I had made good experiences with the Baxandall active gain stage in the JG Self and then it ocured to me that my headphone amp is perfectly prepared for that modification.
So here comes the latest circuit that has also the BC516, BC517 darlingtons instead of BC550, BC560 to increase speed and lower distortion in the buffer. I added gate stoppers to avoid oscilation at full gain. The advantages of the Baxandall circuit are many. Signal-Noise gets better when the gain goes down, channel tracking is better because you can use linear pot´s and the absolute value of the pot is not important. Anything from 10kOhm to 100kOhm should work. The only disadvantage i can see is that the input impedance goes down when the gain goes up. In case of the 10kOhm pot it goes down to around 1.2kOhm at full tilt. A good opamp driving that stage should have no problem but a high impedance tube could run into trouble. To avoid the full tilt situation i raised the maximum gain to 20dB. Another option whould be an aditinal buffer at the input.
So here comes the latest circuit that has also the BC516, BC517 darlingtons instead of BC550, BC560 to increase speed and lower distortion in the buffer. I added gate stoppers to avoid oscilation at full gain. The advantages of the Baxandall circuit are many. Signal-Noise gets better when the gain goes down, channel tracking is better because you can use linear pot´s and the absolute value of the pot is not important. Anything from 10kOhm to 100kOhm should work. The only disadvantage i can see is that the input impedance goes down when the gain goes up. In case of the 10kOhm pot it goes down to around 1.2kOhm at full tilt. A good opamp driving that stage should have no problem but a high impedance tube could run into trouble. To avoid the full tilt situation i raised the maximum gain to 20dB. Another option whould be an aditinal buffer at the input.
Not much creative work today but a lot of success.
First i installed a TKD pot in my Headphone Amp. I tried the Baxandall and it worked but this is a log pot and the arrangement gave some offset at high volume. A Servo could be installed but i decided to use the pot conventionally and the result was amasig soundwise.
The slightly sterile treble and ill defined bass was totally gone. This is a much better pot then the Bourns 91 and much better channel tracking. Certainly one of the best conventional pot´s i have heard. Thanks to my japanese friend that bought it for me.
The next hours i spend building 5 ! pairs of precission caps for a super accurate RIAA encoder for a fellow DIY´r. He was so nice to me that i agreed but this work really neads a freak like me with good measurement equipment and a huge collection of precission parts. His goal was accuracy to 0.05% !
This is like a game of Chess, Domino and cracking the Roulette Bank the same time.
Anyway i got it done.
I will not do this anytime again soon so please do not bug me for precission parts.
Do not take me wrong. I could do that all day when i am thrown in yail because i have stolen too many ideas from Siegfried Linkwitz and John Curl but i could then do nothing else and i have far to many ideas to let that happen.
First i installed a TKD pot in my Headphone Amp. I tried the Baxandall and it worked but this is a log pot and the arrangement gave some offset at high volume. A Servo could be installed but i decided to use the pot conventionally and the result was amasig soundwise.
The slightly sterile treble and ill defined bass was totally gone. This is a much better pot then the Bourns 91 and much better channel tracking. Certainly one of the best conventional pot´s i have heard. Thanks to my japanese friend that bought it for me.
The next hours i spend building 5 ! pairs of precission caps for a super accurate RIAA encoder for a fellow DIY´r. He was so nice to me that i agreed but this work really neads a freak like me with good measurement equipment and a huge collection of precission parts. His goal was accuracy to 0.05% !
This is like a game of Chess, Domino and cracking the Roulette Bank the same time.
Anyway i got it done.
I will not do this anytime again soon so please do not bug me for precission parts.
Do not take me wrong. I could do that all day when i am thrown in yail because i have stolen too many ideas from Siegfried Linkwitz and John Curl but i could then do nothing else and i have far to many ideas to let that happen.
Attachments
I'll bail you out of jail.
Joachim,
Just make sure you don't make your Private project's commercial products.
If you can't control yourself and eventually (by mistake) do sell them, just tell them it's OK and let me know, I'll sell my old Toyota and will bail you out
Jan, help je mee:
Gr,
Audiofanatic
P.S. Joachim, I don't seem to have much luck in downloading the file. I'll try later.
Joachim,
Just make sure you don't make your Private project's commercial products.
