These should be "pretty boards" with 2 red led's. I will keep them to confirm CCS operation even with 2 tranny CCS's and 2 green mini leds for the hawksford. It will look "mirror image" as well (like a butterfly). 
This design simulates SOOOO good , no LT error log ... can be compensated down to 15 pf miller wise (150v/us symmetrical slew). Fired it off into 10uF capacitive loads (BANG) with minimal ringing ... NICE !!
OS
This design simulates SOOOO good , no LT error log ... can be compensated down to 15 pf miller wise (150v/us symmetrical slew). Fired it off into 10uF capacitive loads (BANG) with minimal ringing ... NICE !!
OS
Put me down for four boards...........
I will make boards for people , I have THAT down pat!!
Hey everyone. For those wanting to help me with electronic stuff:
If I had $40 I could get 100 pairs of 2SD669A/B649A (very good transistors!) from profusionplc.com cheap. I have $20, and am willing to settle for 50 pairs, but Profusion only sells in batches of 100. If someone else could split a batch with me or work something out, I'd be thrilled. I also wanted to order 100 pairs of 2N5551/5401 from the same place, but I am focusing on the 669/649 so I can build stereo pairs of my headphone amp with the small-signal transistors I have left. I am in need of small-signal voltage tolerant transistors such as the 5551/5401, or whatever OS would recommend. Other than that, any number of ordinary Mongrel-size electrolytic filtering caps would help.
To make this post more topical, here are some pictures of the to be Mongrel AX. Licon 470uF caps harvested from a downed Harman/Kardon, with 1uF mylar bypass. The trafo in the background is a 12/24V 8/4A brick found at the local repair shop. Good for a low power class A amp maybe?
Thanks,
- keantoken
If I had $40 I could get 100 pairs of 2SD669A/B649A (very good transistors!) from profusionplc.com cheap. I have $20, and am willing to settle for 50 pairs, but Profusion only sells in batches of 100. If someone else could split a batch with me or work something out, I'd be thrilled. I also wanted to order 100 pairs of 2N5551/5401 from the same place, but I am focusing on the 669/649 so I can build stereo pairs of my headphone amp with the small-signal transistors I have left. I am in need of small-signal voltage tolerant transistors such as the 5551/5401, or whatever OS would recommend. Other than that, any number of ordinary Mongrel-size electrolytic filtering caps would help.
To make this post more topical, here are some pictures of the to be Mongrel AX. Licon 470uF caps harvested from a downed Harman/Kardon, with 1uF mylar bypass. The trafo in the background is a 12/24V 8/4A brick found at the local repair shop. Good for a low power class A amp maybe?
Thanks,
- keantoken
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Looks as if you harvested the heat sink from the H/K as well!!!
Normally I would be glad to help out and split an order or something of the sort - BUT - 17 Y/O GD just ran up a buncha medical bills - again. Heck - I just got finished paying off the last batch!!!
C12 where. I was in such a rush to get your box out I forgot to give you the AX V1.1 overview. It is below, copy and print it. Your PB60 is the same as mine.. current V1.2-final. The C's on the PB60lp go back from C99,c98, etc. As far as being "blameless" ,my big ones (PB250) have never left the 17mv I set them at 2 months ago.
OS
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hi keantoken,
I'll pay for 100 pairs of 2SD669A/B649A and 100 pairs of 2N5551/5401 but here's the catch, you have to match them and send me half (not all the bad ones either
)BTW: I still intend to send you the BAKSAs, I just haven't placed my order for resistors yet.
regards
I meant the schematic you posted earlier in this thread, post 754:
http://www.diyaudio.com/forums/solid-state/169590-mongrel-supersym-ii-16.html#post2342212
- keantoken
http://www.diyaudio.com/forums/solid-state/169590-mongrel-supersym-ii-16.html#post2342212
- keantoken
I gave you all the transistors for the PB's and the AX's were stuffed .. you should be set for discretes , even an extra pair of NJW's. All you would need is a couple fastons,
63v caps -15-18mm ,
220uf 35-50v NP dc cap,
4.7u input, and any power supply stuff.
You have the heatsink , cool.
Worst case , I might be able to send more 11/10.
Regarding C12 , it also is on my PB250 , no issues. Ran it from 40F nights to 95F days/ 2 months , always 17mv (.27Re) +-1mv !!
If you want to play , go for it.
OS
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Hey Greg!
I read somewhere that the 669/649 were already very well matched out of the box. How well matched do you want? I suppose you want Hfe match and not Vbe match? And at what Ic?
That's a good idea though... I could match transistors for a commission!
I have most of what I need for the Mongrel. I already have 470uF caps for the PB60's. Thanks for the extra pair, OS.
- keantoken
I read somewhere that the 669/649 were already very well matched out of the box. How well matched do you want? I suppose you want Hfe match and not Vbe match? And at what Ic?
That's a good idea though... I could match transistors for a commission!
I have most of what I need for the Mongrel. I already have 470uF caps for the PB60's. Thanks for the extra pair, OS.
- keantoken
Also , keen ... look at the AXV1.2final there is an alternative compensation scheme. The AX will retain proper margin with either 47/68p miller , R17 = 22 or 47R ,feel free to degenerate the ltp and CM to your liking as well.The 1.1 and 1.2 are almost exactly the same. (below) Yours had a little mistake but is very usable (I fixed it - led trace on CCS)
OS
OS
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Hi keantoken,
I am happy with a simple hfe match using a multimeter. I usually do a 100 at the time and group them in batches within 3 to 10 hfe. This depends on the spread of hfe for the bactch of transistors. When I go to build am amp I then rematch to within 1 hfe from these small prematched groups. Hfe really changes with temperature so you can't handle the transistors for more than a second and you can't do 50 today and then 50 tomorrow.
In this case, I am happy to accept matching to whatever standard suits you.
Now you have to work out how to order from profusionplc.com and have me pay them. Email me the details.
regards
I don't have a multimeter that measures Hfe. What is the usual bias for drivers? I could use a 100 ohm resistor to emitter, base to ground through a 100R resistor, and adjust test current with my variac.
Do I get a bonus if I tin the leads?
- keantoken
We have to be careful we don't pollute ostripper's fine thread with our conversation, so do a little research and open a new thread if necessary. I normally only match small signal transistor for LTP or mirrors. I'd be happy with that. You can also use the diode function on the DMM to measure them.
hi keantoken,
Do you want to look into this? or will I proceed with plan A.
regards
Those parts are manufactured by unisonics, cheap china made, crack one open and youll notice the small dies, their bigger power transistors use the white paste.
DestroyerX, better you stay at your own threads, go back to school and learn first manners and then electronics
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