steven365 Posted June 7, 2017 Share Posted June 7, 2017 Hi Guys Need your help. I'm planning to purchase a pair of Magnepan 1.7i and is searching for a power amp that will match well with my Calypso tube preamp and the Magnepan 1.7i After reading a lot of reviews, I narrowed my options down to Sanders Magtech and Pass Labs X250.5. Both are very powerful amp and should have no problem driving the Magnepan 1.7i. However, quite a few reviewers also mentioned the importance of input/output impedance match between the pre-amp and power-amp. Unfortunately I have no knowledge in this area. I have listed below the specs for the Calypso tube preamp, the Sanders Magtech and the Pass Labs X250.5. Could you please kindly check for me if these power-amps are good match for my Calypso tube preamp impedance wise? Also some reviews mentioned that the Sanders Magtech sounds a bit 2-dimensional...Is it your observation as well? Considering that I might upgrade speaks in the future, does Magtech work well with other speaks as well or just panel speaks? Sorry for too many questions. I thank you in advance for your help : ) CALYPSO SPECIFICATIONS Inputs: 5 line RCA or XLR (balanced), plus 1 tape, RCA or XLR Outputs: 2 RCA (SE) and XLR (balanced), 1 tape RCA Line level gain: 23 dB single ended (SE), in/out, and 29 dB balanced/out Volume control: switched resistor network volume control with 88 1 dB steps Front panel controls: main input, tape input select, volume, balance, phase, mute, display, and bypass Remote controls: main input, tape input select, volume, balance, phase, mute, display, bypass and standby Frequency response: +- 0.25 dB, 20 Hz - 20 Khz Signal to noise: measured at 70 dB minimum, A-weighted (ref 1 mv input, 75 dB gain setting) Line input impedance: 40 k ohms SE, 80 k ohms balanced Maximum line input: 3.5 volts SE, 7.0 volts RMS balanced Output impedance: 1K ohms SE, 600 ohms balanced Recommended amplifier load: 10K ohms or greater (SE), 20K ohms or greater (Balanced) Tubes, each channel: (line section) V1 (12AX7 or equivalent), V2 (6922/6DJ8) Power consumption: 20 watts standby, 60 watts active Physical dimensions: 4 3/8" high, 17 7/8" wide, 18" deep including jacks Shipping weight: 40 lbs. PASS LABS X250.5 SPECIFICATIONS Class-AB Type-Stereo Gain (dB)-26 Full Pwr @ 26 dB gain (V)-2.24 Low Frequency Response-1.5 Hz High Frequency Response-100 KHz Power Output/ch (8 ohm)-250 Power Output/ch (4 ohm)-500 Distortion (1 KHz, full power)-1% Input Impedance (SE & BAL Kohms)-30/20 Damping Factor-150 Output Noise (uV)-200 Power Consumption (Watts)-300 Temperature (deg C.)-53 Number of Chassis-1 Dimension (W x H x D) (In.)-19 x 9.2 x 21.5 Unit Weight (LBS)-88 SANDERS MAGTECH SPECIFICATIONS Power (Stereo Version)-500 watts RMS per channel into an 8 ohm load/900 watts RMS per channel into a 4 ohm load Bandwidth-DC through 100kHz Class of Operation-Class AB Slew Rate-500 Volts/microsecond Input voltage required for full output-2 Volts Input Impedance-100kohm (both balanced and unbalanced) Gain-26dB Noise-More than 110dB below rated output Damping Factor-Greater than 600 into an 8 ohm load THD-Less than 0.004%, 20 Hz - 20 KHz Voltage-Voltage is user selectable for use world-wide. IMD-Less than 0.003%, 20 Hz - 20 KHz Link to comment Share on other sites More sharing options...
Zaphod Beeblebrox Posted June 7, 2017 Share Posted June 7, 2017 Either power should work properly with your preamp. Although the output impedance is high, it is not as high as many. If you want to know which power amp is best suited to your speakers, then you should arrange to listen to both, in your system. NEVER buy an audio product, without first listening. Do not choose based on what reviewers or strangers tell you. You MUST listen for yourself. Always. Link to comment Share on other sites More sharing options...
Addicted to music Posted June 7, 2017 Share Posted June 7, 2017 Agree with What @Zaphod Beeblebrox in the above post said. Youre in Sydney so you are a lot closer to Bill McLean Audio; http://www.mcleans.info/home-entertainment/home.do;jsessionid=8F9DB343B7990AE64492D2DFC33E6AAF He will have the 1.7i and the Magtech for auditioning, and you will need to bring your Preamp on board to get a feel of that combo. Also bring some music thst you are familiar with. just remember that all Magnaplanar panels need space and space from the rear wall too. 2 Link to comment Share on other sites More sharing options...
Guest Arni Posted June 7, 2017 Share Posted June 7, 2017 checking the web, found below: http://www.sasaudiolabs.com/sasaudio.htm Link to comment Share on other sites More sharing options...
georgehifi Posted June 7, 2017 Share Posted June 7, 2017 (edited) Impedance match preamp and power amp? There is no general written rule to this, but I'm on another forum that the likes of Nelson Pass and John Curl (gods or hifi) frequent, and they always say that a 10 x rule is safe to apply for no loses, between source and preamp, also between preamp and poweramp. EG: if the output impedance of the preamp is 100ohm output impedance, then the input impedance of the poweramp should be > 1000ohms (1kohm), same goes for source to preamp. And I've A/B'ed this, and believe they are right, Cheers George Edited June 7, 2017 by georgehifi Link to comment Share on other sites More sharing options...
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