Icarium

That 308B amp is hot. What is that clear yellow thing in between 3 tubes on the front right. Flux capacitor?

Well the implication is that it has changed dramatically in a positive direction. I'm not disputing that per se especialy since I am a lay-person. Just that given that he is in the business I'd be curious as to what his perspective is. Those things you mentioned.. most of the more recent production chips I think are not necessarily a step forward. Upsampling from what I can understand jury is still out on as per whether or not it is an improvement... my understanding is that in most implementations you lose headroom as you upsample more. That is if I am remembering correctly... by quality of outputs do you mean hi rez formats? In another thread someone mentioned that a majority of modern DACs reclock the input signal now which makes jitter a non-issue.. I think that was more along the lines of what I am curious about. Essentially I've heard a lot recently about how much digital has advanced in the last 10-15 years, but I just have not seen a lot of explanation as to what in particular has advanced so drastically. Often times I assume that most electronics have changed a lot over time, but I was pretty surprised to learn that very few truly new tube amp designs have really been created in the last several couple of decades. Granted vacuum tubes arent as sexy as they were decades ago as digital must be now... but companies still are coming out with new tube amp products and I wonder if the main focus of research with regards to digital reproduction isn't slanted towards making things smaller and cheaper.

What DAC technology has changed dramatically in that same time period? Hi rez formats? Besides that what else? You seem to be a member of PS Audio so I'm curious what your take is. The digital link III is a pretty decent DAC indeed.

Pfft no way I was being polite.

Sure I don't mind. I of course dont have the capability to test it. Do you want to distribute cost across the group for the prototypes? Another thought is looser101 is close by so shipping costs (Or pickup) for him would be considerably cheaper if we are going to do multiple orders. Ideally that or another DIYer who might use transformers of this type in the future just buying it for themselves.

Hrm I'll have to check out CamExpert. Do you guys have a link to CamExpert and naamanf's place? Well I'll get some quotes from Plitron. It seems like transformers can be ordered further down the line so no hurry. But definitely try and move towards a consensus after the quotes are in. It sounds like dynafet boards will be ready to get a prototype made in not too long... what do people generally like for pcb makers. j4cbo says he's had good results with pcbfabexpress.

Ah that's pretty reasonable re: your guy. Maybe we'll do that. What about the holes for board mounting inside the chassis? Also with FPE do all panels have to be the same or can he accommodate for instance differences in types and number of inputs and outputs? I was looking at the hifi2000 cases and they have the heatsink on the side of the chassis already. Are there different heatsinks besides those and the ones on pcbs? Also what are angle mounts? And what does "tapped" mean?

Nah 14 period

The machine costs would be 99 dollars per person if they want as many holes as I plan on getting and we get 10 people interested. The actual machining cost per chassis is (If you want the number of holes I want) is 67.50. If you want less holes then it is cheaper. Basically use the conventions for estimated time per hole * 0.50 cents a minute to estimate how much cost your particular config of holes will be. The additional 31.50 is to cover cost of membership/gas/drill bits and other consumed tool bits/the 2 hrs of his time he has to spend taking the class to use the workshop. All those costs add up to 315 dollars so that will be distributed across all the people interested in this. If its only 5 people then it will be 63 dollars per person. If it's more than 10 then it iwll be cheaper than 31.50 per person. He is going to do that without any charge since I already am in the process of pirating CAD/Wildfire(?) for him and he doesnt mind doing it from the comfort of his home. Yeah given that j4cbo will be local and is doing my build I'll be coordinating with him very closely with regards to his I/O board and stuff. Moreover if etching/drilling holes can be done for cheaper by anyone else or a service that someone knows of I don't think either of us have a problem with going with them I am not knowledgable at all about this kind of thing so I don't know what's reasonable or what isn't. He knows more than me and thinks this is reasonable, but I doubt he knows really what's out there as far as DIY chassis work. He could use the cash, but he likes his social life too (He just got a job making 60k at my dad's company, and shortly thereafter the company announced that everyone needs to eat a 20 percent pay cut due to the economy). P.S. Yeah I really want laser etching too or whatever. I'll try and work with him to get it done. He said he might be more willing to do it like a month after he does all this stuff so he can recoop a bit but it would necessitate a second membership fee... and all that. It really is just a matter of time and money I guess.

