To test this feature, visit your live site.

A10 after the mods has a very low sound level

Hi guys,

I am a newbie in electronics, must confess, but love to learn and practice.

That was the reason to buy a A10 and use the great generosity of Stheve to modify it and have a better sound companion.

I believe that did it all right - please have a look on the picture attached - but after watching all the videos more than two times I couldn't figure out why my amp, despite playing, sounds very, very low - at a level that is almost impossible to listen anything.

I am clueless and would love some of your help/guidance to troubleshoot it. My speakers have a sensitivity of 88dB, so they are not the most efficient but the A10 should be able to drive them. I also used the pins for the 6N2 instead of changing them for the 12AX7.

In addition, how can I test my tubes in order to make sure they are working?

Thank you so much and my best wishes to you all.

Alex.

18 answers0 replies

18 Comments

alexmp01

May 02

I understand what you are saying....One step at that time!! In that case, what is your indication, if I can abuse your knowledge and support, for a good pair of bookshelf speakers for the A10? All the speakers sensitivity that I have are from 86 to 88dB maximum.

and ...what a coincidence, I was learning a bit about OTL amps and found a video in my native language of a professor of electronics that designs OTL amps and has a crazy audition room at his house. If you want to have a

look for curiosity. This is the link: https://youtu.be/vMA8Hc2AWHg?si=S3nLpyzpHjOtKzBU

The frontal horn on the wall is unbelievable...

And also a cheap OTL headphone amp that seems to be interesting: https://www.hificollege.net/products/xduoo-ta-66-headphone-amplifier-6n2-6n59-high-performance-ta66-tube-amplifier?_pos=1&_sid=ce7d57e72&_ss=r

Well, as I said, on step at that time. Thank you so much for helping me to learn about an amp that has a different soul. Great to listening music in a class A amp!!

My best wishes!!

alexmp01

May 01

Hi guys,

Having a look on my own picture of the soldering, I decided to do a reflow of my work, before taking any voltage measures. I will let you know.

Thanks.

alexmp01

May 02

Replying to

Hey Junkman,

It is working!!!!!

After the reflow, I don't know why but was under the impression it will work, so I just give it a go and BOOOMM....It is singing. Some connections with the ground weren't that solid. That may be the problem.

Honestly talking it does not have all the power I was expecting but, on the other hand, it creates such a beautiful sound stage and the midrange of female voices is amazing. My wife also like the sound volume so, happy life for me. I decided to use it as my desk amp, as with its actual level of amplification it will make no difference playing with the others in my main system. Although is not that powerful I am super happy and would like to thank you so so much for all your attention and help.

Until today I was a bit disappointed with tube amps, but would like to give it another go with a DYI kit, practicing my soldering studying and increasing my knowledge during the assembly.

In that regard, could you give me any suggestions of a nice DYI kit that I could assemble, please?

Again, I can't thank you and Skunkie enough for your help. My best wishes!!

Junkman George

May 02

Replying to

Hi...............

Well, ok, I think that you are coming up on decision time. You have a 6 X 2 watt class A amp that you like the sound of............. maybe a pair of speakers that can work with that low wattage might be in your best interests to own. Nothing beats the sound of a class A amplifier and unfortunately, by their nature, they are usually 10 watts, or less a side. You can push-pull a pair of EL34's to an easy 25 watts a side, but something is lost in what you hear.

Myself, I'm thinking about an OTL (output transformer-less) maybe next winter? Of course it means buying a whole bunch of stuff I don't already own.

https://www.transcendentsound.com/

Skunkie

May 02

•

Replying to

100% agree. a few watts isn't going to make any real difference in sound pressure level. get some 91db or better speakers and this little amp will sing!

alexmp01

Apr 30

Again, thank you so much!

Alex.

Apr 30

Apr 30

Apr 30

Apr 30

Apr 30

Apr 30

Picture 02

alexmp01

Apr 30

Hi Junkman and Skunkie,

Please find a few close-ups in the next posts and thank you so much for your help. As suggested by Skunkie, I will measure the voltages at the schematics points and compare with the expected values. As soon as I have the numbers, will let you know.

Just thinking in a "trouble shooting" way, in your opinion where the problem could be?

The amp was working before the mods. So the problems cause can be:

a) My mistake(s) doing the mods

b) A defective new component - including all the elements in the BOM and the new Sovteck tube. Resistors are very unlike to be defective and there is no bulged capacitors, so my main suspect is the tube. What do you think?

c) Any other reasons you guys can see?

Again, thank you so much.

Kind regards,

Alex.

Thank you so much

Junkman George

Apr 29

Quickly looking, it appears the resistor you installed on the power supply board is not connected on both ends.

You really should post close-ups................... thanks

Skunkie

Apr 29

•

So are you using 6N2 or 12AX7 tubes? And upload some closeup shots of the tube sockets.