This wat i am gonna do: (if i find the time, now busy on extra educucation for work)
For first easy try outs i will crank up the supply voltage, to about 250V if possible. Wil modify R cathode an R anode for the golden midway between gain and distorsion, thinking on R Cat 2k1 and R An. 221k. Then listen again, if it is dissapointing i will try half passive, half active RIAA, will select the caps as good as possible with a capacity meter.(find some reference caps first)
Have a schematic here, but it has a cathode-follower on the end, will skip this, the SRPP line amp should do this task. They advised 340 V supply, but this is not possible with my transformer, Max possible voltage is about 270V unregulated.
Btw,thanks you all for posts here,
For first easy try outs i will crank up the supply voltage, to about 250V if possible. Wil modify R cathode an R anode for the golden midway between gain and distorsion, thinking on R Cat 2k1 and R An. 221k. Then listen again, if it is dissapointing i will try half passive, half active RIAA, will select the caps as good as possible with a capacity meter.(find some reference caps first)
Have a schematic here, but it has a cathode-follower on the end, will skip this, the SRPP line amp should do this task. They advised 340 V supply, but this is not possible with my transformer, Max possible voltage is about 270V unregulated.
Btw,thanks you all for posts here,
Hi Tubee,
Increasing the B+ and Ra is a good way to lower distortion. But if you load the anode with (part of) the RIAA network that network will load the anode with a low impedance at higher frequencies. That will rise distortion at increasing frequencies and is probably the cause of your not so satisfying sound.
Cheers
Increasing the B+ and Ra is a good way to lower distortion. But if you load the anode with (part of) the RIAA network that network will load the anode with a low impedance at higher frequencies. That will rise distortion at increasing frequencies and is probably the cause of your not so satisfying sound.
Cheers
This is true supposing the frequency response of audio card maximally flat.Usually there is an high pass filter on input for dc block and phase rotation protection (and some low pass in circuit for cut high frequency).You should have a know response device ,compensate for a max flat response and correct this compensation file for antiRiaa response.A good know response device can be a Riia or an antiriaaPjotr said:Hi cicero32,
The mic compensation file is just a file that corrects the measured response. So if you use the RIAA curve for it, well it just compensates for the RIAA correction of the pre amp giving a ruler flat final response (if the RIAA in your pre is accurate). Such a compensation file can be made to any accuracy with MS Excel using the RIAA time constants in a Laplace function.
Cheers
network.ciao cicero32
Dear tubee
I send you some link abot split riaa,
this boys have a good reputation as designer and i hope can help you for pick some good idea.
http://digilander.libero.it/paeng/e182cc_based_preamp.htm
http://www.users.globalnet.co.uk/~valveamp/RIAAStageDesign.htm
http://www.geocities.com/rjm003.geo/rjmaudio/diy_pho3.html
No one with ECC83
ciao cicero32
I send you some link abot split riaa,
this boys have a good reputation as designer and i hope can help you for pick some good idea.
http://digilander.libero.it/paeng/e182cc_based_preamp.htm
http://www.users.globalnet.co.uk/~valveamp/RIAAStageDesign.htm
http://www.geocities.com/rjm003.geo/rjmaudio/diy_pho3.html
No one with ECC83
ciao cicero32
cicero32 said:
This is true supposing the frequency response of audio card maximally flat.Usually there is an high pass filter on input for dc block and phase rotation protection (and some low pass in circuit for cut high frequency).You should have a know response device ,compensate for a max flat response and correct this compensation file for antiRiaa response.A good know response device can be a Riia or an antiriaa
ciao cicero32
Maybe you should have a look at ARTA what it is all about
You can do a 2 channel measurement. One channel for actual measuring and the other channel as reference signal. This is also necessary for measuring phase. That way I have less than 0.1 dB deviation from 3 Hz to over 43 kHz at a sample rate of 96 kHz.But if you want to fiddle with a hardware inverse RIAA, no problem, though you can check it with a soundcard anyway
Cheers
Thanks Cicero32 and Pjotr for reply.
Thanks for some phono stage schematics. The last mentioned E88CC one looks good to me, the others i have to investigate further. I like the ECC88, used it often. There are 2 now in my hybrid poweramp.
Pjotr, is it a long time to get used/on the way with this Arta software? I have on a pc never-used speaker workshop software, including cables, jigs, binding posts and so on,i know it could cost a lot of time to get on the way with some software and measurements. But this could because of my pc knowledge.....
Thanks for some phono stage schematics. The last mentioned E88CC one looks good to me, the others i have to investigate further. I like the ECC88, used it often. There are 2 now in my hybrid poweramp.
Pjotr, is it a long time to get used/on the way with this Arta software? I have on a pc never-used speaker workshop software, including cables, jigs, binding posts and so on,i know it could cost a lot of time to get on the way with some software and measurements. But this could because of my pc knowledge.....
Hi JW,
ARTA (which is actually a set of 3 separate programs) is really a lot more easier to use than Speaker Workshop for a lot of audio measurements including distortion measurements. It is quite new. I would suggest to download it and fiddle around with it. The manual and help is good and contains a lot of the under laying theory/math which is a good thing to understand what it is doing. But if that is to much for you, you can skip it and go right away to how to use it. It is really powerful with yet an easy to understand user interface.
Otherwise have a look on the Dutch http://zelfbouwaudio.nl/forum/ at the forum “Meten....”.
Cheers
ARTA (which is actually a set of 3 separate programs) is really a lot more easier to use than Speaker Workshop for a lot of audio measurements including distortion measurements. It is quite new. I would suggest to download it and fiddle around with it. The manual and help is good and contains a lot of the under laying theory/math which is a good thing to understand what it is doing. But if that is to much for you, you can skip it and go right away to how to use it. It is really powerful with yet an easy to understand user interface.
Otherwise have a look on the Dutch http://zelfbouwaudio.nl/forum/ at the forum “Meten....”.
Cheers
Hi EC8010,
Yes I am aware of that and to do it right you have to compensate for it in the RIAA network. But the actual frequency is not that critical IMO. It is usually referred to as the 3.18 us time constant. But I was wondering about the poles in the 105 – 125 kHz region Cicero mentioned, but probably he meant the same.
Cheers
Yes I am aware of that and to do it right you have to compensate for it in the RIAA network. But the actual frequency is not that critical IMO. It is usually referred to as the 3.18 us time constant. But I was wondering about the poles in the 105 – 125 kHz region Cicero mentioned, but probably he meant the same.
Cheers
Ok Pjotr, if i find the time will download it on a Windhoos 2K PC (found an old 400Mhz server on the street!) Now im typing on an overclocked 503Mhz, but is has Linux, the W2K on it is kaputt. Have to make this one dual boot again, but this will cost a lot of time, everything must be formatted/reinstalled then. But Linux has some great points: No spyware trojans, virusses anymore in the time i use it!
Sorry my english is not so powerful.
this the second zero of transfer function (should be out of audio band, in practice in a good riaa pre is in the range 100 - 125/130 Khz).In practice considering this zero you design the gain (of pre)
and the impedence of Riaa net.
Obviously this is what I can explain with my poor english language knowledge.
The points in my opinion are others.
What we want measure?
wich is the limit between measure and evaluation?
ciao cicero32
this the second zero of transfer function (should be out of audio band, in practice in a good riaa pre is in the range 100 - 125/130 Khz).In practice considering this zero you design the gain (of pre)
and the impedence of Riaa net.
Obviously this is what I can explain with my poor english language knowledge.
The points in my opinion are others.
What we want measure?
wich is the limit between measure and evaluation?
ciao cicero32
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