Today i build the time domain subsonic filter or TDSF how i will call it. This time without fancy opamps because i had to use what i have at home. i took the workhorse OPA2134 for the input buffer and the old chestnut NE5534 as output buffer. I thought with the benefit of 100% feedback they whould do the job quite well. No dual mono power supply ether this time. Only two 9V alkaline blocks into 5600 uF Sprague elcaps, bypassed with 1uF Wima MKT and lokally bypassed with 100uF elcaps on each chip. I did not scimp on construction and did a 100% star earth grounding the way i learned from Dennis Morecroft. I used my favourte caps though: 0.1uF 630V Rifa PHE450 in parallel with 0.1uF 160V Röderstein/Vishey MKP. Resistors were standart 1% metalfilm.
I used the TDSF between the RIAA stage and the preamp and first checked for noise. Inserting the circuit i could hear no rise in hum or hiss, ear at speakers, high volume. I also installed a bypass switch.
Listening and using the circuit was quite fascinating. It did surprisingly little damage on the signal and it even improved certain aspects of the sound, the higher the playback volume was. What it lost was a certain siruppy and liquid, honey like tone in the bass and fundamental tone aerea and some feeling of depth (not in imaging but in size). It was replaced with a tighter, faster and more precise redition. Cone movement was not zerro, mind you, at high volume but the low frequency back and forth movement was gone. What i liked too was more precise focus and higher dynamic range. When the unfiltered signal could go on the nervs at extrem volume the filtered version could be played much louder without fatique. impact on imaging was little except the improved focus and slightly reduced size. Micro detail was intact so i can now safely recommend standart high feedback opamps at that voltage level. I am still not convinced if high NFB is a good choice for the first stage of a phonoamp or an I/U stage of a DA converter but here it did no harm even on tiny signals like acoustic information and micro noise. I wonder now how i could have lived without the benefit of a good subsonic filter for 35 years but the ones i tryed so far did not work. Most of the time they took away bass slam without the benefit of much reduced cone movement. I had to design one my selve to resolve the issue. This circuit may not work it´s magic i any system but i think a lot of people have a medium stiff cartridge in a medium to high mass arm. Highly recommended ! I will play that stage in Vegas after hours and i am eager to hear other opinions,
I used the TDSF between the RIAA stage and the preamp and first checked for noise. Inserting the circuit i could hear no rise in hum or hiss, ear at speakers, high volume. I also installed a bypass switch.
Listening and using the circuit was quite fascinating. It did surprisingly little damage on the signal and it even improved certain aspects of the sound, the higher the playback volume was. What it lost was a certain siruppy and liquid, honey like tone in the bass and fundamental tone aerea and some feeling of depth (not in imaging but in size). It was replaced with a tighter, faster and more precise redition. Cone movement was not zerro, mind you, at high volume but the low frequency back and forth movement was gone. What i liked too was more precise focus and higher dynamic range. When the unfiltered signal could go on the nervs at extrem volume the filtered version could be played much louder without fatique. impact on imaging was little except the improved focus and slightly reduced size. Micro detail was intact so i can now safely recommend standart high feedback opamps at that voltage level. I am still not convinced if high NFB is a good choice for the first stage of a phonoamp or an I/U stage of a DA converter but here it did no harm even on tiny signals like acoustic information and micro noise. I wonder now how i could have lived without the benefit of a good subsonic filter for 35 years but the ones i tryed so far did not work. Most of the time they took away bass slam without the benefit of much reduced cone movement. I had to design one my selve to resolve the issue. This circuit may not work it´s magic i any system but i think a lot of people have a medium stiff cartridge in a medium to high mass arm. Highly recommended ! I will play that stage in Vegas after hours and i am eager to hear other opinions,
Yes, it´s after the phonostage and you can bypass it. The idea is also to compensate for the rising trend under 20Hz due to the resonance of cartridge and arm. In fact if you send me the response of your system for example measured with the Doc Feikert software i could calculate a matching filter. I will also design a kind of equaliser that will be able to follow other equalisations then RIIA AFTER the normal phonostage and also has the ability to compensate for room (notch filter) and programm deficiencies. Kind of modern version of the Cello Palette. Martina Schöner really bugged me for years on an universal equalizer ( she likes opera from the fist halve of the last century) but i never liked the concept of switching IN the phonostage, so that idea came up. My fortee is filters, i am a speaker guy from profession.
