General Forum

Re: Fatman Tube/ valve amplifier with B&O speakers

tournedos — Sat, 06 Feb 2010 05:46:04 GMT

I agree with Simon. If you take a modern valve amplifier and put it against any good transistor amp (even from 30 years back) in the lab, it will lose in just about every aspect. But, valve amps have the advantage that most of their imperfections actually sound good. While a transistor amp approaching its limits will create odd-numbered harmonics that sound harsh to the ear, valves distort much more softly, starting already at lower level. Instrument amplifier manufacturers have tried long and hard to reproduce this with solid-state technology.

Old germanium transistors have characteristics that resemble valves a little more than modern silicon semiconductors. That is part of the reason why a Beomaster 900 can sound so nice - just keep it far away from the test lab equipment! Some guitar stomp pedals are still being built around those AC family transistors, just for the sound.

For a while in the '70s, some Japanese manufacturers (mostly Sony and Yamaha) built wonderful amps utilizing V-FET transistors. Their characteristics were very similar to valves, but the technology soon gave way to MOSFETs for reasons I don't know too well (possibly reliability issues).

I personally think the valve pre-amp stuff is mostly bogus when used alone. I would like the preamps to do their job without colouring or affecting the sound in any way. If you want to try a valve amp, use it as a power amp with passive speakers, it is enough to get "the sound". Remember also that the valves (especially in the power stage) have a limited life and replacements are relatively costly.

Buried somewhere with my other eternity projects, I have a DIY valve power amp that has been waiting for me to fix a pair of DIY electrostatic panel speakers (not built by me). Maybe I should dig the amp out and try how it would sound with, say, the Pentavoxes.

Re: Fatman Tube/ valve amplifier with B&O speakers

Peter — Sat, 06 Feb 2010 05:32:45 GMT

It is all about what sort of distortion you like the best! Valve amplifiers produce very different harmonic distortion to transistor amplifiers and some people prefer this.

A number of manufacturers have jumped onto the valve bandwagon recently. Many of the valves used are not designed as audio amplifier components but are cheap. Always audition before buying would be my advice.

Re: Fatman Tube/ valve amplifier with B&O speakers

wirralsimon — Sat, 06 Feb 2010 04:16:16 GMT

The intrinsic superiority (or otherwise) of valve amps is a debate that mirrors the CD vs Vinyl one - you may never get a consensus! That said we are not talking about a high-end purchase here, I think you buy a Fatman for the fun of it not to get the ultimate audiophile system.

Valve amps tend to have a warmer sound and (I a guessing) that would be part of the appeal of a device like the Fatman. I'm tempted to buy one to see how they sound a pair of S45-2's as I think that would be an excellent combination!

Simon

Re: Fatman Tube/ valve amplifier with B&O speakers

dilznik — Sat, 06 Feb 2010 03:51:55 GMT

These same guys make a product called the Mothership:

http://www.fat-man.co.uk/docs/product_07/iTube_Mothership.shtml

If you could get them to sell you just the preamp part, then you could use that with B&O active speakers.

Or you can build one yourself: http://www.shine7.com/audio/12ax7_pre.htm

Re: Fatman Tube/ valve amplifier with B&O speakers

vikinger — Sat, 06 Feb 2010 03:37:35 GMT

Peter :

Rather negates the point. Not sure about this amplifier, but quite a few of the cheaper valve amplifiers have a solid state pre-amp and a valve power amp.

Found the manufacturer's page. It is described as a hybrid. I don't think that I could live with the appearance alongside B&O designs, but I did find some other forum entries suggesting that you should buy this amp without speakers and then add your own. It would still be interesting to compare the spec with typical current B&O........ and how they compare in listening. Are valve power amps still intrinsically superior to the latest solid state transistor circuits?

Graham

Re: Fatman Tube/ valve amplifier with B&O speakers

Peter — Sat, 06 Feb 2010 02:48:32 GMT

Rather negates the point. Not sure about this amplifier, but quite a few of the cheaper valve amplifiers have a solid state pre-amp and a valve power amp.

Re: Fatman Tube/ valve amplifier with B&O speakers

macjonny1 — Sat, 06 Feb 2010 02:20:21 GMT

Can't you use attenuated cables and active speakers.

Re: Fatman Tube/ valve amplifier with B&O speakers

Peter — Fri, 05 Feb 2010 12:36:10 GMT

Maybe a vintage speaker like the Beovox 2400 - easy to drive as valve speakers do not produce a lot of power.

Re: Fatman Tube/ valve amplifier with B&O speakers

dilznik — Fri, 05 Feb 2010 03:05:22 GMT

vikinger:
An exposed valve chassis will not be to the taste of most B&O enthusiasts, but has anyone used one of these Fatman systems with B&O speakers?

Graham

That'll be a cool look but you'll have to use passive B&O speakers since current B&O speakers have amps already in them.

Re: Fatman Tube/ valve amplifier with B&O speakers

bayerische — Fri, 05 Feb 2010 01:56:16 GMT

Graham, you intend to use it with passive speakers right?

I've heard some good things about the Fatman, heard it a few times at hifi shows, but usually these shows are so boomy and loud it's difficult to really judge the quality.

It's relatively inexpensive, but keep in mind that "high-end" valve amps hybrid or valves all the way tend to cost 10 times as much as the Fatman.

Fatman Tube/ valve amplifier with B&O speakers

vikinger — Thu, 04 Feb 2010 18:42:40 GMT

Costco UK will be selling a Fatman valve amplifier system with iPod docking station....... £50 off from next week taking the price down to £176 [from a full original retail price of around £450.] Googling this system brings up some rave reviews, but at the same time highlighting relatively poor original speakers. An exposed valve chassis will not be to the taste of most B&O enthusiasts, but has anyone used one of these Fatman systems with B&O speakers?

Graham