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Van Waarde amp: info/opinions

post #1 of 19
Thread Starter 
I just had a spur-of-the-moment inpulse to look into building a Van Waarde amp, and before i waste much time and/or money on that line of thought i am curious how it would compare to readily available similar amps like the LittleDot II++ and maybe others (i suppose it cant come near a darkvoice?)

And interested to see if there are people around who built one, how problemfree it was to build and rough estimate on building cost.

An ofcourse any suggestions for DIY amps that may be better to look into (looking for a tube-based amp that will not form a weakest link when used with a hotrodded xfi and a 595.
And I'm looking for something fairly simple to build at reasonable cost, I'm not very experienced.

Thanks for any input!
post #2 of 19
Why can't it come near a Darkvoice? The 336/336i is basically an adaptation of van Waarde's amp.
post #3 of 19
I built a van Waarde last summer to drive my DT-880s. It is an excellent sounding amp, and a very straight forward build. The case-work was the most time consuming and difficult part of building it. It will probably cost somewhere between $120 and $250, depending on the parts you choose.

I don't have any commercial amplifiers to compare it to, but I prefer it to all of my other amps for my DT-880s (Pimeta, Millett-Hybrid with diamond buffers, Szekeres, LH0033 buffer, etc.). However, I do not like it much with my Grado SR-80s, most likely because of their low impedance and the small output coupling capacitors I'm using.
post #4 of 19
Thread Starter 
Sounds promising. It indeed looks not unlike the darkvoice, same driver tube i think also.
Michael: Why is it not so good for lower impedance phones? I read that on the van waarde page aswell.. My 595s are 50ohm, is that too low to make this amp shine? And if so can a resistance be added to increase the resisitance of the output?

Also i did not find something like a step by step guide, only schematics. I know thats all you really need but being inexperienced I would find comfort in some pictorial

What I'm mostly unsure about is the power supply.. I'm in europe mainland (220v) so I cant just use a 110v layout
post #5 of 19
Well, the biggest reason I did not like it with my Grados was the lack of bass, since my output coupling capacitors are 100uF, the cut off frequency is too high with the Grados. Increasing the size of these capacitors would likely cure the problem.

I haven't seen any step by step instructions, but the amp is very easy to build. It was my first true tube project, and it worked on the first try, although I've built numerous other projects prior to this one.

As for the power supply, you can use the same schematic, you just need to use a different transformer. So, instead of using a 120V to 2 x 115V transformer, you would need to use a 220V to 2 x 115V transformer. If you decide to go with regulated heaters, you would also need a 220V to 9V transformer. Personally, I built my amp with AC heaters, and there's absolutely zero hum.
post #6 of 19
I built one...
Here's the thread:
http://www.head-fi.org/forums/showthread.php?t=180474

It's my main tube amp. Once I built it, I sold everything else off except my dynahi and dynalo.

But it doesn't do well with low impedance phones. My K271's are 55 Ohm and lack bass when used with this amp. I use my Darth Beyers (250 Ohms) with this amp.

If you can only use low impedance phones, start with 1000uf of capacitance on the output and go up from there
post #7 of 19
My first tubu headamp I build - Morgan Jones on 6n1p. I had only 32 ohm phones at that time, power had not enough.
I start to breadborded and experiment whith different schematics, including van Waarde, MJ was the best on 32 ohm. Downside of van Waarde - R5 and R6 get very hot.

Now with HD580 MJ is excellent, but my new 6n7c(6SN7) Aikido is even better.

So, for low impedance I advise MJ or Aikido with White cathode follower output.

Zigis.
post #8 of 19
Thread Starter 
Quote:
Originally Posted by Zigis View Post
My first tubu headamp I build - Morgan Jones on 6n1p. I had only 32 ohm phones at that time, power had not enough.
I start to breadborded and experiment whith different schematics, including van Waarde, MJ was the best on 32 ohm. Downside of van Waarde - R5 and R6 get very hot.

Now with HD580 MJ is excellent, but my new 6n7c(6SN7) Aikido is even better.

So, for low impedance I advise MJ or Aikido with White cathode follower output.

Zigis.
I just looked at the Aikido.. Looks good and they sell ready-made PCBs which would probably make it easier for a n00b like me. The impedance issue confuses me a bit, they don't really seem to consider it an optimal headphone amp because headphones have high impedance compared to speakers, but they drive high impedance headphones better then low? *confused*
Can I expect good results with this amp with headphones with impedances as low as 50ohm (senn595)? Or should I look elsewhere for that?
Also how does this amp measure up to others, sound-wise? Another tempting circuit i'm looking at is on a dutch DIY site and based on the Earmax Pro.
Finally which would be better for my scenario, the 9-pin or the octal version? I understand the difference is the tubes used, but i'm not sure what the implications are of one vs the other.

As you can see i'm very much new to this and a bit overwhelmed with the (often unstructured) galaxy of options to go with
Basically I'm looking for something that can perform roughly along the lines of the darkvoice 336i, in a simple to understand design that works well with 595.
post #9 of 19
Thread Starter 
I have been looking at this schematic

(warning, dutch language site.. scroll down to see the schematic, which is for one channel)

http://www.circuitsonline.net/circuits/view/114

It is designed for 300ohm headphones. Is there an easy way i can change the schematic to make it more suitable for 50ohm headphones? Will just adding a resistance do? if so, where should it be placed?
post #10 of 19
Headphones less than 100 ohms or so aren't a good match for OTL amps. Especially down around 32~50 ohms you really need an output transformer. I guess 7119/E182CC w/ paralleled sections maybe, but those are pricey tubes.
post #11 of 19
In Your case with 50 ohm phones better is 9pin Aikido, 6H30 in output.
http://www.tubecad.com/2006/04/blog0062.htm
And somewhere John Broskie describe, how to convert output in White cathode fallower mode,this lover output impedance more.

I don't like schematics from dutch site, because C3, Morgan Jones is alike, but better.
post #12 of 19
Yes, it is very much like the Darkvoice 336. However, it does not sound like a tube amp (stereotypical tube amp being transformer-coupled SET amps like 300B). Does not have that special midrange bloom, organic texturing, or holographic imaging associated with a good SET amp.

If you want the tube sound, I recommend a single-ended triode-strapped EL84 driven by 12AX7 (similar to the Doge 6210). There are a ton of such designs on the internet.
post #13 of 19
Thread Starter 
[edit: question was answered before i posted it!]

Zigis, I agree, I tend to lean towards the Aikido more then that dutch one too, it seems better thought over and definately better documented. And thanks for answering my question about the pins before i asked it

cotdt: are there any particular ones I should look for?
post #14 of 19
Quote:
Originally Posted by phalanger View Post
I have been looking at this schematic

(warning, dutch language site.. scroll down to see the schematic, which is for one channel)

http://www.circuitsonline.net/circuits/view/114

It is designed for 300ohm headphones. Is there an easy way i can change the schematic to make it more suitable for 50ohm headphones? Will just adding a resistance do? if so, where should it be placed?
You'd have to dramatically increase the size of C8.
post #15 of 19
Quote:
Originally Posted by phalanger View Post
cotdt: are there any particular ones I should look for?
I like this one:
http://users.otenet.gr/~athsam/tube_...ifier_EL84.htm

Alternatively, the Bottlehead Paramour 45 should be very good, and is an actual kit.
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