If you can't control yourself and eventually (by mistake) do sell them, just tell them it's OK and let me know, I'll sell my old Toyota and will bail you out
Jan, help je mee
: Gr,
Audiofanatic
P.S. Joachim, I don't seem to have much luck in downloading the file. I'll try later.
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Op2 ada4627
Hi Joachim,
Yes the audiotester file!
I'm an idiot regarding computer software, I can fix a defective Computer but can hardly work with these software's!
BTW the OP2 ADA4627 in your pdf needs to be OP3 and not OP2 (if I see this correct).
I'll try again next week.
All the best.
Audiofanatic
Hi Joachim,
Yes the audiotester file!
I'm an idiot regarding computer software, I can fix a defective Computer but can hardly work with these software's!
BTW the OP2 ADA4627 in your pdf needs to be OP3 and not OP2 (if I see this correct).
I'll try again next week.
All the best.
Audiofanatic
Been to Brilon today, visited Joachim, and had the chance to listen to his system. I was deeply impressed by the sound of the quite special setup with two way OB speakers plus OB subwoofer (have a look at Joachim's MPL thread for more on the spaekers).
Of course this was fed with vinyl: TT from Alan Perkins, Lyra Titan cartridge and Joachim's "JG Self" phonostage. The sound is... well, a slap in the face. Unbelieveable open, dynamic, fast, and detailed. Somewhat remindes me of horns, but completely lacking coloration. Nothing for those high end listeners, who want it nice, gentle and pleasant - this one really bites you.
Great stuff, Joachim, hope to get a more intense impression at the Frickelfest.
Some pics:
Of course this was fed with vinyl: TT from Alan Perkins, Lyra Titan cartridge and Joachim's "JG Self" phonostage. The sound is... well, a slap in the face. Unbelieveable open, dynamic, fast, and detailed. Somewhat remindes me of horns, but completely lacking coloration. Nothing for those high end listeners, who want it nice, gentle and pleasant - this one really bites you.
Great stuff, Joachim, hope to get a more intense impression at the Frickelfest.
Some pics:
Attachments
Thanks Holger !
That was a great day, and even the sun was shining.
Phantastic photos by the way.
I started to work on my masterpiece.
A fully balanced, parallel symmetric Phonostage with balanced inductive RIAA.
The input stage is working and i get the rest of the components this week.
Hope to have it working on the weekend.
I will come to the Frickelfest. I hope to have my poweramp ready until then although i could feed that MPL with my preamp.
That was a great day, and even the sun was shining.
Phantastic photos by the way.
I started to work on my masterpiece.
A fully balanced, parallel symmetric Phonostage with balanced inductive RIAA.
The input stage is working and i get the rest of the components this week.
Hope to have it working on the weekend.
I will come to the Frickelfest. I hope to have my poweramp ready until then although i could feed that MPL with my preamp.
Great, Joachim!
I am following this thread from the beginning and I am very curious to hear your pre.
Looking forward to see you there.
Heinz
I am working on the Balanced-In, Balanced-Out, Instrumentation, Inductive RIAA for several days now. It is quite a complex beast and much more delicate work than i thought. For my own use i am building a Low Z version because i simply like the slam and drahma circuits like that provide. The input stage of one channel is ready. I have not closed the feedback loop yet. I wait unil tomorrow and will chek everythig double.
I hate to see smoke or OPamps with red ears. I will post some photos later and will stop to build today. I need a rest.
P.S.: I am looking forward to see you Heinz. I hope to bring a complete DIY system.
What is still missing is a poweramp. I am collecting ideas. Maybe something single ended Cass A or let´s see what Brianco is getting together.
I hate to see smoke or OPamps with red ears. I will post some photos later and will stop to build today. I need a rest.
P.S.: I am looking forward to see you Heinz. I hope to bring a complete DIY system.
What is still missing is a poweramp. I am collecting ideas. Maybe something single ended Cass A or let´s see what Brianco is getting together.
It´s a novel topology with advantages i hope. Needs only one coil for balanced.
I will publish the circuit when it works. To do this with tubes whould be imposible but i use this "dead bug" groudplane style all the time now. No problem with hum and easy to change and repair.
Somebody is now also working on PCB´s for some circuits i consider finished.
I hope they turn out well and make building easier.
I will publish the circuit when it works. To do this with tubes whould be imposible but i use this "dead bug" groudplane style all the time now. No problem with hum and easy to change and repair.
