Date   
ACCOUNTING FOR YOUR CONTRIBUTIONS

 

By now just about everyone has read my post to TekScopes "asking for small
contributions" (my exact words). I owe you a complete financial accounting.
This will take me a day or two to prepare. So please be patient.

With a few exceptions everyone used PayPal so it will be relatively easy to
post a sorted list of PayPal transaction numbers and the amount received
from each transaction. Anyone who contributed will be able to confirm their
contribution has been accounted for by verifying their transaction number
and amount are in the list. No personal information will be revealed this
way.

Please hold any suggestions for how to do this the next time or how to spend
the money. Michael Dunn and I have discussed these very same issues and
more. I will include our thoughts about how this should be handled along
with the financial accounting of the contributions.

I need a few days to create an accounting of the contributions and to
summarize Michael's and my ideas for how to proceed. Until then please be
patient and make space in the forum for our members to ask questions about
collecting, repairing, restoring, and using the wonderful tools Tek's
engineers have created for us to explore and play with.

Dennis Tillman W7PF



--
Dennis Tillman W7PF
TekScopes Moderator

Re: 130 LC meter

Richard Knoppow
 

Re parasitic reactance in resistors. I used my late lamented Boonton RX meter (looking for another, it got knocked off a bench and is unrepairable). I found that in the range of the instrument carbon and metal film resistors had considerably less parasitic reactance than carbon composition resistors. In fact, this is illustrated in the instruction manual. While one would think the spiral construction of the resistor would result in considerable inductance it does not. The parasitic capacitance is neutralized by any inductance. Of course the amount depends on the value and size of the resistor but ordinary quarter or half watt units up to several thousand ohms have very little reactance.

On 1/3/2020 12:11 PM, Albert Otten wrote:
Hi Dave,

Nice to read that at least one person was content with that frequency based calibration method.
Some remarks follow below.

Albert

On Thu, Jan 2, 2020 at 09:21 PM, Dave Wise wrote:

Not the OP's problem but it's about the 130. I want to document some
interesting symptoms and their causes.

I calibrated it using Albert Otten's 2016 topic "Tpe 130 L-C meter calibration
using only a 300 pF cap", https://groups.io/g/TekScopes/topic/7656928#126515 .
It's much easier than acquiring an S-30, all you need is one good close cap
and a frequency counter. Few labs had counters when the 130 was born.
Since I had the counter connected, I decided to try calibrating C7, Resistance
Compensation.

SYMPTOM: Not possible to match readings 1M vs 100K, C7 at minimum still too
big.
FIX: Reducing R8 helps. I put in 680K instead of 1M.
It looks like my C7 is also at the in one extreme but I don't take the risk (of breaking) to adjust his trimcap.
NOTES:
Carbon film and metal film have less parasitic C than carbon comp at these
values and frequencies.
...
Old black Welwyn 1% spiral-cut carbon? film resistors in my junk box which
happen to be the type used in early production of S-30: 100K is 0.4pF, 1M is
0.5pF . > So I adjust R8 so 1M reads 0.1pF higher than 100K.
I didn't try to measure parasitic capacitance of a 1M or 100k resistor. But I did several measurements with resistor clamped in the fixture, excessive lead length cut away. I inserted a resistor, set the offset for a reading at 1.5 pF, the quickly removed the resistor and noted the drop in the reading. Essentially always the reading dropped by 0.25 to 3 pF, for different R values and different ratings (1/2, 1/4, 1/8 W), metal film and cc. So I should be content with the setting of C7 I think. The big Welwyn resistors (body over 1") give a drop of 1 pF or slightly more.
There is also a remark in the manual about line voltage sensitivity when C7 has not enough range. You might look at this.
SYMPTOM: C99 and C100. Tek installed them backwards, they're
drawn backwards on the schematic too.
FIX: Probably EVERY 130 needs them replaced, with anode facing positive voltage.
This seems so obvious that we might guess that Tek had a special reason for this. At full scale deflection the (reverse) voltage is 0.75 V. That might or might not be high enough to cause damage? Could it give some meter protection when the multivibrator frequency approaches zero?
SYMPTOM: 10pF reads high on 30pF range.
CAUSE: Dielectric Absorption in C92 .0047/400 charge pump cap.
This is the first failure I've ever seen that was traceable to DA.
It makes the cap appear larger than it should be, and changing with frequency,
so readings that are low on the scale pump too much charge and get skewed upwards.
NOTES:
You can measure C92, C93 etc in-circuit if the 130 range switch is OFF.
The cap is not leaky.
It's a Sprague 160P DiFilm. (Plastic/paper dielectric.)
Use GR 1680-A to measure C at 1kHz and 400Hz.
Should read 4.7nF, but I see 6.5nF at 1kHz, 7.5nF at 400Hz. Yep.
An ideal cap will be constant C, a cap with DA will increase with decreasing f.
Later I tested it using the soak-discharge-wait-measure method. Significant rebound,
over 10V after 100V soak. That will mess up a charge pump!
FIX: Replaced with polypropylene. Also replaced C93 .015/400 10pF range because
it had some DA too.
I measured C91 to C95 both with the GR 1656 (1 kHz) and with a cheap Aldi DMM. The 2 readings were remarkably close, within 0.5%, except for 3.5% in C91. Also the differences from nominal were <10%, except again for C91. The measurement principles are very different. Hence I would trust C92 to C95 but question C91.
Joke's on me - now 10pF on 30pF range reads a bit low where it used to read high.
I bet those 160P caps had some DA when new, and Tek drew the meter scale to fit.
Maybe I should have used something with more DA. Oh well, |error| is smaller now at least.
LESSON: Replace all paper/plastic caps in positions sensitive to Dielectric Absorption,
even if they test good for leakage.
The scales are non-linear anyway since the frequency deviation is a nonlinear function of the capacitance under test. This is most pronounced at the 300 pF range but hardly visible at the 10 pF range. The 3 pF range can be considered as linear. I doubt that Tek corrected the scale for other effects. I didn't check my 130 yet with 10 pF on the 30 pF range but this should be easy using the frequency counter. Maybe later.
HTH,
Dave Wise
--
Richard Knoppow
dickburk@...
WB6KBL

