This is a song that young lady could sing. I didn't choose Maria Callas as that would be unfair.
https://www.youtube.com/watch?v=mTLF9TIx6lE
I left college in 1974. My last project was a pentode curve for a test for other students. The college was still 90 % valves ( tubes ). I have some GU50 I must get working. I built an amplifer with KT88 and EL 34 . I am sure GU 50 will be a good choice. I prefer EL 34 and GU 50 is more like it. Perhaps by 1980 in the USSR ( CCCP ) GU50 wasn't in colleges?
https://www.youtube.com/watch?v=mTLF9TIx6lE
I left college in 1974. My last project was a pentode curve for a test for other students. The college was still 90 % valves ( tubes ). I have some GU50 I must get working. I built an amplifer with KT88 and EL 34 . I am sure GU 50 will be a good choice. I prefer EL 34 and GU 50 is more like it. Perhaps by 1980 in the USSR ( CCCP ) GU50 wasn't in colleges?
True, the Audax units need to be well kown and researched by the speaker desgner. In all truth, it was totally out of my depth at the time my speakers were being developed, but thankfully, my friend was damn good at it. I don't know exactly what he did, but it's all smooth now, still one of the best speakers I ever heard, and easily THE best ever if you consider the price as well.
Initially, we considered their oval yellowish "Tiger Eye" tweeter, which was supposed to be as good as it gets. It turned out it wasn't, not only with us, but in general, very few people used it and generally got evaluated as having an odd treble. So we took a step down, to their second best titanium tweeter, wich turned out to be a much better solution overall.
Sergey A, a question, if I may.
In the mid-90ies, a friend somehow obtained a Russian made Korvet integrated amp. He paid some silly money for it, those were the Yetsin days of high inflation rate. But what got me is that it sounded absolutely wonderful, officially it was something like 2*30W into 8 Ohms, but it sounded like it was 2*200W into 8 Ohms, zero compression even whe pushed hard. I reember thinking that if exported, that would have been another legend like NAD 3020 in its time.
Is there anything you can tell me about that company, its standing with Russian audiophiles, how it fared and is it still in business today?
In the mid-90ies, a friend somehow obtained a Russian made Korvet integrated amp. He paid some silly money for it, those were the Yetsin days of high inflation rate. But what got me is that it sounded absolutely wonderful, officially it was something like 2*30W into 8 Ohms, but it sounded like it was 2*200W into 8 Ohms, zero compression even whe pushed hard. I reember thinking that if exported, that would have been another legend like NAD 3020 in its time.
Is there anything you can tell me about that company, its standing with Russian audiophiles, how it fared and is it still in business today?
My two friends have interesting equipment. One has Proaudio type active crossovers, one of which is digital. That one can do any type of filter including ones that are impossible in passive. John didn't know it could do first order until he looked. He never uses first order. The other friend has BC1's. It would be interesting to try active BC1's. I have a hunch it would be very good. The speakers I have just made are effectively active as there is almost no filtering. They have active EQ, the nearest to filtering is a 3u3 cap to protect the tweeter. There is something about the way these speakers show things that even headphones can not do. I wasn't exspecting that. As said no filters and in some ways a 4 drive unit design as the mid is passive crossing. I did forget the main bass unit has a 4 uH choke into 5R7, as the driver is near the floor it might not be needed. I had a very nasty idea to fit a $5 piezo at 15 kHz. I have just added some to Tannoy Lancasters with dreadfully good results. We are just fine tuning the crossovers. If these horrible units are crossed high they stop being horrible. Simple first order with a shunt resistor to swamp the internal impedance of the piezo. 2 u2 and about 8 to 12 R is where we start. I have said don't calculate it, just try it. As it is both are wrong. The right result can not be far away. The piezo is on the cab top. It won't go inside as Lancasters are worth money. Very, very nice speaker with less obvious box sound than BC1's. The treble seems a victim of the axial responce of a horn loaded tweeter. Not quite stereo as it should be. My OB are slightly better and it is not their strong card.
To dvv ,
Now I don't know, whether there was at us something suitable
.
Here you can look at a condition of a question.
???????????
Nigel, lamps I studied half a year in a general view. All the rest is independent
http://www.soundup.ru/index.php?cat...binet-12-inch&option=com_content&view=article
Can do it the hearing became worse? It is possible, of course, and to add piezo.
