Active and (at least) two subs, I couldn't agree more and have been running 4way actives for years.
Btw Billy Woodman (owner/founder of ATC) claims that the efficiency gain of active over passive is at least 3dB but depending on complexity of the passive xover can be up to 9dB.
When I first activated my Tannoys I gained exactly 3dB in the bass which uses a very simple 12dB slope. Tannoy even agrees with that as the power handling with passive xover in place was stated as 100w while the bare driver was clearly marked '50w max'.
PS: The german mags I remember reading back in the '80s were Audio and stereoplay.
Measurement galore and in the case of stereoplay all listening test were done in a reproduction of a typical average german living room. They even rebuild it on their stand at the IFA the 2 times I went.
Btw Billy Woodman (owner/founder of ATC) claims that the efficiency gain of active over passive is at least 3dB but depending on complexity of the passive xover can be up to 9dB.
When I first activated my Tannoys I gained exactly 3dB in the bass which uses a very simple 12dB slope. Tannoy even agrees with that as the power handling with passive xover in place was stated as 100w while the bare driver was clearly marked '50w max'.
PS: The german mags I remember reading back in the '80s were Audio and stereoplay.
Measurement galore and in the case of stereoplay all listening test were done in a reproduction of a typical average german living room. They even rebuild it on their stand at the IFA the 2 times I went.
Audio magazines nowadays appear to have a half-life period, as someone commented on a thread about Image Hifi at Holger's home page earlier this year.
Subs
One thing about subs and very low price . One can put the amp on the speaker and use the air to cool it . Naturally that reduces fidelity as it is the type of sub-woofer most of us deplore . However to have it for party mode is not so bad ( switch) .
No class D needed . G is fine ( or whatever people choose to call it now ) . Can switch off G rails if not in party mode / mood .
My friend John worked nearby Mr Woodman by pure chance . He moved into the building they also rented . My friend was even an audio engineer so benefited greatly .
D V V . Have you thought of using Douglas Self's Class A/C ( class G ) ? It would seem ideal for your application of active ? It is public domain in his book . I made a 4 transistor Class A/C of 8 watts 21 W ( 42 W 4 ohms ) for this very application . Just a bit of fun and now replaced with KT 88 anyway . Mine does not look like class C to begin with . It is very over biased class B . Not the same exactly but similar . If higher power I would have put in the zener diodes . Mine only needed a 80VA transformer in 8 ohm mode and 2 x 30 000 u F . It had very cheap almost silent PSU to VAS using a voltage multiplier and RC filter chain . Funny thing is I ran it below the maximum voltage as it sounded better even though I lost a few watts ( I used +/ - 20 V when + / - 25 would be optimum power wise and was available ) . It clipped more gracefully ( not soft clip , that is different ) . When going into class G ish B I include a small bootstrap to clean it up . I can not measure any transition into this nicer type of B after many adjustments . Not having Beta doubling effects at crossover point is no small deal .
One thing about subs and very low price . One can put the amp on the speaker and use the air to cool it . Naturally that reduces fidelity as it is the type of sub-woofer most of us deplore . However to have it for party mode is not so bad ( switch) .
No class D needed . G is fine ( or whatever people choose to call it now ) . Can switch off G rails if not in party mode / mood .
My friend John worked nearby Mr Woodman by pure chance . He moved into the building they also rented . My friend was even an audio engineer so benefited greatly .
D V V . Have you thought of using Douglas Self's Class A/C ( class G ) ? It would seem ideal for your application of active ? It is public domain in his book . I made a 4 transistor Class A/C of 8 watts 21 W ( 42 W 4 ohms ) for this very application . Just a bit of fun and now replaced with KT 88 anyway . Mine does not look like class C to begin with . It is very over biased class B . Not the same exactly but similar . If higher power I would have put in the zener diodes . Mine only needed a 80VA transformer in 8 ohm mode and 2 x 30 000 u F . It had very cheap almost silent PSU to VAS using a voltage multiplier and RC filter chain . Funny thing is I ran it below the maximum voltage as it sounded better even though I lost a few watts ( I used +/ - 20 V when + / - 25 would be optimum power wise and was available ) . It clipped more gracefully ( not soft clip , that is different ) . When going into class G ish B I include a small bootstrap to clean it up . I can not measure any transition into this nicer type of B after many adjustments . Not having Beta doubling effects at crossover point is no small deal .
