[taiyoyuden]

How big is the difference between no amp (only dac, no dedicated amp) and amp for k701?

 

[sphinxvc]

This big.  
 
 
 
 
 
 
 
 
 
 
 
 
 

 - kidding.  It depends on the receiver / amp/DAC and dedicated amp.

 

[grmnasasin0227]

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How big is the difference between no amp (only dac, no dedicated amp) and amp for k701?

Night and day, considering a DAC will only clean up the signal...and a soundcard can already do that fairly well (I'm currently using an Auzentech Forte).
 
 

 

[grmnasasin0227]

Bump--can anybody clarify on a need for a "warmer" amp to take the edge off the K701 (and perhaps the Big 3 in general)? A tube amp would serve the warmth need better than an SS, correct? Would something like a Woo 6 suffice?

 

[ocswing]

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Bump--can anybody clarify on a need for a "warmer" amp to take the edge off the K701 (and perhaps the Big 3 in general)? A tube amp would serve the warmth need better than an SS, correct? Would something like a Woo 6 suffice?

That's getting into personal preference somewhat. A lot of people feel the 701s have a weird mid section and fatiguing highs so a warmer chain will definitely help with those issues. It could be that you naturally like the sound of the phones though so in that case you'd want a more neutral chain. 
 
Generally speaking tubes are warm and SS amps aren't, but there are variances within that so it's more of an amp by amp thing.
 

 

[ProtegeManiac]

A warm amp with lousy current/drive will still make the K701 sound thin even if it takes the edge off. A transparent SS amp with good current drive fed by a smooth-sounding source/DAC will do better than an OTL tube with a not-too-good source/DAC. You'd be surprised though with some amps. My old DAC-AH+Little Dot MkII didn't sound too lousy with the K701 even if it was OTL. It wasn't as full-bodied as a stock HD600 or a K701 with mashed pads, but I wouldn't describe it as "thin," either. It was "just right," although it didn't have any bass rumble to it. Think of really good stand mount speakers with a 6" to 7" woofer and good dome tweeters, but no sub.

 

[sphinxvc]

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Bump--can anybody clarify on a need for a "warmer" amp to take the edge off the K701 (and perhaps the Big 3 in general)? A tube amp would serve the warmth need better than an SS, correct? Would something like a Woo 6 suffice?

The midrange bloom of some tubes give the K701's odd midrange some body, it corrects it in a sense, at least in my experience.  Yes, the Woo 6 did it and so did the 6SE.  What the warmth does for the phones depends on your personal preference for tonal balance as ocswing said.
 
On the K701 appreciation thread you'll find some mods documented and done by MadMax that supposedly "fix" the odd resonances and other issues the K701s have.  So that's a low-cost solution if you want to give that a shot.  I've never heard the modded K701s but his impressions say it fixed the quirks. 
 

 

[grmnasasin0227]

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A warm amp with lousy current/drive will still make the K701 sound thin even if it takes the edge off. A transparent SS amp with good current drive fed by a smooth-sounding source/DAC will do better than an OTL tube with a not-too-good source/DAC. You'd be surprised though with some amps. My old DAC-AH+Little Dot MkII didn't sound too lousy with the K701 even if it was OTL. It wasn't as full-bodied as a stock HD600 or a K701 with mashed pads, but I wouldn't describe it as "thin," either. It was "just right," although it didn't have any bass rumble to it. Think of really good stand mount speakers with a 6" to 7" woofer and good dome tweeters, but no sub.

Thanks for the advice, duly noted. Can you recommend such a DAC? I'm after something that is rather clean with its signal, probably $400 or so tops.
 
 


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The midrange bloom of some tubes give the K701's odd midrange some body, it corrects it in a sense, at least in my experience.  Yes, the Woo 6 did it and so did the 6SE.  What the warmth does for the phones depends on your personal preference for tonal balance as ocswing said.
 
On the K701 appreciation thread you'll find some mods documented and done by MadMax that supposedly "fix" the odd resonances and other issues the K701s have.  So that's a low-cost solution if you want to give that a shot.  I've never heard the modded K701s but his impressions say it fixed the quirks. 
 

Conversely though, the HD650s are labeled by many as being rather warm and bassy. Would the Woo 6 over-color this characteristic and make it muddy?

 

[Ajani]

I've been using the Benchmark DAC1 as DAC/Amp with my K701s for about 3 years now. So I can certainly recommend that combo.

 

[sphinxvc]

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Conversely though, the HD650s are labeled by many as being rather warm and bassy. Would the Woo 6 over-color this characteristic and make it muddy?

 
Pick different tubes.  Honestly though, both phones ask for different things, and I'm not sure about the Woo 6/HD650 synergy, you'll have to read elsewhere about that.  HD650s have a good rapport with OTL tube amplifiers.  And there are many cheap but decent OTLs out there.  I think you might be able to get two good amplifiers for each phone for the price of a Woo 6 (unless you're buying used).

 

[grmnasasin0227]

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Pick different tubes.  Honestly though, both phones ask for different things, and I'm not sure about the Woo 6/HD650 synergy, you'll have to read elsewhere about that.  HD650s have a good rapport with OTL tube amplifiers.  And there are many cheap but decent OTLs out there.  I think you might be able to get two good amplifiers for each phone for the price of a Woo 6 (unless you're buying used).

