[hauntingtheholy]

Minus the exrta small tube on the Little Bear, are these amps super-close in quality?

I've heard reviews of DarkVoice, but not litlte Bear p8, so if anyone has heard that one, I'd love to hear your thoughts.  Here are some links to the two for sale, Mass Drop not active yet for DarkVoice, but that's what I'd wait on.  But the DV will still be 40-80 bucks more money after the drop.

http://www.ebay.com/itm/Little-Bear-P8-metal-BLK-valve-tube-Headphone-amplifier-amp-preamp-by-FedEx/291172574397?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20131017132637%26meid%3D3d2bf006c42c44ef9273084ec4fde58a%26pid%3D100033%26prg%3D20131017132637%26rk%3D3%26rkt%3D4%26mehot%3Dpp%26sd%3D221653113575
 
https://www.massdrop.com/buy/dark-voice-366se?s=dark%20voice

 

[sgbwill2]

Build quality and components used in the 336 are far superior when looking at pictures of the internals. I wouldn't chance the Little bear personally and the 336 would be worth it for only $40-80 more. I haven't heard either amp but I own the La Figaro 339 which is essentially the 336's big brother and the build and sound quality is very nice.

 

[kramer5150]

My thoughts... (Admittedly NONE of which are actual listening impressions, so take this FWIW)
 
My main amp is a 337, which is basically a dual mono topography using two 336 amps in the same chassis... one per channel.
 
The little bear looks like its using electrolytic caps for output coupling.  Either that or some severely under-spec'd (in some way) wimas.  I would hope the latter is not the case.  An under-Voltage spec'd coupling cap reservoir failure on an output tube can fry your headphones!!   Electrolytics work fine from an amplification standpoint, assuming the value chosen is sufficient for the application.  In theory the caps V ceiling should be at least ~1.5x that of the tube plate voltage.  The total farad value of the reservoir should be sufficient for the 20-20k audio band, given the impedance presented to the tube by the headphone voice coil.  The capacitor in series with a voice coil create a first order high pass filter, so if the wrong mfd value is chosen it can result in a low bass roll-off depending on the impedance of the headphone.
 
The darkvoice (and sister company LaFigaro) designers spent a fair amount of time / energy / effort enhancing the output coupling capacitance aspects of the 336-339 amps as they have evolved over the years.  From an audio-fidelity standpoint, paper / oil audio caps are the way to go, not electrolytic (in many peoples eyes).  I think theres a lot of room for debate on this last topic.  There are some very well respected/liked OTL amps on HF use electrolytic coupling caps.  One things for sure, that open PCBA on the LB allows for some degree of DIY modding.  That aspect in itself I think is something that could tip the scale into its favor... if you're the DIY type.  "Buy low mod hi".
 
Those no-name volume pots are a real hit & miss in my book.  As a very low volume music listener, channel tracking linearity can be a problem for me.  I personally have never had a problem with Alps pots... for the $$ they are the way to go without going hog-wild ($$$) into step attenuator land.  I have several amps that use Japanese Alps pots and I have never had channel balance issues with any of them.
 
The main power supply resistors (the gold aluminum ones) in some iterations of the DV amps has been known to be a problem.  Where the designers under-spec'd the resistor values by a significant amount.  In these circuits they generate a TON of heat in the chassis that needs to be vented out.  I wonder why LB put them so far "inside" the layout and right next to the 6as7G tube?  If they are being asked to dissipate a lot of heat, that could be a problem.
 
LOL at the red electrical tape over the main AC.  Hopefully theres a fuse somewhere in there.
 
Whats the deal with the male/female connector on the AC main?... never seen that before.  I'd splice that thing out of there asap and point to point it wherever it needs to go.
 
Another concern could be earth grounding and EMI/RFI shielding running an open PCBA.  But that would depend heavily on ones noise environment.

