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33286

General Discussion Area / Re: Formal Dialog with Vauxhall Customer Service

« on: 16 November 2007, 13:45:03 »

I don't believe VX would be able to contribute much to the level of expertise available here either.

Kevin

33287

General Discussion Area / Re: Covering number plates?

« on: 14 January 2008, 15:37:45 »

I guess in these litigeous days the BBC are worried that someone'll have their number plate shown on TV and then sue the broadcaster when someone clones it.

As opposed to someone just seeing it in Tesco's car park and cloning it anyway. (Actually, I guess you'd sue Tesco then )

Kevin

33288

General Discussion Area / Re: Scrap value

« on: 14 January 2008, 15:40:22 »

.. and why they can't be bothered to help you out with bits and pieces worth a couple of quid any more.

 

Kevin

33289

General Discussion Area / Re: Crude oil $92 a barrel - diff oil £92 a litre

« on: 14 January 2008, 13:21:35 »

What a joke.

Sounds like they haven't twigged that it's RWD and thus has a separate diff

Kevin

33290

General Discussion Area / Re: Valve Amps ? Who knows About Them

« on: 13 January 2008, 13:30:43 »

I am always amazed by the power ratings of todays speakers. A few (30!) years ago, I had a Clestion 18" 100W speaker, fed by a Marshall 50W which was very loud (we got plenty complaints so it must have been!) . Nowadays you can get 1250W RMS speakers for not a lot. When and where can they wind them up ?. The SPL must be deafening.

Ken

It's always worth checking the sensitivity too, though. 30 years ago amplifier output was at a premium so speakers had to be efficient. Nowadays, sensitivity can be sacrificed in the design of speakers.

Kevin

33291

General Discussion Area / Re: Valve Amps ? Who knows About Them

« on: 13 January 2008, 12:33:04 »

Its interesting what Sir Craig was saying about speaker voice coils distorting over time. The price of old speakers is amazing, people paying stupid amounts for vintage 1968, 1970 Celestions etc. I would imaging they must be shot by now.

Ken

This is very true. One teenager's party and the tweeters will never be the same again, especially on older speakers that weren't designed with huge power handling.

Kevin

33292

General Discussion Area / Re: Valve Amps ? Who knows About Them

« on: 13 January 2008, 12:09:11 »

Semi-con amps are nice but the sound of this is in a class of its own !



They are a bit heavy tho !

Ken

He He.

Years ago when I was about 17 our window cleaner came round and, seeing the collection of test gear in my bedroom, asked if I would be interested in fixing one for him. He duly brought it round and it was a 5 minute fix. A mate of mine played a guitar and, like all wannabe guitar heroes of the time, used to have wet dreams about Marshall valve amps so I invited "the band" round, much to our neighbour's disgust, for an impromptu concert.  

You know you're not trying with one of those unless you can look in the back and see the anodes glowing!

Kevin

33293

General Discussion Area / Re: Valve Amps ? Who knows About Them

« on: 13 January 2008, 11:38:57 »

Valves are not as reliable as semiconductors & it is a myth that they are better....

Oh, I absolutely agree. In practical terms semiconductors are a much better bet and if I were humping amps around from place to place valves would ne a no-no. In terms of stage amplification you can achieve the same sound using effects so why make your life difficult?

From a point of view of home construction and Hi-Fi, however, you can build an amp that sounds excellent using a very simple design and straightforward construction techniques using valves, so I think they still have a place. It's much easier to design and build a crude semiconductor amp and much more difficult to furnish yourself with an excellent semiconductor amp IME.

If you're buying new off-the-shelf you'd be mad to go for valves because they're massively overpriced and you can get a very good solid state amp for not a lot of money these days.

Just like steam trains and old Bentleys, they are in the most part totally obsolete, but it'd somehow be a shame if you didn't come across them now and then.

