Jump to content

Cloned 2a3 integrated single ended tube amp


BBZink

Recommended Posts

Good Day all,

 

i have purchased a 2a3 Bowei integrated amp on ebay, and it plays well. Now i want to upgrade  chinese tube on it. there is 2 potentiometer (behind the tube), i could access with a screwdriver. Does anyone knows what is the purpose of those potentiometer?

 

Could not find anything on it, so my guess was to ask you all?

 

Also tube on this amp are weird, could i replace them with something more standard or NOS? exemple 2a3C=?; GZ3=? and 6h8c=?

 

regards

Link to comment
Share on other sites

30 minutes ago, tapajeurs said:

2 potentiometer (behind the tube), i could access with a screwdriver. Does anyone knows what is the purpose of those potentiometer?

Those are most likely the bias adjustment pots for the amp.  There may be a bias ranged printed near the two  adjustment pots.

 

33 minutes ago, tapajeurs said:

Also tube on this amp are weird, could i replace them with something more standard or NOS? exemple 2a3C=?; GZ3=? and 6h8c=?

Until you find out the bias adjustment range I would keep the tubes that came with the amp.  A lot of people want to quickly get rid of the Chinese tube.  They just assume that they are not good.  Actually, they make some pretty good tubes.  China and Russia never stopped using tubes when the US went thru the transistor age.  A lot of tubes made in China and Russia are re-branded for overseas sale.

 

Try and find a manual for the amp.  Let us know how you like it.

  • Like 1
Link to comment
Share on other sites

Could not resist that candy red look! it work flawless.  And banzai, i have put the tube on, sound amazing! but not sure i have the proper "noise" adjustment?

 

only downsize, no phone socket.

 

ps

i found back the seller, send a question, will wait and see!

 

Sometimes i am to much in the problem to think outside the box... Thanks

IMG_0028.JPG

IMG_0029.JPG

Link to comment
Share on other sites

57 minutes ago, derrickdj1 said:

Those are most likely the bias adjustment pots for the amp.  There may be a bias ranged printed near the two  adjustment pots.

 

Until you find out the bias adjustment range I would keep the tubes that came with the amp.  A lot of people want to quickly get rid of the Chinese tube.  They just assume that they are not good.  Actually, they make some pretty good tubes.  China and Russia never stopped using tubes when the US went thru the transistor age.  A lot of tubes made in China and Russia are re-branded for overseas sale.

 

Try and find a manual for the amp.  Let us know how you like it.

no ranged print.

 

NOS Marconi are on, couldn't wait, but will keep china as backup

 

and no manual, but found seller contact and send my question, so far the only thing i learn it is for the noise floor. it is suggested to play with them until there's no noise? not sure if i understand this and why?

Link to comment
Share on other sites

here what was written in original ad: (sorry for bold text, it is cut and paste)

 

"2A3C is compatible with 2A3 and 2A3B . Direct heating cathode and low power consumption. Two triodes can be used for class A and AB amplification".

 

What does that mean?

 

regards

Link to comment
Share on other sites

3 hours ago, wdecho said:

Mike Stehr is most likely correct. Most 300B/2A3 SE amplifiers have a noise adjustment pot. Bias adjustment pots are mainly for push pull amps. As long as you stick with the same kind of tubes you should be good for different brands of the same tube. OPT is an abbreviation for output transformers. Nice looking amplifier and I bet it sounds great. I have heard the difference between a 2A3 and 300B is "not much."

 

I just looked on Ebay for a price, great deal. I do not exactly know what the seller is saying about being used as Class A or A/B. To my knowledge all single ended tube amplifiers are class A. Probably just a sales pitch for those that do not know the difference. As much as I like buying American there are great deals coming from China on tube amplifiers vs American prices. You can expect the prices to go up soon due to tariffs. 

So my NOS Marconi are in good hand, the amps is long to break-in almost 6 month/12 hours a day, but after that smooth sound, and voicing is incredible. NOS ad a little something on the warm side and this amp is dead quiet (i mean noise floor), one of the quietest i had so far.

 

As far as i could afford it, i'll go with north american product, but here, it was a steal deal and most likely "tweakable" if needed by my 80years old technician that help me in the past bring back to life old tube amp and tube receiver.

Link to comment
Share on other sites

  • 2 weeks later...
  • 3 months later...

Just to let you know, lately i have a hum, after few research myself and with the help of the cable guy, he discover that the cable company installation has forgot to ground there cable before going in the house, so when i was hooking tv on computer, there was a hum in the system, took me two week to find the source and then cable guy work 2 hours, checking cable from the house to the pole.

 

Still enjoy my amp, great bargain, lovely sound.

 

One upgrade i want to do, is to replace the potentiometer for volume, any clue to what i should put in?

 

regards

 

ps, i am looking maybe for my other hifi room to buy a cav45 from CJ, is it a good choice? any comment? maybe i should star a new post for this one?

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...