K updating for you. Looks like we are already at 14 sowters.. what's the next price break lul.

Ah okay. Well I am of course not opposed to spending a bit more money on transformers to get the best shizzy. Really more the will of the group.

Okay my brother and I have priced out the chassis work. chassis pricing - Google Docs <- This is the spreadsheet as it stands right now. It is based on a rough preliminary version of the build I want which probably is more holes than most of you need. Basically he is pricing his labor at 50 cents a minute (30 dollars an hr). If it ends up taking a little bit more time than is estimated... and we imagine it will especially for set up. That cost will be covered and not passed on to you guys. He then gives a time estimate for each type of hole that I could think of. Obviously if you only need 2 rca input holes and only enough holes to mount 2 boards versus my fairly tricked out build then you will save significantly. If this needs to be updated with more types of holes then let me know. But if you are interested in his services then I would need to know of your interest and what holes you need drilled. Also he asks that we try and keep on/off switches to those of a circular shape. One time costs will be fairly distributed across all those interested. I priced this out to 10 chassis, but I imagine we'll either get less or more so cost will go down or up depending on those interested. I think he ideally would like to cap this out based on time. I think he is at most willing to dedicate ~20 estimated hrs to this thing. If any costs seem unreasonable to you we can discuss it further. He is flexible and isn't particularly trying to make money, but it is a fairly tedious effort and some sort of basic compensation would be nice (Which is kinda how we tried to price it). Also if time estimates based on your guys' experiences are inaccurate in some way perhaps you can offer feedback as well and we can calibrate it further to that. We probably will want to get at least 1 extra chassis just for him to calibrate and test things out. That will probably be a distributed cost as well. If it ends up taking a LOT less time or a LOT more time then costs may be adjusted... but you will be informed of this as soon as possible. Like if it ends up taking 10-30 percent more time either way then he'll probably just suck it up.. but if we are talking about like 2x or half as much time as estimated then some renegotiation may occur if that seems reasonable. Now besides holes.. laser engraving is a possibility as well. He estimates it would take ~15 hrs to engrave everything. He is not particularly willing to do 15 hrs on top of 20 hrs. Since laser engraving is mostly a set up and let it run type activity... if we can parallelize things then it may not be significantly more cost... but it largely is dependent on machine availability as he doesnt have dedicated access to all these machines (Other people will be using them and in fact it may be pretty busy on weekends). It may make sense for either me or j4cbo if this goes down while he is in town to also get access to help out. Like my brother says if he's looking at 10 hrs of labor for chassis hole making then he will be more interested and willing to explore laser engraving. He basically isn't really willing to spend 35 hrs on chassis stuff as that's like probably 3 weekends mostly dedicated to this. By the way you might see a class cost listed on the spreadsheet. Yeah he knows his stuff so it's not like that class is for him to learn how to use the machines... it is a shop requirement for him to be able to use the machines. It's a 2 hr class. If we do laser engraving he will be forced to take a 2 hr class for that as well. Anyways any feedback is of course appreciated Everything is negotiable to some degree.

Updated. Starting to include sowter transformer info as well so if yall could start thinking about how many of those you want (Including 0) that works as well.

Okay cool I'll add that to the spreadsheet. I think I need 2 pairs as well for me and j4cbo.

Hrm the SumRs you have are they shielded? I was basically operating under the assumption the shielded ones would not have a problem with hum. I have no problem contacting plitron and figuring things out there as well. Someone mentioned that they might have a quantity requirement but if we can hit 10 pretty easily then that shouldn't be a problem. I am leaning towards getting a 200-230VA one for my 4 board build, but I'm curious to see what values others want as well.

http://www.head-case.org/forums/casino/5732-group-buy-dynafet-contd.html#post208187 Okay as promised here is the thread specifically tailored for group buy discussion. The reason I separated it out to a different thread was to avoid it being mired on page 23/24. Please read it over and check the spreadsheet. If your name is not in Bold or in the appropriate section please let me know asap. Bold means locked in and ready to commit to the initial dynafet transistor buy. Out means that you've pulled out. Thanks! Btw some of you might notice the second spreadsheet. I have created that for organizing who is populating who's boards. If people are comfortable with it then I'd like to put at the very least what state people live in so we can coordinate shipments and board population in a way that makes geographical sense. If you guys are extra comfortable with zip codes then I can also use that to estimate shipping costs accurately when it comes time for that without relying on an exchange between me and you. What would be awesome is if some of you (Like Dreadhead/vvs_75 or Team Spain though they won't really be interested in group buys past boards/transistor) are close enough to receive a single package for multiple parties. That will definitely cut down on confusion/shipping costs/packing pain.