Kevin

33294

General Discussion Area / Re: Valve Amps ? Who knows About Them

« on: 13 January 2008, 00:57:06 »

I started off with a Maplin kit, as it happens. Will take some pictures but it's basically one of these :

http://www.livinginthepast.demon.co.uk/xfrmrvt425.html

Although I built them as a pair of monoblocks because the power supply is a bit underrated for both amps in any case.

Keep meaning to do a  few more tweaks to them as the design is lacking in a few areas.

Kevin

33295

General Discussion Area / Re: Valve Amps ? Who knows About Them

« on: 13 January 2008, 00:47:07 »

On the subject of BBC monitor speakers, I was talking to a mate of mine a few months ago and it turns out his father was one of the team who developed the LS3/5A.

His web site: http://www.ls35a.com/

Kevin

33296

General Discussion Area / Re: Valve Amps ? Who knows About Them

« on: 13 January 2008, 00:39:51 »

So What I am wanting to know which valve amps are ok but not stupido money, and what do all these valve numbers mean like  EL34, ECC83, ECC81 i am guessing these are different kinds of Valves

To answer this bit, yes, there are hundreds of different types of valve. Just like transistors, for example, you have several different fundamental types of valve and also different applications call for different shapes and sizes. Some handle very small signals at low power levels, some handle large amounts of power, some high frequencies, some low.

The numbers do follow some logic regarding the number of electrodes, heater voltage and so on, but there are also so many exceptions and conflicting systems of numbering that you may as well just google them to find some data.

Kevin

33297

General Discussion Area / Re: Valve Amps ? Who knows About Them

« on: 13 January 2008, 00:33:08 »

I have a pair of valve amps that I built about 10 years ago because they seemed an interesting project more than anything else.

One thing I would say is that if you like tight, punchy bass they're proabably not for you, especially if the speakers are on the large side. They just don't have the damping to achieve that.

IME, They give very good, involving midrange and treble doesn't have the harshness that solid state amps and bad digital source material sometimes gives - nor the detail, if I'm honest. Much as I like to think everything can be measured I'm going to have to finish by saying there's "something" about them....

Having said that they come in many shapes and sizes and each have their quirks. A 300b single-ended amp without feedback is a very different beast to a push-pull pentode design with a load of negative feedback.

Blag a listen to a few, ideally with your speakers, is the best advice.

Kevin

33298

General Discussion Area / Re: Topman Timbuk

« on: 13 January 2008, 11:17:01 »

Super so its a corporate hospitality do is it, I love those. Pity the booze always makes you sick though.

Yeah, you're really going to have to be careful.  The booze is moonshine from timbuk's new still and the food is pot brownies.  He's giving it out free to try to get us hooked. You did know that the car repair business is just a front, right?  

There are going to be some Omegas running round with "interesting" cam timing then  

Kevin

33299

General Discussion Area / Re: who has a V6 locking kit?

« on: 12 January 2008, 11:07:12 »

No rush, James.  

I know what the problem'll be usual 3.2 aggro.

Was on vapours so pulled into a Total garage I don't normally go to and put a splash in (too expensive to fill up). 1/2 a mile up the road the light came on.

Kevin

33300

General Discussion Area / Re: who has a V6 locking kit?

« on: 12 January 2008, 01:22:47 »

If the crank is set to 60degrees BTDC you can do what you like to the cams so you only need the kit to reassemble.  

Don't think I'm up to much this weekend if you wanted to pop over. It's probably a full day's work but do-able I'd say. When we did ClarCE's cam change it took from 10 AM until I had to disappear at about 6 when he was just refitting the cam belt. Then he did one of his legendary all-nighters and put it all back together.

You'll obviously need new cam cover gaskets, cam oil seals to be safe and the 2 types of sealant for the cam cover gaskets and the front cam bearing shells. A low range torque wrench would be good too.

Would be investigating the emissions light that came on yesterday if I had my cheapo Tech2. Any bets? Post cat Lambda readings?

Kevin