 

[hauntingtheholy]

@kramer5150 - Whoa, man.  You are so far "Headphonus Supremus" beyond me it's not even funny!  While I don't know much about the internal workings of amps, I did notice that red tape you mentioned and the jacks right by the main AC, it's like....What?  Weird.  Thanks for that info on how NOT to fry my HD650's.  You might remember from the other thread that I am struggling to get the right bass out of them.  I have never heard ANY tube amplifier but from what I've read, it's definitely the sound I'm looking for.  I really don't like this Magni 2 Uber I bought.  I swear my memory of my friends HD650 sound from what I heard them a year ago is that my freaking iphone (plugged the 650's straight in just out of curiosity) had better bass on them than this amp.  Seems impossible.  And his *really* had excellent bass out of his home theater jack.  Once the Mass Drop hits for the DV336e, I'm probably going to get it, unless you or someone else convinces me to get something else.  My amp budget is in the 250-300 range - yeah, it's been increased a little.  :-D   I just hope the DV336e has enough *power* for the 650's.  Another user on here said he loves his 650's from the DV, so we'll see.  I'm debating whether to return the Magni 2U for the 15% restock and shipping deduction, or keep it and re-sell once I got the DV or some other tube amp.  *scratches chin*
 
You are smart to be a low volume listener.  Due to some frustration about the bass I was feeling after plugging in to the Magni 2u, I was screwing with the EQ and turned the volume WAY UP trying to get the bass right and I hurt my ears!  I felt really, really dumb.  Like, What was I thinking?  I actually went to the Doc and he put me on Prednisone for 5 days.  When I work my jaw I get that "popping" sound one gets when they take a flight.  I should probably share this story in a seperate thread as a warning to some other noobs/morons so they don't hurt themselvs, LOL.  I'll be fine, though.

Any other tube amp recomendations you can think of?  What about this Little Dot 2 or a Hybrid amp some people like?  Anything that'll give a very warm sound and bring out the 650 bass.  

 

[hauntingtheholy]

@sgbwill2 - Thanks for those pics and your info.  I didn't know the La figaro 339 existed so I looked it up.  Damn, $660 - out of my range!  I guess you must feel it's worth it.  Maybe I should try to find a strong amp used, it's tough though b/c they are still expensive and it seems worth it to pay a little more for a warranty.  Having tubes with unknown hours on them makes me feel this way more so than a solid state....

 

[sgbwill2]

  @sgbwill2 - Thanks for those pics and your info.  I didn't know the La figaro 339 existed so I looked it up.  Damn, $660 - out of my range!  I guess you must feel it's worth it.  Maybe I should try to find a strong amp used, it's tough though b/c they are still expensive and it seems worth it to pay a little more for a warranty.  Having tubes with unknown hours on them makes me feel this way more so than a solid state....

Ye its kinda expensive but its worth it. My previous amp was a little dot MKIII which was great at the price but the La Figaro is in a completely different league. You may also want to consider the LD MKIII as it fits within your budget. But if you are looking for a warmer sound the DV336SE is probably a better direction to go than the LD but if you want to do lots of tube rolling with different tube variations the LD is better in that regard. Up to personal preference really but they are the 2 most competitive tube amps within your price range that I know of.

 

[hauntingtheholy]

  Ye its kinda expensive but its worth it. My previous amp was a little dot MKIII which was great at the price but the La Figaro is in a completely different league. You may also want to consider the LD MKIII as it fits within your budget. But if you are looking for a warmer sound the DV336SE is probably a better direction to go than the LD but if you want to do lots of tube rolling with different tube variations the LD is better in that regard. Up to personal preference really but they are the 2 most competitive tube amps within your price range that I know of.

Cool.  I'm actually not too interested in tube rolling.  I'm hoping to plug the 650's into the DV336e (which is what it'll be, if it's the warm sound people say) and start enjoying it without any wanting, we shall see.    How much better is your La Figaro than the 336e?  Is it a situation where the DV336 is the Cake and the Figaro is the added cherry?  Or is it an entirely more bombass cake?  0-o

 

[sgbwill2]

  Cool.  I'm actually not too interested in tube rolling.  I'm hoping to plug the 650's into the DV336e (which is what it'll be, if it's the warm sound people say) and start enjoying it without any wanting, we shall see.    How much better is your La Figaro than the 336e?  Is it a situation where the DV336 is the Cake and the Figaro is the added cherry?  Or is it an entirely more bombass cake?  0-o

Never tried the 336SE but have read comparisons and the 339 is better, as to be expected with the price difference and use of better components etc. If you were to purchase the 336SE I would advise to upgrade the stock tubes as the chinese ones they provide are cheap and pretty terrible (the 339 came with cheapo 6as7's and 6sj7's and they were really bad). Even a cheap Svetlana 6h13c or RCA 6as7 and a cheap american or British 6sn7 would vastly improve the stock sound of the 336SE so I would advise at least doing this and if you decide not to tube roll the sound from these tubes would still be pretty good even compared to the really expensive tubes out there.

