Apogee Rosetta DC voltage at input

[scott2000]

So I had some TL064 soic chips around and decided to swap one of the AD8513 until I can get a replacement.


Pretty sure it fixed everything including the meter issue.


Thanks everyone, ccaudle you got it, and especially Heikki for helping me out big time through all of this when the Rosetta issue showed it's ugly head after building his compressor. I'm not sure of the specifics but it has something to do with the floating output caps in the compressor. It's the only piece I have like that so, I never realized I had an issue with the Rosetta worth worrying about until I tried interfacing the 2 together.

At least I think I have that correct.

Sweet.

 

[Heikki]

I forgot to put resistors to ground after the output coupling caps on the PCB. Not the end of the world in most cases but with Scott’s faulty apogee inputs it resulted in a lot of noise and distortion.

 

[Whoops]

I'm happy that you were able to fix the unit, well done

Apogee can't provide schematics and,I was told in many cases, they can't provide service for this because of parts unavailability .

I started trying to trace the input circuit in hopes that something will stand out.

It's really shameful, Apogee could provide schematics it's not they can't it's they don't want to. Doesn't look nice that you have to trace your unit when they have the schematic in front of them.

Some years ago (6 or 7 years) Apogge repaired the AD8000 and AD16 units of the studio I worked in, they had a Policy for repairs that they only charged the parts needed replacing and not the labour. I don't know if it's the same nowadays but if they are not repairing the Rosetta unit which is from 2004 and not 1998 like the AD8000, I guess they changed the Policy.

Planned Obsolescence is dreadfull

 

[scott2000]

I'm happy that you were able to fix the unit, well done



It's really shameful, Apogee could provide schematics it's not they can't it's they don't want to. Doesn't look nice that you have to trace your unit when they have the schematic in front of them.

Some years ago (6 or 7 years) Apogge repaired the AD8000 and AD16 units of the studio I worked in, they had a Policy for repairs that they only charged the parts needed replacing and not the labour. I don't know if it's the same nowadays but if they are not repairing the Rosetta unit which is from 2004 and not 1998 like the AD8000, I guess they changed the Policy.

Planned Obsolescence is dreadfull

Yeah I had only asked for the input section schematic because that's where the issue seemed to be. I'm glad we found it before having to draw the rest of the input although it seemed like it was getting more understandable if looking at some app notes.


Not sure about the parts only cost. I was told ,for these units , it's usually a pre-paid $599 repair fee and I'm not sure that includes shipping. I'd have to check. They were going to discount that a lot I guess because some of the troubleshooting/checks being done led them to believe it would be easy enough maybe.


Still waiting to hear back from them if they have any suggestions for a replacement for the AD8513 since it's pretty hard to locate in the near future. I'm going to put some OPA4134 in when they arrive.

Tempted to replace all the tant supply bypass caps with some little electros while it's open but I'm not sure if I should yet . So much time spent trying to mod different gear in the past has made me lazier.

 

[Whoops]

I know many people that have AD8000, AD16 and similar units from the same era and also Rosetta that have dead channels.
Probably all of them have the same problems but without schematic and being it surface mount they're hard to repair.

The units when working are great and sound great, still useful in the present, are definitely not obsolete, but it seems Apogee designed them to die after some years and want it to stay that way by not releasing schematics of "legacy products"

 

[scott2000]

Yeah. wouldn't know why they take their position. I'm just glad it didn't end up costing me to ship this both ways and whatever it may have cost outside of the additional minimum cost for diagnostics/repair had I decided to send it.

I guess they were thinking it wasn't going to be as easy as replacing a couple of chips and the reason for them not wanting to explain the possible fix process to me any further was because of something else they may have suspected. They did point out the AD8513 early though.

I was thinking that's the first time anyone has ever told me it's "easier done than said"..lol

But I feel that way sometimes...

My correspondence with them was a bit chaotic with me sending multiple responses after I forgot something, or wanted to add another finding so I can see not wanting to explain and go back and forth with a more involved process.

 

[JohnRoberts]

1- Manufacturers do not design product to fail.
2- charging only for parts cost and not labor does not compute unless parts costs are marked up to cover labor.
3- it is possible, and arguably more educational to repair gear without schematics. If you can read the part numbers of ICs the manufacturer data sheets and application notes can be pretty revealing.
4- small companies can be protective of schematics especially when competitors are inclined to "borrow" any inventive ideas. Registering IP and litigating infringement can be expensive and not always successful (I know).

JR

 

[scott2000]

1- Manufacturers do not design product to fail.

I'm pretty sure some experimenting was the most likely cause of the issue I had.. Should probably invest in a cheaper test set up....

 

[Whoops]

1- Manufacturers do not design product to fail.

Yes they do, and actually it's pretty standard nowadays and for many years now, unfortunatelly.
It's part of the "planned obsolescence" concept, it's pretty well known and documented.

But I'm pretty sure you know all this JR, so I might have misinterpreted your post

 

[JohnRoberts]

In my decades of experience designing products for my own company(s), including managing an engineering group at Peavey with several design engineers reporting to me, I/we never designed a product to fail and /or become obsolete. If that was the plan I surely would have been involved in it.

I recall the research I did when we (Peavey) extended our warranty from 3 years to 5 years. That was surprisingly easy, because the products were not designed to fail!

Am I being clear?

JR

 

[Brian Roth]

Peavey is often sneered at for no good reason. They've built decent equipment for decades. I personally know because that was a brand carried by a music store where I worked in the early 70's. Other brands we carried included Kustom, Fender, etc. That gear was built to last. I still encounter older gear (Peavey included) which is WAAAY "past the expiration date on the milk bottle".

