Cary SLI-80 tweaks and improvements?

Hello all,

I have an older Cary SLI-80 that I'm trying to find a path forward to a wider sound stage and improved dynamics.  In comparing it to my Decware Taboo, yes, it has a boat-load more power available, however, the Decware has a much wider sound stage, better channel separation and decay from instruments like cymbals, compared to the Cary.  The channel separation is much better on the Decware and this is especially apparent with songs that feature heavy panning from left to right and back again.

The Cary is running vintage Bugle Boy 6922's, vintage Sylvania 6S7N's, and Ruby 6550's.  

I have been looking at a couple of different paths forward:

Moving to EL34's or another power tube?

Upgrading the internal capacitors such as upgrading to the F1 mod?

A combination of both?

Any other ideas to try to capture the performance of the Decware are welcomed.

Thank You!


I received a reply from Cary.  It looks like their upgrades have expanded beyond what's on their website.  They now offer an upgraded choke as well as some Solan bypass caps that can be installed.  Also, the larger coupling caps are now Mundorf caps as decooney mentioned.  Mine must be a bit older since I have the Jensens in the kit.

I'm emailing the gentleman there for some clarification on a couple of items.

There's a local technician that I found that mostly works on vintage guitar tube amps that I have used to test my tubes as I come across them.  I'll see what his thoughts are if he wants to tackle this project.

What's funny about this thread is the amp sounds quite good, actually.  But since we can be a weird bunch and I think I must have been spoiled with the Decware, here I am chasing that last bit of detail.  


I have a couple of other questions:

1) When installing the 4 Hexfreds, do they just replace the standard diodes that are there, while retaining the tube rectifiers, or are they meant to replace the existing tube rectifiers all together?  The installation "diagram" doesn't say anything about this.

2) I can't seem to locate a Grayhill volume control pot mentioned anywhere such as a part number or anything on Cary's website.  Would you have that info, as well?


Thanks for all the replies and help, so far!

1) yes, you are replacing them as I understand it.  Best to ask Cary what they do.  Personally I like the tube rectifiers but I'm sorta old school in my thinking perhaps.  

2) Grayhil is the updated input selector switch, as pehare noted above.  

I'm not sure where my local tech sourced the volume control and he's long retired and out of all that now. Just doing the caps, input selector, silver wiring at the back to one set of inputs and possibly speaker terminal too can help.  

As noted, there is nothing wrong with the stock form amp, has it's own warmed signature the stock way too. The new/upgrades add a bit more transparency and detail IF that's what you are looking for. Some are NOT.  A personal taste imo.    I originally had the Jensen oilers in mine and later went to the Mundorf caps. The older-older gen1 version Jensen oilers should be replaced, they had some batches fail years back. This leaned many to try the newer Mundorfs that had different results most seem to like.  Best to go for it and listen, see if you like it or not.  

I actually like the tube rectifiers as well.  They just look cooler, in my opinion.  😎 

I was looking at this photo which shows the internally modified bits and it appears that it matches the diagram I have where the Hexfreds replace the existing standard cylindrical diodes.  It shows the rectifier tubes are still in place on this example:

Cary Audio SLI-80 Signature Stereo Tube Integrated Amplifier - The Music Room (

I can see what Cary has to say for clarification, just to make sure, though. 

Cary informed me that the hexfreds just replace the existing diodes and the tube rectifiers stay.


Also, does anybody know the plate voltage in these?  I can't find a stated value any where.  It would be helpful for trying different tubes.