Somebody is now also working on PCB´s for some circuits i consider finished.
I hope they turn out well and make building easier.
I have now 130 Ohm and 300 Ohm resistors from Simon that measured well ( see Blowtorch thread) and i got 138 Ohm ( recommended by David Wilson for the Lyra Olypos
i have in house) and 300 Ohm naked Z Foils from Sigurt.
I am just building the latest version of the High Z MPP with transimpedance 75usec and capacitive RIAA to make the listening test. I will build that in a proper cabinet.
Dear Salas, i am still not finished with your Shunt but i have all parts now.
i have in house) and 300 Ohm naked Z Foils from Sigurt.
I am just building the latest version of the High Z MPP with transimpedance 75usec and capacitive RIAA to make the listening test. I will build that in a proper cabinet.
Dear Salas, i am still not finished with your Shunt but i have all parts now.
Resistor swapping
Today i did the first round of listening to loading resistors. I am using the latest version of the High Z MPP Transimpedance, Capacitive RIAA. The culmination of 1 year of hard work. It sounds just w........
Picture and circuit included. I use a current and voltage buffer to drive my 5m long cable to my high speed ( 25MHz -3dB) reference preamp. I use my MPL speakers.
The reference resistor is a Dale NS-2B 300 Ohm wirewound. That resistor sounds better then a 1kOhm TX2352 naked foil in my system but i will try a 300 Ohm naked foil tomorrow. So let the cat out of the sack as we say here. The resistor i listened to for comparison is a Dale Mil.Spec. RS65E i got from Simon.
i comfortably trampled the NS-2B. The soundfield with this resistor is much more populated in the midle and tonality is much more homogenious like listening to a full range speaker. There is no doubt any more what kind of instrument is playing. a Flugelhorn is a Flugelhorn and not a trumpet. Distortion is subjectively very low. I know that beacause i can play louder as usual without my right ear starts to distort. Distortion always starts in my right ear first. I think i have to go to the doctor to blow some dirt out. I did that ones and the gain in sound quality was amasing. Voices are magically 3 dimensionally delineated. This resistor is highly recommended and not so expensive. Ceveat : It is BIG. It has a 1/2 watt military rating but it looks more like a 2 watt.
Today i did the first round of listening to loading resistors. I am using the latest version of the High Z MPP Transimpedance, Capacitive RIAA. The culmination of 1 year of hard work. It sounds just w........
Picture and circuit included. I use a current and voltage buffer to drive my 5m long cable to my high speed ( 25MHz -3dB) reference preamp. I use my MPL speakers.
The reference resistor is a Dale NS-2B 300 Ohm wirewound. That resistor sounds better then a 1kOhm TX2352 naked foil in my system but i will try a 300 Ohm naked foil tomorrow. So let the cat out of the sack as we say here. The resistor i listened to for comparison is a Dale Mil.Spec. RS65E i got from Simon.
i comfortably trampled the NS-2B. The soundfield with this resistor is much more populated in the midle and tonality is much more homogenious like listening to a full range speaker. There is no doubt any more what kind of instrument is playing. a Flugelhorn is a Flugelhorn and not a trumpet. Distortion is subjectively very low. I know that beacause i can play louder as usual without my right ear starts to distort. Distortion always starts in my right ear first. I think i have to go to the doctor to blow some dirt out. I did that ones and the gain in sound quality was amasing. Voices are magically 3 dimensionally delineated. This resistor is highly recommended and not so expensive. Ceveat : It is BIG. It has a 1/2 watt military rating but it looks more like a 2 watt.
Attachments
Hi Gerhard,
I just took a look into the vishay datasheet. To me it seems this resistor (Vishay NS02B) is rated at 3 watts. I think this is the reason why it is such a big one. I've been gone for quite a long time here from diyaudio. Really a nice, straight forward design.
Thanks. Yes, in the commercial world this whould be a 2W or 3W resistor but Mil.Spec.
parts are rated more critical.
This resistor (RS65E) may be good for speakers too. 3W is just enough for a tweeter but we could parallel some for higher wattage.
By the way the NS02B is slightly smaller.
parts are rated more critical.
This resistor (RS65E) may be good for speakers too. 3W is just enough for a tweeter but we could parallel some for higher wattage.
By the way the NS02B is slightly smaller.