Oscilloscope question

[roblegion]

Almost there, Main board, dual rail power supply and calibration board finished, just waiting for usb soundcard.

[perfrej]

Ah, the venerable 741... You know it only manages 0.5V/uS on a good Sunday, right? For a 5V signal that limits the bandwidth to 50kHz - again on a good Sunday morning. Good drop-in replacement with 12V/uS performance would be the TL071. I modified all audio 741-based devices I came across to use the TL071 in the eighties. Made wonders for the sound quality

 

/per

[roblegion]

I know, it's only for audio for now, the 741's are only on the poer supply and calibration board, the main 'scope board is a 2134, maybe a bit overkill, but I ten to use what I've got and I Know it's only gonna be good for 20Khz. Caus thats the limit of the soundcard.

[Stub Mandrel]

I went over to CA3130E IIRC :-)

[roblegion]

My god, I think those are older than me (OK maybe not), different chips for different fish. But boy do those 2130's sound sweet in my pre-amp

[perfrej]

Me tube man! I have a pair of vintage, unmodified Quad II:s with close serial numbers and a whole bunch of spare tubes from new old stock.  Lucky me!

/per

[Stub Mandrel]

I have one of these new-fangled guitar amps that models all sorts of other amps and effects, a Vox Valvetronix VT-20. It  has a tube preamp in it to provide overdriven valve sounds,and things like a master volume to set the output power from 0-30 watts without (greatly) affecting the sound. To me at least it sounds incredible and the various presets and amp models are convincing. The thing that impressed me most is it's sold as a 20W amp but it actually goes up to 30 amps RMS!

 

[Alien 13]

Completely off topic but the sound of an amp is 99% due to its power supply valves make PSU design simple which is why they perform so well and I agree that the Quads are magic.

I have gone the whole route over the last 40 years and use a combination of valves for the preamp/phono stages an chips on the power output.

Alan

 

[Stub Mandrel]

1 hour ago, Alien 13 said:

I have gone the whole route over the last 40 years and use a combination of valves for the preamp/phono stages an chips on the power output.

Alan

 

That's basically what the valvetronix do with the addition of a few layers of DSP.

[roblegion]

Hey Guys, i've no prob about off topic, don't know if the mods will agree, maybe should be moved to Non Astro lounge from here in.

I love the valve sound UP TO A POINT, it's warm and forgiving.

I always hankered after monoblock NAIM's. (In my dreams) So I had to build the bad boys!

[roblegion]

The pre amp design  (2 x 2134) from Rod Elliot (ESP) is an inspiration, in 40+ years one of the best pre's I've ever heard, It will blow away anything at £500+.

In my system the powers let it down (for now), I will keep the massive Toroidals and DC protection and replace the actual amplifier circuitry at some point (soon).

I am in the middle of building a pair of Paul Carmody's "Amiga" speakers, my god the size of the crossovers would scare a small country.

The large inductor on the bottom left is about 75mm diameter.

can't wait for some drier weather to get the cabinets finished outside, (I ain't playing with MDF indoors. lol)

[roblegion]

Tested the 'scope today, IT LIVES.

Tried it on its own calibration circuit, perfect square wave at 1Khz, 2vac (1vRMS), tried on pc software own function generator, super.

Now the tricky bit, just gotta build a case for it, boss at work has let me have a few 1.5mm sheets of aluminium, about 600mm x 300mm, so time to start welding.

Will post build piccies soonest.