|Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum|
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
||Thread Tools||Search this Thread|
|19th November 2009, 05:18 AM||#1|
Join Date: Sep 2008
Presonus Bluetube makeover
Hello all -
The subject of the Presonus Bluetube mic preamp was mentioned in another thread as a possible subject for mods. To get the ball rolling - kevinkr offered these suggestions :
"I replaced the original quad op-amps with National LME49740 - see here: LME49740 - Quad High Performance, High Fidelity Audio Operational Amplifier
The supply in this thing is one of the real weak points IMO and a separate toroid and full wave rectification of the rails would be a real enhancement. A separate winding for the tube would be good too."
thx to all --
|19th November 2009, 05:26 PM||#2|
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Here's that link again since it did not copy over correctly to the new thread:
LME49740 - Quad High Performance, High Fidelity Audio Operational Amplifier
These parts are SOIC (surface mount) so some skill in their replacement is required.
The 12AX7A in mine was Chinese, nothing special. I replaced it with a vintage Mullard..
Again I have no idea what effect these changes will have on the sound of this mic pre as I have not yet used it to record anything.
The tube in the Bluetube pre is really there to add some distortion, err, warmth in the signal path. This isn't a tube mic pre in any sense.
One thing worth considering as I pointed out in another thread is power supply improvements. A nice toroid and an entirely outboard supply providing +/-15V or so and 60V for the tube would be worthwhile I suspect. The supplies are mostly regulated, but IIRC there is nothing special about the circuit, and because a wall wart (18VAC) is used as a source all of the supplies are half wave.
"Extraordinary claims require extraordinary evidence." - Carl Sagan
|Thread Tools||Search this Thread|
|Thread||Thread Starter||Forum||Replies||Last Post|
|Aria 6P14 makeover.||audio1st||Tubes / Valves||8||29th June 2012 12:12 AM|
|FS: Presonus Firebox 24/96 capable preamp/DAC/headphone out||Glowbug||Swap Meet||3||7th October 2009 11:45 PM|
|Presonus Firebox Audio Interface||Tenson||Swap Meet||1||15th June 2008 09:19 PM|
|CD Makeover!!!||sandstorm33||Digital Source||4||14th February 2007 01:21 AM|
|Silvertone 1472 Makeover||Gunny||Tubes / Valves||2||25th February 2006 08:39 PM|
|New To Site?||Need Help?|