McIntosh C28 All Analog Vintage Preamp - Clean

Description

McIntosh C28 All Analog Vintage Preamp - Clean
SkyFi Audio - Curators of Vintage Audio GearSkyFi Audio is a small startup business specializing in the purchase, reconditioning, and reselling of high end audio equipment. We only buy equipment that we admire and are passionate about. No mid-fi, no gimmicks, no junk. Each piece of equipment is cosmetically restored and fully tested in our well-equipped lab by an engineer with 30+ years of experience in the HiFi world. If it does not meet or exceed the original manufactures specifications, it will not be sold. We are very selective about the equipment we purchase, focusing on mostly analog, high-build quality, American, and European built units.Through our sister company, which is an authorized dealer for McIntosh, Audio Research, Sonus Faber, ClearAudio, Project, and Sony ES, we have access to OEM parts, service, and support.----------The C28 is the best McIntosh selling preamp in our shop.  It's easy to service, has a low noise floor, great vintage looks, and every feature we would want. The individual left and right tone controls are a nice plus.   Cosmetically it's very clean - the glass is perfect except for a missing red dot and the paintwork and stenciling are super nice.  Chassis is super clean with no signs of rust or corrosion. This has been fully tested in our our lab where it performed well.  Previously Serviced Note:Our investigation at the bench revealed that this C28 was serviced in the past. Several electrolytic caps on the main board and power supply were replaced. 3 of the power supply caps were tacked on to an existing multi-section can. This is not the method that we normally use here at SkyFi, but in our detailed testing the repair was confirmed that the unit is functioning as intended. We cleaned the controls and cleaned the unit.SkyFi Cosmetic Note: There is a small black burn-in mark on the red mode selector filter. C28 Standout Features: • Use 3 Tape Machines2 with their own electronics and 1 tape playback deck with complete easy front panel switching• Built-In Headphone AmplifierListen to your favorite music --- privately• Main and Remote Loudspeaker SwitchingTurn the main speakers on or off without affecting the remote speakers and vice versa (operates with accessory relay)• New Low Noise Phono InputListen to your records with a new quietness• Individual Channel Phono Level ControlsMatch levels from different phono cartridges without degrading signal to noise ratio• Individual Channel Output Level ControlsPerfect balance from your stereo always• Individual Channel Tone Control SwitchesComplete, repeatable flexibility• New Compensation ControlOne position for loudness compensation, one position is flat and a third position that adds presence compensation! The SkyFi Testing Process for Preamplifiers: We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect the PCBs for discoloration from resistors or transistors that may have been running hot. On vintage units we often spot check select capacitors for value and ESR. When we first power on a preamplifier we connect its RCA output to a Sencore PA81 Power Analyzer which simulates real world loading conditions and gives us an oscilloscope interface. The first order of business is checking that the volume control works smoothly throughout its entire range with acceptable channel balance. This is accomplished by feeding a 1KHz sine wave into one of the preamp’s line level inputs while monitoring the preamp’s output on an oscilloscope. We then switch to a 1KHz square wave to test the tone controls, loudness function, and filters where applicable. During this step we are watching for equal alteration of the test signal by both channels. This also helps us identify dirty controls that will need treatment. Once the basic line stage functions are verified, we test each input individually. This is especially important for devices that use relays to select their sources. If the preamp is equipped with a phono stage we test that as well. We use an inverse RIAA filter which allows us to feed a reference test signal into the phono input with the proper RIAA equalization and level. A square wave or sine sweep is used to verify that the device’s phono stage is faithfully reproducing the RIAA curve. If the preamp under test has balanced inputs and/or outputs these are tested as well. We finish up our bench testing with a listening test with our bench amplifier and reference speakers. During this test we check for hum or hiss that may not have shown up in earlier testing. We also check that all of the tone controls and filters perform as expected. If the preamplifier has remote control functions these are also tested. Preamps with tube circuits or complicated power supply topologies are connected at our long term test rig for extended stress testing under real world conditions. Item Included Original Box Not Included Manual Not Included Remote Not Included Cables Yes - Power Only Physical Condition 7 / 10 Working Condition 10 / 10 ----------PURCHASING GUIDELINES:1) We do not review or accept any offers that do not go through the official eBay system. We have too many items for sale and it is nearly impossible to keep track of offers outside of the official system. Please do not message, email, or text any offers. 2) All listings are eligible for the eBay Global Shipping Program, unless the item exceeds the maximum weight/price requirements to your country. If this is the case simply message us via eBay as we accept bank wire transfers for international payments and frequently ship worldwide via UPS.3) Please ensure your shipping address is correct within eBay as we will ONLY ship to the eBay/PayPal Confirmed Shipping Address. No exceptions.4) eBay may charge and collect sales tax to your state/jurisdiction. Please understand the have no control over this.eBay v1.4
SkyFi Audio - Curators of Vintage Audio Gear
SkyFi Audio is a small startup business specializing in the purchase, reconditioning, and reselling of high end audio equipment. We only buy equipment that we admire and are passionate about. No mid-fi, no gimmicks, no junk.