Now I don't know, whether there was at us something suitable
. Here you can look at a condition of a question.
???????????
Nigel, lamps I studied half a year in a general view. All the rest is independent
http://www.soundup.ru/index.php?cat...binet-12-inch&option=com_content&view=article
Can do it the hearing became worse? It is possible, of course, and to add piezo.
Last edited:
Sergey, that little amp was little only in terms of output power, and the fit and finish was not up to very high Japanese standards, but it sounded better to much better than most much costlier Japanese rivals. With a little external design and more manufacturing care, I believe it would have been a great success everywhere.
I have also seen and listened to a Russian made power amplifier, rated at 200W into 8 Ohms. That was built like a tank, it seemed nothing but a direct nuclear hit could ever harm it. Again, a good sounding product, with sound better than an arguable average in that class, but not as stunning as the small Korvet. Nobody expects a small integrted amp to sound that good, so it had the advantage of the element of surprise. It strongly reminded me of the legendary Otala/Lohstroh power amp. It's all there, but nothing pushes and nothing pulls, just right.
I have also seen and listened to a Russian made power amplifier, rated at 200W into 8 Ohms. That was built like a tank, it seemed nothing but a direct nuclear hit could ever harm it. Again, a good sounding product, with sound better than an arguable average in that class, but not as stunning as the small Korvet. Nobody expects a small integrted amp to sound that good, so it had the advantage of the element of surprise. It strongly reminded me of the legendary Otala/Lohstroh power amp. It's all there, but nothing pushes and nothing pulls, just right.
This must be the most understated high end amp I have ever seen. The ГУ-50 pentode called LS50 by Germany. FU50 in China if that's allowed.
https://www.youtube.com/watch?v=I-Ens4jyiq4
Here as the Germans saw it. This valve is a 1942 design almost like the 1950's EL 34 and close to KT88/TT21. If I ever get around to do it, it is said to better them all. Should have been in the film Solaris.
https://www.youtube.com/watch?v=3Mij96s5ZZo
https://www.youtube.com/watch?v=I-Ens4jyiq4
Here as the Germans saw it. This valve is a 1942 design almost like the 1950's EL 34 and close to KT88/TT21. If I ever get around to do it, it is said to better them all. Should have been in the film Solaris.
https://www.youtube.com/watch?v=3Mij96s5ZZo
Good valve amps sound much less distorted. The negative side is no easy route to what a transistor amp does with great ease. I totally beleive what I say when saying valve amps sound less distorted. Simply put they can sound more like a human making music. Now if we make a bad tube amp it so easilly falls apart. Out of this a false science comes to life. One that simplistically relates lumped distortion with reality.
How so a false sceinece? Easy. The religion of hi fi sets apart the distortion of the speakers from that of amplifers. As with all inconvient things in religions hi fi ignores this with steely determination. Why is 0.001% THD a shameful result when 3% THD for a speaker is job done ? KEF are very pleased with 0.8%.
Some things that must be observed if any of what I say is to be midly true. The maximum wattage I have ever had from a valve amp I liked is 8 watts. I will one day perfect my SE in PP out design. It might give 30 watts. Most of the big valve amps sound like dancing with divers boots on to me. The Marantz Model 9 is one that is good and the Dynaco ST70 less so.
Next thing that must be right is the speakers must be suited. One should look at current drive as the amp almost forces that use. The speakers I have just built would be ideal. Given a full range driver of 99 dB/watt ( speaker to 100 Hz, amp to 18 Hz ). The bass by transistor amp from 30 Hz to about 500 Hz ( - 12 dB, - 3dB 5 Hz from the amp ). The top of the speaker a super tweeter most likely driven with the full range. The transistor amp is vital, it only does up to 500 Hz max and realistically 200 Hz. The speakers will be OB and sound very fast. You will hear detail you will not hear on headphones. The reason is simple, the bass is required and it is the body not the ears that hear it. The brain needs this to hear minute detail. Bonker but easy to hear. A pipe organ works the same. The Organist has to fight the organ to get it to work. The sharpe mid sounds need correctly timed bass to have depth. Most can never do this as the organ fights so hard to ruin the sound.
