Inu

How about remove RK27 then use space for add 2SA1968 0.5mA (150mW) CCS option for the 2nd stage?

Kevin, Not flipped NFB line. Each 6CA7 sinks or sources about 27mA (11W) is correct? 450V Line (included 300V line) = total 61mA/ch -450V Line = total 54mA/ch

If possible, For the 0.22uF/1000V Add extra mounting hole for the PCM 22.5mm capacitors (EPCOS) For the 0.1uF/450V(400V) Add extra mounting hole for the PCM 15mm capacitors (EPCOS and MKP10)

Oops, Making > Marking. How about adding protection resistors (5.1K 1W) to the outputs?

Minor issues.. Missing (or deleted?) the protective diode between the TL783 In and Out. Making "AC2" and "-" for the bridge rectifies (KBU4x) were reversed (patterns are OK).

I think electorlytic capacitor 220uF/100V is too close to the hot 6CA7. I know mounting these on other side but...

2SC4686A 100 - 249pcs = 58JPY/pc. They can take order from US but only ship to the address in JPN... http://jp.rs-online.com/web/p/products/6011674P/

I want to see picture of your 2SC2705... and A970, C2240.

Congratulations! → Kerry, Chnsettawong and pedefade. I'm very interesting in your DIY phones too. → Chinsettawong.

I am using T2 three to four times/week since I build it but I have no noise issues after I modified around the pots. I used TAKMAN REY for the most part.

FYI 2SA1413 (Z) / 2SC3632 (Z) = TO-251 (TO-252) version of the 2SA1486 / 2SC3840.

Yes, it is genuine Renesas FET. I am using same one in my T2.

Sorry, I should have posted on the "Discussion on the design of the T2 & other circuitry"

I have no idea that use semis for first stage is good or bad for the sounds. Article from MJ 1995/5 (Page 37) --------------------------------------------- “The first stage is a cascaded differential circuit that uses two 7308 tubes that are equivalent to the 6DJ8. A transistor constant current source was added to both the plate load and the cathode. The supply voltages for this differential circuit are +250V and -600V. The reason tubes are used for the first stage is to avoid thermal related parameters. If semiconductors were used in this circuit, the junction temperature would be influenced by the current. It would be easy to unbalance the differential circuit when the current changes. However by using tubes, the temperature is already biased by heaters so regardless of changes in current, the operating parameters will be very stable. These tubes are covered by metal shielding caps.”

2SK216 = @231JPY in Japan. $2 each is good deal! Date Code = 2W5 Hitachi’s date code format: A (Jan) … L (Dec) ... W( )

The fake K216(left)in the picture is from Israel. Seems he is getting different version of K216 from HKG distributor now. https://picasaweb.go...263986452551218 Simple test: Use it to the T2: If blowup it was fake, stop use it.

It looks remarked on 2SK213,214,215 or counterfeit. 1. Hitachi logo is slightly different. 2. Date code format is strange. “912”? Probably they misread “9 I2” (9=1989 or 1999 I =Sep) when they copied. 3. Font is same as my other counterfeit transistors.

Congratulation!

Craig, I hope you’re feeling better. 650KHz… You can use a potable AM radio for the investigation.

I measured my T2 with HP8903B Audio Analyzer and Tektronix TDS3054 500MHz Digital Oscilloscope. Output noise is approximately Rch = 7mVrms / Lch = 8mVrms in 80KHz bandwidth. I used 1/2W TAKMAN REY + few PRP, Shinko Tantalum and military surplus resisters.

I brought my T2 to the test bench and check the noise again, but does not observed any oscillation with and without 120PF load. Perhaps I am using a different type of the resistors for the NFB… While I’m investigating the PS OSC problem, I gave up the large MILLS resisters that picking up a lot of noise and unstable when finger or tip of the probe is moved closer to these resistors. It becomes stable and no more body effects after I replaced these to the TAKMAN.

MY counterfeit Nippon Chemi-con 680uF/450V from HKG: Printed "Negative Black" on the body but no black inked on the negative terminal and original Nippon Chemi-con KMG/KMH has not printed "Negative Black" on the body. Printed "KMG". The KMG series are the read type and up to 47uF for 450V. Date Code is "B459" When peel the shrink cover on the body, the cap has a "X" shape slit on the top. Nippon Chemi-con uses "Y" shape. Capacitance is OK but I can't trust them to use for the high voltage applications. http://www.chemi-con.co.jp/e/counterfeit.html http://picasaweb.google.com/inuponken/T2#5563286571084384946

I need 6DJ8 FETRON for my T2

I see. The holes next of the connecters are for the plastic standoff?

Is the 1min delay circuit on other board?