The industrial design guy in me is dieing to see how he places the "7" on his logo/badge ... bet it's gonna be sexy.
Thanks very much for the reference to your description of tube-rolling. I enjoyed reading it.
Any information on Craig's timing? I don't want to drive him nuts, but I can't stop myself from emailing him about once a month; however, it's too early to send him the next request for an update.
TY. I can imagine a longish tube-rolling thread once people get their hands on this amp. Last I heard, he was finalizing the transformers, overall design, and the option set; all while trying to the price low. I just noticed this on his website:
***In August we will begin the run of the entry level 6SN7 headphone amp previewed at a recent Los Angeles meet. Look for it under meet impressions Venice Beach on head-fi.org. If you want to be included in the limited run, be sure to email Craig as the list is now forming.
Hi all, I did shoot Craig an email and will update whatever info I can. On the tube note we have run the Treasure CV181 on the driver and it worked great w/o issue. It simply wasn't the best synergy for the HD800. I have asked about other permutations up to and including 7 CV181s hypothetically and have updated further inquiries. This is the best reply I have based on my last inquiry a few weeks ago.
"The 6.3V heater windings are 3 amps times two. Separate winding for left, and right channels. The driver heater is regulated and will handle the EC32 .95 amp heater. So yes the proto can run 7 EC32, or CV181 tubes, however the gain bandwidth product will cause some loss in high frequency response.
The new Super 7 will support the EC32/CV181 as the driver, but the max heater current is 2 amps per channel so a standard 6SN7 or equivalent 0.6 amp heater is max for the output sections."
As it stands let's just say the Super7 is being put through the design wringer and is moving in a rather unique and innovative direction so I'm not sure how valuable any further input about the prototype might be. The inherent layout and design is intact but everything is being significantly refined. I will say it sounds like exciting stuff, no pun intended.
To clarify or expound on this question it's best to say the Super7 is better able to yield a more euphonic, warm and lush experience w/ a more satisfying low end response using the HD800. If you desire such a tube configuration. The BA will always be, for the most part, more accurate and refined. So the question is a matter of sonic preference rather than performance. I think Purrin will agree with this. What is remarkable is the level of performance for the price wrt the BA.
Remember, this is all related to the prototype.
To be precise, we were able to find a more suitable tonal balance for the HD800s on the Super 7 than my BA (with the Brimar driver and EML 300Bs). The tonal and overall differences were small. For most musical material, I would not be able to immediately tell the difference between the two if someone snuck in the Super 7 in place of the BA (as they were configured.)
As you know, the BA is not one of those "lush" tube amps. It is extremely resolving, neutral, and incredibly fast. But overall I would still favor the HD800 out of the BA over the Super 7 for these qualities. But I can easily see anyone going the other way as a matter of preference.
Some snippets from Craig:
"The transformers grew so large they take up most of the inside of the amplifier. I tried to make the amp as foot print friendly as possible. I think it is neat that it could be a desk top headphone amp run from a computer to drive speakers, and headphones. This is my first amp without the extra external power box, umbilical, and mess that goes along with that. As far as I know this is the only headphone amp with output, power, and inductor all on a double c core. The power transformer just doesn’t leak, one can’t even tell it’s on it runs quiet, cool, with zero emission. When you add up the innovation, sound, and cost the amp is an incredible bargain."
"the Super 7 will be a headphone amp with speaker outputs. The speaker outs are so quiet they can also be used as balanced or unbalanced line outs to drive other amplifiers."
Waiting on feedback about the 6SL7's and 6f8g's.
"The S7 driver is designed to use the 6SN7. 6F8G with an adapter which is equivalent. The plate resistor is 24K, and the cathode resistor is 1K, plate volts 250V less the drop across the 24K plate load resistor. The 6SL7 will operate with higher distortion."
I wonder if it would be possible to find a combination of tubes to make the Sony SA5000 sound good out of this amp. I've always been curious with that headphone.
Sure. How much foam do you have?
Anyone have new titbits about the Super 7?
All I have is that the originally intended transformers were not able to be designed to Craig's specifications and standards. He has since decided to go with higher grade transformers than those that were in the prototype but will have to pass on the increase in cost which translates to an extra $100. I haven't heard it yet and can't speak to how the sonics change but Craig says it sounds better and has superior square wave performance to the proto. Rather than keep the price point and produce inferior sound compared to the prototype he felt going the other direction was a better decision.