I think I remember you are planning to sell the parts for the IRON PRE through the DIYaudio store?
I wonder if you should be sure this thing is going to stick around.
I posted a question about whether the matchd FETs would be re-stocked and have yet to hear an answer one way or another which seems like the behaviour of folks running a project that is winding down.
Seems like an easy question to answer. Would think some kind of answer would not be too much trouble to post?
Don't want to see this project end up in the mire of a disinterested party. Would a regular old group buy be a better choice?
I wonder if you should be sure this thing is going to stick around.
I posted a question about whether the matchd FETs would be re-stocked and have yet to hear an answer one way or another which seems like the behaviour of folks running a project that is winding down.
Seems like an easy question to answer. Would think some kind of answer would not be too much trouble to post?
Don't want to see this project end up in the mire of a disinterested party. Would a regular old group buy be a better choice?
Store Jfets will be restocked. Need to deal with Linear's supply chains and the like, we are the only place you can buy small quantities, and we can only get so many from them.
They need to go through many steps before they actually make it to the store, the process is slow, it's a bummer, but there's nothing I can do to make it any faster. 🙁
The Iron Pre will be in the store, the wheels are rolling. (Slowly, as is always the case with volunteers, but still rolling. 😀 )
They need to go through many steps before they actually make it to the store, the process is slow, it's a bummer, but there's nothing I can do to make it any faster. 🙁
The Iron Pre will be in the store, the wheels are rolling. (Slowly, as is always the case with volunteers, but still rolling. 😀 )
6L6,
I love the idea of the store and would be very disappointed to see it diminish or go away.
I finally got around to sending a contribution to this site due to my happiness from being able to get those FETs.
Relieved to hear your news. Sorry I had to go into histrionics to get an answer.
Take care,
I love the idea of the store and would be very disappointed to see it diminish or go away.
I finally got around to sending a contribution to this site due to my happiness from being able to get those FETs.
Relieved to hear your news. Sorry I had to go into histrionics to get an answer.
Take care,
I just did a rather crude measurement on my transformers to verify my pcbs.
The Jensen JT-123-FLPCH seem to give about 5.1dB steady gain across a wide frequency range.
The M2 edcors gave about 14.45dB at 20KHz and then rise at something like 15dB at 50KHz
Do my measurements make sense? It is more or less what I expected, although the jensen gain seems a bit low
The Jensen JT-123-FLPCH seem to give about 5.1dB steady gain across a wide frequency range.
The M2 edcors gave about 14.45dB at 20KHz and then rise at something like 15dB at 50KHz
Do my measurements make sense? It is more or less what I expected, although the jensen gain seems a bit low
regarding db - dependable of source impedance and loading ..... besides losses in xformer itself , everything completely logical , impedances acting their play ......
Dear ZM,
I am worried this project has become bedridden.
So in the interim I am going forward with the TOSHIBA FET buffers and autoformer/transformers for the gain.
I have attached a simple map of what I plan to do. The autoformer is the SLAGLE volume control. Resistor values for the buffers are what you specified.
I am wondering - I figure if I use a 1:2 transformer instead of an autoformer I can switch polarity? Will this work or am I dreaming.
Please let me know if I am on the right track. Am I using too many buffers?
I have a buffer after the DAC since I will be using the AUDIO-GD DAC and it requires a buffer. The SOEKRIS would drive the autoformer volume control but I am not sure the AUDIO-GD will.
The AUDIO-GD is a new R2R DAC using resistors if you have not noticed it yet. ºÍ§Ó*µ响
Your comments, please.
I am worried this project has become bedridden.
So in the interim I am going forward with the TOSHIBA FET buffers and autoformer/transformers for the gain.
I have attached a simple map of what I plan to do. The autoformer is the SLAGLE volume control. Resistor values for the buffers are what you specified.
I am wondering - I figure if I use a 1:2 transformer instead of an autoformer I can switch polarity? Will this work or am I dreaming.
Please let me know if I am on the right track. Am I using too many buffers?
I have a buffer after the DAC since I will be using the AUDIO-GD DAC and it requires a buffer. The SOEKRIS would drive the autoformer volume control but I am not sure the AUDIO-GD will.
The AUDIO-GD is a new R2R DAC using resistors if you have not noticed it yet. ºÍ§Ó*µ响
Your comments, please.
ok , looking at your sketch :
- if DAC is having decent Rout (say less than 100R) you can skip first buffer
-xformer must be there for galvanic isolation , yes ?
- no need for buffer in front of autoformer , if you already have decent Rout from preceding xformer (presuming it's 1:1 jobbie)
-fix connection of autoformer ; as you drew it , you have attenuation , not gain
-buffer prior to Yamaha xover - you don't need it ....... all you need is properly sized resistor to ground , to dominate node input impedance
bedridden .......... naah ........ every custom product needs time
in this case AVCs are main object , demanding patience and care
- if DAC is having decent Rout (say less than 100R) you can skip first buffer
-xformer must be there for galvanic isolation , yes ?