Sadly, those long lived machines are becoming an exception to the rule in much more recent times. And to make matters worse, many manufacturers (not just in audio) regularly obsolete a model a few years after sale, and refuse to offer any parts and support, forcing the owners to purchase a new item. It's all a Race to the Bottom found in multiple industries, abetted in large part by the buyers always looking for a low price and imported brand suppliers more than willing to flood the market with cheap crap.

OK....rant over! Happy 4th to my friends here in the USA.

Bri

 

[JohnRoberts]

I should mention that my Peavey experience was over two decades ago so maybe they went over to the dark side after I left.

One trend that was ramping up back then was offshore manufacturing. There is a huge difference between running a steady production line inside your US factory, just keeping up with sales and using a contract manufacturer across the pond to make thousands at a pop to realize cost efficient order quantities.

Providing repair parts, or assemblies, is simple when you have a production line running nearby constantly. Large batch runs, far far away, make repair parts much harder to accommodate. I can imagine the rhythm of large batch runs a few times a year to be more compatible with making more frequent model changes with subsequent batches. Sometimes the changes are to fix a mistake or add a new feature to be more competitive, having a new model designation doesn't usually hurt sales. Of course this is speculation on my parts.

JR

 

[MisterCMRR]

So I had some TL064 soic chips around and decided to swap one of the AD8513 until I can get a replacement.


Pretty sure it fixed everything including the meter issue.


Thanks everyone, ccaudle you got it, and especially Heikki for helping me out big time through all of this when the Rosetta issue showed it's ugly head after building his compressor. I'm not sure of the specifics but it has something to do with the floating output caps in the compressor. It's the only piece I have like that so, I never realized I had an issue with the Rosetta worth worrying about until I tried interfacing the 2 together.

At least I think I have that correct.

Sweet.

Glad you found it. As I explained on Thursday, a broken op-amp is the only defect consistent with the DC voltages you were seeing!

 

[scott2000]

Yes thanks Mr.W! After reading that explanation/analysis it most certainly made my weighing of possible options a bit lopsided towards replacing them.

 

[Michael Tibes]

Apogee got back to me and asked my board revision, said to check U3 (5361 ADC)on the main board for the meter issues, and said I may need to replace the AD8513.

Wow, I never got a usable reply from them. In most cases they wouldn't even understand my question (or they didn't bother)... So how did you contact them? I have some dissolving AD16s I'd like to keep using if I could make them stop putting out crazy DC levels. Since they show the same symptoms across different channels it doesn't seem like a random error and I'm sure there will be someone at the company who knows exactly what's going wrong. Knowing what to look for would save me a lot of time. I tried to contact them through their message system some years ago, but nothing usefull came out of it. Do you have a better tip?

Thanks,

Michael

 

[scott2000]

Wow, I never got a usable reply from them. In most cases they wouldn't even understand my question (or they didn't bother)... So how did you contact them? I have some dissolving AD16s I'd like to keep using if I could make them stop putting out crazy DC levels. Since they show the same symptoms across different channels it doesn't seem like a random error and I'm sure there will be someone at the company who knows exactly what's going wrong. Knowing what to look for would save me a lot of time. I tried to contact them through their message system some years ago, but nothing usefull came out of it. Do you have a better tip?

Thanks,

Michael

I just used the support page.
https://apogeedigital.com/supportI opened a ticket as opposed to using the chat function for no particular reason. Patrick was the person who was in contact with me who seemed to be the liaison between my messages and their lab and he seemed pretty great at relaying all the info back and forth.
They do seem really busy and the responses could take up to a week or more in some cases.

It's not clear where they are in regards to how much time they are able or willing to spend providing support on these because ,at the end of the day,, the parts availability becomes a big factor to them. If the exact original parts aren't available, they won't be able to do anything from what I was told. Which is unfortunate, but I wouldn't know if or how it has affected the gap of knowledge available from them regarding these older units.

I think like JR mentioned, the app notes of the different chips can be pretty useful in seeing what's going on in the different sections. I have no clue what these circuits do but, bringing up questions here and to Apogee with some drawings as best I could seemed to help so maybe starting where the problem is and drawing out the area with some voltage readings will help generate more focused responses and increase the chances of finding issues.

Definitely takes time that would be easily saved if schematics were available but it is what it is. There are some visible traces that can be followed under the main board on this as well which could possibly help speed certain things up in a very small way as well I noticed.
Really makes one wonder if it's worth it. The thought of moving on to another thing and giving up was already stronger in my mind when replacing the AD8513. Probably would've stopped after drawing the entire input section and possibly their connections to the digital area. But who knows.

 

[Khron]

I have some dissolving AD16s I'd like to keep using if I could make them stop putting out crazy DC levels. Since they show the same symptoms across different channels it doesn't seem like a random error and I'm sure there will be someone at the company who knows exactly what's going wrong.

Might i suggest starting another thread and posting some internal photos of one of them?

There's only so many ways to skin that particular cat, and opamps have standard pinouts...

 

[Michael Tibes]

I opened a ticket as opposed to using the chat function

Thanks, I just opened a ticket (again). Maybe something has changed since the last time a few years ago and they are more helpful now than just the standard 'you'd have to send it in to get it fixed' I received last time. I'd much rather build something new than reverse engineer my DA16s...

I'll start a new thread on the DA16 when I proceed, with or without Apogees help.

Michael

 

[Obsoletemachines]

Fixed my Ad8000 without schematic, posted in the other thread.

Had a rail down on Ch1. Turned out to be broke trace on a board which is very difficult to trace properly as its black. Five tantalums had gone short because when i put the 15+ rail back , on that channel, those tants began smoking. Suspect one went short and the others followed before a trace was burned out.