• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

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
 

EC8010

diyAudio Moderator Emeritus
2003-01-18 7:57 am
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.
 

mach1

Banned
2004-09-13 4:06 am
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
 

analog_sa

Member
Paid Member
2002-08-14 1:47 pm
Cascais
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.