The mistake most people make is to install a valve amplifer into a system they have used for years. Mostly is sounds dreadful. Reason is the transistor amp grabs the speakers and says what to do. What no one seems to do is say how did we get where we are ? The simple answer is transistors are a very simple solution to cheap engineering. 99% that's what you want. The 1 % is divided between good transistor and good valve designs.
Look inside the pentode valve for a minute. By careful setting up of grids the ideal transistor oppertion is had. Outcomes are different as the valve is a high voltage low current device, transitors can do that. MJE340/350 just about workable. The flow of electrons if such things exist is though a vacuum. That's the purest path. If the grids are changed by a number of routes a triode is possible. This takes the transistor like abilities and allows it to resemble a transistor with negative feedback without a wire needing to be connected. As a result the output resitance Rp is very low. This becomes almost a good way of driving a transfomer. As the triode is not a great current amplifer the story is best left there. The transistor is a better device for that. Because the religion of valves will not accept that we don't see bipolar output buffers much. If we see anything we see a cathode follower which is a bad idea.
To ignore the simplity of valves is to not see how they are good. The linearity can without too much trouble be good for purpose. If a GU 50 valve was used as the VAS we might get something. If a variation of the HC Lin amp most of the devices are current ampifers so not too bad. That amplifer might really shine. 20 mA for a GU50 is nothing. It might last 20 years .
BTW. If a tube amp sounds nice that is not what I mean. It should sound very fast and white. Any lumpiness is wrong. It can be low cost and do the right things. My recent design was OK to 62 kHz. 15 Hz was the other limit although 20 Hz was less distorted. The output transformer about $100 .
How so a false sceinece? Easy. The religion of hi fi sets apart the distortion of the speakers from that of amplifers. As with all inconvient things in religions hi fi ignores this with steely determination. Why is 0.001% THD a shameful result when 3% THD for a speaker is job done ? KEF are very pleased with 0.8%.
Some things that must be observed if any of what I say is to be midly true. The maximum wattage I have ever had from a valve amp I liked is 8 watts. I will one day perfect my SE in PP out design. It might give 30 watts. Most of the big valve amps sound like dancing with divers boots on to me. The Marantz Model 9 is one that is good and the Dynaco ST70 less so.
Next thing that must be right is the speakers must be suited. One should look at current drive as the amp almost forces that use. The speakers I have just built would be ideal. Given a full range driver of 99 dB/watt ( speaker to 100 Hz, amp to 18 Hz ). The bass by transistor amp from 30 Hz to about 500 Hz ( - 12 dB, - 3dB 5 Hz from the amp ). The top of the speaker a super tweeter most likely driven with the full range. The transistor amp is vital, it only does up to 500 Hz max and realistically 200 Hz. The speakers will be OB and sound very fast. You will hear detail you will not hear on headphones. The reason is simple, the bass is required and it is the body not the ears that hear it. The brain needs this to hear minute detail. Bonker but easy to hear. A pipe organ works the same. The Organist has to fight the organ to get it to work. The sharpe mid sounds need correctly timed bass to have depth. Most can never do this as the organ fights so hard to ruin the sound.
The mistake most people make is to install a valve amplifer into a system they have used for years. Mostly is sounds dreadful. Reason is the transistor amp grabs the speakers and says what to do. What no one seems to do is say how did we get where we are ? The simple answer is transistors are a very simple solution to cheap engineering. 99% that's what you want. The 1 % is divided between good transistor and good valve designs.
Look inside the pentode valve for a minute. By careful setting up of grids the ideal transistor oppertion is had. Outcomes are different as the valve is a high voltage low current device, transitors can do that. MJE340/350 just about workable. The flow of electrons if such things exist is though a vacuum. That's the purest path. If the grids are changed by a number of routes a triode is possible. This takes the transistor like abilities and allows it to resemble a transistor with negative feedback without a wire needing to be connected. As a result the output resitance Rp is very low. This becomes almost a good way of driving a transfomer. As the triode is not a great current amplifer the story is best left there. The transistor is a better device for that. Because the religion of valves will not accept that we don't see bipolar output buffers much. If we see anything we see a cathode follower which is a bad idea.
To ignore the simplity of valves is to not see how they are good. The linearity can without too much trouble be good for purpose. If a GU 50 valve was used as the VAS we might get something. If a variation of the HC Lin amp most of the devices are current ampifers so not too bad. That amplifer might really shine. 20 mA for a GU50 is nothing. It might last 20 years .