Each piece of equipment is cosmetically restored and fully tested in our well-equipped lab by an engineer with 30+ years of experience in the HiFi world. If it does not meet or exceed the original manufactures specifications, it will not be sold. We are very selective about the equipment we purchase, focusing on mostly analog, high-build quality, American, and European built units.
Through our sister company, which is an authorized dealer for McIntosh, Audio Research, Sonus Faber, ClearAudio, Project, and Sony ES, we have access to OEM parts, service, and support.
----------
The C28 is the best McIntosh selling preamp in our shop.  It's easy to service, has a low noise floor, great vintage looks, and every feature we would want. The individual left and right tone controls are a nice plus.
Cosmetically it's very clean - the glass is perfect except for a missing red dot and the paintwork and stenciling are super nice.  Chassis is super clean with no signs of rust or corrosion.
This has been fully tested in our our lab where it performed well.
Previously Serviced Note:
Our investigation at the bench revealed that this C28 was serviced in the past. Several electrolytic caps on the main board and power supply were replaced. 3 of the power supply caps were tacked on to an existing multi-section can. This is not the method that we normally use here at SkyFi, but in our detailed testing the repair was confirmed that the unit is functioning as intended. We cleaned the controls and cleaned the unit.
SkyFi Cosmetic Note:
There is a small black burn-in mark on the red mode selector filter.
C28 Standout Features:
• Use 3 Tape Machines
2 with their own electronics and 1 tape playback deck with complete easy front panel switching
• Built-In Headphone Amplifier
Listen to your favorite music --- privately
• Main and Remote Loudspeaker Switching
Turn the main speakers on or off without affecting the remote speakers and vice versa (operates with accessory relay)
• New Low Noise Phono Input
Listen to your records with a new quietness
• Individual Channel Phono Level Controls
Match levels from different phono cartridges without degrading signal to noise ratio
• Individual Channel Output Level Controls
Perfect balance from your stereo always
• Individual Channel Tone Control Switches
Complete, repeatable flexibility
• New Compensation Control
One position for loudness compensation, one position is flat and a third position that adds presence compensation!
The SkyFi Testing Process for Preamplifiers:
We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect the PCBs for discoloration from resistors or transistors that may have been running hot. On vintage units we often spot check select capacitors for value and ESR.
When we first power on a preamplifier we connect its RCA output to a Sencore PA81 Power Analyzer which simulates real world loading conditions and gives us an oscilloscope interface. The first order of business is checking that the volume control works smoothly throughout its entire range with acceptable channel balance. This is accomplished by feeding a 1KHz sine wave into one of the preamp’s line level inputs while monitoring the preamp’s output on an oscilloscope. We then switch to a 1KHz square wave to test the tone controls, loudness function, and filters where applicable. During this step we are watching for equal alteration of the test signal by both channels. This also helps us identify dirty controls that will need treatment. Once the basic line stage functions are verified, we test each input individually. This is especially important for devices that use relays to select their sources. If the preamp is equipped with a phono stage we test that as well. We use an inverse RIAA filter which allows us to feed a reference test signal into the phono input with the proper RIAA equalization and level. A square wave or sine sweep is uséd to verify that the device’s phono stage is faithfully reproducing the RIAA curve. If the preamp under test has balanced inputs and/or outputs these are tested as well.
We finish up our bench testing with a listening test with our bench amplifier and reference speakers. During this test we check for hum or hiss that may not have shown up in earlier testing. We also check that all of the tone controls and filters perform as expected. If the preamplifier has remote control functions these are also tested. Preamps with tube circuits or complicated power supply topologies are connected at our long term test rig for extended stress testing under real world conditions.
Item
Included
Original Box
Not Included
Manual
Not Included
Remote
Not Included
Cables
Yes - Power Only
Physical Condition
7 / 10
Working Condition
10 / 10
----------
PURCHASING GUIDELINES:
1) We do not review or accept any offers that do not go through the official eBay system. We have too many items for sale and it is nearly impossible to keep track of offers outside of the official system. Please do not message, email, or text any offers.
2) All listings are eligible for the eBay Global Shipping Program, unless the item exceeds the maximum weight/price requirements to your country. If this is the case simply message us via eBay as we accept bank wire transfers for international payments and frequently ship worldwide via UPS.
3) Please ensure your shipping address is correct within eBay as we will ONLY ship to the eBay/PayPal Confirmed Shipping Address.
No exceptions.
4) eBay may charge and collect sales tax to your state/jurisdiction. Please understand the have no control over this.
eBay v1.4
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