Parafeed

Yes, I agree. But that's just the way it is. Even with companies like parceltogo.com which allow non-business customers to ship using DHL, etc. etc. at near to business rates, the default compensation level is £50. Then it's 5% of insured value. So you can ship a 10kg package from the UK to Germany for £15. Need to insure it for £1000, then add £50!

Yes, that's pretty much a representative cost from the UK to anywhere in the EU. I did say that adding insurance really does bump the price. Figure the insurance cost at 5% insured value - it's in that ball park. Prices are much, much cheaper for companies that have accounts with shipping companies. But private individuals do not have access to that.

A typical (UK) price for insurance would be £4.50 (GBP) for each £100 cover after the first £100, which costs £1.20. So insurance would add £37 to the intra-EU shipping cost. Don't know the dimensions of the box, or shipping weight of the DAC, (assuming < 10kg and not oversize), but I'd guess the shipping cost (intra-EU) without insurance to be somewhere around £15.

2 comments, not that I'm trying to put the dampers on this, but..... Shipping in Europe isn't that expensive until you add insurance. This bumps the price significantly. ISTR there was a requirement to insure for full value. Insurance for $1495 is really going to bump the shipping cost, possibly 2x or 3x what it would be without. Taxes.... Well, if the item enters the UK (from outside the EU) with an insured value of $1495 printed on it then it isn't going to avoid taxes. (Regardless of any labelling. eg. sample.) Having played the game with trying to reclaim taxes for an imported item that was returned to the manufacturer after 2 weeks, and the hoops that needed to be jumped through regarding documentation, I would suggest that either Neko is prepared to send the DAC with an insured value of $1 or the scheme is a non-starter unless someone is willing to take a hit on the taxes and fight to get them back.

LOL. But seriously, I'm surprised. Insulation can fail over time. That's a fact, it does happen. I've seen it on older gear. While it is extremely unlikely and CE certification or not, my common sense dictates that especially in this instance, (primary with high B+ and secondary connected to an object that is fixed to your head), safety is the only consideration, no matter how small the percentage chance of something failing! Why take the risk? (Even if Craig has listened with and without the secondary grounded, and deemed not to ground it for SQ reasons, I would hope that he is at least giving customers of this "floating" design a warning, even if he considers the risk infinitesimal, and the option of grounding the secondary for safety reasons.)

Let's hope that EC's idea of "floating" the secondary is not what we think it to be. The more I think about this, I can't believe that a commercial manufacturer, (even a relatively small boutique one), would do this. Craig is way too wise to do this. Although safety seems not to be taken as seriously as it once was. No names mentioned, but I have issues with people who should know better selling amps without a bleeder resistor to discharge the HT caps, or with an output plug instead of a socket, (exposed high voltage pins without the umbilical connected) on the chassis of a standalone PSU unit or better still, an amp that came my way last week for a mod - metal chassis, not grounded - earth tag on the IEC - no connection to it. That's one way to ensure your equipment doesn't have an issue with ground loops!

My own "experiments" with floating the secondary of a headphone amp transformer have shown no SQ advantage (that I could hear anyway) over grounding the secondary. I'm not sure how comfortable I would be with an amp, especially a 300B amp with a series feed transformer, high voltage B+ on the primary and the secondary not tied to ground. Regardless of the improvements in constructions techniques and materials, it makes me nervous. Not so bad if it is a parafeed configuration, where one end of the primary is tied to ground in any case, and of course there is the DC blocking cap, but series feed .....

OK, I understand that. cap/resistor rolling - that's not quite what I meant by design and component choices. For me the whole DHT headphone amp experience was a chance to evaluate DHT filament heating with AC, DC voltage regulated, DC current regulated and the Tent VCS module. The differences between "sound" when using various supply methods on the DHT filaments are not subtle, even more so with a headphone amp. Likewise, evaluating and tuning "sound" using a choke or CCS on the driver stage and grid chokes instead of resistors on the output tubes. Swapping a carbon film resistor for a tant, or switching one poly cap for the latest and greatest, currently being raved about cap, wasn't quite what I meant. That is the great thing about DIY, being able to experiment. But I take your point, anyway!

No problemo! Just throwing a suggestion out there and not trying to take your thread off at a tangent. One other thing that has got me a little curious and in no way is a criticism, but it seems that the way you work is that you take a design, buy the parts, build it and it's done. There isn't an intermediate stage where you breadboard and "fiddle" with the design and component choices before finalizing a build and punching a chassis?

Sorry, I was purposely trying to avoid hijacking this thread. Just throwing a suggestion out there having tried about 10 or so different driver tubes with the 307A last year. (I went through a DHT head amp "phase" before heading back to high gm/mu spud tubes, which is pretty much where I started.) My best results with the 307A were choke loading it, parafeed output with a pair of Peerless TL-404's, driven by a choke or CCS loaded 6H30. Tent labs filament supplies. Active grid bias circuit for the output tubes, rather than self-bias cathode resistor. Sources: Analogue: SME 30/2 turntable, SME Series V tone-arm, Koetsu Urishi cartridge Digital: Sonic Frontiers Transport 3 CD transport & Processor 3 D/A processor Digital: Logitech Transporter Phones: Senn HD-650's (a couple of pairs, one with Cardas cable which is normally my weapon of choice.) Grado RS-1 Grado GS-1000 ATH W5000 JVC HA-DX1000 (I think the above list of phones is correct at the time I was "voicing" and using the 307A amp.)

If you can, try a 6H30 for the driver, run reasonably hot, like 18-20ma. For a dynamic and fast sound, it can't be beat when coupled with a 307A. A perfect "foil" to the 307A which I found a little "understated" and "slow" sounding when driven by a 6SN7.

So the design is a Pete Millet (TTVJ) 307A, (or slight variation of), with a 307A driven by a 6SN7?

Why not? (Just curious.)

Thank you. I concur - both filaments are used! Glad we sorted that out. (Sorry, English humour! ;-) I have no axe to grind and I've never heard a one of his amps, but I have to figure his stuff must sound good, otherwise why would people put up with paying up front and waiting eons for his amps?

Did you ask Craig for a picture? I'm inclined to believe this (what with him being the amps designer) but without a picture we just can't be sure ....... ;-)

Pictures have nothing to do with this. ;-) I own a Zana Deux. I have drawn the circuit diagram. I have measured all voltages. I know for a fact that both filaments are powered on this unit. As to whether Craig may have only used one filament per 6C33 on units prior to or later than serial number 38, sure, ask Craig. Both heaters are wired on my unit. FACT.

Kevin, no disrespect intended, but I'm not guessing, I'm stating a fact! Let me say again, the Zana I have in front of me powers both 6C33 filaments. I don't need to email Craig for confirmation. (Serial Number is 38.)

Beg to differ. That's not the case with the Zana I have in front of me. Both filaments are used.

I think the circuit diagram is still on my work PC. Will try and find it tomorrow. I have various headphone amps - DIY and commercial. The two in current use are a Zana Deux and my 300B DIY amp. The 6SN7 SRPP amp is no more. The parafeed Sowter outputs were 'borrowed' for the DIY 300B amp. (Several amps were 'destroyed' for the 300B amp. The chassis belongs to what was a Chazz 6550 amp.) You can just make out the Sowters behind the 300B's and in front of the Llundahl plate chokes.

I made an amp that sounded rather good with HD650 a couple of years ago. 6SN7 gain stage, driving 6SN7 SRPP, with Sowter 8665 output transformer. I'll see if I can find the circuit if you're interested.

I just saw that and laughed out loud. But it's more sad than funny.

But you' ll have to run the central heating in the winter instead of just switching on the Zana! ;-)