recstar24

Rob I don't know your amp but in the 300b amps I have heard the EML 300B have always sounded better to me than the WE300B's. The EML has the same midrange richness and tonality but is much more extended on the top and bottom and a bit more transparent as well.

awesome.

I'm tethered! Cooooollllll.....hope I don't get charged extra for this EDIT: Surprised how fast it is. Considering how buggy my comcast modem and netgear router can be, plus how old the network card on the laptop is, tethering may be a feasible option for me.

Nowhere NEAR what the AVVT had. The EML's are much more reliable and stable. I have been using my EML 45's for over a year without a hitch and expect them to last at least another 5-10 years. I don't think any of the new companies can hold a candle to NOS American and British but of the new tube companies EML is one I trust, Shuguang from China is another one.

Be very careful with the AVVT tubes because they have reliability issues, you are much safer to go with EML, same thing as falkon above just posted. You'll notice the build quality on the AVVT compared to EML is much worse. I had on loan a set of the AVVT 2a3's and they would actually arc on power down, sending a huge pop through speakers/headphones (and actually blew out one of my original cicada drivers).

Which one are you referring to that sounds better, ZD or ZDT? (Excuse grammar nazi for coming in as the pronoun "it" is not clear enough:p)

I believe that the ZD/ZD SE also measures better as well. In the same review I mentioned Craig stated "The Zana Deux distortion, square wave response and bandwidth are better than any transformer-coupled amp." I haven't heard the ZDT but would imagine it to provide similar performance. I think if your happy with the ZD then that is just fine, unless you specifically needed the extra power.

The only thing that I have read about a tube design with actual published specs and measurements that seems to even come close to solid state stuff is here: Axiom Project Doug I sent you a link to that a while back, I would love to hear your comments. Some of it I believe you already agreed with, specifically the idea that tubes should be operated as constant current, variable voltage devices. The axiom uses plate choke loading where you have used a CCS for my amp and some of yours, I think a choke however has some non-linearities towards the extremes of the frequency response. I wonder what your thoughts are on his claim about the use of diodes in the cathode circuit reducing distortion. As for tubes vs. transistors the only applicable thing to this thread I can add is that when I asked Craig about it when I reviewed the original ZD, he felt that tubes captured the signal transfer characteristics that resembled music much better than transistors. He also said that if you were to compare the perfect output transformer to the perfect output coupling cap the transformer would be better due to lower source resistance, better drive and bandwidth and less loading of the tube. In the real world that is not ideal especially SE because SE transformers need big cores to allow DC without saturating but big cores means not as good coupling between the primary and secondary, and doing both is very hard and expensive. Good coupling caps with good dissipation factors are much easier and cheaper to build but some people's ears just tune better to one or the other. Again this is for SE pushpull is a different story.

As in the John Grado family? Or the John Grado family of custom headphones that sound good with bowls that don't drill your ears with piercing treble?

ALO Amphora;D

It was initiated by Lebron - he directly asked the Nike reps to confiscate the tape. He is really just a young kid asshat like on headfi:palm: He showed his true colors by not bothering to congratulate any of the magic players. Great role model there for young kids buddy.

My HF-2s are charged and shipped! Woohoo, can't wait for my F1's to arrive, away with you blurry correct spelling HF2's to Beely:basement:

That is the one Jacob just posted, which he just clarified is works for 3.0, thanks!

Does anyone have a link or can help with tethering for 3G with 3.0 OS for ATT? The link jacob posted was pre 3.0 and I guess it is different for OS 3.0 as tethering is already embedded in the software. EDIT: If anyone has recs for screen protectors and/or cases that would be great. I prefer the slimmer, polycarbonate/rubbery types vs. the hard metal bulky types.

Being a Chicago Cubs fan, I just realized that blaming Les for the HF2 lettering debacle is similar to to the reaction that Steve Bartman got for interfering with the foul ball that somewhat led to the breakdown in a clinching game of the 2003 NLCS. If only Bartman paid some freaking attention and let Alou get a honest attempt at the ball, maybe Cubs make it to world series. If only Les shut the hell up maybe Grado keeps the original engraver and there is no lettering mistake. Most people don't like to mention how Prior, after the Bartman interference, completely lost his cool on the mound, losing his pitch control and giving up the string of hits that would eventually lead to Florida taking the lead in the 8th. or the blatant error from Alex Gonzales at Shortstop who normally was golden glove solid at the position on what was a routine grounder. Obviously Grado should take the major of the blame here and not Les; but it cannot be denied the apparent cause and effect relationship that is perceived from the community regarding the lettering debacle. Though its fairness is debatable, I do believe Les Garten will forever be known as the one that led to the lettering debacle though some weird twisted cause effect alignment of the stars fate sort of way. At bare minimum he deserves a custom title:p

Word.

Maybe its supposed to be Head-F1 = HF1, an allusion to the previous HF1 series and now the HF2, so that the legacy of the HF series will always be present regardless of what headphone you have.

