TOPIC:

What are the pros/cons of using an existing preamp with the SHD? I am thinking to use my XLR outputs on my preamplifier into the XLR inputs on the SHD. What approximate gain setting on the SHD would keep volume control on my preamp the same as it is without the SHD?

For context I'll first say that I use my SHD as a pre-amp connected directly to a power amp.

Do you have a subwoofer you are looking to integrate or will you just want outputs from the SHD for left and right main speakers? If it's the latter then placing your pre-amp between SHD and power amp is a different option to the one you proposed, provided you don't want to keep using your existing pre-amp to switch between more sources than the SHD can handle?

Connecting a pre-amp to the analogue input on an SHD will mean you'll need to make sure the pre-amp output voltage doesn't exceed the maximum the SHD can handle. Provided this is the case then setting the SHD gain to 0 dB will achieve what you asked of keeping your current volume control setting as it is. I'm not sure why you are specifically targeting this though? An advantage of having your pre-amp after the SHD is that you can actually use it to provide a higher output level than the SHD produces if you need to, which you probably won't but could depending on your power amp and speakers.

The most obvious 'cons' of continuing to use your pre-amp are that it's potentially hardware you don't need and so wastes both space and money. With a hifi hat on some would argue that the addition of the pre-amp will just add distortion over a shorter signal path without it, but ultimately if you prefer the sound with the pre-amp in use (and many do) then clearly the is the best option for you.

So would this make sense?

Or this?

Definitely not the second one as you need you'd need your preamp to control the volume to all drivers.

Do you already own an SHD or are you thinking of buying one?

Good point. I have a SHD on order and it shipped this morning.

My speakers are Audio Artistry Beethoven Elite (4 way passive) with their own proprietary active crossover (analog). The low frequencies are in 2 separate cabinets (4 x 12" per side) but are not called subs. They do easily go down to 20db but the systems is designed for these to be right next to the main speakers. Not sure they would benefit from the sub integration agility of the SHD. If I did want the use the crossover in the SHD for a low pass than I would not be able to use my current preamp.

I just love the tube sound of my Modwright LS 36.5 DM

So if I use my preamp for volume, what level should I set the SHD to?

Looking at the specs it show max input and output are the same so the SHD has no gain? Installing it in front of my preamp would require volume to be set to max for normal gain to the preamp?

martinwh wrote:

So if I use my preamp for volume, what level should I set the SHD to?

I answered this above for you.

Your situation is complicated as you have so many sources. What are they out of interest?

I'd suggest you start by connecting your SHD between pre and power amps as you'd intended. If you get obvious distortion without Dirac running it would probably indicate that the output voltage of your pre-amp is too high. If you don't get distortion with Dirac off but do with Dirac on (once you set a filter) then this is likely due to clipping in the digital domain and will be fixed by reducing the SHD volume from 0 dB to provide the required headroom. - 10 dB will almost certainly be enough but you may get away with a smaller reduction.

Actually I've just remembered you were intending to use a music server connected directly to your SHD? If so I'd start with keeping your SHD volume at - 10 dB and see how you get on.

Thanks for the input. My XLR sources are an Oppo UDP-205, Modwright Elyse, Modwright PH-150 and a Sony APR-5003. I also have some SE RCA sources, Nakamichi Dragon, Technics RS-1500 and Yamaha CT-7000. Yeah, I like music.

I can connect my server (Technics ST-G30) to the Oppo, Elyse or the SHD so I have options there. I show it connected to the SHD in the diagram because I would like to try that.

The more I think about it, I like the idea of using the SHD in front of the pre-amp to avoid any excess gain problems. Still not sure what volume to have it fixed at to do this so that it is close to being transparent to the levels coming in from the sources?

Use -10 dB on the SHD. You want to do this to provide headroom to prevent digital clipping from boosts applied by Dirac filters.

Got it, thanks!

One last question though. If I decide to use the SHD without a preamp, won’t this headroom problem persist? I have plenty of gain in my amplifiers but am curious about the impact of a no gain preamp in front of them? If -10db is needed to make sure there is enough room for the DSP range, what happens if my volume needs exceed -10db?

martinwh wrote:

Got it, thanks!

One last question though. If I decide to use the SHD without a preamp, won’t this headroom problem persist? I have plenty of gain in my amplifiers but am curious about the impact of a no gain preamp in front of them? If -10db is needed to make sure there is enough room for the DSP range, what happens if my volume needs exceed -10db?

The answer is that you would deliberately not exceed -10 dB. Or at least you would for any input that might give close to a 0 dBFS input signal. I'm giving you a cautious limit to get you started here, which will pose not problem at all with your preamp where you intend.