This is a site for the group buy of boards for a Krell KSA 100 Mk-2 Klone. You will need one board per complete channel. There are no output boards made as part of this pcb!!
I am locking up the G.B. as of tonight as the quote I have is for 200 boards and we are at 180 now... a few extras will cover any problem boards that might arise. If you are a late commer please add your name below the closed typo and if none of the extra boards are needed thay will be sold to those that sign up on a first come first serve basis.
Boards are $19.00 each U.S. funds. I will ONLY accept payment by
PayPal! No Exceptions... I had a number of foreign bank checks from the last G.B. that my Credit Union would not accept and I ate... I am not going to open a Bank Account for just a few checks... I hate banks as much as the rest of you do! If you don't have a
PayPal acount please set one up. If you can't set one up perhaps a friend could help or perhaps someone else here could launder the $$ to me for you.
Boards specs are to be: .093 thick G-4 fibreglass, gold plated traces, blue solder mask, white silkscreen on top only.
Board payment is to my
PayPal Account: cinerama84106@yahoo.com Please add3% to cover fees. This is the same account used for the KSA-50 G.B.
I cannot cover this over $3,000.00 board order myself but I will cover some of it if need be to get things rolling along. When I have received 2/3 of the total payments I will order the boards with a 4 week turn around. Sometimes the board house will do a 2 week for the same price as a 4 week so if thats available I will get it in two weeks. I will post here when 2/3 of the money is collected and the boards are ordered. I will order the boards pre-paid from the board house just as I did for the KSA-50 G.B.
Shipping to all U.S. locations is $4.95 by Priority Mail. Foreign shipments are $9.95 to all locations except Italy which requires a special envelope shaped like a Ferarri... The cost for that is 3.00 on top of the $9.95. Since I am an honest guy and I don't want the Feds knocking on my door I will fill out all customs forms LEGALLY! This probably means that on foreign orders you will have to pay for any duties and taxes. I WILL NOT WITE GIFT ON THE CUSTOMS FORM SO DON'T ASK!!!!!
Any excess funds to be donated to DIY Audio. If I could sell the 90 or so KSA-50 boards I'm still sitting on I'd donate that too!
_________________________________________________________________
- CONSTRUCTION INFORMATION***
- The thread is located here:
https://www.diyaudio.com/forums/showthread.php?s=118d334b2d292364d34bbdebdb5f5e39&threadid=78129&perpage=10&pagenumber=1
- The schematics are located at Lloyd McLeans? web page. Scroll to the bottom and download all the KSA-100 MK-2 stuff, enjoy the nice photos of one being restored while you're there!!
https://home.ca.inter.net/~lloyd.maclean/Krell/Krell.htm (The schematic was removed)
New Schematic link:
https://www.diyaudio.com/forums/attachment.php?s=&postid=1420922&stamp=1202271617
- The latest Bill Of Materials plus an extensive Everything You Need To Know About The KSA100 Clone Was But Too Afraid To Ask section. It's not the basic assembly instructions, but more directly applicable to the KSA100 Mk2 and the boards and can be seen as a paraphrased version of most of what has been covered on the thread so far.
https://www.diyaudio.com/forums/showthread.php?postid=1072173#post1072173
- The KSA-50 wiki can be found here:
https://www.diyaudio.com/wiki/index.php?page=Building+guide
Many guidelines and tips from the KSA50 project are relevant for building the KSA100.
Another option would be to try the Diycable transformer model UCD400: 1000VA, prim: 0-115-230V sec: 40-0-40V @12A, 13-0-13V @ 1A, 0-16V @ 1A
This transformer sells for as low as $ 88.00 Could be worth to try it? Link to UCD400 here:
https://www.diycable.com/main/product_info.php?products_id=597&Cid=10837a22828516e8e5961976a49e1892
Price quotation from Avel Lindberg was � 155.00 each for a minimum order of 5 (5-29 units) of the original Krell transformers (summer 2008)
- Which MOSFETS to utilize as suggested by PWatts:
I've advocated the IRFD devices since they were IMO superior to the
2210's, easier to replace, stackable for more power and with better
heatsinking properties. However, the 2210, the SMD G-suffix in
particular, seems overall like a better bet. The only advantage offered
by the G over the A will be slightly improved signal path and greatly
improved power dissipation ability due to the large copper plane and
vias I provided. Only disadvantage of course is that once the tab has
been soldered it's nearly impossible without special tools to remove it
without damaging the board should something blow up.
- Suggestions when building by PWatts:
- VR2 is positioned a bit high up close to the driver heatsink. This is still sufficient for the original Krell sink that didn't cover the entire package area, but for those wishing to cover all the way down may have to mill out a notch for it to fit.
