Low Noise Transistors: Comparing the ZTX1053A and ZDT1053 (Dual) vs. the ZTX689B and ZTX851

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mediatechnology
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Re: Low Noise Transistors: Comparing the ZTX1053A and ZDT1053 (Dual) vs. the ZTX689B and ZTX851

Post by mediatechnology » Tue Mar 17, 2020 10:22 am

2SB737: https://ka-electronics.com/shop/index.p ... uct_id=108

I'm not shipping internationally right now due to reduced flights and long mail delays.

But I have them...
Their history: https://proaudiodesignforum.com/forum/p ... =11&t=1195
https://ka-electronics.com

Plandemic Series: "Pland3mic - Indoctornation" https://proaudiodesignforum.com/content ... nation.mp4
Plandemic Series: "Plandemic - Doctors In Black" https://proaudiodesignforum.com/content/Plandemic.mp4

CDC: "For 6% of the deaths, COVID-19 was the only cause mentioned. For deaths with conditions or causes in addition to COVID-19, on average, there were 2.6 additional conditions or causes per death." https://www.cdc.gov/nchs/nvss/vsrr/covi ... /index.htm

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mediatechnology
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Re: Low Noise Transistors: Comparing the ZTX789A to the 2SB737

Post by mediatechnology » Tue Mar 17, 2020 11:27 am

A comparison of the PNP ZTX789A to the PNP 2SB737.

Image
Low noise transistors. Comparing the ZTX789A (top) to the 2SB737 (bottom).
https://ka-electronics.com

Plandemic Series: "Pland3mic - Indoctornation" https://proaudiodesignforum.com/content ... nation.mp4
Plandemic Series: "Plandemic - Doctors In Black" https://proaudiodesignforum.com/content/Plandemic.mp4

CDC: "For 6% of the deaths, COVID-19 was the only cause mentioned. For deaths with conditions or causes in addition to COVID-19, on average, there were 2.6 additional conditions or causes per death." https://www.cdc.gov/nchs/nvss/vsrr/covi ... /index.htm

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JR.
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Re: Low Noise Transistors: Comparing the ZTX1053A and ZDT1053 (Dual) vs. the ZTX689B and ZTX851

Post by JR. » Tue Mar 17, 2020 4:00 pm

If only we had these devices back in the day.... :lol:

Oops we did.

JR

PS: BTW I found a partial tube of old panasonic MN3001 BBD chips.... I doubt these are in high demand these days but $15-$20 ea back in the 70s
It's nice to be nice.

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mediatechnology
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Re: Low Noise Transistors: Comparing the ZTX1053A and ZDT1053 (Dual) vs. the ZTX689B and ZTX851

Post by mediatechnology » Tue Mar 17, 2020 4:44 pm

JR. wrote:
Tue Mar 17, 2020 4:00 pm
If only we had these devices back in the day.... :lol:

Oops we did.

JR

PS: BTW I found a partial tube of old panasonic MN3001 BBD chips.... I doubt these are in high demand these days but $15-$20 ea back in the 70s
"And we still do both old and new."
(And it rhymes. :lol:)

I think the MN3001 are in demand.
We used the MN3001 in the "Time Warp" at MicMix.
https://ka-electronics.com

Plandemic Series: "Pland3mic - Indoctornation" https://proaudiodesignforum.com/content ... nation.mp4
Plandemic Series: "Plandemic - Doctors In Black" https://proaudiodesignforum.com/content/Plandemic.mp4

CDC: "For 6% of the deaths, COVID-19 was the only cause mentioned. For deaths with conditions or causes in addition to COVID-19, on average, there were 2.6 additional conditions or causes per death." https://www.cdc.gov/nchs/nvss/vsrr/covi ... /index.htm

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JR.
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Re: Low Noise Transistors: Comparing the ZTX1053A and ZDT1053 (Dual) vs. the ZTX689B and ZTX851

Post by JR. » Tue Mar 17, 2020 9:51 pm

mediatechnology wrote:
Tue Mar 17, 2020 4:44 pm
JR. wrote:
Tue Mar 17, 2020 4:00 pm
If only we had these devices back in the day.... :lol:

Oops we did.

JR

PS: BTW I found a partial tube of old panasonic MN3001 BBD chips.... I doubt these are in high demand these days but $15-$20 ea back in the 70s
"And we still do both old and new."
(And it rhymes. :lol:)

I think the MN3001 are in demand.
We used the MN3001 in the "Time Warp" at MicMix.
I recall the Panasonic distributor (in NJ) threatening to cut me off because I was selling them for less than full retail through my kit business... I told them sorry but 500,000 copies of that kit article are already out in the world. They demurred. 8-)

JR
It's nice to be nice.

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mediatechnology
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Re: Low Noise Transistors: Comparing the ZTX618 and ZTX1049A to the ZTX851

Post by mediatechnology » Thu Mar 19, 2020 3:53 pm

Image
Low noise transistors. Comparing the ZTX618 (top), ZTX1049 (top, overlaid) to the ZTX851 (bottom).

