We use cookies to make your experience better. To comply with the new e-Privacy directive, we need to ask for your consent to set the cookies. Learn more.
Hand Crafted, Moving Coil (MC) Cartridge Step-up Transformer (SUT) built with exceptional quality SKY Transformers. These specially designed SUTs are designed specifically to amplify a Moving Coil's output high enough so it can be connected to the MM input of your phono preamplifier, regardless of whether that's a stand-alone phono preamp or one built into a receiver or a preamp.
SKY series SUTs feature gold plated hardware and a hand-polished black powder-coated cast-aluminum enclosure. All lettering is laser etched.
Optional XLR connectors are available on a larger custom chassis which is not laser etched.
Premium construction using C&K Silver-contact toggle switches and Deluxe Gold Plated RCA jacks. Most models include 2 switches: one to switch between high & low gain, the other to lift ground.
All connections are Resistance Soldered using the American Beauty system which eliminates heat damage which might occur on the delicate insulation on the hair-like wires of the transformers. Even the test equipment Bob's Devices uses is very-low current to avoid saturating the transformer cores. This is your assurance of a premier state-of-the-art product.
NOTE: To assure compatibility, please enter MC Phono Cartridge and MM Phono Stage in the text box above!
All Sky models include a ground post which is used to connect the turntable ground and your preamplifier ground.
A nice touch is that Bob's Devices also includes a ground "lift" switch, here's how it works:
In all modes, the transformer cases and faraday internal shielding to the transformers are connected to the ground screw.
In the "Ground" mode, the negatives of the phono system are connected to the ground lug. This configuration works well for those systems where the turntable ground is connected to the negative leads coming from the phono cartridge or where the negative inputs to the preamp are internally connected to ground.
In the "Lift" mode, none of the conductors in the RCA jacks are connected to the case, ground, or shield and there is no electrical connection between channels. This design allows for much greater flexibility when seeking to mitigate ground loops, regardless of the configuration of the other equipment.
The S-Series is a step-up (pun intended) from their predecessors. These models are heavier and meatier. They feature the same ratios as before and are designed for highly resolving analog systems. Bob 's Devices spent a great deal of time developing the S-series, trying many combinations while trying to improve on the standard set by their previous series.
They found that by increasing the length of the core, they were able to change the winding scheme just a bit, which results in a much more open, more dynamic and more fluid presentation. You will definitely "Hear the Magic."
Ultra High quality laminations, lower inductance and superior sound. These transformers were especially designed and tested with several low-output moving coil cartridges. The transformers used are very difficult to construct and require a precision manufacturing process . The construction techniques used are the same as in other Bob's Devices series, except that the inductance of the SKY-S series is much lower. In addition, the bandwidth is extended further into both extremes.
SKY 40 Switchable: Switchable ratios, 1:20 in LOW (+26 dB) / 1:40 in HIGH (+32 dB)
SKY 30-S: Switchable ratios. 1:15 in LOW (+24 dB) / 1:30 in HIGH (+30 dB)
SKY 20-S : Switchable ratios, 1:10 in LOW (+20 dB) / 1:20 in HIGH (+26 dB)
SKY 10-S : Switchable ratios, 1:5 in LOW (+14 dB) / 1:10 in HIGH (+20 dB)
SKY 5 Fixed: Features a single ratio of 1:5 in LOW (+14 dB), usually used (but not exclusively) with ARC phono stages that only have 55dB of gain
SKY 40 Fixed: Features a single ratio of 1:40 (+32 dB)
NOTE: To assure compatibility, please enter MC Phono Cartridge and MM Phono Stage in the text box above!
A Sky Step-Up Transformer increases the output of your MC cartridge to a level high enough to work with an MM phono stage!
In order for the SUT to work correctly, you'll need to know two things:
A) The amount of gain your MM phono preamp has and...
B) The output voltage of your MC phono cartridge
Most modern MM phono stages have 40dB of gain. However, some MM phono stages have far less gain and we've even heard of some having a bit more. The gain specification is published for every MM phono stage made, so before going further, do your research and ensure you know how much gain you're working with. Once you have that figure, use the handy reference guide below to figure out approximately how much total gain you'll need to optimally drive your MC phono cartridge.
Once armed with that info, simply select the Sky SUT from the Variants list on the previous tab to select the version with the optimum amount of gain for your ideal output level.
Example: Your MC cartridge has 0.3mV output. Looking at the gain chart below, it appears you'll want about 60dB of gain for optimal playback. If your phono stage has 40dB of gain, select the Sky 20-S, which delivers +20dB of gain, for an ideal 60dB of gain. The Sky 20-S also gives you the option of switching in an extra 6dB of gain, should your next MC cartridge have lower output.
NOTE: If you don't see your cartridge's precise voltage shown below, don't worry! These broad voltage segments are provided merely as guidelines. When in doubt, err on the side of slightly higher gain.
If your cartridge has:
0.5mV output (or higher), you'll want a total of ~55dB of output
0.4mV output, you'll want a total of ~58dB of output
0.35mV output, you'll want a total of ~59dB of output
0.3mV output, you'll want a total of ~60dB of output
0.25mV output, you'll want a total of ~62dB of output
0.2mV output, you'll want a total of ~64dB of output
0.15mV output, you'll want a total of ~67dB of output
0.1mV output, you'll want a total of ~70dB of output
NOTE: To assure compatibility, we ask that you please enter your MC Phono Cartridge and MM Phono Stage in the text box above when ordering. This way we can verify the Sky SUT you're purchasing is compatible with your analog rig!
"MAP" products are not Frequent Flyer eligible.
The pricing indicated is the absolute lowest allowed by the manufacturer. Our "Frequent Flyer" Program offers pricing and/or freight incentives for any order over $100 domestically ($300 internationally). Frequent Flyer is a cumulative program, so you will get credit for all previous orders each time to place a new order! With us, everyone’s a Frequent Flyer - no prior signup needed. After you place an order for Frequent Flyer eligible products, we will calculate applicable incentives. Your order amount will be adjusted and we will confirm the calculations by email within one business day. Click for more details.