Obsolete parts… did I just waste $12?

[krupdb8]

This is on me for not looking at the BOM before adding The Creamery Compressor (PCB301) to my cart, but…

I ordered the PCB a couple days ago and started to gather parts yesterday. This pedal requires four “KA4558” and two “THAT2159”.

I looked at the datasheets and there are differences between KA4558 and other 4558 variants, so I assume it specifically requires those — though I am guessing any 4558 will probably work well enough.

The big problem is the two THAT2159 chips. They are unobtanium with no alternative, apparently.

Did I just waste $12 on this PCB? Not a big deal and yes, I normally check the BOM before considering a PCB and didn’t this this because I was shopping from my phone.

Cheers,
Ken

PS it would be great if PedalPCB (and other board makers) had some sort of red/orange/yellow status on the PCB product page to note when critical components are obsolete and unattainable and/or there is no available substitute (red—so make sure you have some!), obsolete but still available and there is no substitute (Orange), or obsolete but widely available , or there is an available substitute (yellow). Just a thought. I know this could be a maintenance nightmare for ppcb to try and keep track of the availability of components but thought it might be helpful to shoppers.

 

[Bricksnbeatles]

There’s either an Xvive or coolaudio clone of the chip but it’s also hard to come across. I need a handful of the 2159 chips too, but I always forget about it when they’re available. Regardless, fear not— they might take a while to find, but they pop up often enough

 

[szukalski]

You can try a 2181. It looks to work:

THAT 2159 chip supplier?

Sos eeing the Creamety compressor out where would I be able to find a THAT2159 chip? I checked Mouser and Smallbear so far with no cigar.

forum.pedalpcb.com

 

[krupdb8]

I didn’t see that Coolaudio produced a V2159! But it appears as rare as the original THAT2159 these days.

There are a couple of threads here that say the Coolaudio V2181 “might” be a drop-in replacement, and it is currently available from cabintech!

… I just found a post on vintage-radio.net of a manufacturer’s note on using the 2181 to replace 215x chips. It says to eliminate the resistor that goes to pin 2 and the cap at pin 8 can be reduced to as low as 22pF. Also it appears pin 4 is not used on the 2181?? Interesting!

 

[krupdb8]

I ordered V2181L from cabintech and will try to figure out the proper integration later.

Am I right that any 4558 chips should work fine with this build?

Thanks all!
Ken

 

[ICTRock]

any 4558 will do

 

[delayed]

Maybe utsource? https://www.utsource.net/itm/p/1431680.html
States used

 

[Gordo]

Not really understanding the question. Is it the THAT chips? I have a Creamery here, I think, so if need be I can pull the chips and get them to you. I loved the comp but it never made it to my board. Still, if I found the chips so they must still be out there.

 

[manfesto]

Not really understanding the question. Is it the THAT chips? I have a Creamery here, I think, so if need be I can pull the chips and get them to you. I loved the comp but it never made it to my board. Still, if I found the chips so they must still be out there.

Smallbear had CoolAudio v2159s for a bit, but they’ve been out for some time now.

There are some THAT2159s on eBay of questionable provenance from overseas that are pricier than I’d feel comfortable gambling on.

I asked @StompBoxParts if they could source them or the CoolAudio repros a while back, they responded in the negative.

 

[manfesto]

Maybe utsource? https://www.utsource.net/itm/p/1431680.html
States used

Haven’t heard of them before, googling for reviews seems to imply that they have a track record for selling fakes. Not sure I’d risk it, I’d give 2181s from Smallbear a shot first at least.

 

[benny_profane]

The THAT2181C is the closest-in-spec replacement for the 2159, but the THAT2180 (pre trimmed) can also be used. Per table 3 in the app note, omit R2 (51R) in figure 1.

https://www.thatcorp.com/datashts/dn137.pdf

 

[Bricksnbeatles]

The THAT2181C is the closest-in-spec replacement for the 2159, but the THAT2180 (pre trimmed) can also be used. Per table 3 in the app note, omit R2 (51R) in figure 1.

https://www.thatcorp.com/datashts/dn137.pdf

Thanks for the info! I finally got my Uv files ready for my two creamery builds after like 2 years, but I forgot to get the 2159s when they were still attainable. Gotta say though— that’s gotta be the most bizarre font choice I’ve ever seen for a technical datasheet

 

[almondcity]

The 2181 was in stock at Mouser for a normal price last time I checked a few months ago. This is a nice compressor don't abandon it!

 

[RetiredUnit1]

I use the MP1584EN adjustable DC to DC power converter in numerous power supply projects. It was marked obsolete and 'to be replaced' with a newer, betterer number I cannot remember TWO YEARS ago. The new number is still not available last time I checked about 3 months ago.

https://www.matts-electronics.com/wp-content/uploads/2018/06/MP1584EN.pdf

 

[Chuck D. Bones]

Maybe utsource? https://www.utsource.net/itm/p/1431680.html
States used

Do not trust UTsource. They sold me a bunch of counterfeit transistors. Some were dead and none met spec. I eventually got a refund, but it took a fair amount of effort.

 

[Bricksnbeatles]

To revive this thread– In the Creamery schematic, if using the 2181 in place of the 2159, R31 is to be omitted as it correlates to the 2181 Design Note Page's R2 for IC2.
For IC5, there doesn't seem to be a connection between pin 2 and pin 4, or rather there is, but it's via a 33k resistor- R23. This configuration however bares similarity to figure 7 and figure 8, which would suggest that R23 is comparable to R3, which the Design Note Page suggests should be calculated for minimum THD via the datasheet, but the fact that pins 2 and 4 have an internal 25Ω connection, and both are connected to Vref in IC5 would suggest that R23 is completely inconsequential since it would no longer be providing any function other than to reduce the internal resistance of pins 2 and 4 from 25Ω to 24.98Ω; that said, no point in omitting it since it doesn't do any harm.
Now– R32 has a lot in common with R3 with regard to IC2, but I can't seem to find in the 2181 datasheet where it says how to calculate what size that resistance should be given the supply voltage– that said 1K for R32 definitely seems way small compared to the 130k-680k values given for R3 when assuming a bi-polar 15v supply, so I'm not sure what, if anything, to change R32's value to.

Anyone else have any thoughts on my observations, or any further insights into what should be changed when using a 2181 in place of the original 2159?