BTW. If a tube amp sounds nice that is not what I mean. It should sound very fast and white. Any lumpiness is wrong. It can be low cost and do the right things. My recent design was OK to 62 kHz. 15 Hz was the other limit although 20 Hz was less distorted. The output transformer about $100 .
I can remember our first TV, a 12 inch b&w tube job with terrible contrast that needed the curtains to be pulled for daylight viewing.
When I think of how much our lives have been changed because of solid state and digital technology, it seems kind of crazy to believe that tubes can produce better audio.
Nige, you oversimplify a bit here. Not saying you are wrong, mind you, but it's not quite as simple as that. Tube technolgy is bulky, energy wasteful and naturally limited in some respects in comparison with SS - take power outputs for one thing. Sure, you can get 1 kW of output power with tubes, but at what cost in money, space and useless heat?
Have you ever wondered why quite a number of vintage solid state audio sounds better than modern fare, when we didn't know half of it then as we do now? I know you still remember well how the development process went the as opposed to now. Then, transistors were none too cheap, even if they were much cheaper than tubes. But in those days, there were no simulators, we all did it by building base circuits and the tested them by changing this or that. You thought twice then about using another pair of output devices. Nowdays, transistors, even power ransistors, rae basically cheap, few would fail to start with a simulator because that's more tome and cost efficient, the unfortunate sideline being that most people with sim programs quickly turn into sim jockeys and in fact have little idea of the difference between a sim and a protoboard in vivo model. Paradoxical as it may be, people have now become much lazier because they can.
While I do not doubt there are some awesome sounding tube gear around, I contend that most of it is at best average sounding, because tubes are in vogue now and jst mentioning tubes automatically hikes up the prices to what I feel are unreasonable levels. In fact, EXACTLY the same as is happening to SS audio electronics.
It's not just the technology which has changed, it's the whole nature of the audio business. As is the whole nature of mankind, I'd say, few if any even speak of quality, everybody talks only of pries and monikers. When have you seen last any comment to the effect of this thing is junk, it falls well short of its price tag in the sound it provides? Write that and that company will never advertise with you again, telling you that it's the audio business which has the magazine balls well in hand.
Have you ever wondered why quite a number of vintage solid state audio sounds better than modern fare, when we didn't know half of it then as we do now? I know you still remember well how the development process went the as opposed to now. Then, transistors were none too cheap, even if they were much cheaper than tubes. But in those days, there were no simulators, we all did it by building base circuits and the tested them by changing this or that. You thought twice then about using another pair of output devices. Nowdays, transistors, even power ransistors, rae basically cheap, few would fail to start with a simulator because that's more tome and cost efficient, the unfortunate sideline being that most people with sim programs quickly turn into sim jockeys and in fact have little idea of the difference between a sim and a protoboard in vivo model. Paradoxical as it may be, people have now become much lazier because they can.
While I do not doubt there are some awesome sounding tube gear around, I contend that most of it is at best average sounding, because tubes are in vogue now and jst mentioning tubes automatically hikes up the prices to what I feel are unreasonable levels. In fact, EXACTLY the same as is happening to SS audio electronics.
It's not just the technology which has changed, it's the whole nature of the audio business. As is the whole nature of mankind, I'd say, few if any even speak of quality, everybody talks only of pries and monikers. When have you seen last any comment to the effect of this thing is junk, it falls well short of its price tag in the sound it provides? Write that and that company will never advertise with you again, telling you that it's the audio business which has the magazine balls well in hand.
There is that bias as well, all too true. No technology will ever become ripe without people playing around with it, learning all the ins and outs, that takes time.
All I can say is that personally I have heard some op amp based devices which did and do sound much better than you'd expect them to sound, judging from the origins of their makers and the materials they used. I own one such device.
THAT'S why I am supportive of Frank's (Fas42) efforts to bring back some sanity into all this. To be sure, I don't always agree with him, nor do I support him by default, but I mostly agree with his efforts simply because I too have done such things and know from experience that it works. Which begs the question why was that not done in the factory, if not for "product niches" (translation: If we make this one as good as we can, who's going to buy our expensive models?).
All I can say is that personally I have heard some op amp based devices which did and do sound much better than you'd expect them to sound, judging from the origins of their makers and the materials they used. I own one such device.