I do not use feedback in the TDSF so source buffers can be substituted for the opamps.
see the attached diagram for a symmetric B1 buffer.
Today i substituted the Hiraga Optime Transimpedance RIAA for a low Z Mpp with inductive RIAA. I had the TDSF in the circuit and the difference was easily audible. I am more and more convinced that the TDSF is virtually transparent, so instead of switching it in and out i left it in the system all the time. Today is holy night and we have a tradition to listen to my system with the whole family. My wife likes music from the 60th and 70th. She was a Hippy. So we listened to Jaques Brell, Melanie Safka, James Taylor, Bob Dylan etc. The sound was extremely enjoyable. I was specially surprised about the Melanie album. She was a minimal artist ! It´s so pure and clean with very little instrumentation. Later my son and i listened to Donald Fagen, Jenifer Warnes etc. He likes the same music then me and found out that the cones where not moving as much as they did before so we had an interesting discussion about the Doppler Effect.
The MPP Inductive RIAA did not disappoint. In terms of musicality it is better then the slightly cold Hiraga Optime Transimpedance. I still believe this is a great value and the MPP Inductive is much more expensive to make. Sound was again so good that we totally forgot about the HIfI and just listened to our favorite music. Frohe Weihnachten !
see the attached diagram for a symmetric B1 buffer.
Today i substituted the Hiraga Optime Transimpedance RIAA for a low Z Mpp with inductive RIAA. I had the TDSF in the circuit and the difference was easily audible. I am more and more convinced that the TDSF is virtually transparent, so instead of switching it in and out i left it in the system all the time. Today is holy night and we have a tradition to listen to my system with the whole family. My wife likes music from the 60th and 70th. She was a Hippy. So we listened to Jaques Brell, Melanie Safka, James Taylor, Bob Dylan etc. The sound was extremely enjoyable. I was specially surprised about the Melanie album. She was a minimal artist ! It´s so pure and clean with very little instrumentation. Later my son and i listened to Donald Fagen, Jenifer Warnes etc. He likes the same music then me and found out that the cones where not moving as much as they did before so we had an interesting discussion about the Doppler Effect.
The MPP Inductive RIAA did not disappoint. In terms of musicality it is better then the slightly cold Hiraga Optime Transimpedance. I still believe this is a great value and the MPP Inductive is much more expensive to make. Sound was again so good that we totally forgot about the HIfI and just listened to our favorite music. Frohe Weihnachten !
Joachim, Frohe Weihnachten!
Is it that same Melanie that made the interpretation of 'these boots...' ?
It's extremly cool!
You are confusing me, however: which circuit is which? Did you post the TDSF? The inductive hiraga? (never heard of an inductive circuit from him)
Did you made the entire RIAA behind the hiraga transimpedance? I stood under the impression, you pulled down 75µS only here.
Have some nice days, all!
Rüdiger
Is it that same Melanie that made the interpretation of 'these boots...' ?
It's extremly cool!
You are confusing me, however: which circuit is which? Did you post the TDSF? The inductive hiraga? (never heard of an inductive circuit from him)
Did you made the entire RIAA behind the hiraga transimpedance? I stood under the impression, you pulled down 75µS only here.
Have some nice days, all!
Rüdiger
Hi Holger, Rüdiger and Brian ! I hope you are well !
The name of the Artist is Melanie Safka. The track we heard was "Hey Mr. Tamborin Man ",
I am not shure but that may be a Bob Dillan composition.
Rüdiger, sorry if i have confused you. You will see the circuit i used tonight in the attachement. I think i have not published it in full here. see the 25mH coil. That makes the circuit inductive. Between this stage and the preamp i used my new subsonic filter called
TDSF and not TDFS as i wrongly stated. It´s an acronym for Time Domain Subsonic Filter. If you have any questions about the whys and whats of the circuit i can explain in more detail. How does the Instrumentation amp comes about ?
I show the TDSF here implemented with source followers. You can use any kind of buffers here. if you go back on this thread i have shown plenty.
The name of the Artist is Melanie Safka. The track we heard was "Hey Mr. Tamborin Man ",
I am not shure but that may be a Bob Dillan composition.
