of tubes. Compromises could be made with regards to rectifiers, which don't have to be DHT's........ Heck I'm even leaning towards SS rectification for starters and pehaps tube rec's if I don't like the sound(I hope I'm not stepping on any toes here!).
Now there's also an added twist, in the future if it is at all possible I may use this amp with active crossovers (perhaps parrallel single ended amps would be better for this????) and use my SS amp with it, ofcourse this could be a can of worms.........
Thanks
Raja
I don't quite know the individual charecteristics of tubes one would typically see in SE amplifiers, but here goes,
Frank if you think an otl SE can sound good and getting rid of the output cap is a complex issue, then I'll go with the cap....
I'd like it to be class A biased
As quite a few of you may know I've recently built the cd enhancer II with 3a5's, there's just something so fluid and musical about the sound.
As it happens I'm now looking for simple single ended design that has undescribable fluidity, harmonic texture and 'air' (have I hust described the perfect amplifier?)
I'm very open minded (apart from the SE bit ofcourse), and upon more serious thinking an otl would help keep costs down... But I'll still consider opt's as well......
With regards to DHT's, going on what I've personally heard, yes I would prefer that the signal is amplified using these type of tubes. Compromises could be made with regards to rectifiers, which don't have to be DHT's........ Heck I'm even leaning towards SS rectification for starters and pehaps tube rec's if I don't like the sound(I hope I'm not stepping on any toes here!).
Now there's also an added twist, in the future if it is at all possible I may use this amp with active crossovers (perhaps parrallel single ended amps would be better for this????) and use my SS amp with it, ofcourse this could be a can of worms.........
Thanks
Raja
try and find a copy of a se design published in "hi-fi world"afew years back designed for them by mr T dePARAVINCI a quite a simple design using 6080 /= 6as7g's [ both relatively easy to find and inexpensive too!!!]in the O/P with 6dj8 /ecc 88 / 6922 et all & a 12ax7 fronts I have the circuit in one of their diy supp's and could email you a copy but havent hooked up my scanner yet:
errr; humph! shows how fast time flies I just dug out the supplement and it was dec /93 10 yrs ago!/ now only a whisker short of 11years.... only seems like yesterday to me:
cheers and regards to all Tomcat
will try and do something about that dang scanner@#**** bye, byeRaja,
Do you know how much power you need? That is determined by your speakers' efficiency, your room size, your normal listening volume, and some other factors. Once you've figured out how much power you need, then you can figure out if you can get there using SE DHTs.
I recently built an SE 2A3 amp with a design taken from the www.angela.com website (they have 2 SE 2A3 designs there, I built the one with the SRPP 6SL7 driver stage). The driver has since then been replaced with something different, the output transformers have been upgraded, and I've been trying out other things on it. So, in my experience, that is a good amp to start with, it's simple, sounds pretty good, and has plenty of room for upgrades and experiments. I think I spent about $500 for my first iteration of this amp (I think it cxan be built cheaper). So if 3.5W of power is enough for you and $500 isn't too much, this would be a good candidate.
Hope that helps.
Saurav
Do you know how much power you need? That is determined by your speakers' efficiency, your room size, your normal listening volume, and some other factors. Once you've figured out how much power you need, then you can figure out if you can get there using SE DHTs.
I recently built an SE 2A3 amp with a design taken from the www.angela.com website (they have 2 SE 2A3 designs there, I built the one with the SRPP 6SL7 driver stage). The driver has since then been replaced with something different, the output transformers have been upgraded, and I've been trying out other things on it. So, in my experience, that is a good amp to start with, it's simple, sounds pretty good, and has plenty of room for upgrades and experiments. I think I spent about $500 for my first iteration of this amp (I think it cxan be built cheaper). So if 3.5W of power is enough for you and $500 isn't too much, this would be a good candidate.
Hope that helps.
Saurav
Here are a number of nice online projects with nice discussions about the circuit and project in general. The last three are not sets but worth the look nonetheless.
* Ralph Power Building your Own DIY Tube Amp: Ralph discusses how he put one of Gary Dahl’s VV30B amp together. A nice intro read on how to go about it: http://www.intergate.com/~Rpower/buildamp.htm
* Fred Nachbar’s Mini-Blok SET http://www.dogstar.dantimax.dk/tubestuf/miniblok.htm
It might not look like much but don’t judge a book…….Fred has provided lots of info and a nice explanation of the circuit. Read his article on the little PP amp at his site too.
