bbest
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Posts posted by bbest
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7 hours ago, simmconn said:
The closest sub for LT1021 is the LT1236. As far as I know they only differ in long-term drift specs. There are other shunt mode 10V references but none come close to the noise performance of LT1021/LT1236.
Unfortunately LT1236 has also insane price.
SUPSIC produces GC2M1000170D 100% the same specs as C2M1000170D, costs 1.5$.
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C2M1000170D produced by SUPSIC and Inchange Semiconductor. But don't know if they are reliable or not.
PS: Is it possible to replace costly LT1021DIN8-10, something with Negative Shunt Reference (only 2 active pins)?
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Repairs.
Of cause it was some problems (for T2 this is normal, nothing special). It was successful first run. But after some modifications I had bad connection for tubes filaments 6.3V.
* so fried couple times 2SK216 + went to rip 4-6pcs LTL-4221NLC. Silent dead, no sparks.
* PSU lines -500V, +500V (not alone here, other members had same problems): zener 24V, 2n3904, fqpf8n80c.
Thanks all who helped in repairs.
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Hello everybody!
Almost finished T2 started in 2022. It was very funny and pleasant build, very interesting. For base I took PCB developed by jamesmking in 2020. For me it was most convenient layout, it is possible to rearrange in case two channels. Plus no absolete elements.
In this build changed:
* DC offset resistor R64 from 510 to 649Ohm
* 2SJ79/2SK216 on TTA004B/TTC004B
* FQPF8N80C on STP8NK80Z
Some pics
Amplifier.
TTA004b/TTC004b
And PSU
More pics here https://cloud.mail.ru/public/mHh6/ktC6SknZ5
Thanks jamesmking, JoaMat and other guys for help in assembling.
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On 8/2/2023 at 10:36 AM, jokerman777 said:
Wanted to buy some FQPF8N80C seems uk rs-online only let me enter UK address, is there a way to get them ship worldwide?
Hello all!
Same question - how to replace it or where to buy?
May be something from this:
* FQP8N80C
* STP8NK80Z
* STP7NK80Z
?
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2 hours ago, jamesmking said:
FJPF5027OTU seems to be a possibility, seems to have similar specs except lower current rating and the same pinout.
Hfe of FJPF2145 is 20 - 40 which is the same as the O variant of the 5027all good, but output capasitance 60pF vs 11pF.
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Hello all!
Now FJPF2145 obsolete on Mouser. But I need to finish my T2. Where it is possible to get or how to replace them?
What you think?
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On 4/17/2023 at 7:05 PM, usa_love said:
is it a regulator that is based on different resistance of different turns in transformers? Wow
Not exactly resistance - different lengths of second's wires. Very pure sound after this TVC, especially on low level volume.
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PSU for both: Carbon and GG (Ground Grid). With delay board for tubes filaments. Compact 22AWG wires can handle 700v DC, double shielded.
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Read many good reviews on such kind of DACs, so get latest version of boards dam2941-12. Wanted to power it with Salas Reflektor-D and Salas UltraBib.
b.
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6 hours ago, Pars said:
I personally prefer the CFP3 to a Dynahi, but I have only compared SE directly. The CFP3 is probably my favorite dynamic amp, but my SE Dynafet is awfully close (and better than an SE Dynahi in my opinion).
I've never built a Beta22, but have heard them at meets (10 or more years ago). I don't recall being particularly impressed then, even though I have a lot of respect for Ti.
And what difference between CFA3 and Dynahi? My balanced Dynahi seems more rude, more simpler then beta22. Last one very close to electrostatic sound.
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Have you heard beta22?
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I just had 2004 boards from another guy and finished the project. And I am not sure what is the best for isodynamic headphones: CFA3 or Dynahi_2004.
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Assembled my balanced Dynahi old version of 2004.
Using it with HiFiman HE-6. Sound: entertaining, opened, dancing cheerful. Compared it with beta22.
Have only couple of questions:
* does it make sence to change main capacitors from Panasonic FC 470uF on Nichicon KG 680uF
* DC offset without opamp +-10mV, with opamp OP27 +-2mV. Is it ok, left as is or try to make it better by changing on opa134 or something like this
* does it make sence to make some other mods
What you think?
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On 2/24/2023 at 2:21 PM, MLA said:
I've sucessfully used stn0214 as replacement for ksc5026M as per JoaMat's recommendation in several other builds. Don't know the heat dissipation requirement for the position where they are used in KGSSHV, but someone more knowledgeable than me might chime in here.
Not so far ago it was expected in JUL-23 on mouser, but now shift to 19-Aug-24. So only stn0214.
Quotebtw I think I'm going to use STP8NK80ZFP instead of the obsolete FQPF8N80C, at a glance the specs looks very similar other than a different Id rating and speed.
here said https://www.mouser.com/PCN/onsemi_Generic_PD24419ZB.pdf it could be replaced on FQP8N80C, but mouser also suggested STP8NK80ZFP
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some intermediate results of PSU (followed by jamesmking assembly)
Used 0.5mm transformer wires for AC HV (red ones): compact and reliable.
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On 2/6/2023 at 4:22 AM, jamesmking said:
Here the latest T2 psus, I have modified the layout to provide more space around the rather hot R11 3W resistor and added vent holes to the pcb. The pcbs, transformers etc still fit inside a 400mm deep case without issue.
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This pcb is 220mm wide by 137mm deep and contains the -260V, -560V and +250V rails
tiny mistake: FQPF8n80s -> FQPF8n80c. But anyway, FQPF8n80c completely obsolete. May be it make sence to change it on FQP8n80c.
PS: compared to previous gerber version
fixed wrong silk for IXCP10M90S: KAG -> GAK, good 👍
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very strange, now mouser shows for IXCP10M90S
Quote1,180 Expected 26-Apr-23
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Mouser has changed delivery date for IXCP10M90S on 08-Aug-2023. So where to buy it?
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I have 4 sets of T2 boards of morden jamesmking's design. If smb wanted just pm me.
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9 hours ago, JoaMat said:
If it’s ksc5026 in KGSShv style power supply you can probably use stn0216 intstead. Solder it standing on the to126 pads (might be to220 pads on your board?). Power dissipation there is something like 40 – 60 mW, I think.
you mean this one
https://www.mouser.com/ProductDetail/STMicroelectronics/STN0214?qs=pmcUWs1B1IKOCzUPe9wAgg%3D%3D
stn0214? So tiny
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20 hours ago, Craig Sawyers said:
It's an ONSemi part. I really don't know what has happened with ONsemi. They bought Fairchild and Sanyo, and have obsoleted most of the really useful audio parts. Anything remaining has ended up on ridiculous lead times.
We're well beyond the Covid excuse, and I'm left with bungling corporate incompetence as the only explanation remaining
so may be find some analog for KSC5026MOS, on Aliexpress some shops try to sell 1pcs for 24$ 🤔
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On 8/20/2022 at 8:02 PM, sbelyo said:
I need at least 4 but could use 12 of KSC5026MOS for GRHV. Does anyone hve 4 that they could spare? Or a trusted source?
I also needs KSC5026MOS, for T2. On mouser it will be available in summer of next year. How know where to buy it ...
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Hello!
I could get now DynaMight 4pcs boards version 2004. Does anybody know is there any difference for balance amplifier between: DynaMight and Susy Dynahi v 1.43?
The ultimate DIY? A Stax SRM-T2!
in Do It Yourself
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If you have a little practise so it became very easy to twist legs.