Comparing the ZTX851 to the ZTX618 and ZTX1049A.

ZTX851 433pV√Hz
ZTX618 622pV√Hz
ZTX1049A 638pV√Hz

I decided to look at the ZTX618 and ZTX1049A because they were low VceSat transistors and had high hFE. (Both are around 400 typical.)
Low VceSat, in the Zetex line, tends to correlate with low noise, low rbb' characteristics.

Both the ZTX618 and ZTX1049 are a tad noisier than the superb ZTX851 but good enough when higher current gain is required.
For mic impedances all of the ZTX transistors I've tested are more than adequate being << 1nV√Hz.
https://ka-electronics.com

Plandemic Series: "Pland3mic - Indoctornation" https://proaudiodesignforum.com/content ... nation.mp4
Plandemic Series: "Plandemic - Doctors In Black" https://proaudiodesignforum.com/content/Plandemic.mp4

CDC: "For 6% of the deaths, COVID-19 was the only cause mentioned. For deaths with conditions or causes in addition to COVID-19, on average, there were 2.6 additional conditions or causes per death." https://www.cdc.gov/nchs/nvss/vsrr/covi ... /index.htm

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mediatechnology
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Re: Low Noise Transistors: Comparing the ZTX951, 2SB737 and ZTX789A

Post by mediatechnology » Fri Mar 20, 2020 2:25 pm

A noise comparison of the ZTX951, 2SB737 and ZTX789A.

Image
Low noise transistors. Comparing the ZTX789A (top), 2SB737 (middle) to the ZTX951 (bottom).

Noise density:

ZTX951 376pV√Hz
2SB737 496pV√Hz
ZTX789A 673pV√Hz
https://ka-electronics.com

Plandemic Series: "Pland3mic - Indoctornation" https://proaudiodesignforum.com/content ... nation.mp4
Plandemic Series: "Plandemic - Doctors In Black" https://proaudiodesignforum.com/content/Plandemic.mp4

CDC: "For 6% of the deaths, COVID-19 was the only cause mentioned. For deaths with conditions or causes in addition to COVID-19, on average, there were 2.6 additional conditions or causes per death." https://www.cdc.gov/nchs/nvss/vsrr/covi ... /index.htm

terkio
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Re: Low Noise Transistors: Comparing the ZTX1053A and ZDT1053 (Dual) vs. the ZTX689B and ZTX851

Post by terkio » Tue Apr 07, 2020 3:51 pm

mediatechnology wrote:
Tue Mar 10, 2020 3:15 pm
The ZTX1053 looks ideal for mic preamps.
hFE for the ZTX1053 I tested ranged from 300-500 at low test currents.
Cobo is also low-ish around 21 pF.

With the ZTX1053 single looking so promising I'll be checking the dual ZDT1053.
I bought 6 - the Vos spread of the pairs was <<500 µV on all 6.
Great for mic preamps.
What is the hFE spread ?
You measured 300 - 500 about singles.
What matching accuracy can we expect from a batch of ZTX1053 ? Depending of batch size.
What about the hFE spread of the dual ZDT1053.
Should we go with duals or go with singles that we have carefully matched ?

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mediatechnology
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Re: Low Noise Transistors: Comparing the ZTX1053A and ZDT1053 (Dual) vs. the ZTX689B and ZTX851

Post by mediatechnology » Tue Apr 07, 2020 5:15 pm

I haven't tested enough of the alternative higher-hFE transistors to know but my experience with the ZTX851 shows that devices which have a good Vbe match usually have close hFE.

As best as I can recall the hFE difference is usually <=5% often better with the ZTX851 when the Vos is matched <500 uV.
Occasionally I find a pair that has a close Vbe match and a large hFE mis-match but they're odd-balls.
https://ka-electronics.com

Plandemic Series: "Pland3mic - Indoctornation" https://proaudiodesignforum.com/content ... nation.mp4
Plandemic Series: "Plandemic - Doctors In Black" https://proaudiodesignforum.com/content/Plandemic.mp4

CDC: "For 6% of the deaths, COVID-19 was the only cause mentioned. For deaths with conditions or causes in addition to COVID-19, on average, there were 2.6 additional conditions or causes per death." https://www.cdc.gov/nchs/nvss/vsrr/covi ... /index.htm

terkio
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Joined: Thu Feb 07, 2019 4:17 am

Re: Low Noise Transistors: Comparing the ZTX1053A and ZDT1053 (Dual) vs. the ZTX689B and ZTX851

Post by terkio » Tue Apr 07, 2020 8:04 pm

I am thinking about matching for a Vbe / Hfe compromise.

Considering a preamp with two 1K bias resistors.
Hfe 400, 5% Hfe match, 4 mA Ic.

We have Ib 10uA.
5% gives delta Ib 500nA
So, we have delta Vb 500uV, which is consistent with delta Vbe 500uV.
In the preamp, we want delta Ve < 500uV

What I have in mind is using a matching gig where I insert a resistor in the transitor base to represent the bias resistor that will be used in the final circuit.

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