getting a pop when i power down, help

parkerfly · 10th December 2009, 10:22 PM

i have a Cayin ta-30 (el-34) hooked up to a passive pre which i run with a Single driver set up. The amp runs 4 el-34's biased at 350 to give it 30 watts.. The amp is set up so that you can take out 2 power tubes and bias it to 700 and it becomes a SEP (4 watts). Everytime i do this (with a pre or without) i get a pop through the speakers after about 5 seconds when i power off. I turn all the volumes down and still get the pop. the pop dose not happen when all 4 tubes are running only when i take 2 out and bias at 700. I built the speakers , interconnects and speaker cables which all work well with my other gear. Am i doing something wrong? can it be fixed?

Any ideas would be helpful.( my technical knowledge is not great)

Thanks.

Gordy · 15th December 2009, 01:36 PM

If you post a circuit diagram the forum members might find it easier to offer advice...

Palustris · 15th December 2009, 04:33 PM

bias it to 700

700 what? A, Ma, V, mV, W?

parkerfly · 16th December 2009, 11:55 PM

Meter is set at 2000(mV) range, the link below explains how to do it. Could not find a schematic, sorry.

http://www.angelfire.com/biz/bizzyb/...JUSTMENTS.html

richwalters · 17th December 2009, 02:40 PM

Sounds like going through a bout of instability when volts falls in certain amp sections. Otherwise guessing.-> Need CCT diagram to make sense.

richy

parkerfly · 17th December 2009, 07:57 PM

its looking like i am not going to be able to provide enough information or insight to be helped. Thank you for looking, i'll regroup and get more info.

10th December 2009, 10:22 PM	#1
parkerfly diyAudio Member Join Date: Sep 2009	getting a pop when i power down, help i have a Cayin ta-30 (el-34) hooked up to a passive pre which i run with a Single driver set up. The amp runs 4 el-34's biased at 350 to give it 30 watts.. The amp is set up so that you can take out 2 power tubes and bias it to 700 and it becomes a SEP (4 watts). Everytime i do this (with a pre or without) i get a pop through the speakers after about 5 seconds when i power off. I turn all the volumes down and still get the pop. the pop dose not happen when all 4 tubes are running only when i take 2 out and bias at 700. I built the speakers , interconnects and speaker cables which all work well with my other gear. Am i doing something wrong? can it be fixed? Any ideas would be helpful.( my technical knowledge is not great) Thanks.

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15th December 2009, 01:36 PM	#2
Gordy diyAudio Member Join Date: Nov 2006	If you post a circuit diagram the forum members might find it easier to offer advice...

15th December 2009, 04:33 PM	#3
Palustris diyAudio Member Join Date: Aug 2006 Location: Cape Cod	bias it to 700 700 what? A, Ma, V, mV, W?

16th December 2009, 11:55 PM	#4
parkerfly diyAudio Member Join Date: Sep 2009	Meter is set at 2000(mV) range, the link below explains how to do it. Could not find a schematic, sorry. http://www.angelfire.com/biz/bizzyb/...JUSTMENTS.html

17th December 2009, 02:40 PM	#5
richwalters diyAudio Member Join Date: Sep 2003 Location: Alps:Tube amp designs over 150W, SMPS guru.	Sounds like going through a bout of instability when volts falls in certain amp sections. Otherwise guessing.-> Need CCT diagram to make sense. richy

17th December 2009, 07:57 PM	#6
parkerfly diyAudio Member Join Date: Sep 2009	its looking like i am not going to be able to provide enough information or insight to be helped. Thank you for looking, i'll regroup and get more info.

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