TDA2030A Audio Amp

Hi, I have a couple of unused TDA2030's

I can't remember if I bought them for a project or if I just acquired them in some sort of sale, they don't have an A on the end of the number though. I also have the fifth edition of Loudspeakers by G. A. Briggs with R. E. Cooke, B. Sc. (Eng.) as Technical Editor.

I bought the book for a guide for making my discotheque speaker enclosures, (although it's lost its dust cover) for two Goodmans Twin Axiom 12" speaker units in each enclosure. My late brother and myself bought the units from Smiths electrical shop in Tottenham Court Road, London. We carried a pair each from there to a garage park in Edgware Road via the underground. As for Valves v/s transistors, my brother and I had various different views on the subject, however I built a stereo valve amp from a design in Babani BP12 Hi-Fi, P. A. , Guitar & Discotheque Amplifier Design Book. That was a push-pull design using EL84 valves giving 15 watts per channel, the output transformers for which were bought from Henrys Radio in Edgware Road, London and the Valves were Zaerux from Z & I Aero Services Ltd., in Tottenham Court Road. I still have the amp in an outbuilding, but it's way past its sell by date, but it did do a lot of disco's in its day. The two enclosures with the Twin Axiom's are accompanied with a small unit each that houses two High Frequency units and crossovers, the Hi Frequency units I bought in a shop in Leicester but the crossovers I made from a design that was published in ETI magazine, two crossovers were made for each unit so they could by used on a 4ohm or 16ohm system. The speakers are still in use in my lounge, connected up to my HF-Fi and still sound good.

Regards Nick.

Edited By Nicholas Farr on 14/02/2018 23:59:19

Very few live gigs will offer anything remotely like the sound quality of a tidied up live recording (even Jeff Lynne's ELO!)

That's said, any reproduction is incomparable with a live experience - the interplay between the musicians and each other and the audience means every performance is unique. The times I spent with a bunch of mates, a couple of guitars and The Beatles Complete murdering some of the best pop songs ever in the gyp room were probably as enjoyable as any CD or vinyl, but no-one would want to hear them recorded!

That said, I have always preferred live recordings to studio ones, even if they have been 'tidied up'. To me the appeal of albums like 'Live Rust', 'Live and Dangerous' and 'Live at Leeds' is partly the limitations and added opportunities provided by playing live. I also have to admit to being hugely smug about some of the live recordings that have me in the audience - notably Stevie Ray Vaughan's set at Reading 1983 on his first visit to the UK.

Neil

Surprised this hasn’t come up in the thread so far.

**LINK**

Discuss!

Pete

I suppose that depends on your individual interpretation of the term "sound quality" .

Part of the experience of live rock and pop music is the distortion introduced by the amplifiers, speakers, and so on. Who can say what sound is right? It is a matter of personal preference.

Orchestral music on the other hand played on un-amplified instruments in a concert hall is a different matter. IMHO.

Russell

Absolutely, and just as well as one concert , maybe in the late 80's / early 90's caused me to curl up in a ball and hide behind the seat in front to try and avoid the painful bass that coincided with the resonant frequency of my chest cavity. I must have been around 30 rows from the front so who knows what they were feeling closer to the speakers. If could have moved without vomiting over everyone I would have walked out. P.S. No drink was involved!

I have taken a special interest in 'audiophiles' ludicrous proposals regarding fuses, cables, connectors, etc. Whenever I want a good laugh, I head for the previously mentioned Peter Belt's website, and others, praising oxygen free copper cables (All commercial copper is oxygen free, house wiring, water pipes, steam locomotive fireboxes etc., it's in the nature of the refining process) square wire, skin effect (at audio!) sticky labels or grains of rice resting on top of the speaker cabinets, there is no lunacy which they ignore. And the cost! £25 for a 5p fuse with a label stuck on. It's been 'conditioned' you see, for xx hours and didn't blow...

Geoff

+1 for live recordings even if they have been worked on, I would add UFO Strangers in the Night to your list even if it does get criticised as a best of from the tour and even having studio bits added in, who knows the truth? I have been to some gigs where the sound has been shocking even for the headlining band, it seems common practice to sabotage the support. It appears it is not down to incompetent sound engineers but the band turning up their amps rather than the monitors so the sound engineer cannot compensate. Also find that some venues with a house PA have a good sound engineer that knows his venue but the band use their own man and its crap. Pink floyd always made an effort with their sound and have always sounded very good. Due to late arrival at a PF gig at the now defunct London Arena we were sat in the vip area right behind the mixer, the sound was excellent there but distracting watching what was going on on the desks, some of the VIPs were quite distracting as well.

Mike

Hi Peter

the Nutube looks like an updated version of the Nuvistor valves
used in the head amplifiers in the Ampex 2-inch quadruplex vt machines (~1960?)

Hi Mike

In the past I used to have various band managers trying to tell me how to mix during rehearsals
on transmission I ignored them
and only took notice of the IBA and BT (BT didn't like their microwave links being over driven)

John

I suspect we agree, to a point.

Even the finest auditorium (e.g the revamped Albert Hall) will only offer the very best listening experience to a small percentage of the audience, most of whom (including me) wouldn't be able to detect the difference though.

Most live music (of all types) is played in venues awash with reverberation, awkward echoes and resonance. Fortunately the brain assesses the acoustics of wherever you are and decodes the original content pretty darn well - something 'audiophiles' comprehensively ignore.

The best sound is usually at an open air rock festival, especially for a rich, pure bottom end sound, although the top end can be a bit wanting, sometimes being projected far above the heads of the audience.

