I like the GP Lightstone for this.
Soundsamples in my post in
this thread.
The DHA VT-1 and also the EBS Valvedrive are Overdrive pedals which have on low gain settings a pretty nice clean sound.
The GP Lightstone is not a starved plate design, but runs the tubes at 200 Volts with plenty of clean headroom available. As Overdrive pedal it fails, but as clean to slightly gritty tube pre-amp pedal it rocks !!!
