[estreeter]

Hi All,
 
     Forgive my total ignorance when it comes to tube amps, but many of the impressions I am reading of amps like the MP301 and other entry-level tube amps seem to favour higher impedance, low sensitivity cans. Same-same with the Bottlehead Crack, although the enthusiasm levels for that amp are so high that its tough to find a critical POV.
 
     I've followed the links in Skylab's brilliant 'Top 29 Tube Amps' thread, but I remain confused. What I'm aiming for is a bedside rig that is euphonic and serves guitar-based rock (metal to the softer stuff) from a relatively small footprint, preferably without too much heat. I know this is a tough order and I'm not giving you a lot of dollars to work with, but the next step up the ladder seems to be the WA6 and I'm not sure I'm willing to go there yet. Headphones are lower-end Grado and ATH-AD900 for the purpose of this exercise - I love the mids on both, even from the humble D4.
 
    My dream amp would be a 'transportable' about the size of the XP-7 that matched the dynamics of SS with the lush mids I'm told tube amps deliver - I dont think such a creature exists in my price range, so I'm buying the P4 and an entry-level tube amp. The extremist is telling me that the sum total would buy the WA6, but I'd like to dip my toe in this whole tube rolling thing first.
 
Thanks,
 
estreeter

 

[estreeter]

29 views and not a single response - nice work guys. Is it possible that some of those 29 views might have been from people with a similar request ?
 
If its just 'understood' that tube amps arent the best choice for 32-ohm cans, fine - it would have been nice if someone could have mentioned that. 1 sentence.

 

[baka1969]

I may not be the last word in tube amps but I thought the Little Dot MKIII sounded really good with the HF2 when I had them both. It wasn't better than the solid state amps I had but was still very nice. I wouldn't exactly call it transportable though.

 

[estreeter]

Thanks baka - greatly appreciated. I know the 'transportable' thing is a bit of a stretch, and I wasnt going to get the WA22 for $350 anyway, but I wanted to list the 'ideal' and see where it went.

 

[baka1969]

Quote:Originally Posted by estreeter 

"Thanks baka - greatly appreciated. I know the 'transportable' thing is a bit of a stretch, and I wasnt going to get the WA22 for $350 anyway, but I wanted to list the 'ideal' and see where it went."


Lmao. If the WA22 is transportable then any amp is game. I have the WA6SE and even half of that, which is more or less the WA6, isn't what I'd want to schlep around or travel with. The Little Dot is much smaller yet is still kind of hefty.

Honestly an amp like the Gilmore Lite is terrific for being transportable. It's not a tube amp but it works great with the Grados and it's small enough to shove in a carry on. Although going through airport security will probably be an adventure. LoL

Sorry I couldn't help further.

 

[WyldRage]

Well, there are basically three main type of tube amps: Output Transformer-Less (OTL), transformer coupled and hybrid. OTL and hybrid are generally cheaper (since you don't need output iron), but the first is a poor match to low impedance headphones and the latter might not give you the euphonic sound you search for.
 
Transformer-coupled is costlier, but a good match for Grados, and with the euphonic sound you seek (especially SET amps, single-ended triode). I must warn you however, that they can be a bit slow and sound congested on fast and complex music. My SET, the Hagerman Castanet, sounds good on everything but Thrash Metal. If you listen a lot to Thrash and faster genres, I would recommend an hybrid instead. If it's mostly rock, try to find a SET.
 
Well, I'm just checking the manufacturers I know, and I see two possibilities for your budget: a chinese amp (Little Dot, HifiMAN or other, I can't help you there) or a used amp. I just checked the For Sale forum and it seems a Bottlehead S.E.X. has just popped up for $325. It's a DIY SET amp, but it's neither small, nor tranportable.

 

[estreeter]

Thanks so much, guys - I will print this out and use it to refine my search
 
Baka, I was attempting to be humourous with my reference to the WA22 - I think the Zana Deux is larger, and I know some of the tube speaker amps are truly humungous (even larger in the flesh, which is the opposite of my experience with SS gear). Sadly, the price tags on a lot of that stuff look like someone forgot to put a decimal point somewhere, but when I asked the store owner he just smiled. Hard to believe that the same guy had NOS K501s for $199 - a treasure trove if ever there was one.

 

[baka1969]

Quote:Originally Posted by estreeter 

"Thanks so much, guys - I will print this out and use it to refine my search
Baka, I was attempting to be humourous with my reference to the WA22 - I think the Zana Deux is larger, and I know some of the tube speaker amps are truly humungous (even larger in the flesh, which is the opposite of my experience with SS gear). Sadly, the price tags on a lot of that stuff look like someone forgot to put a decimal point somewhere, but when I asked the store owner he just smiled. Hard to believe that the same guy had NOS K501s for $199 - a treasure trove if ever there was one."


Try shoving a pair of mono blocks in your carry on. LoL Don't forget the preamp.

 

[estreeter]

y
 
Quote:

"


Try shoving a pair of mono blocks in your carry on. LoL Don't forget the preamp.

Laugh it up - I once made a suggestion that we needed a 'Transportable Rigs' sub-forum and was told by another Head-Fier that it would be a silly idea because 'All headphone rigs are transportable'. Well, yes, Mr Einstein - theoretically you could pack up a KI Signature Marantz amp and carry it across town in a large backpack, but who would do that ? We've got some real world beaters on Head-Fi.

 

[Uncle Erik]

The trouble with most OTL amps is that they have an output impedance above 32 Ohms. You need an output impedance below the headphone impedance. Otherwise, the power transfer gets bad and you'll have poor bass control.

