I guess, for the follower, with 33kOhms or 47kOhms input impedance, using a tube preamp, with teflon or polistyrene cap output, is not a bad idea at all. I would love to have such a preamp. But not forget about shunt vs not shunt PS differences.
In the "light" version of the present follower, I would use one RD100 - one RD100 combination, or RD100-K1530 combination, or K1530-K1530 combination. Now I listen to RD100-RD100 "light" version, and sound is so amazing that very long time will pass untill I feel my 300B tube amp missing.
Jay
I guess, if built correctly, an active crossover should sound better than passive. This is based on the fact that one single woofer "sounds" better with active crossover. But when more than one drivers have to work together, the quality will of course be affected by the correctness of the crossover design.
Goran
Hi Jay, I have to admit that im presenting my personal views and impressions. You are right that active setup sounds different..sterill for my ears. (im talking about active setup i have) When im using my PF99 with tube follower preamp and passive speakers (for passive and active setup im using same drivers and same cut-off frequencies) I can hear more music, thats the only way i can explain that sound, and i dont know why it sounds like that.
Jay
It seems that, sound-wise, building a correct active crossover is not as easy as building a correct passive crossover. Many EE here may argue, but if you belief on golden ears existence, you have to know that active crossovers do sound different, in a bad way.
Goran
I think its easier to build an active crossover if you know the parameters of drivers and cut-off frequencies according to distance between drivers. You can make it almost perfect, no matter if you are using IC,s or tubes or ..whatever. Also i have to admit that my active crossover (im using cheap NE5532) is just a project for me to see the diference between active and pasive design. I have spent many hours to select the components C and R and i spend a lot of money to find 8 condensators with 1% difference, it was the same with resistors. The result is extremly clean bass, but im not satisfied with mids and trebles at all. I would say..there is no life in this (My) setup, no magic in sound.
Jay
Goran, The Aikido was not available when I built my PF99s. I have tried to modify my BOZ using more than 100V rail but couldn't solve the problem. I don't know why a tube should be better here. Is it because of the voltage gain?? I will try again using Vladimir's preamp (or Aikido) and use small mosfets for the modified PF99 (IRF630 or IRL510 or IRG4BC20UD-IGBT or laterals if the amp deserves it).
Goran
I really dont had an ocassion to hear how Aikido sounds, to be honest i dont know anything about that pre-amp. I think the tubes in general sounds much better then solid state components if we are talking about pre-amps. From my expirience, the best setup for me is one tube for gain stage, then two in parallel for lowering impedance and then SE solid state design like "power amplifier". For my subjective ears that would be the best setup. For speakers, one full range driver - high sensitive, and one ribbon tweeter, of course some kind of passive crossover would be implemented.
I still dont know how that QUOTE works 🙂
I guess, if built correctly, an active crossover should sound better than passive. This is based on the fact that one single woofer "sounds" better with active crossover. But when more than one drivers have to work together, the quality will of course be affected by the correctness of the crossover design.
Goran
Hi Jay, I have to admit that im presenting my personal views and impressions. You are right that active setup sounds different..sterill for my ears. (im talking about active setup i have) When im using my PF99 with tube follower preamp and passive speakers (for passive and active setup im using same drivers and same cut-off frequencies) I can hear more music, thats the only way i can explain that sound, and i dont know why it sounds like that.
Jay
It seems that, sound-wise, building a correct active crossover is not as easy as building a correct passive crossover. Many EE here may argue, but if you belief on golden ears existence, you have to know that active crossovers do sound different, in a bad way.
Goran
I think its easier to build an active crossover if you know the parameters of drivers and cut-off frequencies according to distance between drivers. You can make it almost perfect, no matter if you are using IC,s or tubes or ..whatever. Also i have to admit that my active crossover (im using cheap NE5532) is just a project for me to see the diference between active and pasive design. I have spent many hours to select the components C and R and i spend a lot of money to find 8 condensators with 1% difference, it was the same with resistors. The result is extremly clean bass, but im not satisfied with mids and trebles at all. I would say..there is no life in this (My) setup, no magic in sound.
Jay
Goran, The Aikido was not available when I built my PF99s. I have tried to modify my BOZ using more than 100V rail but couldn't solve the problem. I don't know why a tube should be better here. Is it because of the voltage gain?? I will try again using Vladimir's preamp (or Aikido) and use small mosfets for the modified PF99 (IRF630 or IRL510 or IRG4BC20UD-IGBT or laterals if the amp deserves it).
Goran
I really dont had an ocassion to hear how Aikido sounds, to be honest i dont know anything about that pre-amp. I think the tubes in general sounds much better then solid state components if we are talking about pre-amps. From my expirience, the best setup for me is one tube for gain stage, then two in parallel for lowering impedance and then SE solid state design like "power amplifier". For my subjective ears that would be the best setup. For speakers, one full range driver - high sensitive, and one ribbon tweeter, of course some kind of passive crossover would be implemented.
