next step for my setup? advice appreciated

Yes, I think a tube preamp will go a long way. Your Oppo will also go a long way. You can integrate stereo preamp to your processor. You'll need HT bypass output from the preamp. Integrating with subwoofer can be done as well. If the sub has dual input, you can connect one from LFE output of processor and one from right channel of the preamp.

Hi,

Glad to see some DIY speaker builders out there. I've built the Gr-Research AV-1, three pairs of Murphy Blaster MBOW-1 for various friends, the Ellis Audio 1801B, and a number of Selah Audio Subs. I think my favorite of the bunch is the MBOW-1 matched with a sub. Amazing sound for the price.

Regarding your question, I am with others here; scratch the idea of a tube buffer. I like the idea of a tube DAC, but I am not familiar with any DIY designs. One issue that you will have with less expensive tube DACs is that you might lose linearity at the frequency extremes. An example of such would be some of the MHDT Labs offerings; not necessarily flat in frequency response, but very musical sounding. Throwing a tube in with your solid state amp will do some nice things.

A decent tube preamp kit is the Trancendent Sound Grounded Grid. The sound is more quick and light than slow and heavy, but the kit directions are easy to follow. The only thing I didn't like about the kit are the stock volume control and the cheap rotator switch, but I swapped them out.

Also, another option would be to build the Pass Labs B1 buffer, although you would have to source the parts yourself. You can buy circuit boards and matched jfets from the PassDIY web site. Its not tube based, but it sounds very good.

Where are you located?

A DAC will sure help out the 980. Tube or SS, that's your call.

I'd prefer add a tube preamp at this point were I in your shoes.

Before that though, I'd consider cabling. Power cables, ICs... etc.

That Oppo and the Rotel amp both respond well to power cord upgrades. Also, I'd fiddle with the isolation (footers) and maybe even a damping weight set on top of the Oppo.... I prefer Herbie's iso cups with the Ebony balls for mine.

it will suprise you what just some footers and a pc for that Oppo can do. For the amp too.

A tube preamp however would my my goal ultimately.

Hi Folks,

This is great feedback:

I'll likely start by adding a DAC to the system seeing as how it will improve two components - the itunes/airport and the oppo. New power cords and footers for the oppo and rotel sound like a simple improvement to make.

After that I'll start digging into tube preamps and see what I can do with a DIY kit.

As for GR Research and DIY speaker kits, I'm hooked on DIY. The Murphyblaster is on my long term list, as is the GR Research Neo2x.

I'm in Broomfield, CO by the way.

thanks folks for all your guidance. It is a fun and addicting journey

Steve