Finally Finished V76

After months of effort and invaluable help from the Lab, I have completed my modified V76. I think I have all the bugs out and it sounds remarkable. Since I have not heard the original, I can't compare them but this amp is by far the best I have ever heard.

Here is my web page: http://users.adelphia.net/~thomasholley/Modified V76.htm

This project is definately not for the fient of heart but for me it was well worth the effort. Thanks to all of you who helped me see this through to completion. Especially CJ for his tenacity.

Excellant Thomas!
I like the wood cabinet!
Where did you get the pi filter choke? Is it that black torroid looking thingy with the tie wrap?
Nice small circuit board, how did you get all those parts on there?
I think you need another resistor on the feedback rotarty switch.(schematic, at least)
Did you ever figure out the tone compensation?
Well, that cap that recieves the negative feedback, C2 in your case, gets closer to ground as the the gain is increased. At max gain, the cap is sitting on top of that 98 ohm resistor to ground. So now the cathode of V1 has a bypass cap, which increases the bass response. Pretty cool, ehh!
Whats that 10 pf bypass cap on the 40 k feedback resistor for? Just a tone tweak?
Glad to be of help.
cj
And cool guitars!!!
:guinness:

:thumb: :thumb:

I see a night light package on your bench..next project LA2??? :green:

steff

Thanks for your interest.

I got the PI filter choke from a friend who salvaged it from an old army radio transmitter. It is just a spool of wire (maybe 34ga) on a paper bobin. I wrapped it in electrical tape and adjusted it's position to get least distortion and tie wrapped it to my shield plate.

I made turret boards from F4 fiberglas board and soldered parts top and bottom. Not a pretty layout as I had to swap things, add and subtract components as I experimented.

The feedback rotary switch on the schematic is wrong. I'll fix it. Thanks for pointing it out. That is a really cool circuit.

The 10p cap on the 40k resistor was used to tame an HF oscillation I had at one point in the journey. I think I could take it out now with no problems but it is hard to get to so I just left it in.

How did you see that nite light with all the crap piled up? Yes it is for an LA2A I hope to do. Also, the black box with plexiglas cylinder is a rig to tune mike capsule mylar.

I have never heard a real V76, just read about them and was intrigued by the work I saw here. I am also going to try a G9 with 6SN7 ( I love those octal triodes).

that's an el night light isn't it? what exactly is it for in the LA2? i've been thinking about starting one but know nothing about it yet..

Svart, do a search on the forum and you will get tons of information.

thanks, yeah i will look it up when i have more time than i do here at work, just wanted to know right quick.

:guinness:

Sweet!
:thumb:

That is truly gorgeous Thomas. I admire the patience, not to mention the skill it must have taken. Congratulations.

:thumb: :thumb:

Thanks for putting this up!!! Appreciate it! :thumb:

:sam: :sam:
Fabio

nice project.

has anybody done much stuff with 6sn7s? i have 6 nos brimar ones i got in a lot i have been meaning to use for somthing.............

Very nice! That baby is certainly one of a kind!

Bjorn

[quote author="toby"]has anybody done much stuff with 6sn7s? i have 6 nos brimar ones i got in a lot i have been meaning to use for somthing.............[/quote]
They are great for line level use, or for power amp drivers.

What do your Brimars look like BTW? Some of the NOS Brimars are actually standard Russian 6SN7s. Most people find those terrible, but I like them...

Best regards,

Mikkel C. Simonsen

Older Ampegs used 6SL7/6SN7 circuits. I have heard them in several DIY audio amps and I use them in my bass amp.

hey mcs

just found them and there 6sn7gt's. foreign ( so russian from what you say.) octal sockets, look about the same size as most power amp tubes.

i was gonna do a clone of somthing like thermonic cultre's cultre vultre with them.