Banggood "Tube Amp 2" Kit

[ken]

I seem to have missed quite a lot of the discussion. The valves I have are the same as the ones in Lawrence's link though the designation marks are not as good on mine. The valve boxes are marked Peking Tube Co. As Peking is now Beijing I suppose this fits. The amp is the same as the one in Andy's link.
I have downloaded the valve info and the diagram. From what has been said above I would have seem to have wasted my time in building this kit as it does not appear to be what I thought it was. I'm now quite disappointed in this kit before I even power it up. As it's not what it says it is I can't recommend it to anybody.

Regards,

Ken.

[Mark Hennessy]

Don't be downbeat about it - it'll be a decent headphone amplifier. Personally, I feel that if the valve isn't adding distortion, then so much the better.

Years ago, Musical Fidelity sold the X10-D tube buffer to the hi-fi market. A box that sat between your CD player and amplifier, and buffered the signal using a valve. The audio crowd loved it!

Funny thing is, according to the manual, the THD was less than 0.004%, so whatever was going on, it wasn't "rich 2nd-order harmonics". Most of it will have been placebo effect (the most powerful thing in hi-fi).

[pwdrive]

Here's a China/ Rest of the the world (almost) equivalents list, according to that The Chinese 6J5 equals a 6AH6 pentode:

http://analogmetric.com/download/Vacuum%...0table.pdf

Lawrence.

[tiv48]

So the valve heaters are 6.3 volts at 450ma so as i thought if they are wired in series 12 volt at 500 ma supply should be fine.
Rob T

[ken]

I downloaded the Shuguang Tube Manual (1973) from Lawrence's link. It's worth a look. I've attached a picture of my kit built as all the others were from the web site. The only difference is I've added a knob. It also shows that the makes of electrolytics vary.  Not really a surprise I suppose. I think I'm going to have to change my avatar.

Regards,

Ken.

[tiv48]

A very neat job
Rob T

[ken]

Hello All,
I decided to complete my conversion to an audiofool and power up my amp. I found a large +12-0--12 with no markings (see pic) but it was big and heavy and I didn't think it would draw much current. I also found a 12V DC wall wart for the heaters. It was not regulated but on load it red 12V. The amp works pretty well. However, based on what was said previously about what the valves were doing I thought I'd switch off the heater supply. So what happened when I switched off the heater supply? Well I though I might leave the answer and see If I got any suggestions.

Regards,

Ken.

[tiv48]

Hopefully removing the valves resulted in no sound otherwise the valves are just for show.
Rob T

[ken]

Hi Rob,
Just to answer the question I posed. When I disconnected the heater supply the heaters went out but the sound through the headphones stayed the same in every respect so it looks as if the predictions about the valves doing nothing were correct. Thanks for the "neatness" comment.

Regards,

Ken.

[Murphyv310]

Hi Rob,
Just to answer the question I posed. When I disconnected the heater supply the heaters went out but the sound through the headphones stayed the same in every respect so it looks as if the predictions about the valves doing nothing were correct. Thanks for the "neatness" comment.

Regards,

Ken.

Hi Ken.
A bit of a con then regarding the valves. That is very disappointing indeed.
I've been asked to build a headphone amp with 6080 valves
 http://www.r-type.org/exhib/aaa0725.htm
Allegedly these are excellent for the purpose, ready built versions can cost up to £600