Well, my fault for not taking a plane to CanJam. At bare minimum Billy could have picked up my pair, arg.... I just called Todd and told him that I still want to keep my order. The 1 doesn't really bother me. I am just happy that John and Todd even bothered to release a special grado headphone. I think there are more important things to bitch about IMO. You have to admit the 1 does add a bit of character, and will lead to a fun little story and conversation when I talk about it with the kids in the future:p

Just a quick update. Snubber caps were placed across the diodes in the power supply to block out any switching hash that might be getting into the filament supplies. Heat sinks were "creatively" attached to the cascode mosfet in the CCS for the input/driver tubes to help dissipate heat. As an extra precaution fuses were placed in series with the plates of the output tubes - if the driver stage fails or something happens to make the bias run away on the output tubes the fuses will trigger saving not only the tubes but also the output transformers as well. Only sonic thing I can add is how dead silent in terms of noise and has the amp is. With my shure se530's plugged in and the volume pot maxed, there is not noise or hash whatsoever. Before there was tube hiss around 12 but nothing serious and definitely not part of my listening volume, but considering the IEM's are pretty sensitive is even more impressive than before.

Thanks JP - I know you were a part of the decision making process for CanJam RMAF and thanks for clarifying your viewpoint. I guess I am just personally skeptical about how speaker people view headphones in general ("ipod" users, not serious or real audiophiles, headphones are toys, etc.), and would hate for the event to dilute the impact that CanJam Chicago could have. If CanJam RMAF is able to suck in some new blood for the headphone community as well as for Canjam Chicago then I think that would be a sign of success.

I am with Dan on this one, and pretty much everyone from the CanJam Chicago team is on board as well with that viewpoint. It's really a preference in philosophy and scope, but it has some pretty major ramifications for the future. Also, from what has been communicated, the "CanJam" at RMAF will be in a separate room of itself, about 12,000 sq. ft., kind of a subset to the traditional RMAF area/sections. At least in terms of venue space, CanJam Chicago's proposed venue dwarfs even the RMAF proposed space and would be the largest venue space of its kind for CanJam weighing slightly under 20,000 sq. ft. (as long as contract negotiations are coming along Jim over two full levels. Yet CanJam Chicago would be devoted purely to the headphone community and not simply operate as side action to the "real" speaker exhibits at RMAF. I would hate for the many vendors that would have loved to be at both "CanJams" but not can only afford one, so they choose the RMAF one. Or perhaps that many west coast members who would have loved to come out to Chicago but now with "CanJam" at RMAF being closer they devote their dollars to go there instead, as well as anyone within that region. Hopefully our goals and vision for CanJam 2010 won't be affected too much and I will remain optimistic.

Excellent Billy, you rock.

I got my iphone last week and finally figured I could actually join this thread...whoa is it huge I need to try and print stuff out to read over vacation:D If someone wants to take pity on me and spoon feed me the basic gists of what I should know/have on my iphone 3g like all the cool kids that would be great.

x3

I just wanted to chime in and say how excellent Doug is. II emailed him a while back about my amp and seeked his opinion on what he saw with the schematic and my description. The man seems to have a very thorough understanding of tube circuits and maximising performance. We got together for him to check out and implement some of the things he felt needed addressing. This included bypassing the cathode bypass caps which were electrolytics with some obbligato films. Doug measured voltage levels and made sure that generally speaking things were running to spec as I had concerns of resistors and caps drifting a bit and whatnot. Doug saw the biggest improvement in my amp to be the input stage, and I agree. I have always thought that Craig with his designs could have delved more into maximising the input stage. The majority of his amps lean on using the 6SN7/6Sl7 resistor plate loaded into the output stage, sometimes with a cap sometimes DC coupled. In my case with the 6J5 though the amp has never disappointed me I always felt and heard that the tube was not running optimally, and never was truly driving the 2a3 or 45 as well as it could. After almost a year with the amp the sound manifested itself simply as a traditional, SE DHT type of sound, a slight softness to tone and just a lack of pop for lack of a better word. Doug sent me some info and links as well as his own experience with using an active load CCS for the plate of the input tube 6J5 (specifically a depletion mode cascoded CCS I believe). I felt this would be a step in the right direction. An led bias was also put in, and current was doubled running through the tube to operate it in a more linear part of its curve. Other than cool red LED lights popping through the hood and portholes I am pretty giddy and startled at the results. More gain for one thing, which was very noticeable on speakers, and a sense of more focus and definitely more clarity. The proverbial "wiping another layer" of grunge that exists in our audio path. The amp was quiet before but I do notice that there is a sense of vividness and contrast that I don't think was there before. I am looking forward to living with the tweaks a bit and just soaking it in and enjoying the music. Doug was really nice and gracious with his time and thoughts, and he is just a super nice laid back guy. In fact we have other ideas and thoughts for the next time we get together, he truly is a perfectionist and he seems to be able to see lots of different angles on how to approach things. The amps that he built, especially his espressivo, are fantastic. That little balanced mosfet follower he has sounded great.