SE 2 watt clean amp?

[johnr66]

I'm new to tubes. I wonder how good a single ended amplifier can sound. I'm not after golden ear hi-fi performance, but want 2 watts per channel of output before clipping, 40Hz - 15 KHz with less than .5% THD.

The purpose of the amplifier would be to boost the output of headphone devices (Walkman) to drive speakers. Since the devices have their own volume control and other sound controls, The amplifier would not need need any controls, just a power switch.

I would think that a triode tube would have enough gain, but not sure if I have to add some negative feedback.

What do you think?

[planet10]

SE EL84 would fill the bill.

dave

[Eli Duttman]

John,

Triode wired 6V6 family tubes will yield 2 VERY nice WPC. A 5965 will be excellent as the voltage amplifier.

You really don't need NFB, if you use good O/P trafos, as the bulk of the HD will be euphonic 2nd order.

[piano3]

Of the two suggestions so far, 6V6 will easily produce the power although EL84 has probably more linear triode curves. If you were to use a 5K transformer with EL84-ra~2k- you would have to swing 100V RMS. Is this easy? My 2 cents worth; how about very linear and cheap Russian 6N6P? I mean running both sections in parallel.

[piano3]

Maybe possible operating point for 6N6P; 180V,25 mA per triode section 2.4k primary impedance. Comments anybody? Actually johnr, your requirement for less than 0.5% THD is a bit steep for SE at full power. A 300B would struggle to get this at 2 watts

[Eli Duttman]

Of the two suggestions so far, 6V6 will easily produce the power although EL84 has probably more linear triode curves.

The 6V6 family makes a better sounding triode than the 6BQ5/EL84. I'm not the only person who thinks that, ask Poindexter. The Russian 6П15П (6p15p), AKA SV83, makes a nice triode too.

Using a tube with a μ in the low 30s is (IMO) cutting things a bit too fine. The 5965 is high gm, low R_P, linear, and its μ is in the 40s.

Check this thread out. Buy 1st class O/P "iron" and that kind of circuitry sings sweetly, indeed.

[azazello]

6V6/triod mode/ & 12AT7
Picasa Web Albums - Nikola Nikolov - amplifiers

6V6 buy from Tube List range 6K4 - 6ZY5G
12AT7 buy from Tube List range 12A - 12Z5
All transformers and chassis buy from Angela.com

[Cassiel]

The 6V6 family makes a better sounding triode than the 6BQ5/EL84. I'm not the only person who thinks that,

Having listened to both tubes in triode mode I can say that I'm another person that thinks like you on this matter.

[Pano]

I've listened to both and may have to agree. (Poinz's amp among them). 6V6 is nice. But neither are bad. Really nice, in fact. And I have some 6П15П that will be put to use soon. Should be interesting.

[johnr66]

Thanks for the replies. I take it a 140 volt supply and appropriate tube is out of the question? I happen to have a transformer plus doubler circuit. I look at the cost of the transformers and WOW is this expensive.