Doug Self's New Preamp Construction and Pictures

[redjr]

While doing some listening today I noticed the LLL LED was flickering, so I guess it's doing its thing just fine. When I finished up the pre I wasn't sure it was working at all or correctly.

Let me first preface my comments with this.... I don't own any high-end gear, or what I like to call esoteric equipment. No Pass Labs amps, ML speakers, or exotic cables. I've been drawn back in to vintage gear, but I think some of my newer and DIY solid-state gear sounds very good indeed. The sounds is not necessarily better, just different. Also, I have not connected up any of my turntables, so I have no comments on how the pre handles LPs, but I can't wait to test that too.

How does it sound? Even with the limited amount of listening I've done, I can heartily say this pre has raised the bar on my stereo rig. I immediately noticed a much more transparent, unveiled sound across the entire frequency range. The tone controls provide a very nice range and you can easily 'dial-in' the exact sound you prefer. I've been leaving them mid-way, which to my ear is where the defeat switch is effective.

With digital sources the sound is very crisp, clear and clean. It's a sound that can be edgy for a lot of people, but I prefer an 'in-your-face' sound. I like to hear the fingers slide on the guitar strings and the breathing of the vocalist.

For me, the mids are right where I like them with a slight emphasis on vocals. The bass appears tight and solid.

My son came in the other day and while I was playing a favorite CD of mine, he said, "Man those vocals sound great. I can hear sounds I've haven't heard on that CD before"! I agree completely. I guess it goes without saying that I am very pleased with the final product and outcome of this project and the sound signature this pre is leaving on my system and more importantly my ears. Kudos again to Doug Self!

[redjr]

One note I forgot to mention earlier... I noticed when testing the balance control that when rotating either to full R, or L, the opposite channel still bleeds through and cannot be totally silenced. Not sure if this is intrinsic in the design, or perhaps as a result of an error in my construction.

[rsavas]

Well done Rick!!
I would have to look at the design ( Elektor articles that i have) to answer your balance question. Hardly ever need complete muting of one channel, as it is.
Always a pleasure to listen to the final product after all that hard work. Reminds me of my first pre-amp I did back in College (1979), simple design with the new NE5533 OP-AMP. Thought that it sounded nicer than my Pioneer SX-950 pre-amp section.
Nice to see that Front Panel Express did good job as well. What thickness of Aluminum plate did you specify?

Cheers
Rick Savas

[redjr]

Hi Rick,

I'm very happy with the results! Frankly, it came out much better (and more costly) than I ever imagined, but then I started work on it back in March - whenever the first Elektor article was published. So I took my sweet time. This DIY process is a lot more involved, and takes longer then building Heathkit's back in the 70's and 80's.

Yes, I'm extremely satisfied with Front Panel Express and their quality product/service. On this project I supplied my own front and rear panels that came on the enclosure I used. You can find it here on eBay if interested. The aluminum plate used for the front panel is 8mm thick. That can present some challenges mounting a lot of standard hardware. My little micro toggle switches were glued from the back using JB Weld metal epoxy. The 4 pots were mounted using a special 3/8" ring nut in a cavity on the front. But the knobs hide them so it wasn't an issue.

Edit: One more very important thing... This pre is dead silent. I can't hear any hum, or noise whatsoever. And as another posted mentioned to me, it does have a lot of gain. It doesn't take much on the volume control to make it sing.

[rsavas]

I can well imagine the costs & time to put it all togther. Glueing the switches, just like the ole days :-) the switches are 1/4"-48 TPI, I think, I guess that they could have been tapped and use a backing nut to tighten/secure them. Good luck finding one of those taps however.

Cheers
Rick

[redjr]

Originally Posted by rsavas

I can well imagine the costs & time to put it all togther. Glueing the switches, just like the ole days :-) the switches are 1/4"-48 TPI, I think, I guess that they could have been tapped and use a backing nut to tighten/secure them. Good luck finding one of those taps however.

Cheers
Rick

In this case (no pun intended), there is an 1/2" aluminum ridge that runs the length of the front plate on the top and bottom used to help support the case top and bottom. And with rectangular plastic housings the switches could not have been screwed in because they rest right on this ridge. I might have been able to raise them up some, but still it would have been a dicey.

As I mentioned in another post, this case was just a little to small and having more room on the front(and back) panels would have allowed for more mounting options. Always a good thing when DIY'ing But, I made it work, even with the tight spaces inside and happy with the result. I think it looks and sounds great!

[rsavas]

Yes I know what you mean by the mechanical design issues. I have my own dilemma with my latest project. Packaging is a big deal in electronics, most put it off til the end, but actually it should be done first or in parallel with the rest of the design.. Happy to hear about your new project.
Rick

[jshowalter]

Originally Posted by redjr

Yes, I'm extremely satisfied with Front Panel Express and their quality product/service. On this project I supplied my own front and rear panels that came on the enclosure I used. You can find it here on eBay if interested. The aluminum plate used for the front panel is 8mm thick.

Really beautiful work!

I have some questions about the front panel.

Case suppliers can typically do front panels with clear or black anodize, and with printing or engraving (and, if engraved, inked or not inked).

Your front panel is clear with inked engraving. Did you look at other options, and, if so, how did you select what you selected? Are you happy with your selection?

[redjr]

Originally Posted by jshowalter

Really beautiful work!

I have some questions about the front panel.

Case suppliers can typically do front panels with clear or black anodize, and with printing or engraving (and, if engraved, inked or not inked).

Your front panel is clear with inked engraving. Did you look at other options, and, if so, how did you select what you selected? Are you happy with your selection?

Hey Thanks. The project was a long time coming together, but I'm pretty fastidious about things. See PM I sent you.