Upgrading Cary CAD 300sei integrated

Would appreciate if Cary users could share their expirience please.
The common upgradis are power and output transformers plus caps, but which one to get? I read a lot good things about Tamura brand and may will be prepare to go for it, but are there some others for less?

From caps, Jensen's been advised by a good friend of my, but than again, which one, mean, want to keep the budget healthy:-)

Also, do you think that I have to upgrade all in once or just starting from transformers may give the huge step up already?

And last, but not least, what are the results and the total financial damage? Do you think it was worth to do or you ended up bying another amp after all?

Well it will only marginally help resale value should you ever go that route ... never come close to re-couping the cost of the modifications. Probably even less so if you do the mods yourself rather than a well known tech.

The AirTight ATM-300B has many of the things you are considering changing in the Cary, most notably the Tamura transformers. Might be a batter way to go if you can track down a used one.

Also SAC Thailand custom makes some BEAUTIFUL amps that could be built to exactly the standard you wish ... no experience with them other than visiting their website though

decisions decisions

I agree with Jrin..dnet. The cost of mods can be prohibitive. IMHO you are considering taking the heart and soul of this amp and by changing the the Trannies.
I can't imagine that such a major mod would sell well unless someone really just wants the highly reputable Tamuras. I would do as little damage as possible -replaced caps are generally better accepted mods.
The resale on heavily modded units not only seems to impact what you can ask but almost never recoups your modding costs. Just browse the for sale section and you will see.
I echo the above if you really want better trannies I for would get a different amp.
Agree with Mechans and J. Don't mess with the trannies. On the other hand Jensen copper/oil caps may be enough of an upgrade to make you feel better, and for not a lot of money.
cap upgrade may be worhtwhile ... I would certainly CONSIDER having it done by Cary Audio though IF I was concerned about re-sale value at all
Oh, and if your amp does not have high speed, soft recovery, diodes, you can inexpensively kick it up a notch with HexFreds, HexFets, or similar diodes.
Hi to all,

Many thanks for your replays, hmmm, so, transformers upgrade isnt that good idea, ok...
I was thinking of Air Tight, but he is out of my price range plus it needs WE to shine, where my Cary already have what he needs, regarding tubes, have best for them, becides, I love what I hear. Thats why I was thinking about possible upgrade of already good sounding unit, simply say increase and not fully changing his sonic basics. If I am going to do this it will be done by Cary dealer for sure, already have good contact with them and done some voltage rewiring from 110 to 230 and fully check through them. I am not US based, so, things bit complicated when you want to deal with Cary directly.


I looked for some info about the recovery diodes, but would you be so kind to tell me, in simple words, what they do please. Sorry for my tech simplicity

O.k. if we are talking about the caps and recovery diodes only, what exactly going to be changed? I supose Cary have some power cap/caps and some output or coupling caps, how many are there and which one make the most influence on the sound sig? Would you be so kind to give me some idea of most important parts inside that must be at high level. Thing is, my amp build in 1994, its a classic model and I am not totally sure what kind of changes been possibly made in these years. So, because of that, the next question is, are there things that must be changed in the time, cos of the age? I mean, wastage plays a part here, isnt? For example, I may possible go for upgrade of transformers, but than go for new one from Cary own, is that an idea? Are the transformers and caps getting worse in the time, I supose they do.
We are not talking about sonic upgrades only, but also improvement of tech part, however they didnt found anything wrong with amp when it was fully checked.

Bottom line, what do you think are crusual and possibly can be done as first basics to get it tech and sonic improvements please.

I THINK there is an F1 version of the 300sei like there is of the SLI-80 (if someone knows for sure, please chime in). A number of thiings are upgraded in those units but it is not inexpensive ... good news is it would be a "factory approved" upgrade

good luck!

First, soft recovery diodes and Jensen copper/oil caps are part of the upgrades that Cary does to make signature models of their amps, so there is nothing here that is out of their normal upgrade path. Cary can do the work, but it is quite simple and can be done by any qualified technician or experienced hobbyist.

Here is a much more cogent explanation of the benefits of soft recovery diodes than I can give:


As far as caps go, you will only need to change the output coupling caps, so only two caps are required.

As to the improvement that this package will make, it will have less noise, greater clarity, better detail, more body and smoothness. If you find your amp to already be too smooth, you can use teflon caps, such as the V-Cap in place of the oilers.

Michael Samra, one of the authorities on audio power supplies, and Cary power supplies in particular, finds the large computer-grade electrolytic caps that you see on the top side of the amp to be total junk and rebuilds the power supplies using film or oil caps. Interestingly conrad-johnson has done away with using electrolytics and uses film caps exclusively. I have not tried it, but my guess is that this would be a giant move forward, sonically, though it would kill the resale value and the large physical size of the oilers or film caps would create aestetic problems as well.
leave it alone it sounds superb as it is plus you never will get back what you spend for the upgrade,,,
I always felt that the remote/volume control was less than ideal when I had my 300Sei.
I tube rolled some nice Brimar 6sn7 to good effect but that was as far as I went.

If I still had mine, I would opt to run it as a power amp and bypass the whole preamp section,volume control as can be done with other integrated amps.

I've had such a great time since discovering the Lightspeed Attenuator that this thread has aroused my imagination about running one with a moddded 300sei.
Cary's website has upgrade suggestions and prices