Aikido users- anyone NOT have turn-off thump?

jayme · 11th October 2007, 03:43 PM

Does anyone have an Aikido linestage that does not exhibit a turn-off thump?

If so, can you describe your PSU?

clivetjm · 12th October 2007, 10:22 AM

This is quite typical with tube preamps. You could implement a relay to short the outputs on switch off. I always turn off power amps first, normal procedure with tube preamps.

Original Burnedfingers · 12th October 2007, 10:36 AM

Quote:

Does anyone have an Aikido linestage that does not exhibit a turn-off thump?

First of all the power amplifier should be turned off first before turning off ANY line stage or preamp.

To answer your question.... None of my Aikido's exhibit a turn off thump. The first is the unit that I bought from a group buy here (thanks again Bas). I also bought the power supply circuit board that was part of the group buy and built it according to Bas's outline.

The others have a power supply that was my own brain child and I will look for a schematic to send you.

clivetjm · 12th October 2007, 05:19 PM

Here's a $35 kit for a muting circuit:
http://www.transcendentsound.com/timedelay.htm

jayme · 12th October 2007, 08:36 PM

Thanks, burnedfingers. I'll retry a simple CRCRC along the lines of Bas' boards. Perhaps it is the chokes in my CLCLC that are causing the issue by maintaining the current.

Also...are you using AC or DC on the heaters? I have AC heaters.

Boris_The_Blade · 12th October 2007, 10:54 PM

This could be cause by too big an output cap...what is your value cap and value of load resistance?

beau2317 · 13th October 2007, 12:43 AM

I don't have turn off or turn on thump. Either with my preamp or with my moskido power amp. If you have the protection resistors you should not get it. In fact you should be able to pull tubes while it's on and not get a thump. (Not tried that one I admit).

Original Burnedfingers · 13th October 2007, 11:47 AM

Quote:

In fact you should be able to pull tubes while it's on and not get a thump.

I wouldn't try this one. The resistors if used are there to protect the tubes in case of accidentally pulling a tube out when it was on. I certainly wouldn't do it on purpose just to check operation unless I was using old tubes and didn't have speakers and a power amp behind it.

Just my .02

Original Burnedfingers · 13th October 2007, 11:50 AM

The Vellman 4700 protection kit imight be a better choice for the same money. It has its own transformer. It can be put into a nice little box that would allow usage with any of your projects. I set mine up to use with amplifiers that don't have DC protection.

Original Burnedfingers · 13th October 2007, 11:57 AM

Picture of board

11th October 2007, 03:43 PM	#1
jayme diyAudio Member Join Date: Sep 2005	Aikido users- anyone NOT have turn-off thump? Does anyone have an Aikido linestage that does not exhibit a turn-off thump? If so, can you describe your PSU?

13th October 2007, 12:43 AM	#7
beau2317 diyAudio Member Join Date: Jul 2005 Location: Pukekohe, New Zealand	I don't have turn off or turn on thump. Either with my preamp or with my moskido power amp. If you have the protection resistors you should not get it. In fact you should be able to pull tubes while it's on and not get a thump. (Not tried that one I admit). __________________ Moskido (Hybrid Aikido/Mosfet); Verumecce (biased interconnects). Buffalo III with Unbalancer tube output; Magnepan 3.6R

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12th October 2007, 10:22 AM	#2
clivetjm diyAudio Member Join Date: May 2003 Location: UK	This is quite typical with tube preamps. You could implement a relay to short the outputs on switch off. I always turn off power amps first, normal procedure with tube preamps.

12th October 2007, 05:19 PM	#4
clivetjm diyAudio Member Join Date: May 2003 Location: UK	Here's a $35 kit for a muting circuit: http://www.transcendentsound.com/timedelay.htm

12th October 2007, 08:36 PM	#5
jayme diyAudio Member Join Date: Sep 2005	Thanks, burnedfingers. I'll retry a simple CRCRC along the lines of Bas' boards. Perhaps it is the chokes in my CLCLC that are causing the issue by maintaining the current. Also...are you using AC or DC on the heaters? I have AC heaters.

12th October 2007, 10:54 PM	#6
Boris_The_Blade diyAudio Member Join Date: Mar 2007	This could be cause by too big an output cap...what is your value cap and value of load resistance?

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