Marshall Valvestate mini stack stuff

[djmartins2]

Hi all,

I scored 20 SGS TDA2030As and was searching for a good use for them.
The old Marshall Valvestate 8001/8010 10 watt combo/stack
schematic grabbed my attention.
All solid state 10 watt amp using a single 1458 and a single TDA2030.
Normal/Boost switch, mid/bass/treble and a MV all on the 1458
feeding into the TDA2030 as a power amp.
Some people say it sounds pretty good for a small practice amp.
Perhaps it is the Marshall name that leads them to say so.
The circuit doesn't seem too fancy....

On the schematic Marshall did not use recommended diodes from
power to output to protect the TDA2030, which is voltage sensitive.
Lot and lots of small wattage practice amps use the TDA2030 and
far to many of them fail due to no power protection or overheating.
I have done this up in Eagle, WITH the diodes and plan to
make a pcb and build one.
Now the questions:

Making it as is gives 10 watts.
I can easily add another TDA2030A bridged to give 34 watts total.
Then I can make a simple 2 speaker combo or stack out of it
with decent volume, yet still practice/headphone amp it.
Since the TDA2030A is simply boosting the
1458 sound, I think it will sound as good with > twice the power.
Do y'all think it is worth it to add another 2030A?
Second idea is to use a JRC4558D instead of a 1458.

Do y'all think this is an interesting project worth
posting a finished pcb design for?

Feedback appreciated

thanks,
Doug

[David]

As long as you're not violating any copyright issues, go for it.  I'd love to see a bridged TDA2030 setup since I'd like to do something similar myself.

[djmartins2]

Uh,

I'm not too sure about copyright issues.
I am modding the design a bit....

Opinions welcome!

DJ

[Ry]

I had the combo version of this amp, it was the first amp I ever bought.  It sounded like slapping a wet noodle against cardboard, IMHO.  I just gutted it and am using the chassis to build a firefly.  It lacked headroom to say the least.

Ry

[Nasse]

I have seen few applications done with TDA2030 using cheap power transistors to beef the output. If I remember right you could get 30...40 watts with one TDA2030 and two power transistors. But you need a big electrolytic cap at output. If you use two 2030´s and four transistors in bridged confiquration you can get up to 200 watts to 2 ohms, and you do not need a cap at output, and the amp works with single or bipolar power supply. Output power and current consumption drops nicely when you use lower supply voltage and/or higher impedance speakers.

But 10 watts is very nice amout of oomph for home practice amp, with almost any 8, 10 or 12 guitar speaker, or bigger cabinet...

[Torchy]

Newbie alert ...


Marshall Valvestate 8001/8010 10 watt combo/stack  ..... got a link for the schematic, please

:oops:

[Prive]

Try here.

http://www.drtube.com/marshall.htm

It's a long list.

Saludos, Marcelo.

[Torchy]

Thanks for the link