Rüdiger, sorry if i have confused you. You will see the circuit i used tonight in the attachement. I think i have not published it in full here. see the 25mH coil. That makes the circuit inductive. Between this stage and the preamp i used my new subsonic filter called
TDSF and not TDFS as i wrongly stated. It´s an acronym for Time Domain Subsonic Filter. If you have any questions about the whys and whats of the circuit i can explain in more detail. How does the Instrumentation amp comes about ?
I show the TDSF here implemented with source followers. You can use any kind of buffers here. if you go back on this thread i have shown plenty.
Today i talked to Siegfried Linkwitz and he was wondering how i did a 6th order filter with only 4 capacitors. Well, again i simulated the TDSF over a 100dB dynamic range and yes ! he is right. It´s a forth order sub Linkwitz response with constant group delay.
But still it´s -60dB down at 2 Hz and i think it´s efficient. I liked the subjective result so much that i will keep it that way.
But still it´s -60dB down at 2 Hz and i think it´s efficient. I liked the subjective result so much that i will keep it that way.
I did more listening today. For the first time i combined my finest DIY efforts, the MPP low Z Led, the inductive RIAA and the PSG Buffer with Alps studio faders. I had experienced a slight loss in bass slam before with the PSG (due to power supply issues i think), so i raised the level of my sub by 0.5dB and lowered the crossover somewhat and the result was :
MAGIC ! Talk about transparency ! I had tweaked the inductive RIAA slightly and it is now dead accurate at my + - 0.1dB measurement limit from 20 to 20kHz. I generate the RIAA curve mathematically so no problem with tolerances in passive anti RIAAs.
Both channels are absolutely the same now in shape and volume. The Alps sliders come really handy because i found that very often the image is of center in many productions.
Mostly slightly on the left. I speculated that can be because most people are right handed or is it because we have the heart on the left side ? I do not know but it´s a fact. Tweaking the balance for each record gives a much better focussed image in my experience. Again i listened with my 16 year old son who has still hearing to 20kHz. He is not a big party animal so his exposure to load music is limited to a minimum.
This time we focussed on well recorded material. First was Belafonte at Carnegie Hall. A recording from 1957, 52 years old as me. How they did that recording is a miracle to me.
There is no audible tape hiss and a huge amount of micro detail on the German ARS Reissue that i had overseen BEFORE Classic Records entered the szene. On Cotton Fields i could hear the acoustic bass on one side and a LOUD echo on the other side ! amasing.
Next was Wonderful World with Luis Armstrong recorded in 1968. Not as clean as the Belafonte but extremely emotional and moving. When he was singing of a baby crying i may have glimpsed a little tear in my sons eyes. Do you know Valery Carter ? She made an amassing sounding solo album "Wild Child" in the 70th. She was there in the room, no question. Even a kitsch song like "Da-Du-Randevouz" came over as a work of Genius, kind of uptempo modern country, very danceable. Of cause Donald Fagen sang our hymn
"IGY". Then came Tina Turner with "Edith and the Kingpin" on the Herby Hancock Joni album. After that the original from Hissing of Summer lawns, still unmatched in my opinion and the sound was good from a Speakers Corner Reissue. They did a god job but added some bass in comparison with the original German pressing that still has the edge in freshness. Then Patricia Barber "Spit" on an Alto Remastering. I felt like in Rio and Chicago the same time. Weird ! and so it goes .........
MAGIC ! Talk about transparency ! I had tweaked the inductive RIAA slightly and it is now dead accurate at my + - 0.1dB measurement limit from 20 to 20kHz. I generate the RIAA curve mathematically so no problem with tolerances in passive anti RIAAs.
Both channels are absolutely the same now in shape and volume. The Alps sliders come really handy because i found that very often the image is of center in many productions.
Mostly slightly on the left. I speculated that can be because most people are right handed or is it because we have the heart on the left side ? I do not know but it´s a fact. Tweaking the balance for each record gives a much better focussed image in my experience. Again i listened with my 16 year old son who has still hearing to 20kHz. He is not a big party animal so his exposure to load music is limited to a minimum.
This time we focussed on well recorded material. First was Belafonte at Carnegie Hall. A recording from 1957, 52 years old as me. How they did that recording is a miracle to me.
There is no audible tape hiss and a huge amount of micro detail on the German ARS Reissue that i had overseen BEFORE Classic Records entered the szene. On Cotton Fields i could hear the acoustic bass on one side and a LOUD echo on the other side ! amasing.
