Hi,
I mostly listen to rock and jazz music. I am going to build a power amp for my paradigm monitor5 speakers which is 91db in efficiency. I want a SE amp, so what about a 2A3 SE amp? Should it be enough power to drive my speaker?
I am not thinking about 300B as they are very expensive. I would prefer to spend my budget on the transformers and caps. BTW the search tells me 300B will be lack of bass for rock music..
Any suggestion?
Thanks
laiben
I mostly listen to rock and jazz music. I am going to build a power amp for my paradigm monitor5 speakers which is 91db in efficiency. I want a SE amp, so what about a 2A3 SE amp? Should it be enough power to drive my speaker?
I am not thinking about 300B as they are very expensive. I would prefer to spend my budget on the transformers and caps. BTW the search tells me 300B will be lack of bass for rock music..
Any suggestion?
Thanks
laiben
laiben,
A 2A3 SET amp will be UNSATISFACTORY. Paul Joppa has provided a useful rule of thumb, which says, in a "typical" room, that an amp/speaker combo should be capable of 102 dB. SPL peaks, at a 1 M. distance. Your speakers require at least 16 W. A taste for "head banger" rock music suggests that yet more power is necessary.
A KT88 operating in pentode mode and using regulated screen grid B+ will do the job. Loop NFB of some kind is needed to provide an adequate damping factor.
If your heart is set on having a DHT amp, look for designs employing the 845. However, you will have to deal with 1.2 KV. B+ and expensive O/P trafos, to use 845s.
A 2A3 SET amp will be UNSATISFACTORY. Paul Joppa has provided a useful rule of thumb, which says, in a "typical" room, that an amp/speaker combo should be capable of 102 dB. SPL peaks, at a 1 M. distance. Your speakers require at least 16 W. A taste for "head banger" rock music suggests that yet more power is necessary.
A KT88 operating in pentode mode and using regulated screen grid B+ will do the job. Loop NFB of some kind is needed to provide an adequate damping factor.
If your heart is set on having a DHT amp, look for designs employing the 845. However, you will have to deal with 1.2 KV. B+ and expensive O/P trafos, to use 845s.
Thanks for the suggestion guys. I will look further about the KT88 SE schematic floating on the Internet. I am running grounded grid preamp but the Mikael looks like a integrated amp with volume control. Could I just short the volume control in the input stage to make it as an power amp?
I am not going to use 845. Though I've bulit an 50W pull-push guitar amp with ~600V, it is pretty scary to touch anything >1000V......
Thanks
I am not going to use 845. Though I've bulit an 50W pull-push guitar amp with ~600V, it is pretty scary to touch anything >1000V......
Thanks
laiben said:Thanks for the suggestion guys. I will look further about the KT88 SE schematic floating on the Internet. I am running grounded grid preamp but the Mikael looks like a integrated amp with volume control. Could I just short the volume control in the input stage to make it as an power amp?
I am not going to use 845. Though I've bulit an 50W pull-push guitar amp with ~600V, it is pretty scary to touch anything >1000V......
Thanks
How can you manage to use ten dollars to settle a hundred bucks bill??? Unless magic!!!
Your spk. only 91db. and your favorite music is pop -----
in order to drive such efficiency spk. at lease required 20 watts.
From data, for Single end design, only transmitting valve could fit.
the common tube like EL34, KT88, KT100 and 6550 only deliever a max. of 12 watts. then back to the tropic, use ten bucks to settle a hundred dollars bill???
Scare of the high voltage, switch to transistor.
18, I have built the SimpleSE and I like all kinds of music, from quite jazz to classical to progressive rock to techno dance music. I have 92dB speakers actively crossed over at 80Hz. The only real issue I have had with this amp is trying to play choral/orchestral music at very high volumes when in triode mode (can switch to U/L with switch on the front). For all other music my ears run out before the amp does. I find it quite loud enough for my taste for home use. Previous to this I had 60 watt home brew chip amps and before that 200 watt Adcom 555.
The SimpleSE comes simply as a PC board. You can put whatever sockets you like on it. I used the part numbers recommended, they are ceramic sockets and after about four months of continuous use the only problem that I have had is a blown rectifier tube (JJ GZ34) and blown silicone diodes. I put the blown tube down to poor manufacturing (not Chinese - Slovac) and the blown silicone diodes down to implementation of the standby switch. Since removing the standby switch option and switching to Sovtek 5AR4 and Winged C 5U4G diode I have had no problems. I think that those sockets might be Chinese, but so is the Apple Macbook Pro I am typing this message on. Poor quality is poor quality no matter where it is made.
The SimpleSE comes simply as a PC board. You can put whatever sockets you like on it. I used the part numbers recommended, they are ceramic sockets and after about four months of continuous use the only problem that I have had is a blown rectifier tube (JJ GZ34) and blown silicone diodes. I put the blown tube down to poor manufacturing (not Chinese - Slovac) and the blown silicone diodes down to implementation of the standby switch. Since removing the standby switch option and switching to Sovtek 5AR4 and Winged C 5U4G diode I have had no problems. I think that those sockets might be Chinese, but so is the Apple Macbook Pro I am typing this message on. Poor quality is poor quality no matter where it is made.
