Valve amp virgin, some advice please on valve choice?

[Ali Tait]

300b and some OB's. G'wan, you know you want to!

[pre65]

If you can wait a bit longer, the next Owston should be an eye opener for you.

[gazjam]

Just to ad my 2d, as you know I prefer SET's myself, but though a 300b may have made a loud noise with 90dB speakers unless you only listen to "girl with a guitar type sounds" which you don't, you will be getting loads of soft clipping and compression. For 90dB I would suggest at least a 211/845/813 or better a gm70 would be needed to get beyond a nice sound.

Thanks Nick, hadn't thought really beyond the 300B being "loud enough"...
I do listen to a lot of non tinkly stuff so PP could be the way to go.

Owsten's going to be an education.

[steve s]

If you can wait a bit longer, the next Owston should be an eye opener for you.

Must get that sorted. Probably may or June?

The wigwam show is next weekend, that's a good day out, there's a few trade rooms this year just announced, and a fair few p/p and SE amps .. Some good kit..
And my kit is in room 74 you want a taste of one route in DIY ...2 1/2 watts and 102 db speakers...

[Cressy Snr]

Hi Gary,

I have gone from a commercial push-pull amp, to building single-ended triode amps, to single-ended pentodes and and back to a push-pull pentode amp of my own design. This push-pull amp drives my speakers better than anything else I have built, so it is with push-pull I am sticking for the foreseeable.

I should have two push-pull pentode amps at Owston, one around 12 Watts, class AB (EL84 valves) and the other, a 50 Watt class A using the new KT120 valve.

There'll also be plenty of single-ended amps there so you'll have a wide variety of gear to listen to, but I would advise as a few people have, that for your average shop bought speaker, a push-pull would suit them far better than a low power SET. Big transmitter valve SETs are a different matter but they are very expensive and run dangerously high voltages, in excess of 1000V.

[pre65]

Big transmitter valve SETs are a different matter but they are very expensive and run dangerously high voltages, in excess of 1000V.

Is 1000v really "dangerous", compared to 400v or 600v ?

And are transmitter valve amps "very expensive" ?

I'm not really in agreement with those two points.

[Cressy Snr]

Big transmitter valve SETs are a different matter but they are very expensive and run dangerously high voltages, in excess of 1000V.

Is 1000v really "dangerous", compared to 400v or 600v ?

And are transmitter valve amps "very expensive" ?

I'm not really in agreement with those two points.

Commercial transmitter valve amps cost several grand unless you gamble on ultra cheap, Chinese.

You are looking at between four and seven thousand pounds for the Icon Audio MB845 series, depending on what you want David to supply you with.

I think you're forgetting the audience Phil.
We all know we can build a DIY transmitter amplifier far cheaper than the Icon Audio amp but Gary is not in that market, well not at the moment anyhow.
Closer to home, if you were to examine the current cost of the Sowter iron on Nick's 211 amp, your eyes would water

We've been there before with this high voltage stuff. I've been thrown on my back by 400V. I'm sure I would have been killed outright by 1000V or more at the same current. I count myself lucky.

[Paul Barker]

A few of us have been lucky. Definately more voltage needs more respect.

[IslandPink]

Voltages over 1000V have a habit of sneaking across a damp valve socket to ground, and setting fire to a carpet .....

[Paul Barker]

What moi

[Greg]

Hi Gary,

There you have it with some of the guys expressing their concerns regarding high output SE amps. Their response, in my view, has been a bit OTT. I suggest you talk with Nick direct. Certainly his advice on going for 211/845/813/gm70 valves makes total sense. You need this kind of SE valve to ensure your amp has the headroom to cope with any type of complex music you want to listen to. It is worth pursuing but as said, I seriously recommend you talk all this through with Nick first. Thereafter, sorry, it probably is the PP option. You'll understand now why that is my own personal choice in my interest in obtaining the ultimate versatility from my system. 300B PP plate dissipated to give 11W in class A works for me in my living room and copes with whatever I throw at it into 90dB speakers.

Regards,

Greg

[Cressy Snr]

Hi Gary,
Thereafter, sorry, it probably is the PP option. You'll understand now why that is my own personal choice in my interest in obtaining the ultimate versatility from my system. 300B PP plate dissipated to give 11W in class A works for me in my living room and copes with whatever I throw at it into 90dB speakers.

No need to apologise for recommending a PP amp Greg. They're not the second best

11W in class A? having heard your amp several times, I always thought it sounded a lot more powerful than that. You live and learn.

[Nick]

We've been there before with this high voltage stuff. I've been thrown on my back by 400V. I'm sure I would have been killed outright by 1000V or more at the same current. I count myself lucky.

Thast the point, it would have not been the sane current. it wouldnt even be 2.5 times the current (that would be bad enough, its mils that kill). The body is not ohmic, 1000v will convert cells to carbon as it goes, carbon conducts well, current is much higher, death is more certain.

[Neal]

We've been there before with this high voltage stuff. I've been thrown on my back by 400V. I'm sure I would have been killed outright by 1000V or more at the same current. I count myself lucky.

Thast the point, it would have not been the sane current. it wouldnt even be 2.5 times the current (that would be bad enough, its mils that kill). The body is not ohmic, 1000v will convert cells to carbon as it goes, carbon conducts well, current is much higher, death is more certain.

....Phil are you convinced yet!?

Gaz, there's a cheapish tweaked WAD K5881 (MK1 AFAIK) for sale on AoS if you want to dip your toes..

[pre65]

....Phil are you convinced yet!?

Yep.

I've been wrong before, and no doubt will be again.