LA2A pcb project

[Deepdark]

sounds like it works!  I had to put www in front of the address to get it to load.

Thanks Doug, I'll check it out!

Yes it works pretty well, not to say

 

[Deepdark]

I have finished testing the unit by my side. I would like to know if there is some gentleman here willing to be the guinea pig and build one and report back the results

Before officially releasing the boards, i want to be 100% sure it works good. Let me know

 

[Deepdark]

Guinea pig found  8)

 

[Deepdark]

Here is an update.

I've just completed a second build. This time with Panasonic capacitors, and a Solen Fast at C5. I tried an Par-Metal semi Steel / semi aluminium chassis. Works great. I tried some tubes at V1 and found the better one in term of noise is the 12AY7 EH and also, JJ was not bad. I tried one Sovtek that were really good at first but not long after, begin to exibit a little hum. Audible only with headphone at max, thought, so way Under audio signal. With the 12AY7, no audible hum and a little more headroom.

 

[Deepdark]

The revision board is nearly finished. Just need to finalise the psu to incorporate the option of using an Toroidal transformer and a bridge rectifier.

Question of interest: How much hum is acceptable. I mean, if you just put in a tube that exibit a little hum, only audible with headphone at max, so really not loud. Is it ok, since it's way Under audio signal? I think the only remaining hum, that can be reduced more with careful tube selection, is with the ac heater. Maybe I could simply make heater DC and use a 7812 regulator, or something like that.

What's your thouht?

 

[Deepdark]

Here is 2 track test. One with the Sovtek 12AX7 and the other one with the 12AY7. I left some seconds of blank at the end of each tracks to compare the actual noise floor along the audio signal.

https://soundcloud.com/user-832864704/12ay7

https://soundcloud.com/user-832864704/12ax7