Traditionally, you lower output impedance by using output transformers. Problem is, output transformers are expensive. Decent ones start around $100 each and go up from there. So if you have $200 into the output transformers and $100 for the power transformer, you're not going to be able to add the caps, resistors, potentiometer, jacks, wire, and case for another $50. You certainly would not be able to include labor and profit, either. This is why you don't find tube amps with output transformers for much under $1,000. If you wan to DIY an amp with output transformers, you could pull it off for about $500 in parts at the low end.

Even then, you might want to spend more. I've got a Ciuffoli SESS in parts. That was about $700 for the power transformer, three chokes and two output transformers. I have another $300 into case parts, jacks, screws, solder points, switch, power indicator light, knob, wire, and other parts. I need to spend another $200-$300 for a good stepped attenuator. Then it'll be 30-40 hours of labor to put it together.

The one commercial OTL with low output impedance is the Zana Deux. The 6C33C has a nice, low output impedance. That's what makes the Zana Deux special - you get the OTL sound at low impedance. I think Millett has a low impedance OTL design, too, but you have to build it yourself.

Impedance aside, the cheap tube amps cut a lot of other corners. The most important part of a tube amp is the power supply. It puts DC directly into the circuit, so you're also listening to the power supply. The cheap amps run the AC through some diodes and a cap/resistor network or two. That's usually not enough to get all the AC ripple off the line. So you end up getting a slight waver in the sound. Likewise, a lot of them run AC to the filaments in the tubes. So instead of steady DC power for the tubes, you have fuzzy AC. This is why the cheap amps don't sound very precise.

If you want a good power supply, you probably want to run a tube rectifier. This can require its own power transformer, which costs more. You'll probably also want to really smooth out the DC for the circuit, so you'll want to drop some chokes in there. Good power supplies have one choke coming out of the power supply which is then filtered by a cap/resistor, then into another choke for each channel. Then you'll want to run DC to all of the filaments, which adds even more cost. Some power supplies even add regulation to ensure that the DC never varies.

As you can imagine, adding all of this costs money. Parts, labor and sometimes a second chassis just for the power supply. It really adds up.

Construction also plays a big role. Cheap amps are on a PCB. Those are OK, but inserting/removing tubes can weaken the solder joints. It's easy to lift a pad if you have to replace a component - that requires major surgery to fix. Tube heat can also lift a trace, which also requires major surgery. You're better off with a point-to-point amp. But those require a lot more labor to build and terminal points/strips cost more than a PCB.

Solid state costs a lot less to do right. They operate at much lower voltages, so you don't have to buy the expensive iron for the power supply. Further, the low voltages let you use chips and other inexpensive parts for really nice filtration of the power. Chips are naturally low impedance, so you don't have to buy expensive output transformers. Also, PCBs work fine for solid state. It's easy to heatsink chips, too. So if you want a good design with an excellent power supply, you can do solid state for much less than the equivalent in tubes.

This is why I don't recommend cheap tube amps. There are too many corners cut in the design. A $300 Dynalo will get you cleaner power to the headphones. If you are willing to build or buy a quality tube amp, however, they are very rewarding.

 

[afrobat]

Isn't the new Musical Paradise MP-301 Mk2 supposed to be transformer coupled? it's $250.

 

[baka1969]

Quote:Originally Posted by estreeter 



"Laugh it up - I once made a suggestion that we needed a 'Transportable Rigs' sub-forum and was told by another Head-Fier that it would be a silly idea because 'All headphone rigs are transportable'. Well, yes, Mr Einstein - theoretically you could pack up a KI Signature Marantz amp and carry it across town in a large backpack, but who would do that ? We've got some real world beaters on Head-Fi."


When I was in the hospital in Oct of '09 I had my brother bring my headphone rig to me. Ok, it was a laptop, iBasso D2+ Boa (used as a DAC), Headroom Micro Amp and my HF2. That's more of a transportable system than you'll likely find in a decent tube amp.

Back to the GLite, they are fairly easy to find preowned on the Sales Forum and are well within your budget.

 

[Asr]

What about the Millett MiniMAX? If you can't build it yourself, pre-built ones are sometimes available on the FS forums.

 

[estreeter]

Thanks for the feedback, guys.
 
Uncle Erik - incredible amount of effort went into your post, and I now have a much better understanding of the reasons why most of the cheaper tube amps seem to be aimed at higher impedance cans.
 
baka - FWIR, Gilmore Lite and 'euphonic' would seem to be an oxymoron - happy to hear otherwise.
 
Asr - I will check out the MiniMax.
 
End of the day, I have set my sights too low. I realise that many who have made the sacrifices for something like the WA6 or the HA-02 are probably thinking 'Just take a few more weeks and buy the thing !'. That said, at least I have a better understanding of what I should be looking for : OTL amps that dont use a PCB.

 

[baka1969]

Quote:Originally Posted by estreeter 

"Thanks for the feedback, guys.
Uncle Erik - incredible amount of effort went into your post, and I now have a much better understanding of the reasons why most of the cheaper tube amps seem to be aimed at higher impedance cans.
baka - FWIR, Gilmore Lite and 'euphonic' would seem to be an oxymoron - happy to hear otherwise.
Asr - I will check out the MiniMax.
End of the day, I have set my sights too low. I realise that many who have made the sacrifices for something like the WA6 or the HA-02 are probably thinking 'Just take a few more weeks and buy the thing !'. That said, at least I have a better understanding of what I should be looking for : OTL amps that dont use a PCB."


There is nothing euphoric about the GLite that's for sure. That said a transformer coupled tube amp like the Woo WA6 will sound more like solid state than other tube designs. There are a few solid state amps that are more an the warm side too. And at 03:30 the damn name of one of the warmest sounding slipped my mind. The Headroom Micro Amp is also on the warm side, has three gain settings, and is quite portable.


Bottom line? You have more options than when you wrote the initial post. Lmao