 

[hauntingtheholy]

  Never tried the 336SE but have read comparisons and the 339 is better, as to be expected with the price difference and use of better components etc. If you were to purchase the 336SE I would advise to upgrade the stock tubes as the chinese ones they provide are cheap and pretty terrible (the 339 came with cheapo 6as7's and 6sj7's and they were really bad). Even a cheap Svetlana 6h13c or RCA 6as7 and a cheap american or British 6sn7 would vastly improve the stock sound of the 336SE so I would advise at least doing this and if you decide not to tube roll the sound from these tubes would still be pretty good even compared to the really expensive tubes out there.

Interesting, I'll need to find another thread with subject "tubes" - perhaps.  As I don't know anything about them.  Don't seem people like the stock tubes?  @kramer5150 - whaddya think?  I'm the kinda listener who buys the cake but not the extra cherry, if that helps.  I plan on using the DAC on my computers soundcard (lotta folks on here would rather commit suicide than do THAT!  lol) and the idea of say, upgrading my HD650 cables for $80 will never even be on the radar, as far as I would think currently.  

 

[kramer5150]

  Interesting, I'll need to find another thread with subject "tubes" - perhaps.  As I don't know anything about them.  Don't seem people like the stock tubes?  @kramer5150 - whaddya think?  I'm the kinda listener who buys the cake but not the extra cherry, if that helps.  I plan on using the DAC on my computers soundcard (lotta folks on here would rather commit suicide than do THAT!  lol) and the idea of say, upgrading my HD650 cables for $80 will never even be on the radar, as far as I would think currently.  

I bought my 337 used with Tung sol 5998 and mesh plate driver tubes.  So I have honestly never heard it with the OEM Chinese tubes.  Its been a very long time since I heard a 336, IIRC it had RCA tubes.  But that was so long ago, it would be wrong for me to comment on it in any way based on my memory alone.   My honest opinion is that in stock form the HD650 and its warm/pleasant demeanor generally tends to mask and color a lot of the sonic attributes of whats upstream.  Its also a very efficient headphone and plays a lot louder than its 300 ohm impedance would lead one to believe.  Just yesterday I was listening to my HD650 straight out of my old Sony D335, and comparing that minimalist setup to my DAC + tube amps using the D335 optical out as a CD transport.  Despite the 300 ohms the HD650 had plenty of dynamics, volume and clarity straight out of the old player.  Not at all unpleasant sounding, or under amped in any way.  The tube amps most definitely do color the sound, giving it more "bloom", resonance and bloat.  Compared to the little CD player which is more "dry" and analytical by comparison.  Its a slight but noticeable difference with a lot of ambient + dynamic recordings.  With more compressed songs (wall of sound) however the difference is much less obvious.
 

 
 
Sometimes as enthusiasts and "tone chasers" (guitar analogy) we lose sight of whats important... enjoying the music. And that I think is what the HD650 really excels at, turn OFF the analysis and just immerse yourself in the tunes.

 

[geetarman49]

  My thoughts... (Admittedly NONE of which are actual listening impressions, so take this FWIW)
 
My main amp is a 337, which is basically a dual mono topography using two 336 amps in the same chassis... one per channel.
 
The little bear looks like its using electrolytic caps for output coupling.  Either that or some severely under-spec'd (in some way) wimas.  I would hope the latter is not the case.  An under-Voltage spec'd coupling cap reservoir failure on an output tube can fry your headphones!!   Electrolytics work fine from an amplification standpoint, assuming the value chosen is sufficient for the application.  In theory the caps V ceiling should be at least ~1.5x that of the tube plate voltage.  The total farad value of the reservoir should be sufficient for the 20-20k audio band, given the impedance presented to the tube by the headphone voice coil.  The capacitor in series with a voice coil create a first order high pass filter, so if the wrong mfd value is chosen it can result in a low bass roll-off depending on the impedance of the headphone.
 