- no need for buffer in front of autoformer , if you already have decent Rout from preceding xformer (presuming it's 1:1 jobbie)
-fix connection of autoformer ; as you drew it , you have attenuation , not gain
-buffer prior to Yamaha xover - you don't need it ....... all you need is properly sized resistor to ground , to dominate node input impedance
bedridden .......... naah ........ every custom product needs time
in this case AVCs are main object , demanding patience and care
The autoformer: it should have been made more clear that it is the SLAGLE attenuator. I have NO idea how to draw that properly, as you can imagine.
The buffer after the low pass filter feeds both the J2s and the crossover. When I measure the room response with the buffer in the circuit the filter has better attenuation in the frequencies above 2kHz. The J2 and crossover are more like 30K and if I use a 3k resistor the Q goes over 1. I will do more checking on this. Need to run the test again and re-assure myself.
The fellow who makes those DAC boards thinks there should be a buffer. He puts a low pass filter on the input of the buffer - this DAC has less output than the SOEKRIS so I thought it might need help driving that capacitor (?). Thinking about using the 2SK170 version of the buffer here.
Neither of my DACs has a Rout of less than 100R. I suspect the audio-gd one is considerable higher than the SOEKRIS but I am not sure of how much. They both are the output of the resistor stacks, alone.
So the next thing is - do you think the SLAGLE autoformer would be OK driving the low pass filter? Another of those things I should try and see what happens with the room response. My only way of checking things and I figure the most important.
I certainly want to use as few buffers as possible. Yet, when I look at crossovers there can easily be lots more of them than here! So, do you think one can quickly have too many buffers in the chain?
Have to repeat that the low pass filter works extremely well and is as quiet as can be.
I have turned the SIT 1 into an active link in the high pass crossover. Using a 0.032 uF cap in the input position and at the speaker a LC filter (using Slagle's amorphous core inductor) with a Q of about 1.2. This results in something in .6 range. The driver/horn measures so much flatter in the crossover region it is like magic. Amazing how a droopy crossover region really screws up the sound of the frequencies above. Before I had used just a cap and when I started trying out LCs I went with Qs in the .5 to .6 region. REALLY droopy.
No need for galvanic isolation (though it could be benefit) the idea for the transformer was to allow polarity reversal. Is it as simple as switching the leads on a transformer to reverse phase/polarity? If this is not as simple as I think it is I will use an autoformer.
Hate to sound like I am arguing with you. It is more that I did not ask my question as well as I should have.
The buffer after the low pass filter feeds both the J2s and the crossover. When I measure the room response with the buffer in the circuit the filter has better attenuation in the frequencies above 2kHz. The J2 and crossover are more like 30K and if I use a 3k resistor the Q goes over 1. I will do more checking on this. Need to run the test again and re-assure myself.
The fellow who makes those DAC boards thinks there should be a buffer. He puts a low pass filter on the input of the buffer - this DAC has less output than the SOEKRIS so I thought it might need help driving that capacitor (?). Thinking about using the 2SK170 version of the buffer here.
Neither of my DACs has a Rout of less than 100R. I suspect the audio-gd one is considerable higher than the SOEKRIS but I am not sure of how much. They both are the output of the resistor stacks, alone.
So the next thing is - do you think the SLAGLE autoformer would be OK driving the low pass filter? Another of those things I should try and see what happens with the room response. My only way of checking things and I figure the most important.
I certainly want to use as few buffers as possible. Yet, when I look at crossovers there can easily be lots more of them than here! So, do you think one can quickly have too many buffers in the chain?
Have to repeat that the low pass filter works extremely well and is as quiet as can be.
I have turned the SIT 1 into an active link in the high pass crossover. Using a 0.032 uF cap in the input position and at the speaker a LC filter (using Slagle's amorphous core inductor) with a Q of about 1.2. This results in something in .6 range. The driver/horn measures so much flatter in the crossover region it is like magic. Amazing how a droopy crossover region really screws up the sound of the frequencies above. Before I had used just a cap and when I started trying out LCs I went with Qs in the .5 to .6 region. REALLY droopy.
No need for galvanic isolation (though it could be benefit) the idea for the transformer was to allow polarity reversal. Is it as simple as switching the leads on a transformer to reverse phase/polarity? If this is not as simple as I think it is I will use an autoformer.
Hate to sound like I am arguing with you. It is more that I did not ask my question as well as I should have.