- The film caps provided for are for the types that expand in length, not width, at higher values (4.5mm wide), so make sure the ones you buy will fit since many caps like Vishay MKP1837 series' values expand in width. The film decoupling caps don't have to be 100nF of course, 10nF should also work. Just make sure that they aren't the only supply caps on board or they could cause oscillation.
- Since the bottom two axial caps are covering the bottom mounting holes, naturally they should be soldered in from the top after mounting. The size provided for were intended for Solen 1uF 400V or Mundorf M-CAP 1uF 400V.
- The 62pF's are placed in front of the predriver transistors, so if buying small heatsinks make sure they won't interfere with the caps' positions e.g. the small "foldover" types. The design intention was for a thin sheet of aluminium to be used for all four, so that may be the easiest instead of individual ones.
- If individual sinks are used; only two of the four cascaded ones should need sinking, so start off with nothing and then add if you feel it's needed instead of going through unnecessary effort.
- If all the on-board capacitance provided for is used (4x 1000uF Panasonic FC will fit besides the other smaller sizes&values), and even more so if the power jumpers are replaced with resistors for improved filtering, there is likely to be a noticeable turn-on thump. For those using an additional small resistor in series with the entire board i.e. drivers included it will be even more. I'd suggest building and starting it up without any capacitance at all, and then progressively add them beginning with the 220uF and film caps.
- Those wishing to experiment without making excessive modifications can try adding a 100uF 50V cap in parallel with the zener diodes.. they will cause thump though.
- The amp should work OK at lower supply voltages, but for optimal performance they should be >42V. This is because of the 39V zeners used for the LTP's resistor current sources. Try to keep it between 48-52V voltage though. There was some confusion over original KSA100's intended values since it depends on which mains it runs on i.e. 220-220V or 110-120V.
- If the DC offset seems stable, try bypassing the feedback caps with jumper J3. No cap is after all better than the best Black Gate. FIRST MEASURE THE OFFSET BEFORE CONNECTING THE SPEAKERS!
- Soldering the SMT Devices by PWatts:
Important thing is to _slightly_ wet the three leg pads with solder or preferable solder paste. Keep about 1mm of the pad exposed. Press the body down and solder the middle pin, and if it sits well the rest. Make sure the whole thing is flat on the board of course. Leave it as it is until the amp is working, and once you're sure everything's OK, apply liberal amounts of solder at the top until the tab itself is also slightly covered. You can also make sure the vias are fully filled by soldering them from top side of the board.
Note that although the tab soldering creates a proper heatsink, it'll also take a fierce amount of oomph to remove it, so once it's on, it's ON. If it blows for some reason later on, I'd rather just heat and lift the three legs and go for one of the other two packages left open than to try removing it with a blowtorch.
Suggested method to remove is to break up the devoce with a small pointed cutters then de-solder each leg seperately.
The Zobel network which is shown in the main schematic but no values given is made up of a 5R6 ohm 5 watt resistor and 100nf capacitor in the MK-2. Solder it across the output binding posts.
If you're on a budget the AN8440 Transformer from Antek might be a good choice. It has not been tested in this amp yet but is very similar to the original Krell Tranny.
https://www.toroid-transformer.com/ Note: This is a different tranny than is listed on E-Bay. The E-Bay trannies do not have the two extra 18 volt 2 amp secondaries.
Floedstroem has also looked into getting the original KSA-100 transformer made again by Avell Lindberg but at about double the price and it would still have to be shipped to the U.S. from Europe.
- Softstart & DC Sence PCB's
Same as in original schematic.
https://www.hififorum.nu/forum/topic.asp?TOPIC_ID=74088
- Build Thread with pictures by Fix
https://www.hififorum.nu/forum/topic.asp?TOPIC_ID=67096
__________________________________________________________________________________________
Fill in between the space bars but omit any pricing until that has been announced. And update the Total.