The darkvoice (and sister company LaFigaro) designers spent a fair amount of time / energy / effort enhancing the output coupling capacitance aspects of the 336-339 amps as they have evolved over the years.  From an audio-fidelity standpoint, paper / oil audio caps are the way to go, not electrolytic (in many peoples eyes).  I think theres a lot of room for debate on this last topic.  There are some very well respected/liked OTL amps on HF use electrolytic coupling caps.  One things for sure, that open PCBA on the LB allows for some degree of DIY modding.  That aspect in itself I think is something that could tip the scale into its favor... if you're the DIY type.  "Buy low mod hi".
 
Those no-name volume pots are a real hit & miss in my book.  As a very low volume music listener, channel tracking linearity can be a problem for me.  I personally have never had a problem with Alps pots... for the $$ they are the way to go without going hog-wild ($$$) into step attenuator land.  I have several amps that use Japanese Alps pots and I have never had channel balance issues with any of them.
 
The main power supply resistors (the gold aluminum ones) in some iterations of the DV amps has been known to be a problem.  Where the designers under-spec'd the resistor values by a significant amount.  In these circuits they generate a TON of heat in the chassis that needs to be vented out.  I wonder why LB put them so far "inside" the layout and right next to the 6as7G tube?  If they are being asked to dissipate a lot of heat, that could be a problem.
 
LOL at the red electrical tape over the main AC.  Hopefully theres a fuse somewhere in there.
 
Whats the deal with the male/female connector on the AC main?... never seen that before.  I'd splice that thing out of there asap and point to point it wherever it needs to go.
 
Another concern could be earth grounding and EMI/RFI shielding running an open PCBA.  But that would depend heavily on ones noise environment.

for $140 delivered this (little bear p8) is a bargain.  but you are right, there is a potential for some issues.
 
1. this ships as a flat-pack so the final assembly rests with you.  & depending upon whether you choose top-side component or bottom-side component pcb, power routing will change. hence, this explains why there is a male/female socket between the ac main housing (iec) & the xfmr.  i.e. end-user will not be required to do soldering.
 
2. the iec assembly IS fused.
 
3. the xfmr assembly bolts to the acrylic (clear or red).  if you accidentally overtighten (like I did) you will crack the acrylic .... in which case you reach for the bondic or superglue.
 
4. there are 4 output caps, all 'lytics --- at the least, these should be bypassed.
 
5. the 4 red wimas are indeed 0.1uf/630v coupling caps --- these too, should be bypassed, if not outright replaced.
 
6. amongst my friends & I, (with at least 4 pcbs) we have not experienced any egregious channel matching issues ---> you do need closely section-matched tubes, though.
 
7. to my knowledge current pcbs do not use those gold-colored metal power resistors --- instead, they are green-colored carbon resistors of considerable size.
 
8. I have used mine for up to 8hr continuously while running burn-in tests w/o issue.
 
9. the stock tubes, esp the driver tubes should be replaced --- i'm using ge jan 5670w.  for output, i suggest rca 6as7g for those on budget, otherwise gec 6as7g.
 
10. I agree ... emi/rfi may be an issue ... but I haven't experienced it ... ymmv.
 
11. the open chassis is both boon & curse:  boon for those into modding & curse, because the 'chassis' is rather flimsy.
 
12. I experienced two issues with my 'kit', both of which were rectified by the seller.  the acrylic panel around the iec mousing was cracked and some of the standoffs were not threaded sufficiently deep to accept the interfacing standoff.  if you're into modding, you will need longer standoffs in order to accommodate large caps - these are readily available on the 'bay.
 
hth,
 


even w/o modding i would be hard-pressed to find an alternative otl valve amp for less that sounds as good.

 

[bala]

I am thinking about the P8 as well but the version with the aluminium casing! Could you care to elaborate on sound impressions, would be greatly appreciated.

 

[kramer5150]

Cool deal.  Under-spec'd components is the main concern with these "mystery-amps".  I'd keep a close eye on those carbon resistors, the solder flux residue there and at the 6as7 tube socket is starting to discolor and turn brown.  Hardly a worthy indication of anything... other than that area of the PCBA is getting some heat build-up.  Might want to relocate those to the tube-side of the PCBA, at least up there the heat can better dissipate.
 
Those blue bypass caps did those come with the amp?... or did you add those?
 
There are two versions of this amp one with a torroid another with a traditional laminated core transformer what is the difference and is one better?
 
EDIT... strange all the aluminum chassis models have been not been replaced on the bay.  There were at least a couple dozen of them a week ago, for around $150-170 free shipping.  Theres only one left now at $199 + $45 S/H.  At that price you're better off with a DV/LF 336.