Er isn't the MSRP of the DAC3 like $2495? I might not get too hopeful that that's inside this.

Noise I don't know.. maybe j4cbo could comment. Complexity-wise it'll just be another board, but will require smd soldering. I think our builds are going to be 4 dynafet boards, a micro controller board, 2 sigma22 boards. Ah cool Nate! Thanks for hooking that up. Yeah I'm guessing we'll go the pre fabbed chassis route.. custom just seems too high, but eh we have time to figure that out.

Input selector schematic.... one half of his uber micro-controller board.

Okay here's what I propose. We keep the group buy for now to boards, board parts, sigma22 boards, sigma22 parts, SumR toroids, Sowter transformers. Chassis, other boards, volume control and other parts will come later. I will at the very least organize the toroids and the sigma22 board buys (amb is local to me so I can just pick them up and mail them). If I can float it then I would be willing to kit out the sigma22s as well by picking up parts (If this requires matching then... yeah nvm I can't do that :/). If I can float it I can cover the dynafet boards too. Luvdunhill will be in charge of organizing the dynafet transistor effort. After we figure out who is buying what I will try and figure out a money exchange scheme that makes the most sense. I think it'd be best if we distribute money to the procurers after all procuring is paid for to figure out the path of least fees, but that is highly dependent on if procurers can afford the initial hit and if they feel comfortable with doing so. I personally am as long as I can afford it. I am also willing to accept money order or personal check if the payer wants to minimize fees. So if people feel comfortable with everything I propose then I will start a new thread to figure out who exactly is opted into what. Hopefully we can lock in the people who are still interested within a week and begin ordering things that it makes sense to order. Please give me any feedback ASAP and tomorrow I will begin a new thread with an updated list of what people seem to be interested in and if people could confirm that they are still interested in that thread. Please really think if you can see this through as I really do not want to eat the cost of stuff if people back out. For non-DIYers who do not have someone to do the full build for them our esteemed board layout meister j4cbo has offered to do some full builds in order to subsidize his own build. There are still 1-2 spots available. Please PM me if you are interested and we will figure it out. There will be more spots if people are interested in single ended versions (Less labor). I need to have an answer within a week or whenever we lock down who is interested and begin making purchases. This is the general design of what the end result will look like. The result will be something like this: - Volume control will be a resistor-ladder based attenuator, similar to the Joshua Tree, of his own design as well (to keep board count low). - Sowter transformers as previously mentioned for unbalanced to balanced input and vice versa (2 are required, left and right). - Front panel user interface will be with a rotary knob and VFD display; this will allow input and output selection, thermal and power monitoring, and volume control without cluttering up the front panel. -Two chassis or single chassis. -Number and type of outputs... flexible. -Number of inputs is also flexible. -We can discuss other features, but some may get veto'd due to difficulty and anything extra fancy will cost extra. He estimates that cost without chassis will be between 1050 - 1350 for a balanced dynafet. Let's just round that up to 1500 for unexpected expenses. If two of us take him up on his offer and we completely subsidize his cost we'd be looking at paying 2250 each. If 3 of us enter this then we are looking at 2000. This is without chassis. He may have more slots if people are more interested in single ended versions. Parts cost for that without chassis will be ~600 dollars and amount you are subsidizing will drop accordingly. Now chassis options are this we can either go with something pre fabbed like this: modushop.biz and having my brother machine any holes we need. He is willing do to this very cheaply (Possibly for some subsidized parts for himself), But a 1 month membership to the machine shop s $125 dollars. TechShop is the SF Bay Area's Only Open-Access Public Workshop -- Start Your TechShop Membership Today This cost will be distributed as well. If we decide to go this route and DIYers are interested as well then he says he could probably easily process all the chassis we need in the space of a weekend. The only tricky thing is we might need to order some extras just in case something happens. Like probably one to test on and possibly a couple extra in case some get damaged in route or they get damaged in our possession (I don't know, but given that company is out of the country... ordering some backups just seems to make sense). The other option is to design something completely custom and he would be willing to machine this as well. But if we do this then cost could be pretty expensive. It'd be 150 for raw materials if we go with a thicker plate chassis... less if we go with sheet aluminum. Then he'd want something for his time as well and the limit would probably be ~5 chassis as it would take quite a bit of time to machine this. We could also anodize which he estimates to be 200 for a batch (Distributed across 2-3 people at the least). So really it's what you want to spend for chassis but expect to spend ~150 at a minimum for a single chassis and 300-400 if you want two. If we go custom then he estimates 300-400 per chassis if we go with some thing simple. Probably closer to 300. So we are looking at basically 2500 - 3000 for a pretty pimped out build. It may cost less or it may cost more. No guarantees at this point in time... we will be very transparent with where money is going and why it is needed. If you want to skimp to save money then that is perfectly workable. Timeframe is this. j4cbo is pretty committed to getting everything done by the end of 2009, but there can be no guarantees. This may push well into 2010. He is coming to Mountain View during the summer for an internship which is where my brother and I live so depending on our free time we can push this project pretty hard during the summer. Summer completion is.. possible, but do not count on it. What we'd be looking for as partners in this.. people who can afford it and are absolutely committed to not flaking and seeing it through. There can't really be any refunds. The end result should be pretty glorious though.