Next was Wonderful World with Luis Armstrong recorded in 1968. Not as clean as the Belafonte but extremely emotional and moving. When he was singing of a baby crying i may have glimpsed a little tear in my sons eyes. Do you know Valery Carter ? She made an amassing sounding solo album "Wild Child" in the 70th. She was there in the room, no question. Even a kitsch song like "Da-Du-Randevouz" came over as a work of Genius, kind of uptempo modern country, very danceable. Of cause Donald Fagen sang our hymn
"IGY". Then came Tina Turner with "Edith and the Kingpin" on the Herby Hancock Joni album. After that the original from Hissing of Summer lawns, still unmatched in my opinion and the sound was good from a Speakers Corner Reissue. They did a god job but added some bass in comparison with the original German pressing that still has the edge in freshness. Then Patricia Barber "Spit" on an Alto Remastering. I felt like in Rio and Chicago the same time. Weird ! and so it goes .........
Thank you very much for your efforts Joachim!
I'm looking three times a day, if there is sth. new on this thread.
I have 2SC3329GR and 2SA1316GR at home, for the second stage of the MC part I would use 2SC1775E an 2SA872E. Luckily there are 4 OPA637 left for the RIAA Stage.
My question is about the 25mH coils. can you tell me a supplier?
The coils you use in the PSUof the MC part are 900mH with 166 R serial resistance?
And the other question is, do I need the servo, when I use the TDSF?
Appreceating your work and again thanks for your efforts
Sam
Greding / Bayern
I'm looking three times a day, if there is sth. new on this thread.
I have 2SC3329GR and 2SA1316GR at home, for the second stage of the MC part I would use 2SC1775E an 2SA872E. Luckily there are 4 OPA637 left for the RIAA Stage.
My question is about the 25mH coils. can you tell me a supplier?
The coils you use in the PSUof the MC part are 900mH with 166 R serial resistance?
And the other question is, do I need the servo, when I use the TDSF?
Appreceating your work and again thanks for your efforts
Sam
Greding / Bayern
Hello Sam ! the parts you choose should work. I tried the 2SC3329 and 2SA1316 in the Rositer and they are as good as the ROHMs. I did not try the 2SC1775 and 2SA872 but any decent low noise low level transistor with a high and straight Hfe curve should work here. The OPA637 are still very good. I use them as a distortion magnifier in my measurement setup.
It was planed to use 900mH coils but after i got the 25mH coils for the RIAA i used them too in the power supply and decided that they are big enough. Implementing them inproved the sound a lot : cleaner and more transparent. You can buy the coils from me. A single coil costs 10,-€ plus shipping. Tolerance is 5%. A pair of coils selected to better then 2% costs 50,- € plus shipping. They need some shielding (Mu Metal) or you can get a low level hum.
I did not use a servo in the TDSF. The offset was quite high with 30mV on both channels due to the poor DC precission of the NE5534 but no problem in my system because i have a cap in front of the poweramp. When you use Fet opamps like OPA134, OPA827 etc. offset should be under 1mV. If you like bipolar more something like the LT1468 gives good DC precission too.
It was planed to use 900mH coils but after i got the 25mH coils for the RIAA i used them too in the power supply and decided that they are big enough. Implementing them inproved the sound a lot : cleaner and more transparent. You can buy the coils from me. A single coil costs 10,-€ plus shipping. Tolerance is 5%. A pair of coils selected to better then 2% costs 50,- € plus shipping. They need some shielding (Mu Metal) or you can get a low level hum.
I did not use a servo in the TDSF. The offset was quite high with 30mV on both channels due to the poor DC precission of the NE5534 but no problem in my system because i have a cap in front of the poweramp. When you use Fet opamps like OPA134, OPA827 etc. offset should be under 1mV. If you like bipolar more something like the LT1468 gives good DC precission too.
i looked up the data sheets of the transistors you will use in the second stage. They should work fine. Gain linearity is a bit better in the BC550 and BC560 ( they are exeptional in that regard) but the ones you coose have very high Hfe and bias is well controled in the MPP low Z Led. To see Hfe over 1000 is rare in non darlingtons. Noise should be fine too. I whould select them for Hfe for lowest offset.