Cary SLP-98L DC or Cap Upgrade details

Ok, I know it's been discussed before but I'm really looking for the details in this upgrade to the SLP-98. I've read direct coupled, F1 upgrade, cap upgrade etc...Now can anyone tell me in detail in what each of these mean and what parts/values go where in the unit itself? I also see various cap values in the upgrades in different units, what does that mean and why do I see these Mundorf SGO caps in various units be of different values? Any help would be great appreciated!



Yeah I’m trying to figure out how to get there and what all is involved.

What is "F1" exactly?

@sqitis As I recall way back the F1 package upgrade well over a decade ago was originally inspired and offered by Upscale Audio. Unless you send in your unit and pay Cary for the upgrades, intel may not be shared. Different people there. I have the SLP-98L with all the upgrades in mine w/Grayhill switch. Here is what i have from my notes, and a site visit today to validate what’s listed right now for the new unit upgrades. A really good tech in your region can upgrade these with good parts too.

I’d recommend using a local tech, if you can. Save on shipping costs to pay for even better upgrade parts, and reduce risk of back-and-forth shipping damage

IIRC, the original F1 inspired package offered, went something like this:

  • Jensen oil and copper capacitors, Hexfreds in the power supply, Kimber cable wired for one of the inputs, real WBT speaker terminals, Grayhill selector switch, +F1 colors.

Today, the new units offered show similar upgrade options minus flashy paint:

  • Silver or Black color, Hexfred Rectifiers x4, One Kimber wired input, Mundorf MCAP EVO Silver-Gold coupling caps, MCAP EVO Silver.Gold.oil for output capacitors. (not seeing Grayhill switch listed).

If you have a unit now or buy a used one, you could try first by upgrading the caps and install your favorite 6SN7 tubes in it. Double box/pack well if you ship it in!


@decooney I have a stock unit now but curious on the parts & values used in the unit. I've seen different cap values from the internet and Cary invoices from other slp-98 ads. Such as, 4.7uf 450V & .22uf 1000v in some units then I've seen 1.0uf 1000v and .33uf 1000v. I have a newer unit with 1.0uf 1000v Music Cap & .22uf 630v Clarity Cap. Now I'm also curious to know what the hell is "Direct Coupled" and how is that implemented?

I do have a local tech ready to do the work as he did on his unit with just the caps/hexfred mod. But before we get started I'd like to hear more about the Direct Coupled mod.

To @sqitis

IIRC the direct coupling on the older version (not sure about new or if anything changed since) preamps potentially eliminates any capacitors coupling the gain stage tube to the driver tube, and the output capacitors would remain - but don’t quote me on that. Worth having your tech check inside.

Oh, btw the Greyhill switch shows as standard on the current site notes, not sure when that started as standard on new units, worth checking yours to see if it has it already or not


I do know that we can’t just remove the coupling caps without modifying other parts of the circuit to accommodate this mod. That’s the part I’m interested in knowing, what is also modified/changed when removing those caps AKA Direct Coupling?

I have scrubbed the internet and can not find out for the life of me what is truly done for the DC version.