Peleus

Hi~ Guys, I know this is late to be interested in doing KSA-5. However, the Alexcp's modified version of KSA-5 inspired me to make one. So, I wonder if you guys had the bare PCB of KSA-5 to offer? I am glade to buy one, please PM me. Sincerely,

I got this DCA75 Pro from digikey. I think it can not be fake one. So, How close the two hfe values of these 15030/15031 are? Can you give me some values as a reference?

Hi, Guys, I'm working on my CFA2 project. I've got a matching MJF15030/15031 question : How nice is the matching? I had a Peak DCA-75 to match these two BJTs, the result is horrible. The hfe values of One bjt are most from 280-290, the other are from 70 to 120. It is seem not nice enough, right? So, how nice is the close enough matching of these two BJT? May I need to buy more bjt to get nice matching?

Hi~ I just finished the GR regulator for my SONY PCM D50. This regulator is from my friend who is the original designer of GR regulator. The schematic of GR regulator is not new at all; however, the parts of the GR regulator is very very crucial. So, check it out and find some awesome points of this new version of GR regulator.

Hi guys, Guess what? I've solved the humming problem! hu....Finally. I asked the transformer supplier, and he said the transformer unlikely the source of problem. He suggested me try to ground the heater line. After doing some research on the google, I choose this solution, but mod little due to I don't have the pot now. This is my solution as the below picture showed. Great, No more hum in the low resistance on-ear headphone. And More, NO rebuild and major modification again. Thanks God! And, Thanks you all guys and your suggestions. Sincerely, Peleus, Taipei, Taiwan

Thanks, it is old and used machine, but still very, very, useful and reliable one. Old tubes humming...umh...I think that I may buy some tubes to try. Luckily, the tube is cheap and easily found in Taiwan. Well...It may help to confirm the source of humming, but I really need a One-Chassis headphone amp. Yes, the shield is grounded. And, Thanks your earthed chassis advice. Yup, You are right. I really be disappointed about the result. You teach me a good advice that figuring out the problem first. Thank you!

Hi, After 3 hrs hard work, I rewired the ground loop. Will, it is still not work!!!! I found this amp is good for the on-ear headphone, although the Huge hum. For the over-ear phone with high resistance, the power is not enough, but no Hum at all. I...give up, and plan to tear down the tubes part, and to re-layout, from lay-down form to stand-up form. And, don't forget to earth the chassis. What a mess!

Hi, guys, Thanks for all your advises and suggestions. Our global audio diy community is always warm and encouraged. Maybe I provide too little pictures of the amp to give you clear picture of the amp. It's not virtual grounding, It is designed as single-end amp. And, I made a star grounding in the up-left corner of the above picture. It's may not clearly to look the grounding due to I used the black wire as grounding line. After a day working, The Neutrik phone socket may have contacting problem, the sound of one channel is unstable. The layout of grounding wiring will be changed. Two boxes? It is not may original making idea. I need a small headphone amp, not a huge and expensive one. Now, it is Chinese New Year in Taiwan. So, I don't have time to work on this amp. The more pictures may help your guys to understand, here it is...

It's done ! It's low B+ voltage version Aikido Hybrid headphone amp designed by John Broskie. However, I replaced the tube, 6GM8, with 12FM6, due to the price of the former is so high to me. Now, I still fight for terrible hum issue !

Sorenb, Thank you very much! I've got the boards just a minute ago. And, It is quite awesome to me that my name is printed on the the envelope in exactly correct Chinese! Awesome! How did you do that? I didn't tell you my Chinese name in English, not even in Chinese! Cool, man!

See! Thanks, sorenb.

Thanks, sorenb. So, may I pay now? How much is the shipment fee? I live in Taiwan, and what shipment you will use? UPS? DHL? or something else?

Thanks sorenb, I need four Carbon PCB. May I pay by PayPal?

Hi~ Joe, I recommend this one, Mundorff supreme 0.33uF/1000V. You can buy it from local web store, Tube Fan Studio. And the most important, Its price is not too high to buy four of them in once. And more...the quality of sound is very good!

Thanks, JimL! I get your point and be appreciated your work of SRX+.

You mean the tail screw is easy to loose, right？ Put some solder on it can fix the problem, only do that after you screw up tightly!

I recommend this ebay item. this teflon socket is very very... yes! very... tight！ http://www.ebay.com/itm/280935223236?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649&rmvSB=true

Hi~ JimL & guys, I've got question, maybe some fool one. Why don't use CCS replaced the 250K resistor near the second 12AT7？

So.....What do you mean？ The fact was there is two time blowup of the PSU. Did the layout cause the blowup in some unknown situation？ That is the issue we really care about. Am I clear for you？

About 3 weeks ago, Joe reported his PSU of KGST blowout twice. After discussion through FB, I suggested reconstructing the whole thing by a skillful someone. I recommend the man, Getpointlee, to take the job. Getpointlee, once a audio dealer and a owner of audio manufacturing, live in Taipei, Taiwan. You may be interested in his blog(http://getpointlee.blogspot.tw/) . Another local DIYer provided a new PSU board for this whole new reconstructing. There are about 3 to 4 Diyers in Taiwan concern the progress of the problem that Joe met. We constantly discussed on the local forum or on the FB through private message. Unfortunately, It blowed up again! First blow is the bias parts, then the positive rail patrs. Very Very strange, right? After detailed check, Getpointlee found the problem may caused by the arc between the TP and the negative output rail. as below picture~ The distance between the TP and the negative rail output line is just only 1mm, but the voltage between theses is almost 1000V！ One mm is enough or not, could be a issue to discuss. However, no one here would like to have third blow again. So, for the safety issue, Getpointlee recommend the mod as below~ Wish these information help your guys to know that the HV PSU blowup may cause by the arc between the TP and negative rail output.

Hi~ Joehpj, I and my friend had noted your problem of KGST, and we found we should be in the same country Taiwan, right? If you did need any local help, please feel free to let me know. There is a discussion on the local forum, AA. I think you should know it. We all be there! Good luck!

Ask a question: KG point to use 270V zener while use ksa1156 to replace 2sa1486. Where is the exact component that KG mean? Would anyone like to provide photos to explain for me? Or using this part of kgsshv psu schematics explain for me. I'm truly newbie indeed !

Thanks KG！ I'll be back to the kgsshv psu while you give me the information of the fets replacement. Thanks!

I draw the schematics to show my modified version of the T2 psu for megatron below. Dose the modified schematics work? Any comments will be welcome. Thanks!

Dear all, I've got an idea to using T2 psu in the megatron plan. Is it an good idea, or not? It's nearly impossible to get 2SC3840 & 2SA1684 in local resource, and, fortunately, I got six 2SC3675！ So, I wonder to modify the T2 psu by adding more one fqp8n80c..... Is it work fine for megatron ?