If he wants more power, why not just parrallel a couple KT88's? I know that some don't like to parrallel devices but it will get him more power and with lower eff speakers will it be that big of a deal anyway?
I was thinking it'd be fun to build a SE amp with 4 trioded KT88's per channel but then finding suitable OPTs is a PITA.
I was thinking it'd be fun to build a SE amp with 4 trioded KT88's per channel but then finding suitable OPTs is a PITA.
As previously posted you can put whatever socket that you want into the board.
Oh, really, I have reclaimed the sockets from prototype PC boards with a propane torch. They don't melt. Anyone that follows my experiments knows that if something can be melted, I can melt it! The ceramic sockets specified in the parts list will not melt when hit with a propane torch, so they will take more heat than the tube inserted in them.
Like anyone the Chinese make some good stuff, and some real junk. The white ceramic sockets from China are as good as anyones these days. They can be bought with gold pins if desired.
I have seen some black plastic 9 pin miniature sockets that don't actually melt, but they do deform and get brittle if used in high power applications like EL84's. Judging from the stink emitted when they do fry, they are not PVC, just some really low quality bakelite. These are not recommended.
Laiben,
As Sherman, I've built an integrated KT88 SE amp, following Mikael's schematic.
You must use the preamp stage of the schematic as the KT88 need something around 30V swing on their grid.
I'm using 92dB speakers with my amp and it goes into very loud volume levels.
For 91dB speakers, at around 7W you'll be experiencing around 97dB of sound pressure. Personally, I rarely past, on a log pot, of 1/4 turn on my amp.
Good luck!
As Sherman, I've built an integrated KT88 SE amp, following Mikael's schematic.
You must use the preamp stage of the schematic as the KT88 need something around 30V swing on their grid.
I'm using 92dB speakers with my amp and it goes into very loud volume levels.
For 91dB speakers, at around 7W you'll be experiencing around 97dB of sound pressure. Personally, I rarely past, on a log pot, of 1/4 turn on my amp.
Good luck!
Simpleton said:
marcelnl said:
I agree with these posts. There is no magic number of watts one needs for any kind of music with any efficiency speaker. It depends on the individual, how loud you like to listen, how far you are from your speakers, how big your listening room is, etc., etc.
I regularly listen to 89dB/1W/1M speakers driven by a 2 watt SE amp. Granted it is in my workbench area and I don't try to crank it up but for that location it works fine.
My KT88 SE amps are connected to a pair of speakers of somewhere around 89-91dB efficiency (don't know for sure) and I'm also happy with that setup though for ear-bleeding volume more power would be necessary. I listen to rock, pop, jazz and classical.
You could definitely use paralleled KT88s for double the power. I looked at this a while back but never built the amp beyond a single channel breadboard. Basically you'd need to add a driver stage, I used a white cathode follower between the input/voltage amp and the output stage. It sounded pretty good.
5 watts from a 6V6, I am feeling a bit wimpy, mine only makes 1.5 watts, and I am bending the specs a bit. I assume you are operating the 6V6 as a pentode.
My 6V6 amp is connected to 87db speakers. I either have the 1.5 watt 6V6 amp or the 1.5 watt 45 DHT amp connected to these speakers. No you won't get complaints from the neighbors, but it is plenty loud enough for most listening. These speakers are near field studio monitors about 3 feet form my ears.
If I really do want to annoy the neighbors, I use a KT88 SE amp connected to the 96 db speakers with 15 inch woofers. I can shake the neighbors walls in UL mode (about 14 WPC).
do o tfeel wimpy, I am just guessing at the power it can give.....
Never felt the need to measure it , it is running in triode mode.....of course ;-)
Always felt that with every increase in Audio quality the perceived loudness goes up, probably something to do with the improved tonality and phase behaviour so your ears-brain manage to process the sound more easily?
Never felt the need to measure it , it is running in triode mode.....of course ;-)
Always felt that with every increase in Audio quality the perceived loudness goes up, probably something to do with the improved tonality and phase behaviour so your ears-brain manage to process the sound more easily?
tubelab.com said:
The socket for 9 pin is made by junk plastic, and the ceramic 8 pin GT socket is fine, but between the contact and the sleeve were too brittle, easily to break and came off, imagine if one socket on the PCB got failure, how many work to replace that damn socket!!
Gold pins !!! just an electrode plating of industrial GOLD ( usually used on PCB edge connector ) on the surface of the junk socket contacts. I never seen China use bakelite to produce tube sockets, only the British did, brand " Bulgin " Judging----- it's junk plastic, of course, not bakelite, is a mixed of fiber with junk plastic, what we called " fire retardant material ", not able to pass any international standard even GB. ( GB is the Chinese Standard ).
Chinese, only good in Coquette and Pros.
tubelab.com said:
For general listening, 1 watt is more than enough, no punch, no beat at all. I use 6V6 SE 4.5 watts X2 for my music entertainment, I only listen to light music like Classics, or Country music. The larger diameter of the speaker, it produce more bass, 14 WPC is eq. to 28 Watts, not a small figure.
laiben said:
I am not going to use 845. Though I've bulit an 50W pull-push guitar amp with ~600V, it is pretty scary to touch anything >1000V......
Thanks
If you building tube amp. no matter 300V or 1000V, it's the same way to hell if you careless.
2A3, 300B too expensive, so, Solid state would be the answer !
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