THAT'S why I am supportive of Frank's (Fas42) efforts to bring back some sanity into all this. To be sure, I don't always agree with him, nor do I support him by default, but I mostly agree with his efforts simply because I too have done such things and know from experience that it works. Which begs the question why was that not done in the factory, if not for "product niches" (translation: If we make this one as good as we can, who's going to buy our expensive models?).
Inside the 8 watt limit magic can happen. As I said I need a big transistor amp to get the 30 Hz to 250 Hz. Without it I don't have what I want by a very long way. 2 x GU 50 ( EL34 ) will use about 100 watts in stereo. Where this amp will score is showing layers in the music. Sometimes that is all the music has that is special. Where it usually fails is tight triming and sometimes top end sparkle. Interestingly zero loop feedback amps seem to have sparkle. Well they might if you think about it. The transistor amp will do the tight bass.
Mostly I would use op amps for the preamp. There are better solutions in transistor or valve but they can take years to get right. Also the op amp can be made to work with something new in minutes with a few resistors.
Out of some perversion I have been subtly upgrading a Quad 33. I wouldn't have given it house room when I was 30. By carefully matching it's gain to a Denon DL110 I am starting to get a sound usually called high end ( I have heard more high end than most people have had holidays ). Detailed, punchy and very deep. The famous enclosed Quad sound is nowhere to be heard. It makes me wonder if this two transistor design has something. It sounded as flat as a pancake in a nice way until I worked out how it should drive the amp. Even the Denon is sounding like something just below my Lyra which is too fragile as a family PU.
You may remember I made a tagstrip FET amp to drive my 15 inch bass units with built in filter ( feedback loop ). I stripped it down for something else. I really ought to finish that as I should build what I have said. The Quad 33 will remain as it will give me a start. The valve amps are in Nottingham so need to come home. Better still buy some more transformers and use the GU50's.
Every time I start something work comes in. Lucky charm or what ? The big Quad 303 clone needs to be finished. 30 % done.
Mostly I would use op amps for the preamp. There are better solutions in transistor or valve but they can take years to get right. Also the op amp can be made to work with something new in minutes with a few resistors.
Out of some perversion I have been subtly upgrading a Quad 33. I wouldn't have given it house room when I was 30. By carefully matching it's gain to a Denon DL110 I am starting to get a sound usually called high end ( I have heard more high end than most people have had holidays ). Detailed, punchy and very deep. The famous enclosed Quad sound is nowhere to be heard. It makes me wonder if this two transistor design has something. It sounded as flat as a pancake in a nice way until I worked out how it should drive the amp. Even the Denon is sounding like something just below my Lyra which is too fragile as a family PU.
You may remember I made a tagstrip FET amp to drive my 15 inch bass units with built in filter ( feedback loop ). I stripped it down for something else. I really ought to finish that as I should build what I have said. The Quad 33 will remain as it will give me a start. The valve amps are in Nottingham so need to come home. Better still buy some more transformers and use the GU50's.
Every time I start something work comes in. Lucky charm or what ? The big Quad 303 clone needs to be finished. 30 % done.
Thanks, Dejan. It's easy to pick from the other threads that the the typical thinking of people who fill this space will not move things one tiny iota forward, they will be saying exactly the same as now, 10, 20, 30, etc years in the future ... very frustrating,
!!Mainly, people in the audio game can't handle the concept of system engineering, they don't want to know about it - hence, they will fumbling around, constantly creating defective setups, and vigorously scratching their heads trying to work out why they're not getting "brilliant sound",
. Ahh, well - if they're happy tinkering with the old car, head buried under the hood interminably every weekend, why should anyone spoil that? ... Edit: how to do more expensive models, if they do decide to to pull their finger out, is to have gradations of maximum competent SPL - something I've thought about ... base model does 108dB, then 114, 120, etc. Real engineering will be needed to produce genuine capabilties that grade in this fashion, and so it all hangs together ...
.
