For sale is apair of RCA 9458 alnico compression drivers / speaker units with very rare,original, new old stock phenolic diaphragms.

By way of background, the RCA 9000 series drivers began with the MI-9443 field coil unit in 1940, and was replaced by the 9448 permanent magnet model after the war. The 9458 came next (possibly early to mid-1950s), then the 9548 in several versions extending into the 60s/70s. Some of the diaphragms in these drivers had a flat compliance, though most used a half roll compliance. Like the early 1400 series field coil units,these fine drivers have been inexplicably undervalued and ignored by collectors and DIYers until fairly recently.

These 9458 drivers have serial numbers: 87667 and 89136.

The original,NOS phenolic diaphragms (with half-roll compliance) both come with original boxes, are both stamped “172607/501” and have serial numbers: 323 and 1044.  

I installed the diaphragms (87667 with diaphragm # 323 and 89136 with diaphragm # 1044) and swept each driver from 20Hz to 20khz (at low volume) and no buzzes, scrapes etc. 

I also tested each with music (again at low volumes) and each sound very sweet indeed.  

They measure very closely at 8.5 ohms and 8.6 ohms DCR installed. 

Will be shipped with diaphragms installed to minimise potential for damage.

Postage:

The international shipping quote on ebay is inaccurate.  If you want to know how much it will cost to ship to your country, please email before purchasing.  Thank you.

Sale is final- no returns.