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In that speech by russian designer, the Ciss and Crss have not been addressed, and they add nothing good to properties of switching vertical MOSFETs.
I do not have experience with UHF OpAmps. Wide bandwidth is only a small part of whole story. In addition, I would say, that the only DIRECT benefit from VHF FETs at output stage is facilitating of proper operation of NFB. However, there are also positive by-products from using VHF transistors, like smaller and less varying capacitances, more linear Vgs-Id curves around 1A current. Similar (even better) starting conditions is provided by tubes, but the issue of output trafo put tubes down. Also, I believe, that good choke is a must in PS of good tube amp. From my comparisons, SS (usually low wattage )amp, with proper parts and specilal topology, wins over tube designs, since similar or less investments into properly composed "output cap" of SS amp give better results, than equivalent or higher investments into output trafo.
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Thank you . I think it is not a fruitful avenue of research as 5 V is very limiting . However - 86 dB distortion for MC stage and 0.9 nV costing $3 is what I have seen ( dual op amp SMD ) . That was for intermediate video functions . Not UHF really . Made by LT and I suspect similar to audio op amps . Sorry I forget the number if asking .
I only did a tube amp to please a friend . Up to now I have no design experience of them . Your words would be my words on that subject mostly . I do notice a holographic effect with tubes ( a type of distortion perhaps ) . My transistor amps do not have it nor others I listen too ( No way Krell has it to my ears ) . I reject tube amps that sound romantic or nice . I do not think a tube amp has to sound that way . Transformers are as you say exspenive . Also $1 capacitor is superior to $100 transformer . That is true .
Transistor amps that have similar distortion as tube amps do not have the holographic effect ( they have some of it I must say , not identical if looking identical ) . I don't think it is microphony ? Analogue tape recorders have similar distortion . They do not have the holographic effect either . However tube analogue recorders do ? The latter effect is less noticeable and I only mention it becasue I suspect tube analogue tape recorders are better . They have comparable overall distortion as tape distortion dominates in that . I assume we go into the red when saying that and good quality tape heads .
I only did a tube amp to please a friend . Up to now I have no design experience of them . Your words would be my words on that subject mostly . I do notice a holographic effect with tubes ( a type of distortion perhaps ) . My transistor amps do not have it nor others I listen too ( No way Krell has it to my ears ) . I reject tube amps that sound romantic or nice . I do not think a tube amp has to sound that way . Transformers are as you say exspenive . Also $1 capacitor is superior to $100 transformer . That is true .
Transistor amps that have similar distortion as tube amps do not have the holographic effect ( they have some of it I must say , not identical if looking identical ) . I don't think it is microphony ? Analogue tape recorders have similar distortion . They do not have the holographic effect either . However tube analogue recorders do ? The latter effect is less noticeable and I only mention it becasue I suspect tube analogue tape recorders are better . They have comparable overall distortion as tape distortion dominates in that . I assume we go into the red when saying that and good quality tape heads .
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Personally I use fairly high-powered class AB bipolar amps made by MC2 Audio.
That said in a phone call to one of the designers I was told that in a domestic environment it is very unlikely that the amps ever leave class A operation.
Probably true as I use a total of around 900W/ch in amps.
You can never have enough headroom IME and small (ie less than 100w) ss amps are the worst.
That said in a phone call to one of the designers I was told that in a domestic environment it is very unlikely that the amps ever leave class A operation.
Probably true as I use a total of around 900W/ch in amps.
You can never have enough headroom IME and small (ie less than 100w) ss amps are the worst.
IF this is a feedback tube amp, probably a pentode? <---EDIT: this idiot can't read! ha.
You might consider altering the fb network so that it does *not* try to make the response flat all the way out to 20kHz. If the iron itself is not flat out there, then using the FB to make it flat always introduces ringing and other "icky" sonic byproducts... you might want to live with a bit of rolloff, it will likely sound better. Also strap the pentodes (if that is what they are) for triode.
Alternately just mod the sucker for very low or no fb and be done with it...
