Darkvoice 337 - A Review

[musicmind]

Mazuki, thanks for the TubeCAD site link, lots of great information there...and btw, also for the great review that got this thread started.

Are you also still regularly using your K1000 with the 337? I never found the actual power rating for the 337, I wonder if it would fare better than the T-amp when used with a K1000?

Thanks

[MaloS]

Originally Posted by Mazuki

Malos, you used to own a Darkvoice 332. It wasn't that bad was it? The FEEL you had for a while didn't blow everything out of the water did it?

No, Darkvoice 332 was superior. Tis a good amp.

[Jo6Pak]

So, what's the hierarchy here? 336 ->332 ->337, in terms of 'quality'? If so, what makes the 332 and 337 so much better? I realize you'll get more power per channel outta the 337, but what about the 332? Are the components in that one so much better than in the 336i? I have had my 336i for a few weeks now and it just keeps sounding better. If DV makes something superior to it, I'm inclined to try it...

[MaloS]

A bit more of
336 -------> 332 -> 337

Different, cleaner design on bigger amps. 337 is dual mono for crying out loud, while 336 uses two dual tubes, each amping 2 channels. Basically higher you go, the more separated the channels become.

[Jo6Pak]

Wow, I had now idea the 336i was that far down the chain from the 332. I'm aware of the dual-ness of the 337, but I'm mostly comparing 2-channel/1-knob stuff here. IIRC from another thread, there is not much difference in price between the 336i and 332 and was curious why the 332 gets higher marks. I could be mistaken...

[cclragnarok]

The 332 is a newer amp than the 336 and the 337. The official word is that they used the exact same topology as the 337, and managed to make the amp smaller without losing too much sound quality.

The 336 is a different design as far as I know. So while "336 -------> 332 -> 337" is the supposed ranking of the amps, the 336 might also sound different (as opposed to strictly inferior).

By the way, the 332 is almost twice as expensive as the 336i in China. Over here, the price difference doesn't seem that big, but that's mostly because the (rather large) cost of shipping is about the same for both.

[Mazuki]

Mazuki, thanks for the TubeCAD site link, lots of great information there...and btw, also for the great review that got this thread started.

No problem, there's a lot of articles on TubeCAD about the Cathode Follower topology. I highly recommend reading all of them. Thanks for the positive comments about my review!

Are you also still regularly using your K1000 with the 337? I never found the actual power rating for the 337, I wonder if it would fare better than the T-amp when used with a K1000?

The K1000s in the picture are actually borrow from a friend. I do not use them anymore. I actually read somewhere on the Darkvoice forum that the 337 might not have enough power to drive the K1000s. An inherent problem with the cathode follower circuit is it's low gain. Therefore even though it definitely did not sound bad, I fear the 337 is probably not driving the K1000 to it's fullest potential.

You could try building a Gainclone for your K1000s. That would most likely work better.

[Mazuki]

The 336 is a different design as far as I know.

Yes, as I mentioned previously, the 336 uses half a 6SN7 to drive half a 6AS7.

The 332 is a newer amp than the 336 and the 337. The official word is that they used the exact same topology as the 337, and managed to make the amp smaller without losing too much sound quality.

Also true, the 332 and 337 both use a pentode as a driver. However the 6C19P tube used in the 332 is only half a 6AS7. So the 337 using both sections of the 6AS7 is inherently more powerful.

Are the components in that one so much better than in the 336i?

All Darkvoice amps share similar components across the board. I have a feeling the 51uF SCR coupling cap on the 337 is unique. However, the transformer, filtering capacitors, resistors, etc, are all shared. All three amps have significant homology.

Also there are plenty of discussions regarding the differences between miniature tubes (used in 332) and octal tubes (used in 336 and 337). Many people swear octals sound better. But we're going into an entirely different territory here.

[NoPants]

I'm curious as to where you found those 6528 monsters...

[Mazuki]

I'm curious as to where you found those 6528 monsters...

I was fortunate to find a nice guy on eBay that had some left-over NOS. It was a great deal, $50 for both tubes, new.

The 6336A tube is essentially two 6AS7 paralleled into one envelope. The 6528 tube is a 6336A with a higher mu (gain).

[cclragnarok]

Originally Posted by Mazuki

Also true, the 332 and 337 both use a pentode as a driver. However the 6C19P tube used in the 332 is only half a 6AS7. So the 337 using both sections of the 6AS7 is inherently more powerful.

I always wondered about that. Do you know what the 337 does with the two sections of a 6AS7? Push-pull maybe?

[MaloS]

Originally Posted by cclragnarok

I always wondered about that. Do you know what the 337 does with the two sections of a 6AS7? Push-pull maybe?

Knowing their topology, push pull would be utterly pointless, so most likely its just parallel.

[cclragnarok]

Originally Posted by MaloS

Knowing their topology, push pull would be utterly pointless, so most likely its just parallel.

I guess if it is push pull, then the topology wouldn't really be the same as the 332. So you are probably right.

[Mazuki]

Knowing their topology, push pull would be utterly pointless, so most likely its just parallel.

If you take a look at the picture in post #99, you can clearly see the two sections of the 6AS7 are paralleled in 337.

[jonoliew]

so after reading alll these pages, the 337 seems to be better than the doge, and there's no real comparison with the bada ph12 (which is rather unreliable due to the mosfets). Then the 332 is close to the 337? so how close is the 332 to the doge? lol.