| name | country | quantity | Cost | Paid |
| cantskienuf | US | 2 | $44.24 | Y |
| acenovelty | USA | 2 | | |
| byu | Canada | 2 | $50 | Y |
| luckylyndy | US | 4 | $85 | Y |
| GeWa? | Belgium | 4 | $89 | Y |
| JoeyDD? | Canada | 4 | $89 | Y |
| dr.Strangelove3 | the Netherlands | 4 | loek | loek |
| Cobra2 | Norway | 2 | $50 | Y |
| AVWERK | USA | 3 | 65 | Y |
| daylne52 | USA | 2 | $44.24 | Y |
| twitchie | Canada | 4 | $89 | Y |
| RKH | USA | 4 | $85 | Y |
| Luke | NZ | 2 | | Y |
| Barryblue | UK | 5 | $115 | Y |
| loek | the Netherlands | 2 | $135 | Y |
| AMV8 | UK | 6 | $128 | Y |
| dabodkin | USA | 4 | $84 | Y |
| flodstroem | Norway | 6 | | Y |
| pollypocket | Canada | 2 | $50 | Y |
| bobgroger | USA | 4 | $84 | Y |
| grimberg | USA | 4 | $83.38 | Y |
| gaborbela | Canada | 2 | $50 | Y |
| farl | UAE | 4 | $86 | Yes |
| Jozual | RSA | 10 | $222 | Yes |
| andrewt | UK | 2 | | |
| gbyleveldt | RSA | 2 | $50 | Yes |
| jacco vermeulen | The Netherlands | 2 | $50 | Y |
| groov | USA | 8 | $162 | Yes |
| TomWaits? | Canada | 2 | | |
| still4given | USA | 2 | $45 | Yes |
| crypt0wind | USA | 4 | $85 | Yes |
| anthony2181 | UK | 4 | $90 | Yes |
| Mark Gulbrandsen | USA | 24 | | |
| valvemaniac | NZ | 4 | $90 | Y |
| BobEllis | USA | 4 | $84 | Y |
| rolandong | Philippines | 4 | $89 | Y |
| andylaser | UK | 2 | | |
| steenoe | DK | 4 | 90$ | Y |
| pool | Sweden | 4 | 90$ | Y |
| NetRunner | Finland | 4 | $89 | Y |
| niconoise | USA | 4 | | |
| MikeBarton? | UK | 3 | $69 | Y |
| AR2 | USA | 4 | $ 83.23 | Yes |
| zygibajt | Poland | 2 | 50$ | Yes |
| haraldr | Norway | 4 | $90 | Yes |
| TOTAL | | 180 | | |
Spares:
| Stuart Easson | USA | 2-10 | | |
| Adusson | SWE | 2 | | |
| Sts9fan | USA | 2 | | |
| Sigurd Ruschkow | SWE | 2 | | |
| daylne52 | USA | 2 | | |
| Harry3 | AUS | 4 | | |
| RAmandi | MEX | 2 | | |
| Acoustech | IRL | 2 | | |
GROUP BUY CLOSED!!!!!!!!!!
Spare boards for me?
primetime / SG / 2
PM650 / USA / 2
haziz/USA/2
rainwalk/South Korea/2
Fix / Sweden / 2 - 2009-01-15 ( I would like to buy 4 new cards... )
bottolfs/ Norway/ 2 2008-03-28
Arick/Canada/2 2009-05-03
Krell-O-Tracker KSA-100 Edition
| Date Finished or IP | Name | Transformer | Total uF Per Channel. | DC Rails | Emitter Resistors | Output Devices & # Per Ch. | Notes, Links, Pics, Comments |
| 1983-1987 | Krell Original | dual transformers, 41-0-41(signal circuits), 62-0-62(output relay circuit), 0-12(unused), VA??? | 2x 40,000uf | +/- 52 VDC | 1 ohm | 4 pr MJ15003/4 TO-3 | 100 WPC Class A |
| 1. Collecting parts | bikehorn | 1x 1250va 4x 39-0-39 secondaries | ESP capacitance multiplier | +/- 39 VDC | 1 ohm | 4 pr MJL21193/4 TO-3P | 50 wpc Class A "Mini KSA-100" |
| 2. Metal work | flodstroem | 2xDiycable 1kVA /40-0-40V @ 12.5A (1kVA/ch. monoblock) | 2x50,000uF Sprague 36DY 95�C | � 55 VDC | 1 ohm | 6 pr MJ15003/4 TO-3 | 100 WPC Class-A, natural convection heat sinking |
| 3. Final Testing | Fix | 2xDiycable 1kVA /40-0-40V @ 12.5A (1kVA/ch. monoblock) | 2x 40,000uf | � 55 VDC | 1 ohm | 4x MJ15003/4 | 100 Watt Class A, Fan solution, https://www.hififorum.nu/forum/topic.asp?TOPIC_ID=67096 |
| 4. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 5. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 6. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 7. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 8. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 9. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 10. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 11. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 12. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 13. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 14. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 15. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 16. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 17. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 18. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 19. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 20. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 21. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
| 22. Date/ IP | B. Name | C. XFMR | D. uF | E. DC V | F. Re | G. # Dev/Pack | H. Notes, links,etc... |