Last edited:
My own story is I put in the bass and got the detail. It works with real music also. I realised the other day what I get that is very rare is many many notes at the bass end. I also get great power. What I don't get is 35 Hz down to 20 Hz. That is a very small trade off. A friend came to listen last night. It was when playing MP3 he got excited. As I said to him my source is via the mains cables and is the DAC inside a Panasonic PVR. Somehow the detail seems better than it should be. Simply put, if the bass it missing as is true of many speakers then effects far worse than MP3 take over. This in quntitive terms will seem impossible. How can the detail of the mid band be mostly related to low distortion true note bass? Well it is and that all there is to it. A good pair of heaphones will be very correct and low distortion. Possible low phase shift. So why do they sound less detailed than good real speakers ? It's the bass. The ear hears very little below 200Hz. For some reason it can not hear the detail if the body does not receive the transient. The reverse is true to an extent. If the harmonics are carefully distorted it can seem the bass is there. This will need something different to standard tone control. Even so I doubt the depth is heard. To ice the cake , before I had the bass the detail was sadly missing. Almost like the drive unit was rubbing. Put the bass in and the sound is very open. Small effects never heard before are now rather large in the music. A drum section plays a tune more than gives a rhythm. It is snappy and with much HF energy. The drive unit in question looks that it could never do this. It should on paper do bass. It doesn't.
Where this is not the usual story is I can build and have anything I like. Everyone in my life likes music and loves it loud. It can be as big as I like and be as ugly as I like. One thing that seems universal is the speakers ideally should be > 96 dB / watt.
Where this is not the usual story is I can build and have anything I like. Everyone in my life likes music and loves it loud. It can be as big as I like and be as ugly as I like. One thing that seems universal is the speakers ideally should be > 96 dB / watt.
My pride and joy for a number of years is a pair of vintage 15 inch Tannoy Yorks which I thought I would never replace, perhaps until now.
A year or so ago I acquired a Paradigm 10 sub bass which sounded terrible on it's own, when connected to a portable CD player, so it was put away and forgotten.
Across from the bar I use is a large charity shop where I purchase my CD's and have a general nose around. A couple of weeks ago I noticed they had a pair of powered speakers by D-Box, a local Canadian company that no longer produces speakers. They were a good weight and in excellent condition so for $8 I took a chance, there were no returns on electrical stuff.
Got the speakers home and when setting them up noticed a sub output and I remembered the sub I had in storage.
I listened to the the speakers for a couple of days and they sounded pretty good so I decided to connect the sub, not expecting too much. Boy was I surprised, if there is a difference between these and the Tannoys, these baby boomer ears are not hearing it!
So, for $8, the sub was free, I get a sound that I find as pleasing as a pair of speakers I recently refused crazy money for.
Perhaps I'm not too fussy, I can remember back in the 60's, listening to Radio Caroline on an AM transistor radio and loving it.
A year or so ago I acquired a Paradigm 10 sub bass which sounded terrible on it's own, when connected to a portable CD player, so it was put away and forgotten.
Across from the bar I use is a large charity shop where I purchase my CD's and have a general nose around. A couple of weeks ago I noticed they had a pair of powered speakers by D-Box, a local Canadian company that no longer produces speakers. They were a good weight and in excellent condition so for $8 I took a chance, there were no returns on electrical stuff.
Got the speakers home and when setting them up noticed a sub output and I remembered the sub I had in storage.
I listened to the the speakers for a couple of days and they sounded pretty good so I decided to connect the sub, not expecting too much. Boy was I surprised, if there is a difference between these and the Tannoys, these baby boomer ears are not hearing it!
So, for $8, the sub was free, I get a sound that I find as pleasing as a pair of speakers I recently refused crazy money for.
Perhaps I'm not too fussy, I can remember back in the 60's, listening to Radio Caroline on an AM transistor radio and loving it.
Thanks Dejan, old world calender I guess ?
As I was shaving today I thought about 40 Hz down to 15 Hz or below. Having heard some speakers that could almost do that I was unimpressed. It's only when I heard some Duke Ellington 78 transfers to CD I realised how special they were. All the engine room noise of the cutting lathe was obvious. On a number of so called low bass speakers I hadn't heard this , we are talking night and day different. I suggested to the designer he critically underdamped them. He made an interesting statement. They could do 20 Hz - 3 dB. If a signal generator was brought into the room and set to 20 Hz nothing would be heard. Many objects would be moving on the shelves to prove it was working. He said the reason we do hear something is the harmonic distortion gives 40 Hz and more. His speakers did not do this at normal levels ( < 100 dB ). The bass units were a custom design by Volt. Mostly his speakers sounded bass light as do mine I have just built. When a real bass note comes they are not bass light at all. Some time delay will cause the last beans of bass not to be heard. It was very nice to test the speakers and get a very strong 40 Hz. At 30 Hz still a nice output which I guess to be 12 dB down. At 20 Hz a suggestion of something.
