| Greg Erskine |
| quote: | Originally posted by meanman1964
Nordic,
I was looking at the part-list and came across C6 with value 2µ2 but where is X standing for?I can't find it on the board or schematic. |
Hi Meanman1964,
I think you are looking at this page, right? This BOM shows a cross reference of Nordic's and my component numbers in the right hand column.
http://users.tpg.com.au/users/gersk...mplifier-12.htm
A little history. Nordic and I worked from Carlos's original schematic and unfortunately came up with slightly different results. The "X" means I could not find the component on Nordic's schematic. I always number my components top to bottom, left to right.
The cap in question is not extremely important and can be located on the Vbe board.
If you are building Nordic's boards, you might be better just sticking to information on Nordic's site.
regards |
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| Nordic |
Morning Greg, thank you..
The BOM from the GB boards is here
https://www.dxamp.com/construction/..._amp_BOM_Ve.txt
It does not include the last resistor changes yet, but otherwise should be fine..
Greg is on to something... there is an (optional) 2u2 cap on the vbe multiplier... I don't use a cap there... |
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| udailey |
Hi Guys,
Daughter is sleeping and I am soldering and measuring. When she wakes I will saw some boards for speakers.
I have run into a few issues that I hope you can tell me if they are really problems or if they are fine.
1. I have 2 2k2 resistors labeled R4 and R9. These placements do not exist on the pcb board for the amp.
2. I have resistors R8 and R23 which are supposed to be 4R7 and are ohming out at 5r5. 17% more.
3. I have resistor R22 that is supposed to be 10R and is 11R1. 11% more.
4. I have R29 270R which has no place on the PCB board for the amp.
5. I have placements on the board for R10 and R19. The BOM specifies 0R22 but the multimeter says 1R, almost 500% more.
6. I have R28 which is 10k and is marked the same on the board. The BOM specifies 4.7k to 5k and to then adjust to max value before installing. I would assume the BOM means max value to be 4.7k to 5k but board and components on hand disagree with BOM.
I will search the thread again for these answers as I wait for replies and will check DXAMP website again.
Thanks
Uriah
EDIT: POST #510 Takes care of R9 and R29. Is R4 the same as R9 but on the other servo board? |
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| udailey |
| On http://www.dxamp.com/construction/# there are links to Transformer wiring for single and dual transformers, troubleshooting guide, and checklist. These links all refer to the top of the page. Are they broken or do the documents exist? |
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| meanman1964 |
| So Nordic,I can use the BOM of your site and do some changes of the resistors and some capacitors like the board is showing |
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| Nordic |
HI Menaman, sorry, the thread showed as read, so I missed your post...
I started doing updates on the website yesterday, as i realised I have not uploaded the latest changes...
The image you have with the pink numbers is correct... only thing I would change further is a larger cap for the input... the 2u2 was a holdover from the plain DX which has a diffirent input impendance... affecting the lower bass rolloff point... If you are going to use a cheap np electrolytic... increase this value drasticaly... |
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| meanman1964 |
| Nordic,what about an 8µ2 for input cap? |
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| Nordic |
| If it is a high quality cap it may start to be a bit bassy, if it is normal np electrolytic it is fine... I am usine 6.8uF SoniCap with the resistor soldered inline.... |
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| meanman1964 |
| It's a MKP from Intertechnic Audyn-cap MKP-QS |
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| Nordic |
| If you allready have it, give it a go... At least you know the first place to check if it is too bass heavy ... it may work just fine... |
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| udailey |
What is the wattage of the zeners on the amp Nordic?
And are the inductors wound like this: 2 layers of 20 turns each for a total of 40 turns on each inductor, or, is it 20 turns made out of 2 layers of 10 turns each? |
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| Nordic |
I would aim for .5 to 1W zeners
and the first option for the inductor is correct...
Tommorrow I should be shipping the last of the orders :) |
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| destroyer X |
watt is already a big overkill....make your choice based in other factors, as how they look, how big they are...those things.
Of course you can use bigger..... will not be bad too....no problems.
Because 500 miliwatts, or 1/2 Watt is enougth.
Carlos |
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| udailey |
| Okay, Thanks guys :) If my Mouser parts come in over this week I hope to have my first try at powering it this weekend as well as building the speaker boxes. |
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| Dougie085 |
| Ok so this groupbuy is over I'm just curious if its possible to get the files so I can order some boards on my own? |
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| es44 |
| quote: | Originally posted by Dougie085
Ok so this groupbuy is over I'm just curious if its possible to get the files so I can order some boards on my own? |
I believe you can look at Nordic's place HERE. There you will still find some goodies. And may i say, you have never seen such a nice package.