I far prefer hearing live music, one factor is that the brain fills in the gaps, especially if you are familiar with the music, so under powered vocals, muddy bass or poor balance become less important. You've only got to hear Black Sabbath's Live at Last to appreciate how bad live sound can be, but it's till an exciting album to listen to.

My first foray into Stereo was to make a Mullard 5-5 Amp. Having heard a stereo record it intrigued me to make an Amp. This i made in the smallest footprint I could get it into and then put it with a turntable with stero capability. Then browsed all the record shops for stereo recordings and as this was in 1957/8 obviously some of them were a bit iffy. I remember wiring up the speakers the wrong way and. 'Motorboating' on the solid floor.

Later i made plug in jacks with a Diode and a tunable beehive cap. and a resistor to a single frequency circuit to pick up radio stations. It worked very well and saved me buying a wireless licence as no one would think a plug in Jack was a radio device. Luckily I had access to an LCR bridge at work so making up these circuits was easy, I think the Diodes were 001's. At that time I was working on massive radio transmitters with water cooled valves about 3 foot tall.Also had 50 HP electric blowers to cool the kit. Radio TX's were E10's and E11's.

In the mid Seventies I was in Dortmund and we would go to the big shops and they had demo's of Hi Fi kit with speakers 1 mtr x 1 mitr square pushing out X watts making the place vibrate, mainly German martial music with Glockenspiels. If you stood in the right place the Stereo effect was terrific, it was like standing right in front of the Band. Nothing I ever bought could match it.

Clive

Edited By Clive Hartland on 15/02/2018 16:51:36

Was it Malcom Sargent who said that a composer who's work premiered at the Royal Albert Hall (before mushrooms were installed) was at least guaranteed of 3 hearings of his work, even if two of them were only echoes...

A couple of gigs had memorable sound problems, I went to the Great British Music Festival in 1976 at Olympia London, the opening day had terrible reflections from the rear wall, we heard it all at least twice, by the third day they had hung some heavy drapes to cut down the reflections which improved thing a lot. Bob Dylan at Blackbushe Airport was outside but the PA had satellite stacks out in the arena and they should probably have used a delay line to sync them with the stage PA, as it was you could hear the delay from the stage compared to the satellite, perhaps we should have got there earlier and been nearer the stage, legend has it that there were 250,000 of us there and it's not often Eric Clapton is the support band.

Mike

Clive - interesting reference to 'standing right in front of the Band'. One of the most impressive sound 'experiences' I recall was in the 60s, when we did a winching demo at the Cheltenham Tattoo. Left the helo at Innsworth and tagged onto the finale parade. The music was by the massed bands of the Royal Regiment of Transport (5 of them). Heading down the arena was fine but the effect on the counter-march turn was mind-blowing. Presumably the change from facing away to facing towards of all that brass!! Can still feel that 'hair on the back of your neck' effect!!

rgds

Bill

entered twice in error

Edited By Cornish Jack on 15/02/2018 17:21:35

Intersting.

The FAQ says they can't explain how it works because it's patented... which is a bit of an odd statement!

Nuvistor's used in an Audio Front-end? Interesting. At around 11 years old I used 1 Nuvistor each in a set of 'Walkie-Talkies' - On 432MHz, or thereabouts..Regen receiver which transmitted nicely as well. 5 x9volt batteries for HT and 2 penlights for heater..

Someone mentioned 807's being used in an Audio amp as well - Did not think of that, but did use 4 of them in a 80m AM ham transmitter amplifier ( 3.710MHz..) - Actually, I lie--The AM modulator used two 807's as well! So that was an 'Audio Amplifier' of sorts.

Joe

Hi Joseph

the nuvistor was used in the video amplifiers for the 4 video heads in the Ampex 2-inch quadruplex vt

https://www.revolvy.com/topic/Quadruplex%20videotape

the Nutube double triode valve looks like a gimmick using the technology and assembly techniques from the vacuum fluorescent display

john

Edited By john swift 1 on 15/02/2018 20:20:04

Hi Neil

the TDA2030 was good enough to be used in broadcast audio distribution amplifiers like this

Edited By john swift 1 on 15/02/2018 21:00:38

Hi Gents, 807's have been popular as amp valves for a long time now. Geloso made many commercial amps on this basis.

Due to the increasing prices for the popular (EL34. KT66 etc) valves, TV line output and similar types are now being designed in. These are valves designed for pulse operation so do not have such a linear response for Vg to Ia.

A circuit technique has evolved for this. The signal is now DC coupled into G2 (quite high level and low impedance) which has a nice linear characteristic. G1 is used to set the bias level on the valve as normal.

Ed

Intrigues me all this talk of sound quality and auditoria. There are two ways of approaching the idea. The first being that the sound is only and wholely the playing of the original instrument and singer and that anything coming after that messes with the sound. The second is  that the entire system is taken into account from the instrument or singer to the final listener ifit be live or recorded.

In the second case it is perfectly reasonable to consider all the steps along the way as being part of the intended sound. The acoustics of a concert hall change the sound in just the same way that the resonances of an instrument do. Therefor the hall becomes part of the instrument and cannot be said to be detracting from the sound quality. There are of course rubbish hall acoustically just like ther are rubbish instruments. In a similar way consideration of the dynamics of sound systems can be factored in to the original recording. This is exactly what the Dolby system does. It modifies the original sound knowing that the sound system will restore the intended frequency response.

There are indeed churches with hollow tuned pillars that work better with music in particular keys than others and resonances that suit some kinds of music better than others.

regards Martin

Edited By Martin Kyte on 16/02/2018 09:17:28

Edited By Martin Kyte on 16/02/2018 09:19:12