User avatar
tubeactive
Posts: 16
Joined: Thu Feb 13, 2014 6:08 pm

Wanted: Ramko Research SP-8 preamp schematic/manual

Post: # 35447Unread post tubeactive
Sun Jun 07, 2015 6:51 pm

This is an early IC equipped phono stage with tremendous gain that was a regular in many broadcast studios. I have the earliest version; no suffix after the SP-8...brown case with white/tan face including two gain controls on the front. Inside, there are a few tweaking pots, what looks and sounds like active feedback RIAA EQ, plus too many electrolytics and a few ceramic caps I would like to upgrade sensibly...BTW, this unit sounds awesome; better than their later efforts IMHO...The scheme would be appreciated...Anyone else tried these Ramko preamps ?

User avatar
tubeactive
Posts: 16
Joined: Thu Feb 13, 2014 6:08 pm

Re: Wanted: Ramko Research SP-8 preamp schematic/manual

Post: # 36200Unread post tubeactive
Fri Jul 24, 2015 5:45 pm

Well; no replies yet...oh well...I am patient. I did begin planning my resto attack. I confirmed that active feedback phono EQ is utilized; thankfully. I will tweak the EQ parts quality, replacing the ceramic caps with polystyrene caps, upgrade some interstage coupling caps; then beef up the power supply storage capacitance banks. Those tired old caps deserve some upgrading. Increasing the electrolytic storage caps' values and quality will simply yield even better dynamic range with more bass control and impact. As previously mentioned, the gain on this early version preamp is admirable. I might also look into upgrading the original op amps...but current sonic flavor is fine...

Post Reply