Best regards
Ebbe |
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| Nordic |
Hey Dougie, I keep on makeing a few of the boards for as long as there is a demand... obviously the price increases a little over when we did a group buy but is still hardly breaking even with the cost of providing this service...
On my website you will find free PCB layouts etc for makeing a DIY version if that is what you want too... free... no charge...a gift from me and uncle Carlos... well, mostly uncle Carlos... |
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| Dougie085 |
| Yeah I'm still trying to decide which amp to do. Only issue with the DX is that I was looking for more power then my chipamp and the DX actually does a little less in 8ohms. I was thinking about doing the Nmos350 as well so have to figure it out. I think I've decided I'm just going to get a laser printer and the stuff to make my own boards though sounds like fun and its nice being able to turn out a board in a couple hours. |
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| Nordic |
Sure chipamp can put out nice peaks, but sounds like **** by the time it gets there... I can not imagine any domestic setting where you would need more power than the HRII can provide... the power rateing is deceptive... especialy whith the full spectrum of sound behaveing and being controlled right up to high level output...
PS.. even a buble jet printer works fine... |
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| Dougie085 |
Well I need a new printer my bubble jet is getting old and I'm tired of replacing cartridges so often. The laser printer I'm looking at should last for like 2000 pages and the toner isn't much more then the ink I have to buy now.
As for the chipamp I put it up against a Rotel amp recently and it killed it completely so I don't think it sounds horrible. I don't think Rotel is a good comparison either though as I've never been to thrilled about them. I may not need more power but it would be nice just to have. My friend has some Maggies (the big ones) and we'd like to try out the new amp on them as he's looking for something to build for those right now he's using a 150wpc gain clone. |
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| rabbitz |
Chipamps (such as the LM3875) can and do sound great and just need careful partnering of equipment to gain the benefits. One advantage of SS amps like the DX, is they are more flexible with partnering equipment and difficult speaker loads.
I've only ever had 1 DIY amp (A**A 5**+) that can work well with everything I have here. All the others needed some sort of matching or system tweaking.
It's all about system matching (not easy to do), application and budget of course. |
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| Nordic |
I just want to confirm that the last outstanding orders shipped today.. order no 83.
I seemed to have missed the send mail tickbox while I did the administration... but your tracking numbers are in your user accounts.
There are about 5 newer orders which will ship later in the week...
The P1 boards from the groupbuy are now all sold out... I will place another order for a small number but the price will go up a bit because of the lower volume job...
I also had most of the items weighed so can now update the ordering system to calculate shipping more fairly than a flatrate, and bring some saveings about to the majority of buyers.
I have also, as promised, done much updateing on the website, which is constantly evolving. Some small touches are still needed but I think the navigation is more sensible now and construction and DIY plans more easily found.
Cheers guys, :D :D :D here's to all of you for pulling us through another production cycle... |
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| meanman1964 |
| What max. values are needed for C1,C2,C8,C9 and C10 to get the results?I do have 4 x 1000µF or is that overkill for C1,C2,C9 and C10? |
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| Nordic |
| I don't think you should HAVE to go any bigger, and may be physicaly restricted in size.... It is not overkill, I run 10 times that on the outputs and 5 times on the inputs... (yep, not a cheap excercise). Build it with what you have first, also build Carlos' recommendations of about 220uF, then use your own judgement. |
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| maxlorenz |
Hi dear,
After an unexpected delay ;) I finally put the amp together today...
Due to this delay I kind of lost the track of the threads, so when I had to buy the caps I ordered ceramic COG type for the 47pF and 10pF little ones...the input cap is WIMA MKS4, 6u8.
I am testing it with my variac, founding bias with little V increments until I got:
# emiter to ground V, for the output transistors is 580mV.
# base to emiter V, for the servo transistor is 647mV.
# DC offset must be 1.1mV (or 0.7mV, if I take off possible error from the meter). I could reach lower value but with a emiter to ground V, for the output transistor of 550mV or so...
# Heatsink is cold.
I'm listening from the PC, some youtube, videos so I can't judge yet the sound. It would appear that there is plenty of HF information. When I get home I will test with my humble scope and with better equipment.
Big thanks to DestroyerX and Nordic!
I feel a little proud for building my first "discrete" SS amp :cool:
Best regards,
M |
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| maxlorenz |
Dear DestroyerX and Nordic,
Your amp is sweet :cool:
Very clean. Detailed but relaxed. With good frequency extension.
Very elegant it sounds, in my system...
Bass is very good.
A few shots of my test setup:
http://picasaweb.google.com/maxlore...XTROYERXHRIIAMP
Many thanks, again.
M |
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| udailey |
M,
Thats one crazy speaker you built!! Pretty cool looking.
Uriah |
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| maxlorenz |
Hi Uriah,
Do you mean the little ones or the BIG ones?
