Not to hurry on my my account!! I got the baby singing allready😀 Man, it sings allright🙂
I dont think anyone cares, but here is a pic of my birdsnest "mock-up" of that preamp🙂 It is a totally DIY thing. Well take a look at that trafo right next to the volume pot!!! I mean, there is no noise at all!!!! Who would have believed that??? The volume pot is a 4 deck Elma, to handle both positive and negative signal🙂 Normally the trafo position would give me more grey hairs than I have allready😱 But no need to on this preamp🙂 As I said, it is one of the most quiet preamps I ever heard🙂 🙂 I only hear the noise of my poweramp, (which is supposed to be nonexcisting😀 ) Or I was just lucky with the grounding scheme😎 Here you go with the pic.
Steen🙂
Attachments
Although the X-feedback provides no benefit in the SE in to SE out configuration, the cascoding of the FET's will substantially lower the distortion and increase the high frequency linearity in all combinations of SE/BAL input to output.
By the way, Steenoe's observations exactly mirror how I perceive my pre to behave. I find there is a very synergistic match between this design and my Aleph-X's.
Steen, glad you are happy with it!
Cheers, Terry
Ok, so I'm getting my A** in gear for the parts kit. The BOM so far is attached.
MKPs are Jantzen from PE. Fets are all IR. Possibly matched.
Goal is a solid baseline kit to keep or build upon, but not break the bank.
Let's start talking...
MKPs are Jantzen from PE. Fets are all IR. Possibly matched.
Goal is a solid baseline kit to keep or build upon, but not break the bank.
Let's start talking...
Volume Pot
Dear Steen,
Would you give more detail information and where to buy ?
Thanks !
Thomas
Dear Steen,
Would you give more detail information and where to buy ?
Thanks !
Thomas
Hi Thomas. I bought mine here in Denmark. The shop is the link below. Unfortunately the homepage is not in english and a bit hopeless also. It hasn't been updated for a long time. I guess the best way is to drop them an email. They do have small pcb's for the attenuator, though. They had two types at the time I bought mine, one with normal surface resistors and one with smd's. I have both and the attenuation curve is best on the smd type. Mine are 10K. If you want other impedance's they have the pcb's without resistors also. The surface resistors on mine are the old green Phillips ones, which I like a lot.
http://www.aanielsen.dk/
Steen🙂
http://www.aanielsen.dk/
Steen🙂
Member
Joined 2002
steenoe said:
I like the transformers 😀.. looks good. Are we going to do a group buy on the boards soon and parts ?
So, as an informal poll, how many people would be interested in a kit to go with the boards sets? Just wondering if I should bother.
Now that the board layout has been tested (thanks again Steeno), we will be taking pre-orders on our page in the next day or two (I'll post here when the page is ready). It's just easier for us to track then a WIKI.
I would be interested in a full kit actually. It would make my job easier and keep shipping cost down for all the parts 🙂
Brian,
1) What is the cut off date to show interest in purchasing the boards & kits?
2) What time frame are we're looking at to get the kits?
I wanted to decide when I should drill the holes on the chassis that I have built so far. Should I drill it per Kari's board or your board? You know the story.
1) What is the cut off date to show interest in purchasing the boards & kits?
2) What time frame are we're looking at to get the kits?
I wanted to decide when I should drill the holes on the chassis that I have built so far. Should I drill it per Kari's board or your board? You know the story.
Okay, here's how we are envisioning the order of operations:
1) I get off my butt and get the preorder page going on our site. (Should be tonight or tomorrow).
2) We make a guess based on how many pre-orders we get of how many boards we should order, and how many people want kits (non-scientific method of extrapolation). This also gives us a little more seed money for the board order.
3) Once we get 14 board pre-orders, we order boards.
4) I order all the parts and make kits like mad.
5) During 3 and 4, we continue to take pre-orders.
6) We ship all boards and kits ordered to date on the specified ship date.
7) We continue to stock and sell boards and kits until we either die, or our wives get sick of it, which could be the same time.
Now, ship date...
Boards will officially take 4 weeks from order to arrive. It's actually usually more like 3, but we will say 5 weeks to allow for wierd things which can happen, but it will likely be sooner.
So, official ship date will be 5 weeks from #3, but likely sooner. We will ship as soon as we are ready. Parts are usually much faster.
Boards will be 2oz copper and come in a set of 2 PS boards and 2 Pre boads (dual mono set).