* Jeremy Epsteins’s Free Lunch Direct Coupled 2A3. A nice SET circuit and an online reading list to help explain it. http://home.earthlink.net/~jeremyepstein/freelunch.html
*Gaby Levinson, Single Ended 12B4A Parts I and II:
http://www.enjoythemusic.com/magazine/equipment/0902/levinson.htm
http://www.enjoythemusic.com/magazine/equipment/1002/levinson.htm[/url]
* Derek Walton’s JE Labs 300b project. A really excellent presentation of Joseph Esmilla’s (JELabs) SE 300b. http://indigo.ie/~walton/300b.html
Deluxe Edition: http://indigo.ie/~walton/300bmk2.html
*The “Darling” SET: http://www.diyparadise.com/Darling.html http://www.geocities.com/bobdanielak/darling.html AND http://members.lycos.nl/Aren/id12.htm
* John Sherwood’s 300b Breadboard : http://www.homestead.com/sparkgap/amp.html. Nice looking breadboard! If you are starting out do not think you have to commit to a chassis right away! It just complicates things sometimes. Complete with nice pictures of the circuit layout.
* 8W SE EL34 by Claus Byrith. Very nice articles that include a lot of theory. Check out his PP at the same site too: http://www.lundahl.se/claus_b_se.html
* Gordon Rankin’s Bugle 45 (Wavelength Audio site) http://www.wavelengthaudio.com/bugle.pdf
* Wardsweb Direct Coupled 2A3: Based on the Loftin-White design by John Day (1929) http://www.wardsweb.org/audio/dc2a3.html
* Aristidis Coumpas’ parafeed 45 (ala Kurt Strain) This is at the Audio Club of Athens Site. While you are there check out the “Audio Papers” section for lots of good projects. http://aca.gr/paper31.htm
* Thorston Loesch’s Legacy 300b: Based on the Western Electric 91 (WE91): http://www.fortunecity.com/rivendell/xentar/1179/projects/legacy/Legacy.html
* 813 Push Pull, transformer coupled. Based on Lynn Olson’s Aurora (this one isn’t so simple): http://www.izzy-wizzy.com/audio/powamp813.html
* Pete Millet’s very cool Zebrawood 829B (a conversation piece if I ever saw one!): http://www.pmillett.addr.com/829b_amplifier.htm
* Randy Carter’s Il Monstro, 845-845: http://www.cognitivEvent.com/av_monstro.html
Cheers
Craig Ryder
* Ralph Power Building your Own DIY Tube Amp: Ralph discusses how he put one of Gary Dahl’s VV30B amp together. A nice intro read on how to go about it: http://www.intergate.com/~Rpower/buildamp.htm
* Fred Nachbar’s Mini-Blok SET http://www.dogstar.dantimax.dk/tubestuf/miniblok.htm
It might not look like much but don’t judge a book…….Fred has provided lots of info and a nice explanation of the circuit. Read his article on the little PP amp at his site too.
* Jeremy Epsteins’s Free Lunch Direct Coupled 2A3. A nice SET circuit and an online reading list to help explain it. http://home.earthlink.net/~jeremyepstein/freelunch.html
*Gaby Levinson, Single Ended 12B4A Parts I and II:
http://www.enjoythemusic.com/magazine/equipment/0902/levinson.htm
http://www.enjoythemusic.com/magazine/equipment/1002/levinson.htm[/url]
* Derek Walton’s JE Labs 300b project. A really excellent presentation of Joseph Esmilla’s (JELabs) SE 300b. http://indigo.ie/~walton/300b.html
Deluxe Edition: http://indigo.ie/~walton/300bmk2.html
*The “Darling” SET: http://www.diyparadise.com/Darling.html http://www.geocities.com/bobdanielak/darling.html AND http://members.lycos.nl/Aren/id12.htm
* John Sherwood’s 300b Breadboard : http://www.homestead.com/sparkgap/amp.html. Nice looking breadboard! If you are starting out do not think you have to commit to a chassis right away! It just complicates things sometimes. Complete with nice pictures of the circuit layout.
* 8W SE EL34 by Claus Byrith. Very nice articles that include a lot of theory. Check out his PP at the same site too: http://www.lundahl.se/claus_b_se.html
* Gordon Rankin’s Bugle 45 (Wavelength Audio site) http://www.wavelengthaudio.com/bugle.pdf
* Wardsweb Direct Coupled 2A3: Based on the Loftin-White design by John Day (1929) http://www.wardsweb.org/audio/dc2a3.html
* Aristidis Coumpas’ parafeed 45 (ala Kurt Strain) This is at the Audio Club of Athens Site. While you are there check out the “Audio Papers” section for lots of good projects. http://aca.gr/paper31.htm
* Thorston Loesch’s Legacy 300b: Based on the Western Electric 91 (WE91): http://www.fortunecity.com/rivendell/xentar/1179/projects/legacy/Legacy.html
* 813 Push Pull, transformer coupled. Based on Lynn Olson’s Aurora (this one isn’t so simple): http://www.izzy-wizzy.com/audio/powamp813.html
* Pete Millet’s very cool Zebrawood 829B (a conversation piece if I ever saw one!): http://www.pmillett.addr.com/829b_amplifier.htm
* Randy Carter’s Il Monstro, 845-845: http://www.cognitivEvent.com/av_monstro.html
Cheers
Craig Ryder
Hi,
Thanks for the replies once again!!
