It is called "visual analyser 2011" in my case 2011, but it appears there is also a new version.
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VA Analyser screenshots for his masters noise
Hi, Im not sure if ive done quite what youve asked for but its my best guess.
I have done 4 shots
1. soundcard input with nothing connected.
2. HMN connected with open input
3. HMN with a shorted inputs.
4. shorted input to ground.
I realised that i needed to short to ground as the inputs on mine are balanced. Shot 3 i had shorted hot and cold input together and not to ground!
Hope this helps.
D.
Hi, Im not sure if ive done quite what youve asked for but its my best guess.
I have done 4 shots
1. soundcard input with nothing connected.
2. HMN connected with open input
3. HMN with a shorted inputs.
4. shorted input to ground.
I realised that i needed to short to ground as the inputs on mine are balanced. Shot 3 i had shorted hot and cold input together and not to ground!
Hope this helps.
D.
Thanks a lot!
Very similar data!
For me it's ultra critical having horn loudspeakers of 100+ dB/W and eventhough the S/N was ok, I had to push it further down.
I worked more than a week on this, including fine-tuning the RIAA curve.
With the trade-off of less overall gain, probably rducing the high CCS impedance but increasing 50/60Hz noise control (but still sufficient gain)...the noise spectrum got a lot flatter (including the 50/60Hz region going towards -90/100dB).
I will share what I did and why (for everyone to choose if they want to use it at own risk/need)
Cheers,
Arno
Very similar data!
For me it's ultra critical having horn loudspeakers of 100+ dB/W and eventhough the S/N was ok, I had to push it further down.
I worked more than a week on this, including fine-tuning the RIAA curve.
With the trade-off of less overall gain, probably rducing the high CCS impedance but increasing 50/60Hz noise control (but still sufficient gain)...the noise spectrum got a lot flatter (including the 50/60Hz region going towards -90/100dB).
I will share what I did and why (for everyone to choose if they want to use it at own risk/need)
Cheers,
Arno
So, checked my notes for my mods:
CCS2: Bypassed with 4.7uF (S/N better especially in mains freq range)
D2: Bypassed with 3.3uF (S/N better especially in mains freq range)
R10: Parallel resistor 47K (since the 1M was om the back of the PCB), After CCS mods, got extra level in low freq of RIAA (several dB's) and could not be balanced back to the rest of the RIAA curve by only adjusting R7/R8/C2, so I needed to lower the low-pass F3 and could approach it by changing C3 or R10. Since I wanted to lower noise as well and want to keep impedances as low as possible R10 was choosen to get the low RIAA back on track)
R7: 19k7
R8: 3k
C2: 34nF
R1: 56k (matching my Benz Wood)
Transformer: Lundahl LL1931 (1:16)
Played a bit with a zobel (16k2+3.08 nF) on the secondary but left it out for now (maybe further investigation later)
Checked the RIAA with Dr Feickert Adjust+, sine generator/Oscilloscope and the spectrum with the visual analyzer.
Driving the pre-amp with a 22k to 10Ohm attenuator.
Cheers,
Arno
CCS2: Bypassed with 4.7uF (S/N better especially in mains freq range)
D2: Bypassed with 3.3uF (S/N better especially in mains freq range)
R10: Parallel resistor 47K (since the 1M was om the back of the PCB), After CCS mods, got extra level in low freq of RIAA (several dB's) and could not be balanced back to the rest of the RIAA curve by only adjusting R7/R8/C2, so I needed to lower the low-pass F3 and could approach it by changing C3 or R10. Since I wanted to lower noise as well and want to keep impedances as low as possible R10 was choosen to get the low RIAA back on track)
R7: 19k7
R8: 3k
C2: 34nF
R1: 56k (matching my Benz Wood)
Transformer: Lundahl LL1931 (1:16)
Played a bit with a zobel (16k2+3.08 nF) on the secondary but left it out for now (maybe further investigation later)
Checked the RIAA with Dr Feickert Adjust+, sine generator/Oscilloscope and the spectrum with the visual analyzer.
Driving the pre-amp with a 22k to 10Ohm attenuator.
Cheers,
Arno
Thanks!
Been tweaking again (since I didn't like the inverted RIAA in between as well as a sine generator)...so test record->record player->audio card->adjust plus curve
Will do some aftermath
Neither. The response is set by C1 and C2.
I still have boards @$3 -- you'll need one for each channel. This is my cost in respect of SY's intellectual property. Demand has waned as the price of D3a's has skyrocketed.
Attachments
I was shocked how rapidly the D3a went from relative obscurity to unobtanium. Not as bad as some of the sweep tube hoarders but still a surprise. Power of the internet I guess!
I am so tempted to stock up on a board, but as I have a backlog of phono stages best I don't.
There are other tubes you can use, but I won't mention -- George says that there's a guy in HK who buys all the available stock when they get noticed on DIYA.
Oh, OK, I will mention that you can triode-wire a 6AU6.
I am amazed how much they went up too! I paid $25 each for my 4, a good price at the time. Now the retail is $99 each! Right now I am so broke I would have a problem paying the postage to send the money order for the boards. I lost my job, retired, moved to another country, got really really sick and evicted from two homes, all in less than a year. I am selling all my ham gear just to buy medicine and get capital for an online business. I have a Heathkit SB-200 that needs some work that is next out the door as soon as I can pay the UPS fee on it. I also my have a special shape and size requirement for my boards. That is why I want a D3a EAGLE file. But $3ea sounds like a fire sale price! Maybe in March. So let SY know he has 1 last typo to fix in his post. How good is a 6AU6?
As a triode, mu is ~40 compared to ~84 for the triode connected D3a
Plate resistance plays an important role for the RIAA network. For the 6AU6 it's probably ~8k to 9k ohms, or 40% of the value of the buildout resistor R1. For the D3a it's less than 2k Ohms, less than 10% of the buildout resistor value.
Perhaps using two in parallel. It certainly is an inexpensive tube!