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Old 21st February 2020, 06:04 PM   #2001
xrk971 is online now xrk971  United States
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No, like this.

Glue Henna Dispensing Needle Tips Luer Lock Blunt End Plastic Tapered Needles 22 Gauge 100 Pieces Glue Henna Dispensing Needle Tips Luer Lock Blunt End Plastic Tapered Needles 22 Gauge 100 Pieces: Amazon.com: Industrial & Scientific

The pink ones flow a little more and can be useful as well.

Fresh solder paste that flows easily is important. Should not make you hurt your hand from having to squeeze to hard. I had that happen and it was 2yrs old way past expiry. Keep in refrigerator in a ziplock when not in use.
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Last edited by xrk971; 21st February 2020 at 06:06 PM.
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Old 21st February 2020, 07:12 PM   #2002
Vunce is offline Vunce  United States
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Thanks for the kind words fellas
I took my time and had to wipe off a few pads because too much paste was applied. One of the steps that really helped was sticking the SMD components (while still in their packaged row) on a piece of blue tape to hold them in the order listed on the parts list. It kept me from misplacing components. When the board was completed, I was amazed with how fast the actual “soldering” went. With enough practice this method is much faster than soldering THT components.
Next up, Aksa Lender preamp SMT DB’s

@IAIMH
The pink tip I used came with a different tube of solder paste. The two nozzles that came with the MGChemicals paste that I used would never have worked, they were much too big. The pink nozzle hole is about 30% as big as the included syringe type nozzle.
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Old 21st February 2020, 07:32 PM   #2003
pcgab is offline pcgab  United States
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Quote:
Originally Posted by Vunce View Post
Thanks for the kind words fellas
I took my time and had to wipe off a few pads because too much paste was applied. One of the steps that really helped was sticking the SMD components (while still in their packaged row) on a piece of blue tape to hold them in the order listed on the parts list. It kept me from misplacing components. When the board was completed, I was amazed with how fast the actual “soldering” went. With enough practice this method is much faster than soldering THT components.
Next up, Aksa Lender preamp SMT DB’s

@IAIMH
The pink tip I used came with a different tube of solder paste. The two nozzles that came with the MGChemicals paste that I used would never have worked, they were much too big. The pink nozzle hole is about 30% as big as the included syringe type nozzle.
I need to get some of those smaller nozzle tips. The one I have is a bit too large for smaller pads and can be a real pain to apply cleanly.
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Old 21st February 2020, 07:37 PM   #2004
jhofland is offline jhofland  United States
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re: ItsAllInMyHead,
The tips you point out are the correct ones. If it matters, I found them on Amazon at a better price.
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Old 21st February 2020, 07:38 PM   #2005
Vunce is offline Vunce  United States
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Hey Pcgab,
If you need a lead-free low temp paste the pink tip was included

No Clean Lead Free Low... No Clean Lead Free Low Temperature Solder Paste 15 Grams - - Amazon.com
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Old 22nd February 2020, 09:57 AM   #2006
ItsAllInMyHead is offline ItsAllInMyHead  United States
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Thanks everyone. I ordered up a variety of the tapered tips. Brilliant. Maybe I can take up a side gig and learn to do henna tattoos. Can't imagine what they'd have to do with henna and hydroponics, but those seem to be tagged keywords.

I never thought to store it in the fridge after use. Noted with thanks. I don't use a ton of paste, so that's a great tip.
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Old 6th March 2020, 07:49 PM   #2007
xrk971 is online now xrk971  United States
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Default Updated Design for 2SK209BL and ZXMN10A8 MOSFET

Hi Folks,
Due to the end of life of my favorite JFET, the BF862 and now, the end of the old MOSFET we used, it is time to update the design to some available options. The Toshiba 2SK209BL actually is working out really well. I am getting some nice performance with about 0.02%THD for 1.0Vpp into a 250ohm load.

xrk971 Pocket Class A Headamp GB-pca-2sk209bl-zxmn10gta-v3-jpg
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Old 7th March 2020, 06:05 PM   #2008
xrk971 is online now xrk971  United States
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I just built a verification unit using the above resistor settings and 2SK209BL and ZXMN10A08GTA. For R3, I did not have a 1k3 on hand so used a 1k2 1210 resistor in its place. It resulted in a slightly higher bias current iof 72mA, but that's ok as I will be using them with lower impedance phones. I am using the 2200uF 16v Nichicon rail cap as the output cap, now bypassed with a 0.1uF 100v Wima MKS. The sound is excellent!

xrk971 Pocket Class A Headamp GB-pca-2sk209bl-zxmn10gta-verification-jpg
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Last edited by xrk971; 7th March 2020 at 06:12 PM.
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Old 1st May 2020, 01:05 AM   #2009
twitchie is offline twitchie  Canada
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I bought the 'PALO' 9V rechargeable batteries from Amazon and even after making sure they are fully charged, when I plug them into this amp, it doesn't turn on and the meter on the batteries show them as completely empty. The amp works fine with alkaline 9V batteries though. Is there anything specific to look for in buying rechargeables for this one?

These are the batteries I bought:
PALO 2-Pack USB 9V 650mAh Rechargeable Li-ion Battery with USB Cable for Keyboard Microphone Universal Remotes: Amazon.ca: Electronics
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Old 1st May 2020, 01:24 AM   #2010
xrk971 is online now xrk971  United States
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Rechargeable batteries have a smart short circuit detector that cuts the battery out to prevent them from burning in case of a short. The sudden in rush of charging the capacitors fools the smart battery into thinking it is a short.

The solution is to quickly turn on/off with 3-5 clicks and each time the cap charges up enough until it doesn’t think it’s a short. This is a known issue and discussed earlier.

Be aware that the 650mAhr rating is based on the native 3.6v lithium ion cell. After DC-DC step up to 9v the capacity is 3.6v/9v x 650mAhr = 260mAhr. Not as high as the EBL batteries which are rated at 400mAhr at 8.2v. OTOH, these have a voltage regulated output and maintain 9v until they die.
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Last edited by xrk971; 1st May 2020 at 01:28 AM.
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