Re: Annual Groups.io Fees

Don Bitters
 

Also restating the obvious, Dennis should put it on his calendar for November or so, to send out a notice for next years billing.  I would have absolutely no problem with him excluding his share of the bill from the total, since he has taken on the task of moderator and handling the account. I greatly enjoy and learn from the accumulated wisdom found here.  I am a neophyte when it comes to TEK ETE repairs, but have used quite a few pieces of TEK ETE over the last 50 yrs.  Most of my gear is HP, Agilent and I have a bit of expertise in repairs usage, and programming of that ETE.Don Bitters

Re: 130 LC meter

Albert Otten
 

Mistake in my previous message: I measured C91 to C94. Everywhere C95 should read C94. Albert.

Re: 130 LC meter

Albert Otten
 

Hi Dave,

Nice to read that at least one person was content with that frequency based calibration method.
Some remarks follow below.

Albert

On Thu, Jan 2, 2020 at 09:21 PM, Dave Wise wrote:


Not the OP's problem but it's about the 130. I want to document some
interesting symptoms and their causes.

I calibrated it using Albert Otten's 2016 topic "Tpe 130 L-C meter calibration
using only a 300 pF cap", https://groups.io/g/TekScopes/topic/7656928#126515 .
It's much easier than acquiring an S-30, all you need is one good close cap
and a frequency counter. Few labs had counters when the 130 was born.
Since I had the counter connected, I decided to try calibrating C7, Resistance
Compensation.

SYMPTOM: Not possible to match readings 1M vs 100K, C7 at minimum still too
big.
FIX: Reducing R8 helps. I put in 680K instead of 1M.
It looks like my C7 is also at the in one extreme but I don't take the risk (of breaking) to adjust his trimcap.

NOTES:
Carbon film and metal film have less parasitic C than carbon comp at these
values and frequencies.
...
Old black Welwyn 1% spiral-cut carbon? film resistors in my junk box which
happen to be the type used in early production of S-30: 100K is 0.4pF, 1M is
0.5pF . > So I adjust R8 so 1M reads 0.1pF higher than 100K.
I didn't try to measure parasitic capacitance of a 1M or 100k resistor. But I did several measurements with resistor clamped in the fixture, excessive lead length cut away. I inserted a resistor, set the offset for a reading at 1.5 pF, the quickly removed the resistor and noted the drop in the reading. Essentially always the reading dropped by 0.25 to 3 pF, for different R values and different ratings (1/2, 1/4, 1/8 W), metal film and cc. So I should be content with the setting of C7 I think. The big Welwyn resistors (body over 1") give a drop of 1 pF or slightly more.
There is also a remark in the manual about line voltage sensitivity when C7 has not enough range. You might look at this.