Last edited:
-So the next thing is - do you think the SLAGLE autoformer would be OK driving the low pass filter?
yes , if driven with low impedance ..... even using it as 6db gainer , that will result in 4-times Rout of preceding stage , so pretty low (enough) for purpose
-No need for galvanic isolation (though it could be benefit) the idea for the transformer was to allow polarity reversal. Is it as simple as switching the leads on a transformer to reverse phase/polarity? If this is not as simple as I think it is I will use an autoformer
yes , phase flip is simple as swapping secondary ends ; however , if you don't need that function as regular tool ( and why would you need that ?) it's simpler swapping leads on driver or amp output
AVC drawing - it depends how you're using it ; if you're attenuating , drawing is OK
yes , if driven with low impedance ..... even using it as 6db gainer , that will result in 4-times Rout of preceding stage , so pretty low (enough) for purpose
-No need for galvanic isolation (though it could be benefit) the idea for the transformer was to allow polarity reversal. Is it as simple as switching the leads on a transformer to reverse phase/polarity? If this is not as simple as I think it is I will use an autoformer
yes , phase flip is simple as swapping secondary ends ; however , if you don't need that function as regular tool ( and why would you need that ?) it's simpler swapping leads on driver or amp output
AVC drawing - it depends how you're using it ; if you're attenuating , drawing is OK
ZM,
I am surprised you do not take polarity as an important part of getting the best sound.
I find "correct" polarity to be variable between recordings. Not as if I have to change it with every recording but it makes itself very audible once you learn to hear it. At this point you are thinking you have records you have dismissed as just a not-so-good recording.
You might be surprised that many recordings are much better than you thought. Once polarity is reversed on that recording.
I think it is mandatory. I like the ability to not use a switch in my phono cable which is what I did for LP playing. With the SOEKRIS you can change the polarity using a computer hook up but this requires leaving a computer ON and connected to the DAC.
The AUDIO-GC dac has a provision for reversing polarity but I am not sure one can use it while music is playing without scaring yourself with a big noise. Not sure, yet, anyway.
Nonetheless, for one who must have it this seems the easiest way.
What would you surmise one loses using a transformer instead of an autoformer here? There is the possibility of a reverse wound autoformer and I could switch between the two (+ and -) autoformers if the sonic loss is considerable. I have cores I have no need that could be converted so it would not be a big loss financially.
Hope this doesn't sound too unhinged.
THANKS and take care,
I am surprised you do not take polarity as an important part of getting the best sound.
I find "correct" polarity to be variable between recordings. Not as if I have to change it with every recording but it makes itself very audible once you learn to hear it. At this point you are thinking you have records you have dismissed as just a not-so-good recording.
You might be surprised that many recordings are much better than you thought. Once polarity is reversed on that recording.
I think it is mandatory. I like the ability to not use a switch in my phono cable which is what I did for LP playing. With the SOEKRIS you can change the polarity using a computer hook up but this requires leaving a computer ON and connected to the DAC.
The AUDIO-GC dac has a provision for reversing polarity but I am not sure one can use it while music is playing without scaring yourself with a big noise. Not sure, yet, anyway.
Nonetheless, for one who must have it this seems the easiest way.
What would you surmise one loses using a transformer instead of an autoformer here? There is the possibility of a reverse wound autoformer and I could switch between the two (+ and -) autoformers if the sonic loss is considerable. I have cores I have no need that could be converted so it would not be a big loss financially.
Hope this doesn't sound too unhinged.
THANKS and take care,
sorry , sorta long day and having annoying flu (this year no-temp type , but with choked sinuses etc. ) ...... so I took (wrongly) that polarity switching as just one driver thingy
agree about importance of general phase switching ; as we said - easy when having xformer in line
difference between xformer and autoformer , later one being less picky regarding drive, to maintain and preserve frequency spectrum ; however , when having good xformer , driven correctly (read - cojones) , there is no difference between autoformer and xformer
agree about importance of general phase switching ; as we said - easy when having xformer in line
difference between xformer and autoformer , later one being less picky regarding drive, to maintain and preserve frequency spectrum ; however , when having good xformer , driven correctly (read - cojones) , there is no difference between autoformer and xformer
Thanks for your counsel.
Hope you get over this flu quickly. You have been sick too often. You must be working too hard and/or eating all of the wrong things!
Take care. We need our one and only ZM to be in good form.
Hope you get over this flu quickly. You have been sick too often. You must be working too hard and/or eating all of the wrong things!
Take care. We need our one and only ZM to be in good form.
naah
having flue once or twice per year** , and occasionally problems with my back
that one luckily less often than few years ago
**having Kido in elementary school is right path for catching it all
having flue once or twice per year** , and occasionally problems with my back
that one luckily less often than few years ago
**having Kido in elementary school is right path for catching it all
WELL,
that explains everything.
Nothing like having a mobile petri dish in the household! Did not realize you were a fully functioning human being. Unlike me who never had children.
I wonder how you do all you do now that I know this.
Take care, ZM.
that explains everything.
Nothing like having a mobile petri dish in the household! Did not realize you were a fully functioning human being. Unlike me who never had children.
I wonder how you do all you do now that I know this.
Take care, ZM.