Audio Innovations L-2

fernando · 11th August 2005, 08:45 PM

Hello
I have an Audio Innovations L-2 preamplifier that I am planning to mod.
I am trying to perform the modifications that Borderpatrol does for this preamp.
“Fit Hovland Musicap, Os-Con and Black Gate capacitors, rebuild heater rectifier with discrete Schottky diodes.”….” Replace volume pot with Danish Audio Connect step attenuator”
http://www.borderpatrol.co.uk/ai.htm

My questions are:
1-Are the musicaps a big improvement over the existing Jensen paper caps?
2-Is the Danish Audio Connect step attenuator worth the $100?
3-What the Schottky diodes improvement is over the standard bridge rectifier for the heaters?
4- Did anyone perform the modification to the power supply suggested here: http://www.audionote.co.uk/tweaks/l2_preamp_mod_01.htm ?

Thank you in advance
Fernando

EC8010 · 11th August 2005, 11:13 PM

1. No idea.
2. If you like the idea of a stereo image that doesn't wobble about as you change volume and a volume control that has a genuine logarithmic law, then yes, it's worth $100. Myself, I wouldn't dream of going back to ordinary volume controls after using stepped attenuators.
3. You'd be amazed at how easily noise on heater supplies finds its way into the audio.
4. No idea.

mach1 · 12th August 2005, 02:00 AM

Cap change - Not better, just totally different: the two capacitors you mention are polar opposites in terms of sonics.

Stepped attenuator - great if you can afford it . Personally I find the Jaycar silver carbon pots mentioned by Joe Rasmussen on this forum to sound amazingly good (and only cost A$5.00!). You may want to consider acquiring or constructing a better pre before you go to all the way to a DACT.

paulm

kmtang · 12th August 2005, 01:41 PM

The bypass capacitors in the B+ would have big impact with the sound. You may try to fit in differnt types to find out how you like them.

Johnny

analog_sa · 12th August 2005, 02:15 PM

1. Agree with mach1 - the Hovlands are very fast and revealing - and not always in a good way. If you system is on the bright side Hovlands may not be an improvement.

2. Worth a $100? Probably. A nice switch alone costs around $60 and you still have to find resistors. A more cost effective improvement is to use a good quality series resistor and connect the pot as a shunt.

3. Dodn't ask, just do it. And don't forget to get a really nice smoothing cap.

fernando · 13th August 2005, 06:53 AM

Hello
Thanks alot for your replies.
I will start with the schottkys in the heater's rectifier and the modification of the power supply (cost~0). I will wait on the DACT and the Hovlands for now.
Fernando

11th August 2005, 08:45 PM	#1
fernando diyAudio Member Join Date: Dec 2004 Location: Boston	Audio Innovations L-2 Hello I have an Audio Innovations L-2 preamplifier that I am planning to mod. I am trying to perform the modifications that Borderpatrol does for this preamp. “Fit Hovland Musicap, Os-Con and Black Gate capacitors, rebuild heater rectifier with discrete Schottky diodes.”….” Replace volume pot with Danish Audio Connect step attenuator” http://www.borderpatrol.co.uk/ai.htm My questions are: 1-Are the musicaps a big improvement over the existing Jensen paper caps? 2-Is the Danish Audio Connect step attenuator worth the $100? 3-What the Schottky diodes improvement is over the standard bridge rectifier for the heaters? 4- Did anyone perform the modification to the power supply suggested here: http://www.audionote.co.uk/tweaks/l2_preamp_mod_01.htm ? Thank you in advance Fernando

11th August 2005, 11:13 PM	#2
EC8010 diyAudio Moderator Join Date: Jan 2003 Location: Near London. UK	1. No idea. 2. If you like the idea of a stereo image that doesn't wobble about as you change volume and a volume control that has a genuine logarithmic law, then yes, it's worth $100. Myself, I wouldn't dream of going back to ordinary volume controls after using stepped attenuators. 3. You'd be amazed at how easily noise on heater supplies finds its way into the audio. 4. No idea. __________________ The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...

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12th August 2005, 02:00 AM	#3
mach1 diyAudio Member Join Date: Sep 2004 Location: Brisvegas	Cap change - Not better, just totally different: the two capacitors you mention are polar opposites in terms of sonics. Stepped attenuator - great if you can afford it . Personally I find the Jaycar silver carbon pots mentioned by Joe Rasmussen on this forum to sound amazingly good (and only cost A$5.00!). You may want to consider acquiring or constructing a better pre before you go to all the way to a DACT. paulm

12th August 2005, 01:41 PM	#4
kmtang diyAudio Member Join Date: Nov 2004 Location: Vancouver	The bypass capacitors in the B+ would have big impact with the sound. You may try to fit in differnt types to find out how you like them. Johnny

12th August 2005, 02:15 PM	#5
analog_sa diyAudio Member Join Date: Aug 2002 Location: Sofia	1. Agree with mach1 - the Hovlands are very fast and revealing - and not always in a good way. If you system is on the bright side Hovlands may not be an improvement. 2. Worth a $100? Probably. A nice switch alone costs around $60 and you still have to find resistors. A more cost effective improvement is to use a good quality series resistor and connect the pot as a shunt. 3. Dodn't ask, just do it. And don't forget to get a really nice smoothing cap.

13th August 2005, 06:53 AM	#6
fernando diyAudio Member Join Date: Dec 2004 Location: Boston	Hello Thanks alot for your replies. I will start with the schottkys in the heater's rectifier and the modification of the power supply (cost~0). I will wait on the DACT and the Hovlands for now. Fernando

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