Amber 3501A Distortion analyzer?

[1audio]

FWIW I still have mine and it is still available: https://www.diyaudio.com/forums/swap-meet/346794-amber-3501-sale.html#post6011521

 

[deepdigger]

Both my 3501A have orange Siemens al. capacitors 10u/40V in quanyity of 30 inside each device.
I'm going to replace them with new Low ESR Panasonic 33u/35V (real ESR is ~0,2 Ohm).

There are some yellow tantalum capacitors too, but I tested them and they are perfect, so no any reason to replace them.

 

[Dilbert]

In a 3501, U1008 is a DIP socket for the auxiliary filter. Filter R’s and C’s are soldered directly to a plug-in header. In one of mine I have an A weighting filter network in that spot. It can also be used to connect signal I\O and power for an umbilical cable if the “C”Message PCB option is installed.

 

[rsavas]

Anyone have a schematic for the 358 frequency counter, mine is not working. The display is dead, but the leds toggle for the switches. Just going to have to get into it. I have another unit as a spare with a 358, so could use as a reference as needed.
So far I have only had to change ITT blue tants caps ...

 

[zapbuzz]

So far I have only had to change ITT blue tants caps ...

what did you replace them with? did you put tantalums back in?

 

[rsavas]

It was a long time ago, but iirc I used some kemet tants. You can also use low esr ecaps as well, won't short out like the tants do.

 

[zapbuzz]

Hi KC,

I have plenty of Amber 3501A sets to play with, I hope I can get results similar to yours. Yes, the price on the AD747 parts seem to be just all over the place, mostly too high. Then, they have "A" parts, AN, ANZ, BN, BRN, and ceramic SQ's, some have ANalog Device logos, some don't - what a mess???

I bought some older stock AD747AN's DIP's, and also some LT1468CN8 DIPs, at less than half the price, these are low noise, 90 Mhz. parts and in almost all ways are very nearly identical to the AD747AN's at 110 Mhz. However, the LT1468CN8's are tuned for lowest noise using pin 8 at the factory, so you have to remove pin 8 to avoid problems in "other" circuits that may try to use pin 8 for compensation.

I will try both the AD747 and LT1468 parts in the three positions you used, and see what results I get. I might also try the LT1468's, or another TI part, in the Oscillator and see what happens, I think I have a few of those 49710, 49720, or 49722's somewhere, if I can find them. I also plan to use 22 uF / 35 volt tantalums in place of the "10" uF parts because these IC's draw more current than the original NE5534AN's did, maybe as much as twice as much current. What fun!!!

I will eventually report back in a matter of weeks (I hope).

Steven

Did you ever try the LT1468 parts?

 

[Chamberman]

No I never tried the LT1468. I did use one in the oscillator of my previous HP339A though.