Nobis Technologies Convigore

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It's a two channel 50 watt class-a el34 amp. 50 watts seems like a lot
for el34s. Sounds pretty good though but has somewhat of a transistor
like sound to it. Ever hear of it?

[Eeyore]

wrote:

> It's a two channel 50 watt class-a el34 amp. 50 watts seems like a lot
> for el34s. Sounds pretty good though but has somewhat of a transistor
> like sound to it. Ever hear of it?

Is it European ?

Graham

[[email protected]]

I think it's a house brand for a small HI-FI shop in Glendale WI.
called Sound Investments Ltd. but i can't find any other info.

On Sat, 09 Sep 2006 18:58:59 +0100, Eeyore
> wrote:

>
>
wrote:
>
>> It's a two channel 50 watt class-a el34 amp. 50 watts seems like a lot
>> for el34s. Sounds pretty good though but has somewhat of a transistor
>> like sound to it. Ever hear of it?
>
>Is it European ?
>
>Graham
>

[Sander deWaal]

said:


>It's a two channel 50 watt class-a el34 amp. 50 watts seems like a lot
>for el34s. Sounds pretty good though but has somewhat of a transistor
>like sound to it. Ever hear of it?


50 watts is achieveable with one pair of EL34s, but it won't certainly
be class A .
I'd say they're biased low, near B.

Don't they mean a 2 x 25 watts design? EL34 PP in A will deliver close
to 15 watts in A entirely, above that (and with a lower than rated
load) it'll shift towards AB.
You'll have to measure the anode voltage and current to determine the
operation point, as well as knowing the Ra-a- of the output
transformer with the rated load.

What's a "transistor sound" like to you?

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[Eeyore]

Sander deWaal wrote:

> said:
>
> >It's a two channel 50 watt class-a el34 amp. 50 watts seems like a lot
> >for el34s. Sounds pretty good though but has somewhat of a transistor
> >like sound to it. Ever hear of it?
>
> 50 watts is achieveable with one pair of EL34s, but it won't certainly
> be class A .
> I'd say they're biased low, near B.

Indeed, that's classic A-B.

I've actually worked on several special 'Sound City' touring amplifiers for rock
bands with 6 x EL34 that were advertised as '200W'.

I was asked to modify them to correct for perceived low sensitivity ( they
belonged to the band 'Argent' btw ) and upped the gain by a good 10+ dB mainly
by adjustment of the feedback path.

The B+ was ~ 600V IIRC and after the mods I got a guitarist friend of mine to
give them a 'work out'. I distinctly recall measuring a peak voltage of 60V (
into 8 ohms ) !

That's 450W - and it sounded like it ! The speaker was an EV SRO15 as it
happens.

It was damn fine too !


> What's a "transistor sound" like to you?

What's " toob sound " like one wonders !

Graham

[Sander deWaal]

Eeyore > said:


>I've actually worked on several special 'Sound City' touring amplifiers for rock
>bands with 6 x EL34 that were advertised as '200W'.

>I was asked to modify them to correct for perceived low sensitivity ( they
>belonged to the band 'Argent' btw ) and upped the gain by a good 10+ dB mainly
>by adjustment of the feedback path.


Hey, that's a Dutch band!


>The B+ was ~ 600V IIRC and after the mods I got a guitarist friend of mine to
>give them a 'work out'. I distinctly recall measuring a peak voltage of 60V (
>into 8 ohms ) !

>That's 450W - and it sounded like it ! The speaker was an EV SRO15 as it
>happens.


It is even possible, according to Philips data, to get 100 watts out
of a pair of EL34s, with 800V at the anodes.

Theoretically, that would mean 300 watts continously in 8 ohms,
provided the load is closely matched.
Peak power (voltages) might even have been higher (who cares about
distortion in geetah amps....)


>> What's a "transistor sound" like to you?


>What's " toob sound " like one wonders !


That's why I asked.
There isn't a specific "tube sound", AFAIC.
The same goes for transistors and MOSFETs.

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[[email protected]]

http://65.29.159.126:20102/amp.jpg

Here's what it looks like.