{"product_id":"ortofon-st-m25","title":"Ortofon ST-M25 Step-Up Transformer","description":"\u003cp\u003eThe Ortofon ST-M25 is a step-up transformer developed specifically for the mono SPU cartridges Ortofon CA\/CG 25 Di MkII and CA\/CG 65 Di MkII. It raises their very low output voltage by 12 dB — for mono playback through both speakers.\u003c\/p\u003e\n\u003ch2\u003eWhy the ST-M25?\u003c\/h2\u003e\n\u003cp\u003eThe classic SPU mono cartridges deliver a particularly low voltage that pushes many inputs to their limits. The ST-M25 is tuned exactly to these cartridges: 12 dB of gain, wideband from 10 Hz to 100 kHz, and it cleanly puts the mono signal onto both channels, so you hear your mono records through your complete stereo system.\u003c\/p\u003e\n\u003ch2\u003eWhat you get\u003c\/h2\u003e\n\u003cp\u003eThe exact-fit complement for an SPU mono setup — a passive transformer that delivers precisely the gain these cartridges need, with no detours and no active electronics in the signal path.\u003c\/p\u003e\n\u003ch3\u003eWho is the ST-M25 suited for — and who isn't it for?\u003c\/h3\u003e\n\u003cp\u003eIntended for owners of the SPU mono cartridges CG\/CA 25 Di MkII or 65 Di MkII. \u003cstrong\u003eStraight talk:\u003c\/strong\u003e the ST-M25 isn't designed for other cartridges — if you have a normal stereo MC, the universal ST-7 is the right choice. This one is a specialist tool, not an all-rounder.\u003c\/p\u003e\n\u003ch2\u003eOur verdict\u003c\/h2\u003e\n\u003cp\u003eThe ST-M25 is a niche product in the best sense: the exactly right match for a demanding mono SPU setup. If you run these cartridges, this is the manufacturer-intended solution. At HD Zürisee in Wädenswil, we help you choose and integrate it.\u003c\/p\u003e\n\u003ch2\u003eTechnical data\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eType: passive step-up transformer (mono)\u003c\/li\u003e\n\u003cli\u003eGain: 12 dB (1 kHz)\u003c\/li\u003e\n\u003cli\u003eIntended use: exclusively for Ortofon SPU CA\/CG 25 Di MkII and CA\/CG 65 Di MkII (mono)\u003c\/li\u003e\n\u003cli\u003eSuitable cartridge internal resistance: 5–50 ohms\u003c\/li\u003e\n\u003cli\u003eLoad: \u0026gt; 47 kOhm \/\/ 200 pF\u003c\/li\u003e\n\u003cli\u003eFrequency response: 10 Hz–100 kHz (±1 dB)\u003c\/li\u003e\n\u003cli\u003eDimensions (W×H×D): 65 × 39 × 98 mm\u003c\/li\u003e\n\u003cli\u003eWeight: 410 g\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eFrequently asked questions\u003c\/h2\u003e\n\u003ch3\u003eWhich cartridges is the ST-M25 intended for?\u003c\/h3\u003e\n\u003cp\u003eExclusively for the Ortofon SPU mono cartridges CA\/CG 25 Di MkII and CA\/CG 65 Di MkII. The 12 dB boost is tuned exactly to their very low output voltage. The ST-M25 isn't intended for stereo MC cartridges — that's what the universal ST-7 is for.\u003c\/p\u003e\n\u003ch3\u003eWhat does the ST-M25's +12 dB do?\u003c\/h3\u003e\n\u003cp\u003eIt raises the very low voltage of SPU mono cartridges to a usable level and puts the mono signal onto both channels. This lets you hear mono records at the correct level through both speakers instead of just one. Active electronics aren't needed for this.\u003c\/p\u003e\n\u003ch3\u003eWhy buy the Ortofon ST-M25 at HD Zürisee?\u003c\/h3\u003e\n\u003cp\u003eBecause a specialist product like this needs the right advice. We work out with you whether the ST-M25 suits your SPU mono setup, and integrate it cleanly. HD Zürisee in Wädenswil is an authorized Ortofon dealer — call or write to us.\u003c\/p\u003e\n\u003ch2\u003eGoes well with\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eGoes well with:\u003c\/strong\u003e a matching \u003ca href=\"\/en\/collections\/tonabnehmer\"\u003ecartridge\u003c\/a\u003e, a \u003ca href=\"\/en\/collections\/phono-vorverstarker\"\u003ephono preamp\u003c\/a\u003e, and a high-quality \u003ca href=\"\/en\/collections\/plattenspieler\"\u003eturntable\u003c\/a\u003e.\u003c\/p\u003e\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"Which cartridges is the ST-M25 intended for?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Exclusively for the Ortofon SPU mono cartridges CA\/CG 25 Di MkII and CA\/CG 65 Di MkII. The 12 dB boost is tuned exactly to their very low output voltage. The ST-M25 isn't intended for stereo MC cartridges — that's what the universal ST-7 is for.\"}}, {\"@type\": \"Question\", \"name\": \"What does the ST-M25's +12 dB do?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"It raises the very low voltage of SPU mono cartridges to a usable level and puts the mono signal onto both channels. This lets you hear mono records at the correct level through both speakers instead of just one. Active electronics aren't needed for this.\"}}, {\"@type\": \"Question\", \"name\": \"Why buy the Ortofon ST-M25 at HD Zürisee?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Because a specialist product like this needs the right advice. We work out with you whether the ST-M25 suits your SPU mono setup, and integrate it cleanly. HD Zürisee in Wädenswil is an authorized Ortofon dealer — call or write to us.\"}}]}\u003c\/script\u003e","brand":"Ortofon","offers":[{"title":"Default Title","offer_id":53306062176592,"sku":"303503","price":699.0,"currency_code":"CHF","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0932\/3262\/8048\/files\/ortofon-st-m25-step-up-uebertrager-schraegansicht.png?v=1788961526","url":"https:\/\/hdzuerisee.ch\/en\/products\/ortofon-st-m25","provider":"HD Zürisee AG","version":"1.0","type":"link"}