SYMPTOM: C99 and C100. Tek installed them backwards, they're
drawn backwards on the schematic too.
FIX: Probably EVERY 130 needs them replaced, with anode facing positive voltage.
This seems so obvious that we might guess that Tek had a special reason for this. At full scale deflection the (reverse) voltage is 0.75 V. That might or might not be high enough to cause damage? Could it give some meter protection when the multivibrator frequency approaches zero?

SYMPTOM: 10pF reads high on 30pF range.
CAUSE: Dielectric Absorption in C92 .0047/400 charge pump cap.
This is the first failure I've ever seen that was traceable to DA.
It makes the cap appear larger than it should be, and changing with frequency,
so readings that are low on the scale pump too much charge and get skewed upwards.
NOTES:
You can measure C92, C93 etc in-circuit if the 130 range switch is OFF.
The cap is not leaky.
It's a Sprague 160P DiFilm. (Plastic/paper dielectric.)
Use GR 1680-A to measure C at 1kHz and 400Hz.
Should read 4.7nF, but I see 6.5nF at 1kHz, 7.5nF at 400Hz. Yep.
An ideal cap will be constant C, a cap with DA will increase with decreasing f.
Later I tested it using the soak-discharge-wait-measure method. Significant rebound,
over 10V after 100V soak. That will mess up a charge pump!
FIX: Replaced with polypropylene. Also replaced C93 .015/400 10pF range because
it had some DA too.
I measured C91 to C95 both with the GR 1656 (1 kHz) and with a cheap Aldi DMM. The 2 readings were remarkably close, within 0.5%, except for 3.5% in C91. Also the differences from nominal were <10%, except again for C91. The measurement principles are very different. Hence I would trust C92 to C95 but question C91.

Joke's on me - now 10pF on 30pF range reads a bit low where it used to read high.
I bet those 160P caps had some DA when new, and Tek drew the meter scale to fit.
Maybe I should have used something with more DA. Oh well, |error| is smaller now at least.
LESSON: Replace all paper/plastic caps in positions sensitive to Dielectric Absorption,
even if they test good for leakage.
The scales are non-linear anyway since the frequency deviation is a nonlinear function of the capacitance under test. This is most pronounced at the 300 pF range but hardly visible at the 10 pF range. The 3 pF range can be considered as linear. I doubt that Tek corrected the scale for other effects. I didn't check my 130 yet with 10 pF on the 30 pF range but this should be easy using the frequency counter. Maybe later.

HTH,
Dave Wise

Re: Accounting...

Alexandre Souza
 

"Why?"

- Gofundme takes a good portion of its earnings, doing virtually nothing.
- Dennis didn't specifically "asked" to be reimbursed for 3 years of paying
the groups' fees. He asked for contribuitions and here it is.
- No one, in the last three years asked in public "hey Dennis, need help
with the groups' fees?". So why have accountability now?

I consider money spent with this group, a return for the lots of help I had
in these years (which gave me $ back some times) and I wish Dennis spend it
as he wishes. I just don't care =)

---8<---Corte aqui---8<---
http://www.tabajara-labs.blogspot.com
http://www.tabalabs.com.br
---8<---Corte aqui---8<---


Em sex., 3 de jan. de 2020 às 15:58, Lyle Bickley <@lbickley>
escreveu:

Hi Dennis,

In retrospect, we should probably have funded group.io support by
"GoFundMe"
(gofundme.com) or other similar method. That way there would be a running
total of funds received, from whom and for a well defined purpose, etc.

Perhaps we should move to this approach now. (Do other's have thoughts on
this?)

At any rate, given we didn't do that, and to stave off any criticism of the
"PayPal" approach we took, it would be wise to keep a running total of the
funds collected and post it to the group periodically - and when money is
spent, say where it is being spent and the new total.