I think to build some IB subwoofers would be worth a try. Same drive units as now ( Fo 30 Hz Qts 1.2 , 15 inch ). I saw some 1 meter x 450 mm ID water pipe at $50 a piece. I really must forget that idea. I think if I limit myself to 15 Hz - 12 db and 50 - 12 dB I might be able to do it. If needed use tons of power. 500 watts in bridge 5R7 is not too hard to get.
Mr RSK I wrote of how I made my bathroom radio work better. The worse a thing is usually the easier to improve. Realistically it is servicable rather than excellent. My friend James has Tannoy Lancaster's . Similar sound as mine. Strangely the wizzer cone of my cheap drivers sounds very much like the Tannoys. They both do the same wrong things. As they share the same principle of tweeter loading they will. One has a paper cup and the other a supurb bespoke tweeter. The limiting factor seems to be the big cone sets the polar distribution. Neither mine nor Tannoy are bad on this. The engineering suggests it shouldn't work at all. I looked at a similar Fane driver. It has output at 17 kHz. The graph clearly shows it. Then you look off axis, 7 kHz or far less. My drivers get to 8 kHz and don't try for what would be a crazy frequency for a wizzer cone. This means 5 kHz off axis is realistic. I think the Fane would need filtering and a tweeter. It might just be worth it.
People will get very worked up about a valve amp having 1 % THD second harmonic. I suspect most people would reject a speaker that had only 1 % THD. They would say it has no bass. If the speaker and amplifier are suited I doubt anyone reading this could reliably tell when the 1% THD valve amp was working. If no attempt is made to match damping factor to the speaker the mismatch will be obvious. It will include poor frequncy responce. A colour analogy, white would be dirty pink. If that amplifer was limited to 50 Hz and had a special transfomer for the tweeter it might be both low cost and very special. The transformer a ferrite doughnut core or better.
Below 50Hz strictly transistor. For that amp all NPN seems fine. The valve and transistor side blend up to 500 Hz. My experiments with class A transistor amps never got far. I mostly don't like them although I can not say why. I have never built a JLH, I can not think I would dislike it from his reasoning. Class AB are fine. I have no great liking for GEC PP valve designs, they sound very bloated to me. I suspect they were always built down to a price as the reason. In fact 90 % of the things people loose sleep over on a eBay don't float my boat. Leak TL 12 + is very OK ( EL 84 ). Rogers Cadet is not my cup of tea, the circuit is wonderful so maybe just the cost of parts. I have some RCA with variable damping factor I can use. My friend Terry has to beat people off who want to buy them. They are very average and sometimes a bit nasty.
My valve design uses a very fast MOS FET capacitance multiplier at 500 VDC. In the ideal world this would be bipolar. Alas none seem right for the job. The MOSFET works as if a very fast Darlington. As it is a current ampifier it has only a mild influence on the downstream devices. Not to have it means very expensive chokes. I did try a 60 V Darlington and protection zener diode. It almost worked. When settled is was fine and gave good measurements. It only has to loose 5 V so 60 V will do. I saw a LM317 doing this job and backwards engineered it. The MOSFET was totally able to see off the LM317.
Now the crunch. Would I recomend valve designs ? Absolutely not. Would I use a valve design ? As long as SE and EL 34 in a hybrid set up I would. Would I want 95% of the valves amps that exist ? No. Do I like 300 B ? Not very much. Do I like KT 88? They are OK. Do I like 2A3? Very much I do. I have suggested to Miss JJ ( Mrs L now ) she makes TR 34 tiode version of EL 34. Hope she does. This might be close to old type PX25.