(or maybe the intermediate ones?) :clown:
Cheers,
M
PS: the down scaled replicas of the Autograph (1:4 and 2:3) are perfect copies of the original; not like Tannoy, that seem to have made a modified enclosure (for the worst). |
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| udailey |
All of them :)
I dont think you could pick them up on radar. They look stealth.
Uriah |
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| maxlorenz |
He, he...and it is a 50 year old design!
I dream about more DIYers understanding the charms of the front and rear horn loaded enclosures...
Nice pictures, BTW :)
Cheers,
M |
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| Nordic |
Hi Max, been a while since I looked at this thread, GREAT!!!!!!!!
Glad you like it. |
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| maxlorenz |
Hi Nordic,
Tomorrow I'll have time to test the other channel.
After that, I only have to decide to buy another transformer to get an extra pair of monoblocks :D
When my wife will ask: why some many amps?, I'll tell her that a Brazilian friend is the inventor and she will find that it is OK (she is fond of Brazil for she lived there a year as a child) ;)
I have no words to thank you enough the big effort you put on that groupbuy. You are great :cool:
The best part is that I still have two more PCB's...
Best of wishes,
M |
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| lineup |
| quote: | Originally posted by destroyer X
Those Sankens, i have received from Klaas Veenstra, are excelent.
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Holland (netherlands) & the african Netherlands (south africa)
are the most great supporters of the dx-amp projects.
;) What is it about Brasil that is so good to them hollanders?
Nordic & Veenstra
maybe you can tell european swedish Lineup about this ;) please, thank you :cool:
>>> web source: http://lineupaudio.freehostia.com/forum/index.php
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| Nordic |
Just a note, I am aware of the problem with the transaction process... failing on the last page.
I have someone working on it. |
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| rabbitz |
Nordic
The selling site working OK?
The reason I ask is I still have an outstanding order (95) and the status has not changed. The emails I've sent in the last 2 weeks have had no answer so there might be something amiss. :confused: |
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| Nordic |
Hi Rabbitz, I appologise.
The site was so broken I could not even get in the order database to get to order data.....
Spend the last week or more trying all diffirent kind of solutions, rebuilds, other software... etc... was so busy I didn't even get to browse this site for days.
Think I gained a bunch of grey hair.
Turns out they upgraded the server without letting me know.... and it was incompatible with my shopping cart....
All semi fixed now, I just have to swap the front page again, but I cannot do it before tommorrow, as the processing side is still on testing mode... which is something a third party has to activate again for me tommorrow morning... after that business as usual...
Orders found to be overdue will be sent through Postnet to get to you speedily... they normaly take about 5 days, but cost me an arm and a leg. |
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| rabbitz |
I though you were having hassles as your number of posts were on the light side.
Thanks. |
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| Nordic |
To put it in perspective it was so long I had to re-enter my password for DIYAUDIO...
The website is back up now...
:)
Sadly it was about as stressfull the first time I made the site... |
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| samsagaz |
| Some boards to sale? :) |
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| Ernesto |
Hi Nordic.
I´m interested in some boards and components.
Please, say me when you will have complete a new group buy, or if I should contact to Carlos ?
TIA.
Ernesto. |
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| destroyer X |
So, hermanos Ernesto and Samsaqas, wait him to return to the forum.
Gracias,
Carlos |
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| destroyer X |
... and i have increased to 1 ampere, and tested into 2 and 3 amperes too (each rail)
... i found that 1 ampere or higher standby bias does not give us any advantage into sound reproduction.... TESTED!
I found was sligthly mufled into higher bias....also i have found the optimized bias point is around 250 miliamperes (as Nordic said..he was rigth!).
Comparisons made, using two identical amplifiers, same parts and same supply, into a single speaker, gave me this result..instead to adjust your stand by bias to 60 to 100 miliamperes, it is better to increase it to 250 to 300 miliamperes because performance was better than lower bias and higher bias.
So.... Optimus is dead....now we have HRII Optimized!
Be happy folks.
Enjoy Dx Amplifier.... sounding near the perfection.
regards,
Carlos |
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| Francois G |
What happened to Nordic and www.DXamp.com? I checked for the last few days and got a domain management company everytime. Did Nordic not renew his domain? Did he move somewhere elso on the web?
I needed the website for instructions on how to construct my speaker protection kit. If anyone has this information please let us know.
Thanks,
Francois |
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| AndrewT |
Nordic has moved to a new home.
Maybe workload of setting himself up has priority. |
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| rabbitz |
| Yeah.... he said he was going to be off the air for a month or so. |
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| dudaindc |
Guys,
I wrote him and understand that everything is fine, but his DSL provider has caused many headaches.
Nordic had no internet access for quite a long time, but he should be back soon.
Cheers!
:darkside: |
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