More on parts kits:
Parts will likely not include a transformer, however, as they are quite heavy and tend to blow shipping. Might offer them seperately if I find something cool. I may also offer a heatsink for the FETs, but as an seperate option.
Kits will include all electronic components to stuff the boards, along with standoffs, screws, fastons, etc. All fets will be new IR parts. EL caps will be Panasonic FC. All .25w resistors will be 1% metal films. Larger resistors have not yet been decided. See the BOM I posted for some more information. Still looking for feedback on that, BTW.
1) I get off my butt and get the preorder page going on our site. (Should be tonight or tomorrow).
2) We make a guess based on how many pre-orders we get of how many boards we should order, and how many people want kits (non-scientific method of extrapolation). This also gives us a little more seed money for the board order.
3) Once we get 14 board pre-orders, we order boards.
4) I order all the parts and make kits like mad.
5) During 3 and 4, we continue to take pre-orders.
6) We ship all boards and kits ordered to date on the specified ship date.
7) We continue to stock and sell boards and kits until we either die, or our wives get sick of it, which could be the same time.
Now, ship date...
Boards will officially take 4 weeks from order to arrive. It's actually usually more like 3, but we will say 5 weeks to allow for wierd things which can happen, but it will likely be sooner.
So, official ship date will be 5 weeks from #3, but likely sooner. We will ship as soon as we are ready. Parts are usually much faster.
Boards will be 2oz copper and come in a set of 2 PS boards and 2 Pre boads (dual mono set).
More on parts kits:
Parts will likely not include a transformer, however, as they are quite heavy and tend to blow shipping. Might offer them seperately if I find something cool. I may also offer a heatsink for the FETs, but as an seperate option.
Kits will include all electronic components to stuff the boards, along with standoffs, screws, fastons, etc. All fets will be new IR parts. EL caps will be Panasonic FC. All .25w resistors will be 1% metal films. Larger resistors have not yet been decided. See the BOM I posted for some more information. Still looking for feedback on that, BTW.
Russ (EDIT- and Brian), can you post the part ##'s of the connectors you are using? It takes forever for me to go through a catalog, find a header, find the plug that fits, and then find the crimp pins that connect to the wire.
I'm looking for something multi-conductor with variations for 2-9 positions. What are you using?
I'm looking for something multi-conductor with variations for 2-9 positions. What are you using?
For the poll,
I'd be interested in a full dual-mono kit (possibly with that heatsink option depending on the cost of the sinks). I'll likely do a pre-order as soon as you get the page up, assuming the cost isn't way more than what I'm expecting.
I'd be interested in a full dual-mono kit (possibly with that heatsink option depending on the cost of the sinks). I'll likely do a pre-order as soon as you get the page up, assuming the cost isn't way more than what I'm expecting.
Brian, the contents in that BOM, are very well chosen. I used parts in similar quality/pricerange in the proto I made, and the preamp sounds very good🙂
If you wanted marginally better sound out of this pre, the price would go crazy.
Those blue Panasonics just look cool😉 As for R1, R2, R6, R7 I recommend to raise those a bit above the board as they run hot.
Dont try 2 watts for those as I started with
Except for Q2 in the power supply listed as a IRF610 (its a IRF9610) It looks pretty good to me🙂 But I mentioned that allready. If you want to go into details, D4 is listed twice in the preamp list, one of them D4's is D5.
Steen🙂
Brian
Could you please indicate where to connect a 10K pot for unbalanced in and out operation in the schematic of post #166.
In advance thanks a lot 🙂
JC
Could you please indicate where to connect a 10K pot for unbalanced in and out operation in the schematic of post #166.
In advance thanks a lot 🙂
JC
Not really my area (not my schematic). I think you'd just add it before the inout or after the output. Singal to one end, ground to the other, and tap off the wiper.
For the BOM, I did some quick pricing thins morning, and it looks like the parts kit will come in around $120 for a complete dual-mono setup (parts for 2 pre and 2 PS boards), not including the boards themselves. Again, this would be everything to stuff and mount the boards. I still need to find a part for the 1uF film on the PS board, but that's not a big deal. I will also match the pre- FETs if people want that.
Also, for the 3W resistors, I was planning on using Panasonic Metal-oxide 3W jobs. Any comments/feedback/thoughts on that?
We have a RFQ into Avel for a price on a 20x4 (160VA) trafo as well, just to find out. That's give .5A per secondary, which should be plenty.
[EDIT] Datasheet for the resistors: http://www.panasonic.com/industrial/components/pdf/AOA0000CE18.pdf