 

[geetarman49]

  I am thinking about the P8 as well but the version with the aluminium casing! Could you care to elaborate on sound impressions, would be greatly appreciated.

if you are considering this unit w/o mods, then I would encourage you to consider the hybrid units offered by garage1217.com instead.
& if you are willing to mod, then I don't recommend the cased unit since it will obviously hinder the modding exercise.
 
stock, the unit is smooth throughout the midrange but with some lower end roll-off and some very mild upper mid to high grit.
a friend has devised a range of mods to eliminate all the issues that concern me, but I cannot post w/o his permission.
with these mods, I cannot think of a better all-tube amp for under $400 usd.
 
if you are seriously interested in this route, I will seek permission to relay the mods.  if you are not into soldering, then I would urge you not to bother (with this amp).
 

  Cool deal.  Under-spec'd components is the main concern with these "mystery-amps".  I'd keep a close eye on those carbon resistors, the solder flux residue there and at the 6as7 tube socket is starting to discolor and turn brown.  Hardly a worthy indication of anything... other than that area of the PCBA is getting some heat build-up.  Might want to relocate those to the tube-side of the PCBA, at least up there the heat can better dissipate.
 
Those blue bypass caps did those come with the amp?... or did you add those?
 
There are two versions of this amp one with a torroid another with a traditional laminated core transformer what is the difference and is one better?
 
EDIT... strange all the aluminum chassis models have been not been replaced on the bay.  There were at least a couple dozen of them a week ago, for around $150-170 free shipping.  Theres only one left now at $199 + $45 S/H.  At that price you're better off with a DV/LF 336.

1. I have closely examined the white tube socket in question --- just some excess flux.  the socket appears to be ceramic & is in perfect condition.  there is, as you say, excess flux residue & I have just been too lazy to clean it up.  I don't notice any real signs of degradation on any of the components themselves.
 
2. I chose the upside down pcb because I feel it is the better configuration for modding.
 
3. the 'blue beauties' were added by me - although, frankly speaking, the ones on the power caps are a tad undervalued.
 
4. at the time that (we) purchased from ebay, there was only the toroid.  as to which is better ... hmmm ... you DO know that this is somewhat of a loaded question.  in theory, with all things equal, e-i is usually selected for low-level applications (like dacs) while toroid for, say, higher powered amps.  but this is not a hard & fast rule by any means and there are numerous arguments either way.  at any rate, we (my friends & I) have no experience with the E-I unit offered on the little bear, but the toroid meets requirements and is not mechanically noisy.
 
5. knowing what I do now, I would order the pcb version w/o standoffs or acrylic plates for $35 and the separate xfmr for $33 and build/mod an open structure like my buddy did in the pic below.
 

 
6. the bear powers my akg k7xx mighty fine & has no probs with senn hd650 according to my friend -- sounds wonderful.  note: it will not power the he-560 properly.
 
7. I previously mentioned the issues I had with a cracked ac module and some standoffs that were not properly threaded.  going over some notes from last year, here are the other issues:
a) a couple of caps were not soldered absolutely flush to the pcb - this caused them to hit the acrylic plate which prevented a couple of standoffs from mating properly.  since I was intending to mod using much larger caps, this issue was rendered moot when I changed ALL the standoffs for much longer ones.
b) the 6.3v supply from the xfmr measured 7.1v   ...  a fair bit of discussion with the dealer and with my engineering buddies ensued -- not a critical issue
c) there was channel imbalance on my unit (& my unit only) ... after much trial & error, it was determined to be a tube issue.  the stock tubes were crap, esp. the drivers - the output tube is okay.  you need closely matched (sections) tubes here - ge 5670w to the rescue.
 
8. I have only done the 1st level of modding (adding the bypass caps) & have yet to do the following:
d) replace coupling caps with audyn true copper
e) replace electrolytic output caps with larger 'lytics bypassed with film/Teflon or replace with larger film/foil.
f) add resistors to increase bias currents.
 
hth,

 

[kramer5150]

Nice!!  Have you guys considered output transformer coupling for low-Z cans?  I do that with my 337 with my Grados and its a world of difference.  The TS5998 tubes just don't like to see low impedance loads.  I would expect the same from 6as7 and the 6080 tube your buddy is using.