Building a Tube Amp

[Rich Grise]

[context snipped ;-) ]
I will post the schematic of an original, probably unique, practical,
just-invented audio amp output stage topology if both of you will
agree to do the same.

Why? If there's something on the shelf that gets the job done, why
reinvent the wheel?

Thanks,
Rich

 

[Rich Grise]

Anybody else want to play with circuits?

I'd be happy to see any circuits, but I fear that as "only a tech", my
designs consist mainly of lifting other people's circuits and connecting
the dots.

I did design an astable multivibrator with a duty cycle range of about
1%-99%, with a 1.5A current driver for a spool gun motor. It wasn't
hard, I just put a pot's wiper to Vcc, and each end through a 1K R
to the bases.

I once designed a FIFO for a digital strip chart recorder, using an
8748 (or so) and the ever-popular 6116 static RAM, but that's digital,
so doesn't count for an analog competition. ;-)

Cheers!
Rich

 

[Eeyore]

Yeah... if it says "Pro", it aint!.

Oh so true and I have someone I need to teach that.

Note the number of cheap Chinese 'pro' amps that expire simply at the sight of
a large signal and a low impedance load. They may not even need that !

Graham

 

[Eeyore]

The idea being that a class A tube preamp gives a fair amount of 2nd
harmonic distortion, say 5%. This is claimed give a nice sound.

All I will say here, is that I quite like the sound of the amp/combo. Its
quite full sounding. This is no doubt due to the tube, the speakers, the
tone controls etc. etc...as to which...I could care less.

Get an original Mullard (I think) data sheet on the ECC83 and it it actually
gives THD values under various operating conditions.

Graham

 

[Eeyore]

[context snipped ;-) ]
I will post the schematic of an original, probably unique, practical,
just-invented audio amp output stage topology if both of you will
agree to do the same.

Why? If there's something on the shelf that gets the job done, why
reinvent the wheel?

As I said earlier sometimes for FUN. Also sometimes for economy or ease of
manufacture.

Graham

 

[JosephKK]

JosephKK wrote:



Several people have done this in the past. The name Phoenix comes to mind which was funded
by (I think by then) ex-members of the band Argent. That's the first I know of.

I suspect Marshall is doing something like this now too but I'm not up to date on their
stuff, it's not actual 'pro' audio, it's what we call MI (musical instrument) technology.

And for the masses we now have what's called prosumer. Near real pro kit performance at a
bargain price and usually in small sizes but more of a 'consumable' than real pro kit. Some
can be quite good actually. I've designed a fair few of that ilk myself.

Graham

My first piece of semi-pro gear is an Ampex AX-300 open reel tape
deck, i still have it. Hey, i can afford to put new heads on it now.
Probably only $2400 now, if i can find them. Damn, i will need a
calibration tape too, if i can find it.

 

[[email protected]]

[context snipped ;-) ]
I will post the schematic of an original, probably unique, practical,
just-invented audio amp output stage topology if both of you will
agree to do the same.

Why? If there's something on the shelf that gets the job done, why
reinvent the wheel?

Because I'm a circuit designer. And, apparently, they aren't.

Actually, he's a salesman, posing as a circuit designer.

He posts a lot more text telling us how wonderful Highland
Technology's products are than he ever posts on the wonderful circuits
his products incorporate.

 

[Eeyore]

bargain >price and usually in small sizes but more of a 'consumable' than real pro kit.
Somecan be quite good >actually. I've designed a fair few of that ilk myself.


My first piece of semi-pro gear is an Ampex AX-300 open reel tape
deck, i still have it. Hey, i can afford to put new heads on it now.
Probably only $2400 now, if i can find them. Damn, i will need a
calibration tape too, if i can find it.

You'll have trouble finding anyone stocking 1/4" tape now too !

I actually have an 8 track 1" tape machine kicking around here !

Graham

 

[JosephKK]

You'll have trouble finding anyone stocking 1/4" tape now too !

I actually have an 8 track 1" tape machine kicking around here !

Graham

Especially blank good stuff like Scotch (tm) Blackwatch (tm) 207.
Calibration tapes will be really challenging, even used. Goggled for
a while, couldn't find either. I could get Maxell UD 35-90 blank tape
though, which is pretty good.

 

[Kevin Aylward]

My first piece of semi-pro gear is an Ampex AX-300 open reel tape
deck, i still have it. Hey, i can afford to put new heads on it now.
Probably only $2400 now, if i can find them. Damn, i will need a
calibration tape too, if i can find it.

For me, analogue tape is like dos, dead.

Throw it away and get a cheap digital one


www.kevinaylward.co.uk

 

[Eeyore]

Especially blank good stuff like Scotch (tm) Blackwatch (tm) 207.

I used 206 and 207 personally a lot. Beware of oxide and binder shed on some tapes of that era.
The popular polyurethane binder absorbs moisture and becomes a mess. It can be fixed by 'cooking'
gently lierally in an oven, then make a secondary master. See rec.audio.pro for details.

Calibration tapes will be really challenging, even used. Goggled for
a while, couldn't find either. I could get Maxell UD 35-90 blank tape
though, which is pretty good.

MRL used to be the guys. Magnetic Reference Labs. Cost a fortune though.

Graham

 

[Eeyore]

For me, analogue tape is like dos, dead.

Throw it away and get a cheap digital one

Lots of mixing engineers still like to 'pre-process' drums through tape
first for the natural compression.

And I know (and have worked in) the Studio that hired in a Studer 4 track
J37 to do last year's ? re-production of Sgt Pepper's Lonely Hearts Club
band.

Graham

 

[JosephKK]

For me, analogue tape is like dos, dead.

Throw it away and get a cheap digital one


www.kevinaylward.co.uk

Not until i finish digitizing some otherwise irreplaceable tapes
recordings.

 

[Eeyore]

Not until i finish digitizing some otherwise irreplaceable tapes
recordings.

Oh. I have a John Peel session of Pink Floyd !

Graham