Banned
Joined 2002
I'm also extremely interested in tracking your progress Peter... I've spent a bit of time over the weekend reading and trying to understand Mr. Olsher's article and design. Quick question... are all the parts standard? Had difficulty finding, for example, 255R, 590R 3W and 1250 15W... looked at data sheets and could not find these values...
Best of luck and keep us posted.
Regards
Mark
Best of luck and keep us posted.
Regards
Mark
A couple of months ago me and a couple of audio friends have compared all of our 300B diy amps in one setup. they where al driven by a transformer coupled 5842 preamp and where driving a pair of diy horn speakers. I don't know exactly all the schematics of the amps but there where four different topology's
1) 5687 srpp / 300B
2) d3A/ecc99 mu-stage, cap coupled, we connected, grid chokes, all Black Gate WKZ, Jupiter wax coupling caps etc amorfe core output stage and chokes (my own ones, total cost about 2500 euro))
3) the biggest one, somewhat similar to the T-rex with massive tube regulated power supplies and d3A/#27 tubes input stage, silver amorfe core output stage etc (total cost about 4000 euro)
4) A monkey style 6N1P/300B with very cheap Italian transformers (don't know the brand name) (total cost about 700 euro)
and (sadly for me) the cheapest amp sounded clearly the best of all, had the best micro detail, the best micro and macro dynamics, the biggest soundstage and more power than all the others. The circuit was based on a monkey style 6N1P / 300B combination.
The friend with the most expensive regulated supply amp has rebuilt it into a monkey as well, he could do it because he allready had the higher voltage needed before the regulator and he says it sound way better than the old configuration (haven''t heard it myself yet)
My next amp is defenitly going to be some monkey design as well, maybe some food for thought
1) 5687 srpp / 300B
2) d3A/ecc99 mu-stage, cap coupled, we connected, grid chokes, all Black Gate WKZ, Jupiter wax coupling caps etc amorfe core output stage and chokes (my own ones, total cost about 2500 euro))
3) the biggest one, somewhat similar to the T-rex with massive tube regulated power supplies and d3A/#27 tubes input stage, silver amorfe core output stage etc (total cost about 4000 euro)
4) A monkey style 6N1P/300B with very cheap Italian transformers (don't know the brand name) (total cost about 700 euro)
and (sadly for me) the cheapest amp sounded clearly the best of all, had the best micro detail, the best micro and macro dynamics, the biggest soundstage and more power than all the others. The circuit was based on a monkey style 6N1P / 300B combination.
The friend with the most expensive regulated supply amp has rebuilt it into a monkey as well, he could do it because he allready had the higher voltage needed before the regulator and he says it sound way better than the old configuration (haven''t heard it myself yet)
My next amp is defenitly going to be some monkey design as well, maybe some food for thought
Konnichiwa,
In fact, it is not. The "drd" and the "Monkey" (also a circuit published in Tubecad under "safe Loftin White IIRC)) all share similar features in the Anode load of the driverstage, however the "Monkey" has a ubique and different bias strategy for the driver, compared to the other two.
The Name "Monkey" is actually an abreviation of the original name, given by Brian Clarke to this circuit, namely "Monkeys on a Stick", after the kids toy, as he claimed the schematic drawings reminded him of this toy.
The "monkey has a few other tricks up it's sleeves in terms of dynamic performance, but going into details would be off topic far too much.
A rather cusory treatment of the "Monkey is here:
http://www.fortunecity.com/rivendell/xentar/1179/theory/seamptheory/SEAmplifiertheory.html
(search for monkey if you don't want to read the whole document, though it's worth reading if I may say so myself...)
Sayonara
Sjef said:
In fact, it is not. The "drd" and the "Monkey" (also a circuit published in Tubecad under "safe Loftin White IIRC)) all share similar features in the Anode load of the driverstage, however the "Monkey" has a ubique and different bias strategy for the driver, compared to the other two.
The Name "Monkey" is actually an abreviation of the original name, given by Brian Clarke to this circuit, namely "Monkeys on a Stick", after the kids toy, as he claimed the schematic drawings reminded him of this toy.
The "monkey has a few other tricks up it's sleeves in terms of dynamic performance, but going into details would be off topic far too much.
