TO-3 SYMASYM - Page 12

Rudi_Ratlos · 20th September 2011, 11:01 AM

I would give the ZTX450 a try, Anton. Why not?

Best regards - Rudi_Ratlos

Atilla · 20th September 2011, 12:00 PM

If I get some good matched pairs, I can give it a shot. But since the datasheet doesn't mention the noise figures, I've no idea if it's good or not. (F.ex. the MPSA18 noise is listed 1.5dB, while the BC550 is 4dB)

evette · 20th September 2011, 12:21 PM

Mr. Rudi you wouldn,t gain anything. Evette

tome · 20th September 2011, 12:21 PM

Hi Rudi
I pay to you yesterday on your bank acc, I hope I'm on your list
regards
tomas

Rudi_Ratlos · 20th September 2011, 01:31 PM

Tomas,

you are of course on my list.

Best regards - Rudi_Ratlos

tome · 20th September 2011, 02:12 PM

thanks

Rudi_Ratlos · 22nd September 2011, 08:37 AM

Dear TO-3 SYMASYM friends,

I am happy to tell you that I received a confirmation of the etching company telling me that the PCBs will be etched and shipped on September 30th.

I will then have the PCBs on Wednesday, 4th of October and will meet Sascha, who will do the shipping, on the weekend 8th / 9th of October.

I suppose that most of you will have the PCBs in week 41 (10th to 15th of October).

Best regards - Rudi_Ratlos

AndrewT · 23rd September 2011, 08:58 AM

Quote:

Originally Posted by Atilla

ex. the MPSA18 noise is listed 1.5dB, while the BC550 is 4dB)

at what Ic and what frequency range and what source resistance?

Atilla · 09:07 AM

MPSA18: Vce = 5.0V , Ic = 100uA, Rs = 10k, f = 1.0kHz.
BC550: Vce = 5.0V , Ic = 200uA, Rs = 2k, f = 1.0kHz. (Actually listed all over the range - 10Hz to 15.7kHz)

Edit: The datasheets that list that don't seem to all list it under the same conditions, sadly.

AndrewT · 23rd September 2011, 11:07 AM

find a datasheet or two or three that have noise graghs for the device.
Plot on those graphs, the two noise figures for the respective devices.
Where these two devices end up, may give you a good clue to how they compare.

23rd September 2011, 09:04 AM	#119
Atilla diyAudio Member Join Date: Jul 2008	MPSA18: Vce = 5.0V , Ic = 100uA, Rs = 10k, f = 1.0kHz. BC550: Vce = 5.0V , Ic = 200uA, Rs = 2k, f = 1.0kHz. (Actually listed all over the range - 10Hz to 15.7kHz) Edit: The datasheets that list that don't seem to all list it under the same conditions, sadly. Last edited by Atilla; 23rd September 2011 at 09:07 AM.

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20th September 2011, 11:01 AM	#111
Rudi_Ratlos diyAudio Member Join Date: Jun 2009 Location: Hamburg / Germany	I would give the ZTX450 a try, Anton. Why not? Best regards - Rudi_Ratlos

20th September 2011, 12:00 PM	#112
Atilla diyAudio Member Join Date: Jul 2008	If I get some good matched pairs, I can give it a shot. But since the datasheet doesn't mention the noise figures, I've no idea if it's good or not. (F.ex. the MPSA18 noise is listed 1.5dB, while the BC550 is 4dB)

20th September 2011, 12:21 PM	#113
evette diyAudio Member Join Date: Jun 2006	Mr. Rudi you wouldn,t gain anything. Evette

20th September 2011, 12:21 PM	#114
tome diyAudio Member Join Date: Apr 2010 Location: Ohrid, Macedonia	Hi Rudi I pay to you yesterday on your bank acc, I hope I'm on your list regards tomas

20th September 2011, 01:31 PM	#115
Rudi_Ratlos diyAudio Member Join Date: Jun 2009 Location: Hamburg / Germany	Tomas, you are of course on my list. Best regards - Rudi_Ratlos

20th September 2011, 02:12 PM	#116
tome diyAudio Member Join Date: Apr 2010 Location: Ohrid, Macedonia	thanks

22nd September 2011, 08:37 AM	#117
Rudi_Ratlos diyAudio Member Join Date: Jun 2009 Location: Hamburg / Germany	Dear TO-3 SYMASYM friends, I am happy to tell you that I received a confirmation of the etching company telling me that the PCBs will be etched and shipped on September 30th. I will then have the PCBs on Wednesday, 4th of October and will meet Sascha, who will do the shipping, on the weekend 8th / 9th of October. I suppose that most of you will have the PCBs in week 41 (10th to 15th of October). Best regards - Rudi_Ratlos

23rd September 2011, 11:07 AM	#120
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	find a datasheet or two or three that have noise graghs for the device. Plot on those graphs, the two noise figures for the respective devices. Where these two devices end up, may give you a good clue to how they compare.