Regards,
Lyle
--
73 NM6Y
Bickley Consulting West Inc.
https://bickleywest.com

"Black holes are where God is dividing by zero"



Tek 2710 SA error: Unable to delete files at startup

Rogerio O
 

Dear all,
I bought one unit with this error some years ago.
Since then I have seen other units on sale with the same problem but I could not find a solution for this problem.
I have been contacted by an Edaboard member who thought I have found the solution described there in an old post.
I copied below the post with a description of the solution to the problem, but, unfortunately the schematic with the mod developed by him was lost due to a database error.
My hope is that one person of this forum that is familiar with the 2710 design could figure out how to reconstruct missing the signals using the 74HCT04 and 74HCT00 as mentioned.
Happy 2020 for all
"*****quote*******
Hi,
here is another 2710 which had this problem.
I bought it from a colleague who described these symptoms before repair:
- Power-on messages about NVRAM / file system errors
- Spurious characters on the display
- Useless files which could not be deleted

After exchanging battery, RAM and bus drivers on the display storage board, he used a logic analyzer to track down the error to a faulty OE- signal from PLD U352 Pin 24 to bus driver U462 Pin 19. The CPU could still write to the NVRAM, but reading was not possible.

The faulty OE- signal could be reconstructed from other existing signals by two SMD logic circuits (74HCT04 and 74HCT00).
After his repair, almost all analyzer functions worked, but many amplitude normalizations always failed.

It cost me some more hours to find out that the CPU will read the acquired signal not only from the NVRAM, but also accesses the ADC data directly. The logic signal for this is called REDAT-.

So I extended the replacement circuit, and now the amplitude normalizations also work. It seems that REDAT- is not used during normal operation, but only for calibration.

A simplified but logically equivalent circuit is attached as PDF. It uses a 74HCT08 and 74HCT00 for reconstruction.

The ICs are stacked onto U566 (right besides the bus connector) and powered by vertically soldered wires on Pins 7 and 14. All other pins have been bent to go out straight horizontally and are connected using thin isolated copper wire (as used e.g. for transformers).
Pin 19 of the bus driver U462 is lifted from the PCB, the original DROE- signal is taken from the PCB-pad and the reconstructed signal is routed to the pin.

I cannot be sure that all 2710 can be repaired this way, but since the symptoms described here are very coincident, there is a good chance to make them all work again.

Good luck,
Andreas.


******** unquote**********

Accounting...

Lyle Bickley
 

Hi Dennis,

In retrospect, we should probably have funded group.io support by "GoFundMe"
(gofundme.com) or other similar method. That way there would be a running
total of funds received, from whom and for a well defined purpose, etc.

Perhaps we should move to this approach now. (Do other's have thoughts on
this?)

At any rate, given we didn't do that, and to stave off any criticism of the
"PayPal" approach we took, it would be wise to keep a running total of the
funds collected and post it to the group periodically - and when money is
spent, say where it is being spent and the new total.

Regards,
Lyle
--
73 NM6Y
Bickley Consulting West Inc.
https://bickleywest.com

"Black holes are where God is dividing by zero"

Re: MEMBERS PLEASE READ: Our annual Group.io payment is due in 2 weeks.

DaveH52
 

I don't have your email address or phone number, and Paypal didn't like Dennis Tillman W7PF or @Dennis_Tillman_W7PF, so I sent $10 to the group owner.
AC2GL.Dave

Re: TDS694C nvram DS1486

George Langston
 

Jay,
All four channels are triggering properly in normal mode, however, the channel in question - ch2 - shows an attenuated signal that looks noisy compared to the other three. Also, ch2, does not respond to the vertical offset control. It does measure a perfect 50 ohms, as do the other three. I'm hoping one of those TL074 jfet opamps is shot. Will do some more tracing today.

-George

Re: MEMBERS PLEASE READ: Our annual Group.io payment is due in 2 weeks.

Andrew Stanworth
 

Have sent a small contibution from across the pond to [dennis at ridesoft dot com] as I could not for the life of me get the @Dennis_Tillman_W7PF to work in Paypal! Hope it reaches you ok!

Re: TDS3044B repair

David Kuhn
 

" The problem turned out to be a bad solder joint on a surface mount choke
that supplied Vcc to the display."

Wow, congratulations! Good job! I could not tell you where to get case
components.

On Thu, Jan 2, 2020 at 12:23 PM Tom B <tbryan@...> wrote:

Hello All,

I finally had time to get back to fixing the TDS3044B with no display.
The problem turned out to be a bad solder joint on a surface mount choke
that supplied Vcc to the display. The crack was so small it could
barely been seen on a microscope. So, the problem was not the display.
For those that need a display for a TDS3000B, the real part number is
NEC NL6448BC20-08E. The other thing that was helpful in troubleshooting
the display was a Hirose connector part number DF9A-31P. This gave me
some more room to probe the display connections on the main board. Now
I need to find the hub bits that hold the handle on the scope. If
someone knows where to get those please let me know.

