Meixing 3008ab problems

laundry2000 · 9th May 2007, 06:41 AM

Hello,

This is my first post here, though I already got much help for reading many useful talks going on.

I just ordered and got a Meixing 3008ab amp(they say it's newer version which uses 2a3 instead of 300b as driver tube), and very much satisfied with its sound even in its original state.

But there are many problems. As this is my first tube amp, I got somewhat perplexed.

1) There comes some noise in speakers whenever I power on. No noise when power off. Is it normal for this amp?

2) There is a slight hum in the transformer. I saw a few users of this amp faced similar problems. How can this be fixed?

3) The transformer got hotter and hotter, and after 5 hrs became almost impossible to touch. Is it also normal?

Sorry for many questions.

Thank you in advance.

Hyun

gingertube · 9th May 2007, 07:32 AM

Check that the amp is set correctly for the line voltage in your country.

If so, make sure you use it in a well ventilated area so that you get good airflow around that transformer and the tubes.

Check the securing bolts for the transformer are tight. If so you may need to actually undo the bolts and fit some vibration damping material between the transformer and chassis - make sure you retain a good earth connection to the transformer metal parts.

What is the noise from the speaker at switch on. Is it just a single thump? or a hum? and how loud. If its a single thump and is not very loud then its not something you need to worry about.

Hope this is of so help,
Cheers,
Ian

Boeing · 9th May 2007, 08:59 AM

Hi ! I am now is just talking about the transformer hot. You mean that you can not touch the trans. after few hours working ? I think :
- That trasformer is overload
- That transformer is sub standard , tell us transformer specification.
I think, however, the transformer get hot is normal if temperature is not exceed temperature range in specification. If it is lower than 70 celcius degree -> OK.

Regards.
Boeing.

laundry2000 · 11th May 2007, 07:31 AM

Thank you, Ian and Boeing for your kind and detailed reply.

I think I solved one problem.

There is a "protective switch" on the front panel of this amp. Until now I always have this switch "on", but the noise is gone when I power on with this protective swicth "off" !!

Actually I sent at least 2 emails requesting the role of this switch to Meixing audio, but got no answer at all.

I hope this helps the users of this gorgeous amp.

Anyway, the hum on the transformers continues.

Hyun

9th May 2007, 06:41 AM	#1
laundry2000 diyAudio Member Join Date: May 2007	Meixing 3008ab problems Hello, This is my first post here, though I already got much help for reading many useful talks going on. I just ordered and got a Meixing 3008ab amp(they say it's newer version which uses 2a3 instead of 300b as driver tube), and very much satisfied with its sound even in its original state. But there are many problems. As this is my first tube amp, I got somewhat perplexed. 1) There comes some noise in speakers whenever I power on. No noise when power off. Is it normal for this amp? 2) There is a slight hum in the transformer. I saw a few users of this amp faced similar problems. How can this be fixed? 3) The transformer got hotter and hotter, and after 5 hrs became almost impossible to touch. Is it also normal? Sorry for many questions. Thank you in advance. Hyun

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9th May 2007, 07:32 AM	#2
gingertube diyAudio Member Join Date: Oct 2004 Location: Adelaide South Oz	Check that the amp is set correctly for the line voltage in your country. If so, make sure you use it in a well ventilated area so that you get good airflow around that transformer and the tubes. Check the securing bolts for the transformer are tight. If so you may need to actually undo the bolts and fit some vibration damping material between the transformer and chassis - make sure you retain a good earth connection to the transformer metal parts. What is the noise from the speaker at switch on. Is it just a single thump? or a hum? and how loud. If its a single thump and is not very loud then its not something you need to worry about. Hope this is of so help, Cheers, Ian

9th May 2007, 08:59 AM	#3
Boeing diyAudio Member Join Date: Apr 2007	Hi ! I am now is just talking about the transformer hot. You mean that you can not touch the trans. after few hours working ? I think : - That trasformer is overload - That transformer is sub standard , tell us transformer specification. I think, however, the transformer get hot is normal if temperature is not exceed temperature range in specification. If it is lower than 70 celcius degree -> OK. Regards. Boeing.

11th May 2007, 07:31 AM	#4
laundry2000 diyAudio Member Join Date: May 2007	Thank you, Ian and Boeing for your kind and detailed reply. I think I solved one problem. There is a "protective switch" on the front panel of this amp. Until now I always have this switch "on", but the noise is gone when I power on with this protective swicth "off" !! Actually I sent at least 2 emails requesting the role of this switch to Meixing audio, but got no answer at all. I hope this helps the users of this gorgeous amp. Anyway, the hum on the transformers continues. Hyun

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