Saurav I don't think I'll need more than a few watts, my own experience has shown that maybe a watt goes a long way.......
My speakers are 90db efficient, but i may use more sensative speakers in the future if required, I don't want earth shattering volume levels, around 90db should be fine!
Ryder you've given me a welath of info there thanks......
Frank have you any info on a SE OTL?????
Thanks
Raja
Thanks for the replies once again!!
Saurav I don't think I'll need more than a few watts, my own experience has shown that maybe a watt goes a long way.......
My speakers are 90db efficient, but i may use more sensative speakers in the future if required, I don't want earth shattering volume levels, around 90db should be fine!
Ryder you've given me a welath of info there thanks......
Frank have you any info on a SE OTL?????
Thanks
Raja
Everyone has been trying to help Raja. This is great and so here is my two cents worth. I think that Raja needs advice on the best tube and topology that can deliver 1W Single Ended Power. Among DHT, I would recommend 45 tube. There was an amp built by Stigla right here in this forum. If Frank or someone can post a link to this thread it would be nice. I do not know, how to do this!
I have a SE design using 45 tube. This was built two years ago and is in use with Lowther speakers…Oris Horn I believe. Very nice and dynamic. If you want the schematic just yell or buy me a lolly if we should ever meet.
My favourite SE amps are those using 6AS7/6080 and 6C41C tubes. These are commercial and so I cannot comment further. However, Raja can dig up some designs on the net and build one for himself.
Mohan
I have a SE design using 45 tube. This was built two years ago and is in use with Lowther speakers…Oris Horn I believe. Very nice and dynamic. If you want the schematic just yell or buy me a lolly if we should ever meet.
My favourite SE amps are those using 6AS7/6080 and 6C41C tubes. These are commercial and so I cannot comment further. However, Raja can dig up some designs on the net and build one for himself.
Mohan
Hi,
Will do.
Small world...
I'm no big fan of the Lowthers as is though, those cones need treatment to tame that nasty nasality.
Both are fine sounding tubes, no doubt about that, you need to drive them properly though.
I even like them better in PP but that's just my personal preference.
BTW, Mohan, did you read the OTL thread lately?
Cheers,
Will do.
Small world...
I'm no big fan of the Lowthers as is though, those cones need treatment to tame that nasty nasality.
Both are fine sounding tubes, no doubt about that, you need to drive them properly though.
I even like them better in PP but that's just my personal preference.
BTW, Mohan, did you read the OTL thread lately?
Cheers,
Raj,
My choice would be Bob Danielak's DC Darling, noted elsewhere in this thread and here: http://www.geocities.com/bobdanielak/darling.html
Bob is a superb engineer, and his design, using an 8532 and a 1626, runs off 400V, using no DC coupling caps for around 1W.
This design has been built by hundreds of triode lovers the world over, and with each iteration Bob has revisited the design to extract even more performance.
To experience the SE sound, albeit not completely DHT, I can't think of a better circuit.
Hi Mohan, nice to see you here!
Cheers,
Hugh
My choice would be Bob Danielak's DC Darling, noted elsewhere in this thread and here: http://www.geocities.com/bobdanielak/darling.html
Bob is a superb engineer, and his design, using an 8532 and a 1626, runs off 400V, using no DC coupling caps for around 1W.
This design has been built by hundreds of triode lovers the world over, and with each iteration Bob has revisited the design to extract even more performance.
To experience the SE sound, albeit not completely DHT, I can't think of a better circuit.
Hi Mohan, nice to see you here!
Cheers,
Hugh
Wow what a response!!
thanks evryone....
are the 300b designs really worth the extra expenditure?
The darling amp seems like a good start.....
But I'm a bit curious of what this 300b design could do
http://indigo.ie/~walton/300b.html
may as well do it right first time..........
thanks
Raja
thanks evryone....
are the 300b designs really worth the extra expenditure?
The darling amp seems like a good start.....
But I'm a bit curious of what this 300b design could do
http://indigo.ie/~walton/300b.html
may as well do it right first time..........
thanks
Raja
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