Tom Bryan

On 11/7/2019 10:00 PM, Tom B wrote:
Hi Dave,

If you look at this video
https://urldefense.com/v3/__https://www.youtube.com/watch?v=Z_gvjmKHN4Y__;!b9GWhakWANQ!wEpfxjysOXjFgv3ZjJzwPT00sPf81J7-h9F-OyCNJMU1-f5Y3AG4Mbyun-yU$
it shows a part number on the back of the display as 65BLM04 and on
the front of the display the tag says NL6448BC20-08. If you search
each of these part numbers on ebay, the price is very different when
they are actually the same part. The cheapest price I could find for
the 65BLM05 is $158.74 (used), while the cheapest price for the
NL6448BC20-08 is $88 for a new part. These appear to be exactly the
same part. Any idea if there is any difference?

Tom

On 11/7/2019 2:28 PM, David Kuhn wrote:
https://urldefense.com/v3/__https://www.youtube.com/watch?time_continue=261&v=iVU0YPIeovM__;!b9GWhakWANQ!wbXzExaWmEY10yA6ddr1j7dzMVPNV7j4iMLI9u6paEFuQ5tXhS6mqOV8S_HN$


https://urldefense.com/v3/__http://lcdparts.net/UBDetail.aspx?ProductID=3796__;!b9GWhakWANQ!wbXzExaWmEY10yA6ddr1j7dzMVPNV7j4iMLI9u6paEFuQ5tXhS6mqCtAAjYv$


Looks like a perfect solution for the NEC on the TDS3000 series and
in the
NEC 65BLM05 Display (virtually the same display as the one TEK uses)
in the
instruments I do a lot of work on.

Unlike the video, I would not remove the paper exposing the glue when
installing the strips. I don't want those LED strips permanently in my
LCDs in case they fail.

Dave

On Wed, Nov 6, 2019 at 11:40 PM Harvey White <madyn@...>
wrote:


Re: 575 vs. 576 comparisons

 

Hi Kelly,

As it says in our homepage:
TekScopes is all about classic Tektronix test equipment, its use, repair,
and collecting.
We are not an alternative to Craigslist or Ebay.
What would be OK is to offer something that our members can use that you
would like to see put to good use.
Our members are frugal above all else so offering something to the group is
fine as long as profit is not your motive.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Kelly
Edington
Sent: Friday, January 03, 2020 8:03 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 575 vs. 576 comparisons

Can I sell on this place?




--
Dennis Tillman W7PF
TekScopes Moderator

Re: 575 vs. 576 comparisons

 

Hi Eric,
Make sure you got the number right. A 570 and a 575 look similar.
If you know it is a 570 and it is for sale DO NOT HESITATE.
570s are extremely valuable and highly sought after.
Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Eric
Sent: Friday, January 03, 2020 7:01 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 575 vs. 576 comparisons

John,

Actually I think i might have had the models mixed up I was thinking the
570 not the 575.

Eric

On 1/3/2020 9:57 AM, Eric via Groups.Io wrote:
Depends on if you are working with tubes. The 575 lends it self to
testing tubes given how the test fixtures are built and used. The 576
is better for solid state devices both can be used for both with some
home-grown test fixtures 576 needs a heater supply at the very least.
If I remember correctly the 576 is more sensitive on the low end
measurements as well.

On 1/3/2020 9:46 AM, John Griessen wrote:
Can someone point me to good talk about the differences in the
groups.io archives?

There's a cheap 575 available, but I'm trying to reduce down for a
move to NM...

576 is better by far and best to wait for, right?







--
Dennis Tillman W7PF
TekScopes Moderator

SG5030 and SG504 leveling heads

 

I've considered doing a head leveling replacement for the SG5030, but without one on hand to develop on it has not happened. The SG504 head I made runs at nearly double the frequency range of the SG5030 so I imagine it is quite possible to develop.

The capital Investment for the SG5030 and the mainframe for it makes the exercise not a sustainable one so far, unless the replacement heads have some guaranteed sales.