As I was shaving today I thought about 40 Hz down to 15 Hz or below. Having heard some speakers that could almost do that I was unimpressed. It's only when I heard some Duke Ellington 78 transfers to CD I realised how special they were. All the engine room noise of the cutting lathe was obvious. On a number of so called low bass speakers I hadn't heard this , we are talking night and day different. I suggested to the designer he critically underdamped them. He made an interesting statement. They could do 20 Hz - 3 dB. If a signal generator was brought into the room and set to 20 Hz nothing would be heard. Many objects would be moving on the shelves to prove it was working. He said the reason we do hear something is the harmonic distortion gives 40 Hz and more. His speakers did not do this at normal levels ( < 100 dB ). The bass units were a custom design by Volt. Mostly his speakers sounded bass light as do mine I have just built. When a real bass note comes they are not bass light at all. Some time delay will cause the last beans of bass not to be heard. It was very nice to test the speakers and get a very strong 40 Hz. At 30 Hz still a nice output which I guess to be 12 dB down. At 20 Hz a suggestion of something.
I think to build some IB subwoofers would be worth a try. Same drive units as now ( Fo 30 Hz Qts 1.2 , 15 inch ). I saw some 1 meter x 450 mm ID water pipe at $50 a piece. I really must forget that idea. I think if I limit myself to 15 Hz - 12 db and 50 - 12 dB I might be able to do it. If needed use tons of power. 500 watts in bridge 5R7 is not too hard to get.
Mr RSK I wrote of how I made my bathroom radio work better. The worse a thing is usually the easier to improve. Realistically it is servicable rather than excellent. My friend James has Tannoy Lancaster's . Similar sound as mine. Strangely the wizzer cone of my cheap drivers sounds very much like the Tannoys. They both do the same wrong things. As they share the same principle of tweeter loading they will. One has a paper cup and the other a supurb bespoke tweeter. The limiting factor seems to be the big cone sets the polar distribution. Neither mine nor Tannoy are bad on this. The engineering suggests it shouldn't work at all. I looked at a similar Fane driver. It has output at 17 kHz. The graph clearly shows it. Then you look off axis, 7 kHz or far less. My drivers get to 8 kHz and don't try for what would be a crazy frequency for a wizzer cone. This means 5 kHz off axis is realistic. I think the Fane would need filtering and a tweeter. It might just be worth it.
People will get very worked up about a valve amp having 1 % THD second harmonic. I suspect most people would reject a speaker that had only 1 % THD. They would say it has no bass. If the speaker and amplifier are suited I doubt anyone reading this could reliably tell when the 1% THD valve amp was working. If no attempt is made to match damping factor to the speaker the mismatch will be obvious. It will include poor frequncy responce. A colour analogy, white would be dirty pink. If that amplifer was limited to 50 Hz and had a special transfomer for the tweeter it might be both low cost and very special. The transformer a ferrite doughnut core or better.
Below 50Hz strictly transistor. For that amp all NPN seems fine. The valve and transistor side blend up to 500 Hz. My experiments with class A transistor amps never got far. I mostly don't like them although I can not say why. I have never built a JLH, I can not think I would dislike it from his reasoning. Class AB are fine. I have no great liking for GEC PP valve designs, they sound very bloated to me. I suspect they were always built down to a price as the reason. In fact 90 % of the things people loose sleep over on a eBay don't float my boat. Leak TL 12 + is very OK ( EL 84 ). Rogers Cadet is not my cup of tea, the circuit is wonderful so maybe just the cost of parts. I have some RCA with variable damping factor I can use. My friend Terry has to beat people off who want to buy them. They are very average and sometimes a bit nasty.
My valve design uses a very fast MOS FET capacitance multiplier at 500 VDC. In the ideal world this would be bipolar. Alas none seem right for the job. The MOSFET works as if a very fast Darlington. As it is a current ampifier it has only a mild influence on the downstream devices. Not to have it means very expensive chokes. I did try a 60 V Darlington and protection zener diode. It almost worked. When settled is was fine and gave good measurements. It only has to loose 5 V so 60 V will do. I saw a LM317 doing this job and backwards engineered it. The MOSFET was totally able to see off the LM317.
Now the crunch. Would I recomend valve designs ? Absolutely not. Would I use a valve design ? As long as SE and EL 34 in a hybrid set up I would. Would I want 95% of the valves amps that exist ? No. Do I like 300 B ? Not very much. Do I like KT 88? They are OK. Do I like 2A3? Very much I do. I have suggested to Miss JJ ( Mrs L now ) she makes TR 34 tiode version of EL 34. Hope she does. This might be close to old type PX25.
- Status
- Not open for further replies.