Sounds good. Tube rolling can make that big of an impact? Sounds fun, kinda like the hardware tinkering I'm used to on a PC
 
 

 

[sphinxvc]

Here's a great post about tube-rolling the WA6 for beginners by Xcalibur255:

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All of the drive tubes for the WA6 are vintage, none have been made since the early 80's.  As some may know I am a champion of the 6SN7 adapter route for this amp because I feel, no exaggeration present in this sentence, that it doubled the performance of the amp overall.
 
Now, having said that, I do NOT recommend you jump into this at this time.  The 6SN7 tube hunt is one that gets expensive very fast, and it is best to absorb some knowledge of tubes in general first.  Also, you must understand you are operating a tube that technically was not designed for the amp, and that is something you must be comfortable with before doing it.  Finally, given you just got the amp you should give yourself some time to get used to its as-designed sound using drop-in compatible tubes before trying other tubes via adapters.  That is my advice anyway, for what it is worth.
 
There are a variety of 6DE7, 6FD7, 6EW7 and 6DR7 tubes available for the amp if you look around the net.  The best part is they are very affordable for the most part.  The 6FD7 tends to be the popular choice, but each type has its own character and I honestly feel the best thing to do is try one of each and let the tubes tell their story.  What headphones you are using will also matter a lot. The Sylvania 6FD7 is very well liked, but I have not heard one myself (and might have to change that just for the heck of it).  Of the tubes I tried before going to 6SN7 my favorite was a pair of RCA 6FD7 with the earlier dual black plate design, but these tubes are hard to find in this vintage.  I think the Sylvanias are a better bet, or if you are looking for a nice big soundstage and a more mellow sound the 6EW7 is a good tube to try.  Stick to the fat bottle tubes where possible (the 6FD7 and 6EW7 were made in both thin and big bottle), they tend to have better dynamics and soundstage.
 
Before trying a Sophia or EML rectifier give a few NOS tubes a try first as well.  A Tung Sol 5U4G or RCA 5R4GY can be had for $20 NOS, and the choices don't stop there by a long shot.  In my experience the rectifiers Jack includes with the WA6 are not usually anything special (I got a 5AS4 that sounded soft and muddy), so this area in particular can be improved upon without spending much money.  If you are the type that likes to experiment and try different combinations tube rolling should be a fun experience in this amp.
 
On the subject of buying tubes, what I did was read threads on this forum and absorbed knowledge until I was comfortable.  To address your specific questions though, they don't *technically* have to be the same brand of tube but they absolutely should be since the sound will be different from the left to right channel if you do that.  They absolutely *must* be the same type of tube in each socket, and ideally should be matched both electrically and physically.  What this means it that the seller has tested the tube in a tube tester to check its emission rate, trans-conductance and plate current.  Very often sellers will only do the first of those things, but the good part is the Woo doesn't strictly need closely matched pairs in order to operate correctly.  It is desirable if possible, but the most important thing is making sure the tube has been tested at all so you know it is safe to use in the amp.  A tube with a short or other fault can damage the amp.  Over the years the physical design of many tubes changed too, so making sure both tubes are of the same vintage is also important or you will get tone mismatches between channels.
 
A person could make some generalizations about what the various tube brands sound like, but each person hears differently and it is just opinion.  The broad view is, if it helps narrow down choices for you, that RCA tubes tend to have a thick and warm sound, Tung Sol and GE tubes tend to have a neutral and balanced sound, Raytheons tend to have an accurate or slightly dry sound, and Sylvania tubes tend to have a lean and airy, clear sound which can be either bright or sweet sounding depending upon the specific tube.  These are big generalizations though so take them with a big grain of salt and trust your own ears.  Somebody else might disagree with part or all of what I just wrote because we each hear something unique.  Other brands are usually a rebranded version of one of the above, though there are exceptions.  Hope that helps a bit.

 

 

[grmnasasin0227]

Thank you kindly! I have a feeling that tubes are going to find their way to my Christmas list hehehe...

 

[ProtegeManiac]

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Thanks for the advice, duly noted. Can you recommend such a DAC? I'm after something that is rather clean with its signal, probably $400 or so tops.
 

 
I suggest you try the NFB12, then if it's not good enough for you driving the K701, take the change, save a bit more get a separate amp. Trust me, even if the K701 is very transparent, if some people can enjoy them with an iPod Video and a Toucan, then the driving power of the amp is definitely what most people who don't like them lacked. And of course the NFB12 is certainly a better source than the iPod, too.

 
 

 

[grmnasasin0227]

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I suggest you try the NFB12, then if it's not good enough for you driving the K701, take the change, save a bit more get a separate amp. Trust me, even if the K701 is very transparent, if some people can enjoy them with an iPod Video and a Toucan, then the driving power of the amp is definitely what most people who don't like them lacked. And of course the NFB12 is certainly a better source than the iPod, too.

 
 

The price on that is great, but I'm almost concerned for the quality at that price--how does the DAC section in that unit compare to one of their DAC-only units, such as the NFB-3 (which admittedly is $100 more)?