I still dont know how that QUOTE works 🙂
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Goran,
To "quote" just click on "Quote" in the post; then you see the text, and you can delete what you do not want to quote; don't remove the (quote) at the start and finish of the text.
You can write your comment then under the quote.
To "quote" just click on "Quote" in the post; then you see the text, and you can delete what you do not want to quote; don't remove the (quote) at the start and finish of the text.
You can write your comment then under the quote.
I know I prefer the shunt PS, but what do you mean exactly?
I hope my proposed "lighter" version using IRF630/IRL510/IGBT will also be good enough 😉
Have you had an idea about driving the mosfet with small fet like in zen v9?
As for me, designing crossovers is very specific field. Even when I simply tried to connect a subwoofer to my system, I had permanent trouble as for correctness of low-pass frequency I have set. I could not simply listen to a music and to forget about this adjustment. I am really afraid of possibilities provided by a three or four band active crossover, one never will get a peace in his soul.
In my experience, tube amps in general are not suitable to drive solid state amps (of course a bit different with SE amp). Aikido is an exception. May be because its gain usually is bigger than most preamps.
I agree on the statement that active crossovers sound bad compared to the same speaker with a shunt type crossover.. I believe that the reason is that in a passive solution the drive units sort of compensates each other.. meaning that the inductive current losses are played by the other unites in the system.. Also bear in mind that in a shunt type filter the drive units share the same current in the crossover region.. thus they are current wise locked together..this will newer happen in an active system...somehow it looses the pace and the rhythm,,,
I agree absolutely.
Im in hell this days, i like the clean bass with active setup, but from the other side im not shure if all is fine with frequency responce..real hell 🙂
I think i should back on my passive speakers and power follower.
By the way, i would like to ask you, I had 2 separated transformers for my PF99 per chanell.
One of them burned up a few days ago.
Now im using only one transformer for both chanells, but there is some buzzzzzzzz in speakers. I set the bias to 1,8 Amp and i have the same situation.
Any solution what that sound in speakers could be? Whats the reason for that buzzz?
I mean that tube schematics usually are not equipped with shunt PS, and they are not perfect to me in this respect.
Not cascoded like in Zen9, but I simply tried medium power j-fet (similar to CP650, Ciss=10pF, Id up to 1000mA) which's source connected to bases of a triplet of HF bjt transistors. Although not very reliable, but result was wonderful.
But, for design simplicity, I would prefer RD100.
Also, maybe the problem is in all that transistors packed in IC,s im using for active crossover.
This is one of the difficulties inherent to class A with permanently loaded trafo.
For class A applications, trafos must be designed in a different way than for standard industrial applications.
I guess in your case you deal with a kind of transformer steel magnetic flux saturation, with all bad consequences related to this.
Be careful with standard theoretical considerations, saying that the worst situation for trafo - situation of no load.
Also we need look at your number of windings and how diode bridges are connected.
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Before, with separated trafo's per chanell the PF was perfectly quiet, and it goes on 3A per chanell. It have regulated power supply, with one trafo it should work quiet also. But i dont understand electronics that much..so maybe im wrong.
It have 33V on secundar, and trafo and diode bridges (i have them one per chanell) are in separated box, connected to PF with 50cm cabel.
I would propose that you look at oscilloscope the power supply voltage pulsation, after regulation. If they are more than few mV peak-to-peak, you need to add additional RC components to power supply circuit.
I dont have an oportunity to use oscilloscope, anyway thanks for your suggestion. I think it will be the best to buy new trafo, maybe two toroidal and it will solve the problem.
I ordered 200 peaces of Vishay 220Mf low impedance for the outputs. I dont know if i made a right choice buying these capacitors. But i like to try your suggestion about using a lot of smaller cap. on output to achieve a better damping factor.
I hope it will work.
What i noticed, the PF99 works really good if you connect it directly to CD player and bypass the gain stage, maybe its just my imagination...i dont know.
I see. Also the use of chokes is really different. I just don't know why it seems that not all chokes will fit into a circuit. Not just the bigger the better. May be its relation to the C values, but I couldn't find any formula relating to this.
If I knew amp design I would try that cascode idea. What stand out in the PF99 is imo the power supply. So keeping the power supply idea and improving the amp stage may improve things.
Sure it is not imagination, any additional stage can cause some additional distortions and, in addition, some "losses of microdetails" to the sound. I stress here that "losses" are not ordinary distortions, I would call them as "microvolts level distortions", that are not measured by standard instruments.
It is very difficult task to design and assemble a preamp that will not be "heared".
MiiB,
I've been searching for meaning in this, can´t find any... What is a shunt type crossover in the first place?
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