My development of a SG504 head occurred because I own a SG504 and found that the David P's groundbreaking head kit was a bit difficult to assemble/use without an OEM head housing on hand (and also required an additional calibration step) . So offering a more compact, complete working head in a custom enclosure negated the need for the DIY calibration. Overall the community supported my efforts and the head I designed/built still sells occasionally (one every 2 months or so) online on EBAY, but I rarely promote it now as I have other products in the pipeline to manufacture.

However, never say never. I may have the opportunity one day to work with the SG5030.

Re: 575 vs. 576 comparisons

ke5lly@...
 

Can I sell on this place?

Get Outlook for Android<https://aka.ms/ghei36>

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Eric <ericsp@...>
Sent: Friday, January 3, 2020 9:00:44 AM
To: TekScopes@groups.io <TekScopes@groups.io>
Subject: Re: [TekScopes] 575 vs. 576 comparisons

John,

Actually I think i might have had the models mixed up I was thinking the
570 not the 575.

Eric

On 1/3/2020 9:57 AM, Eric via Groups.Io wrote:
Depends on if you are working with tubes. The 575 lends it self to
testing tubes given how the test fixtures are built and used. The 576
is better for solid state devices both can be used for both with some
home-grown test fixtures 576 needs a heater supply at the very least.
If I remember correctly the 576 is more sensitive on the low end
measurements as well.

On 1/3/2020 9:46 AM, John Griessen wrote:
Can someone point me to good talk about the differences in the
groups.io archives?

There's a cheap 575 available, but I'm trying to reduce down for a
move to NM...

576 is better by far and best to wait for, right?



Re: MEMBERS PLEASE READ: Our annual Group.io payment is due in 2 weeks.

 

Hi Victor,
Thank you for your contribution.
It looks like everything is OK.
This is what PayPal sent us yesterday.
Dennis
--------
Payment from Victor Silva of $10.00 USD on Jan 2, 2020 is being sent
Dear Marian Tillman,
We have completed our review of this transaction.
Amount: $10.00 USD
Transaction ID: 3098855529393613G
Sender: Victor Silva
View the details of this transaction
This transaction is no longer pending and the money has been released to your account balance. Thank you for your patience.
Sincerely,
PayPal
--------

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of victor.silva via Groups.Io
Sent: Thursday, January 02, 2020 7:00 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] MEMBERS PLEASE READ: Our annual Group.io payment is due in 2 weeks.

Hi Dennis,

I made a contribution and Paypal came back with this message.
It's probably not a problem, I've never seen this kind of message.

--Victor Silva

===================================================
Your payment is being reviewed because of regulations.
We're working fast to resolve this. In the meantime, here's some information about the situation:

We usually complete this process within 72 hours, with your cooperation.
For now, this review only involves this transaction and does not affect the use of your PayPal account.
We'll send an email soon to keep you in the loop, and will follow-up with you when it's complete or if we need more information.
===================================================




--
Dennis Tillman W7PF
TekScopes Moderator

Re: 575 vs. 576 comparisons

Eric
 

John,

Actually I think i might have had the models mixed up I was thinking the 570 not the 575.

Eric

On 1/3/2020 9:57 AM, Eric via Groups.Io wrote:
Depends on if you are working with tubes. The 575 lends it self to testing tubes given how the test fixtures are built and used. The 576 is better for solid state devices both can be used for both with some home-grown test fixtures 576 needs a heater supply at the very least. If I remember correctly the 576 is more sensitive on the low end measurements as well.

On 1/3/2020 9:46 AM, John Griessen wrote:
Can someone point me to good talk about the differences in the groups.io archives?

There's a cheap 575 available, but I'm trying to reduce down for a move to NM...

576 is better by far and best to wait for, right?


Re: 575 vs. 576 comparisons

Eric
 

Depends on if you are working with tubes. The 575 lends it self to testing tubes given how the test fixtures are built and used. The 576 is better for solid state devices both can be used for both with some home-grown test fixtures 576 needs a heater supply at the very least. If I remember correctly the 576 is more sensitive on the low end measurements as well.

On 1/3/2020 9:46 AM, John Griessen wrote:
Can someone point me to good talk about the differences in the groups.io archives?

There's a cheap 575 available, but I'm trying to reduce down for a move to NM...

576 is better by far and best to wait for, right?

575 vs. 576 comparisons

John Griessen
 

Can someone point me to good talk about the differences in the groups.io archives?

There's a cheap 575 available, but I'm trying to reduce down for a move to NM...

576 is better by far and best to wait for, right?