_-_-bear
Hey Bear. Yeah, I think it has pretty heavy FB, as the overall gain isn't outrageous and it's pretty flat out to 35KHz. It does have a Triode mode switch, which I neglected to test. I like the idea of messing with the FB and will give it a try. I'll be tickled pink if I can make it sound better AND measure that difference.
Thanks.
Thanks.
You obviously haven't been following the right threads here on diyAUDIO.
Multiple subs has been the subject heated debate.
My observations were taught to me by a Jesuit priest . I am not a catholic if wondering . He asked me to help him with some 8 bit digital for controlling air valves . It was obvious to me he knew more than me . I said it was perfect and he said he thought that also . He taught me how church organs voice and time delay . It was fascinating and has helped me greatly . Mostly to accept what I can not change .
Someone spoke of Belgium . It was in Tournai in 1983 ( Chee de Lille ) . They also have bi-phase 230V in that street ! ( 115 - 0 - 115 , nice ) .
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It was long ago and my French has almost vanished . I was useless at French however he didn't speak English . For a Jesuit that is rare . They are not to be taken lightly . I had Messiaen played for me . I simple adore Messiaen's music .
près de . ? I think Chee is postal abbreviation ?
près de . ? I think Chee is postal abbreviation ?
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You're welcome to my share of glowies in the great cosmic scheme. I do not deny their qualities, but they are definitely not for me. Not my cuppa.
Frankly, no, Nige, I haven't, but then D. Self is not a topic I care to think about, as I disagree with him far too much.
Again, not my cuppa.
Besides, what was the longest YOU ever had that you built along the guidelines of somebody's project, before you swapped it for your own design?
Come clean now, don't be shy.
A (Imperial) gallon of Zomerzet zider for your thoughts! You obviously haven't been following the right threads here on diyAUDIO.
Multiple subs has been the subject heated debate.
You are quite right, I haven't. I am only on this thread, I don't have the time to go snooping around, although I'm sure I'd find a few more very interesting topics (to me, that is).
Anyway, I'm glad to learn that. It was about time people stopped reading theories and started using their ears instead.
Nige - what does it matter? Who cares?
So long as you enjoy them, that's all that counts.
" Frankly, no, Nige, I haven't, but then D. Self is not a topic I care to think about, as I disagree with him far too much.
Again, not my cuppa. .
Besides, what was the longest YOU ever had that you built along the guidelines of somebody's project, before you swapped it for your own design?
Come clean now, don't be shy. " Quote D V V
My friend accused me of copying other people designs . I said I do . However not truly as I usually reject how they do it . As Ross Walker of Quad said to me " There are only 3 ways to connect a transistor and one of them is wrong " . Let's not correct him about that . He said as long as people didn't say Current Dumping he didn't mind . As I said to my friend some ideas work best and only a fool does it differently .
The D Self design was not about the design just the idea . It seems inescapably sensible ?
As you say 4 transistors of mine is hardly a copy of Douglas Self . However my need to be honest has to say he inspired me to try it .
BTW D V V . Having a Cornish Pasty now . You must have tried them ? No offense if you don't like them . Italian coffee on special at the Co op . This day just gets better .
Again, not my cuppa. .
Besides, what was the longest YOU ever had that you built along the guidelines of somebody's project, before you swapped it for your own design?
Come clean now, don't be shy. " Quote D V V
My friend accused me of copying other people designs . I said I do . However not truly as I usually reject how they do it . As Ross Walker of Quad said to me " There are only 3 ways to connect a transistor and one of them is wrong " . Let's not correct him about that . He said as long as people didn't say Current Dumping he didn't mind . As I said to my friend some ideas work best and only a fool does it differently .
The D Self design was not about the design just the idea . It seems inescapably sensible ?
As you say 4 transistors of mine is hardly a copy of Douglas Self . However my need to be honest has to say he inspired me to try it .
BTW D V V . Having a Cornish Pasty now . You must have tried them ? No offense if you don't like them . Italian coffee on special at the Co op . This day just gets better .
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There was still a good bit of bi-phase in Paris when I worked there. We had to have a bi-phase to triphase transformer installed in the theater for the new dimmer rack. The bi-phase actually came into the building as 4 110V legs.
IIRC, the bi-phase was done so that you had the possibility of 110V or 220V, whichever you needed. The last 110V sections of Paris were "phased out" in the late 1980s. They were on the Left Bank, right near the Seine.
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