That foil on one dac chip cover is really bizarre though.

Yeah this is what I'm angling towards as well. If things could still be designed (I think the main thing is where holes are drilled in the chassis and where holes are drilled in the boards) to fit this spec.. then I think it won't be a 100 percent a lost cause for non-DIYers. If it can be designed in a way where you simply screw in some boards and connect some wires (This will probably require soldering)... then either I can figure out how to do this myself or have a family member do it. But this would require buy in from the group and someone willing to do the chassis leg work with figuring out where to generate holes and to have those holes generated. If this is too much work for anybody to assume then I personally will be happy and satisfied with populated boards and whatever other group buys happen. I will probably have my brother do the machining on the chassis. Also I think the relationship you have with PICAudio is great. If I didn't live in a different continent I would probably be pming him right now to try and arrange a similar relationship. Another option is maybe we can approach some of the semi-pro guys more local to us to do a similar thing as PICAudio... like MisterX or Thrice? Still though there are no guarantees and I think a non-DIYer should go into this with the knowledge that there is a risk that you will end up with just populated boards and some other parts unless they secure someone to help them with the rest. Anyway... if we stick with the luvdunhill vision though of something that might be assembled even by a non DIYer that is willing to spend some effort (Like 5x of putting together a PC) then shrug... that's $$$$$.

The Assemblage 3 had a mod that uses the DF1704 in a little board. I pulled it out and put the PMD100 back in. The UX-1 may use the DF1704. The D70 I know has a PMD200 in it but it may have a DF1704 as well... I know it doesnt use the PMD200 full time I don't think and may only use it for decoding HDCD. The Assemblage uses the PMD200.

Yeah I didn't think that was your intention I was only offering my conjecture. I love the PCM1704 myself. I own 4 sources that use it

They aren't the first company to take a possibly backwards step.. I don't really understand why Spectral would go from using Ultra Analog parts to the delta sigma AD1853 which I believe is the same chip they use in the benchmark and the apogee rosetta I believe... Who knows Despite that though I'm sure the SDR-4000 sounds pretty awesome as DAC chip is only like 1/3rd of the puzzle at most with I/V and analog output stage being pretty key.. as well as digital filter. That being said that PCM1704 is probably just as good or nearly as the Ultra Analog part. As is the PCM63. These "vintage" chips (PCM1704 is still in production) are still very competitive. Still, I think the only clear "upgrade" feature is that the PCM1704 is the only mass produced resistor ladder (R2R) dac that will do 24/96. The PMD100 does not do 24/96, but the PMD200 and numerous other digital filters do. This is possibly why made the change. Dunno. Did you get a chance to stop by Goodwin's yet Mr. Pak?