When we’re not pressing great vinyl at Furnace MFG, we’re constantly buying records for Furnace Record Pressing collections. My buying preference is vinyl since most LPs include download cards—the best option for on-the-go listening. However, I'm often disappointed by the quality of the vinyl I purchase. Use the following tips to guarantee the vinyl records you purchase—or have manufactured—were pressed correctly.
(Quick tutorial: A record pressing machine has one mould for each side. Metal stampers containing a "negative" imprint of the grooves then fit onto each mould. Using heat and pressure, the press forms the grooves in the vinyl biscuit.)
The ORANGE PEEL effect:
Look at the inner grooves: Is the surface smooth or textured? The so-called orange peel effect is often caused by a worn / damaged record mould or an over-used stamper. This orange peel like texture negatively effects the groove floor and will cause unwanted noise and artifacts during playback.
A well maintained pressing machine mould should have a mirror-like, pristine finish to ensure the stamper is the only surface that makes an impression into the vinyl. As moulds are costly and time-consuming to replace or repair, some plants forego regular maintenance to cut costs and to minimize down-time on their machines.
The overuse of metal parts is another possible cause of orange peel. The stamper is a metal plate that sits over the mould and contains the grooves. Stampers have a life span of between 500-1000 impressions before they begin to degrade from the heat, pressure and stress from the pressing process. When one is used past its recommended lifespan, the imprint leaves a inferior record in its wake. Since stampers are also an expensive piece to produce and take valuable time to change on the press, it's not surprising that some pressers will overuse them to save time and money.
Pits and Valleys:
Do you see little pits or divots speckling the playing surface? This effect is the result of a dirty or damaged mould, or a poorly formed stamper. As with orange peel, these pits will negatively effect the playback quality.
(As mentioned in the orange peel section, a bad mould = a poorly pressed vinyl record)
The other primary cause is poorly created stamper plates. After the stamper emerges from the galvanics tank, there are miniature imperfections on the back of the plate from the electroforming process. A well-prepared stamper is closely inspected and then sanded in a uniform motion until it's impeccably smooth. An immaculate stamper on a spotless mould is the first step in creating a superb sounding record.
Where’s the FILL?
Do you see odd looking grooves that cause an audible "swish" or dropout during playback? This is likely caused by non-fill.
Non-fill occurs when the hot vinyl biscuit doesn’t fully melt to fill each groove in the stamper. The alchemic mix of cycle timing, correct pressure, heating and cooling, and the use of high-quality PVC material is paramount to pressing a superior record. In the end, experience is key as there isn't a one-fits-all setting on a 40-year-old pressing machine.
Furnace Record Pressing spends considerable time and money ensuring that all of our equipment is well maintained and operated by experienced crafts people who know the machines (and the squeaks and squeals they make) like the back of their hand. Furnace MFG presses each LP with the care, attention (and love!) necessary to ensure that YOU won’t be disappointed when spending your hard earned money at the local record shop.
Happy listening.
Eric
Furnace MFG
Furnace MFG