A rather cusory treatment of the "Monkey is here:
http://www.fortunecity.com/rivendell/xentar/1179/theory/seamptheory/SEAmplifiertheory.html
(search for monkey if you don't want to read the whole document, though it's worth reading if I may say so myself...)
Sayonara
The design seems to be overly complex, missing the point of a 300B SET.
But most importantly, the local NFB (Negative FeedBack) seems to be in the wrong place or unnecessary.
300B has superb linearity but also has a low amplification factor of around 3.5. To produce a 700V peak to peak output swing, for example, will require 200V peak to peak input swing at the grid. This is a very large amount of output swing that many driver tubes will suffer a linearity problem. As a matter of fact this is a well known problem in 845 SET and why many 845 SET's use 300B in the driver stage.
A local NFB to further improve the already very linear 300B output stage seems to be unnecessary. On the other hand it will reduce the gain of the output stage and demand even larger output swing from the already suffering driver stage. Not a good idea.
Tube Express
But most importantly, the local NFB (Negative FeedBack) seems to be in the wrong place or unnecessary.
300B has superb linearity but also has a low amplification factor of around 3.5. To produce a 700V peak to peak output swing, for example, will require 200V peak to peak input swing at the grid. This is a very large amount of output swing that many driver tubes will suffer a linearity problem. As a matter of fact this is a well known problem in 845 SET and why many 845 SET's use 300B in the driver stage.
A local NFB to further improve the already very linear 300B output stage seems to be unnecessary. On the other hand it will reduce the gain of the output stage and demand even larger output swing from the already suffering driver stage. Not a good idea.
Tube Express
After more than a year since the T-Rex amp has been built I finally have it for evaluation in my system.
I have it hooked up to Fertins 20 EX, preamp is S&B TX102, sources: CEC TL0 and heavily modified BiDAT.
I must admit that the amp sounds very good and I don't really miss my previous reference.
Comparing to Patek it has very similar tonal balance, very similar low end performance, but more texture and space. Patek has somewhat better PRAT and more emotional involvement.
However, the T-Rex is built with rather average parts, the 300B tubes are from JJ presently but I will be switching to WE soon. I'm seriously considering building another set, but this time with more attention to proper parts choices.
I have it hooked up to Fertins 20 EX, preamp is S&B TX102, sources: CEC TL0 and heavily modified BiDAT.
I must admit that the amp sounds very good and I don't really miss my previous reference.
Comparing to Patek it has very similar tonal balance, very similar low end performance, but more texture and space. Patek has somewhat better PRAT and more emotional involvement.
However, the T-Rex is built with rather average parts, the 300B tubes are from JJ presently but I will be switching to WE soon. I'm seriously considering building another set, but this time with more attention to proper parts choices.
Attachments
Banned
Joined 2002
Peter Daniel said:After more than a year since the T-Rex amp has been built I finally have it for evaluation in my system.
I have it hooked up to Fertins 20 EX, preamp is S&B TX102, sources: CEC TL0 and heavily modified BiDAT.
I must admit that the amp sounds very good and I don't really miss my previous reference.
Comparing to Patek it has very similar tonal balance, very similar low end performance, but more texture and space. Patek has somewhat better PRAT and more emotional involvement.
However, the T-Rex is built with rather average parts, the 300B tubes are from JJ presently but I will be switching to WE soon. I'm seriously considering building another set, but this time with more attention to proper parts choices.
DUST!! WOAH!!
I wonder how much that thing weighs ?
Banned
Joined 2002
Peter Daniel said:After more than a year since the T-Rex amp has been built I finally have it for evaluation in my system.
I have it hooked up to Fertins 20 EX, preamp is S&B TX102, sources: CEC TL0 and heavily modified BiDAT.
I must admit that the amp sounds very good and I don't really miss my previous reference.
Comparing to Patek it has very similar tonal balance, very similar low end performance, but more texture and space. Patek has somewhat better PRAT and more emotional involvement.
However, the T-Rex is built with rather average parts, the 300B tubes are from JJ presently but I will be switching to WE soon. I'm seriously considering building another set, but this time with more attention to proper parts choices.
nice to see your working with tubes, do i see a kit in the future
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