Simplistic NJFET RIAA - Page 117 - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 24th February 2009, 01:43 PM   #1161
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Its not huge, its relatively big ratio to the low signal you passed. Still 55dB lower than your signal. So the software must be calculating something non correlated. Is it looped or using external hardware gen? Calibrate ARTA and card for 1V=0db. Then use 5mV 1kHz for feeding the phono. Yours is the lowest gain MM only version, right? Make 1:100 LPAD RCA and assign 0.5V out to the software sig gen. It will not be good in giving good signal at mV range directly. Feed it after the LPAD. Loop it. When you will put the transformer inside the box and ground the chassis to the mains, you will see more hurdles to solve. In my experience, about 20cm can be adequate for a 50VA non shielded toroid or Rcore if in same box. Best is that a phono box is having external PSU and trafo box, only DC entering the main unit, and any AC mains cables kept well away from TT signal cable. Common practice in expensive equipment. See something interesting also. This is with a lesser than EMU card 16bit octave scaled FFT from a friend's realization using PCB with a grounding scheme that was nice but not best. I powered it with a battery so to see what it was doing excluding his PSU or trafo field. Guess what, his GND loop with the card (laptop on battery too) was picky enough so to have -90dB 50Hz hum with no equipment around... Some alias filter spikes in the HF, but the 16kHz TV scan bug is absent because of the no mains related battery PSU.
Attached Images
File Type: gif battery.gif (13.9 KB, 463 views)
  Reply With Quote
Old 24th February 2009, 02:38 PM   #1162
iko is offline iko  Canada
diyAudio Moderator
 
iko's Avatar
 
Join Date: May 2008
Location: Toronto
You're a gold mine of information!

What is LPAD?

The signal generator used was the one in A.R.T.A., so, it was looped through the phono. You too noticed the difference, with the laptop plugged in, or on battery. The laptop switched power supply will push all sorts of high freq noise into the measurements. For all my experiments I unplugged the laptop from the psu, ran it on its battery.

Yes, I am running the MM cascoded and buffered version, from page 8.

Edit: salas, I hope you don't mind this question. Does this
http://cgi.ebay.ca/E-MU-Tracker-Pre-...1%7C240%3A1318
look like a good price for that device?
  Reply With Quote
Old 24th February 2009, 02:49 PM   #1163
RCruz is offline RCruz  Switzerland
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Blog Entries: 1
Bypassing the 4.7u MKP Mundorfs with the ERO 1832 is a success !!!

Inittially lost the bass and everything sounded a mess... after a while (3 records...) the sound opened and the dynamics are now awesome, harshness in the highs became sweet loads of detail...

I am already thinking what a really good output cap could do.

Salas, what type of cap are you using "auricap ?" and is it bypassed ?

Ricardo

Now the TT is five fingers over the CDP.
__________________
RC
  Reply With Quote
Old 24th February 2009, 03:05 PM   #1164
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Quote:
Originally posted by ikoflexer
You're a gold mine of information!

What is LPAD?

The signal generator used was the one in A.R.T.A., so, it was looped through the phono. You too noticed the difference, with the laptop plugged in, or on battery. The laptop switched power supply will push all sorts of high freq noise into the measurements. For all my experiments I unplugged the laptop from the psu, ran it on its battery.

Yes, I am running the MM cascoded and buffered version, from page 8.

Edit: salas, I hope you don't mind this question. Does this
http://cgi.ebay.ca/E-MU-Tracker-Pre-...1%7C240%3A1318
look like a good price for that device?

An LPAD attenuator is a series resistor feeding a parallel resistor. The signal at their node is X times lower given their ratio. See.

That is a very good price for EMU Tracker Pre. I prefer USB box to PC card due to its connectivity and mobility features.
  Reply With Quote
Old 24th February 2009, 03:15 PM   #1165
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Quote:
Originally posted by RCruz
Bypassing the 4.7u MKP Mundorfs with the ERO 1832 is a success !!!

Inittially lost the bass and everything sounded a mess... after a while (3 records...) the sound opened and the dynamics are now awesome, harshness in the highs became sweet loads of detail...

I am already thinking what a really good output cap could do.

Salas, what type of cap are you using "auricap ?" and is it bypassed ?

Ricardo

Now the TT is five fingers over the CDP.
You see? I wasn't bugging you to bypass the Mundorf for no reason...

Auricap is much more musical than basic Mundorf (looks like tarted up SCR to me) in my opinion, and I always try to get my tone right by choosing the most adequate cap without the aid of bypassing.
I would use Russian Teflon there if it was available at 2.2-4.7uF range. To make it out of many 0.XXuF is a bad idea for bulk and performance scope. VCAP Tin Foil Teflon is the best for a single cap in few uF range IMO, but the expense is HUGE given the cost of the phono + PSU. I would get Auricap, and see if it can do any better with a 0.1uF FT3 in parallel or not. In my box I don't have the space to parallel an FT3 so to tell. Sometimes they marry, sometimes they fight. Its a hands on thing so to know.
  Reply With Quote
Old 24th February 2009, 04:41 PM   #1166
diyAudio Member
 
nicoch58's Avatar
 
Join Date: Oct 2004
as Salas report vcaps or Auricap teflon are the best ,nex mundorf silver or gold but in that range cost too much !!!

my hot suggestion is to tray the cheaps but very good obbligato ,can found in EE ,after play with bypass if...

I have used the cheaps and good claritycaps Sa (there is new model improved)// 0.1 mundor silver with good result....

dont forget what you have on the amp input !!!
__________________
Sic58
  Reply With Quote
Old 24th February 2009, 04:54 PM   #1167
diyAudio Member
 
nicoch58's Avatar
 
Join Date: Oct 2004
obbligatoand kiwane

here claritycaps esa,ampohm (good), mundorf and tantalum resistor

auricap
__________________
Sic58
  Reply With Quote
Old 24th February 2009, 05:40 PM   #1168
RCruz is offline RCruz  Switzerland
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Blog Entries: 1
Thank you.

Your info is precious !

I believe I do not have any cap in the signal path inside the pre and the power amp, So there will not be any incompatibility.

I will try the auricaps or maybe the obbligato.

Salas, can you please post the FT3 diameter so I can determine if I can fit them easily ?

Ricardo
__________________
RC
  Reply With Quote
Old 24th February 2009, 06:27 PM   #1169
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Unfortunately I did not measure them. But maybe IKo or Kent still have some in hand to measure?
  Reply With Quote
Old 24th February 2009, 06:46 PM   #1170
iko is offline iko  Canada
diyAudio Moderator
 
iko's Avatar
 
Join Date: May 2008
Location: Toronto
Hi Ricardo,
I'm not home now, but I can tell you with some certainty that the diameter is between 30 and 35mm; lenght, about 70mm.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 10:20 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2