aikido thump

jayme · 22nd October 2006, 12:17 AM

Anyone else get a loud thump when turning off their aikido-based preamp?

Just wondering if the issue is with my PSU section...

ray_moth · 22nd October 2006, 01:50 AM

It is reportedly common practice, among those who use separately powered preamps, to switch off the main amp first, wait a second or two, and then switch off the preamp.

jayme · 22nd October 2006, 02:02 AM

Yeah...I am familiar with that practice...but I'd like to look for an overall solution other than a guideline (my wife likes to shut everything off at once...)

Original Burnedfingers · 22nd October 2006, 03:11 AM

I put an idiot sheet next to the equipment. It spells out the turn on and off procedure.

Problem solved

Andypairo · 22nd October 2006, 07:27 AM

I use a relay that shorts out the output (after the cap) with its NC contacts.
I energize the relay after a delay at turn on and de-energize it immediately at turn off.

No thumps.

Cheers

Andrea

triode_al · 22nd October 2006, 08:37 AM

Quote:

Originally posted by jayme
Anyone else get a loud thump when turning off their aikido-based preamp?

Just wondering if the issue is with my PSU section...

jayme
In my Aikido I have a 1.200 micro farad capacitor at a 215 V. It takes some time to load and similarly - to unload.
The result is: no thumps on turning on, and no thumps on turning off. It just fades (the tubes are cold befor the power line really drops).

I switch my power amp with the power switch of the Aikido. My power aplifier is transistor (LeMonstre) and would really show up any odd issues. Maximum at turn on is 3 volts for 1 second at turn on (after 30 sec) and none at turn off. For safety, you should really add Andy's relay.

success
albert

jayme · 22nd October 2006, 03:13 PM

How would I implement a relay? Just have a switch which shunts B+ thru a resistor to ground?

I don't need the protection at start-up...I use a 5AR4 rectifier, which gives me a slow ramp up.

My PSU doesn't have a lot of big caps: it is CLCLC with 3.3uF, 20uF, and 40uF caps, respectively. I use some big 15H chokes for the inductors.

Klimon · 23rd October 2006, 03:32 PM

Quote:

I put an idiot sheet next to the equipment. It spells out the turn on and off procedure. Problem solved.

Andypairo · 24th October 2006, 12:29 PM

Quote:

Originally posted by jayme
How would I implement a relay? Just have a switch which shunts B+ thru a resistor to ground?

I don't need the protection at start-up...I use a 5AR4 rectifier, which gives me a slow ramp up.

My PSU doesn't have a lot of big caps: it is CLCLC with 3.3uF, 20uF, and 40uF caps, respectively. I use some big 15H chokes for the inductors.

I was talking about shunting the output (=signal) after the coupling cap.

Cheers

Andrea

Bill*B · 26th October 2006, 01:30 PM

My own Aikido has a subsonic output at turnoff - you can see the speaker cones thrust out, although there's no sound. I've never tried to track down the source, although I (like you) suspect that it is the power supply - I used a regulated unit and I'll bet the voltage surges when the voltage reference falls out of conduction.

22nd October 2006, 12:17 AM	#1
jayme diyAudio Member Join Date: Sep 2005	aikido thump Anyone else get a loud thump when turning off their aikido-based preamp? Just wondering if the issue is with my PSU section...

22nd October 2006, 07:27 AM	#5
Andypairo diyAudio Member Join Date: Sep 2002 Location: near Milano , Italy	I use a relay that shorts out the output (after the cap) with its NC contacts. I energize the relay after a delay at turn on and de-energize it immediately at turn off. No thumps. Cheers Andrea __________________ I don't believe in audiophile components - except when I can get them at frugal-phile(tm) prices

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22nd October 2006, 01:50 AM	#2
ray_moth diyAudio Moderator Emeritus Join Date: Jan 2004 Location: Jakarta	It is reportedly common practice, among those who use separately powered preamps, to switch off the main amp first, wait a second or two, and then switch off the preamp.

22nd October 2006, 02:02 AM	#3
jayme diyAudio Member Join Date: Sep 2005	Yeah...I am familiar with that practice...but I'd like to look for an overall solution other than a guideline (my wife likes to shut everything off at once...)

22nd October 2006, 03:11 AM	#4
Original Burnedfingers diyAudio Member Join Date: Nov 2002	I put an idiot sheet next to the equipment. It spells out the turn on and off procedure. Problem solved

22nd October 2006, 03:13 PM	#7
jayme diyAudio Member Join Date: Sep 2005	How would I implement a relay? Just have a switch which shunts B+ thru a resistor to ground? I don't need the protection at start-up...I use a 5AR4 rectifier, which gives me a slow ramp up. My PSU doesn't have a lot of big caps: it is CLCLC with 3.3uF, 20uF, and 40uF caps, respectively. I use some big 15H chokes for the inductors.

26th October 2006, 01:30 PM	#10
Bill*B diyAudio Member Join Date: Sep 2004 Location: tampa, florida, USA	My own Aikido has a subsonic output at turnoff - you can see the speaker cones thrust out, although there's no sound. I've never tried to track down the source, although I (like you) suspect that it is the power supply - I used a regulated unit and I'll bet the voltage surges when the voltage reference falls out of conduction.