logoA.gif (6156 bytes) ELECTRO - TECH, INC.

Classic Car Speakers

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Electro-Tech is proud to announce our new website where you can browse, shop and purchase our products directly.

Please visit us at our new site: www.smelectrotech.com

S & M Electro-Tech has developed a complete line of new replacement speakers engineered to fit in collector cars and function properly with OEM radios. Our speakers are manufactured in the USA using compact high energy neodymium (NEO) magnets that allow these speakers to fit where others won't. Neodymium magnets (commonly referred to as super magnets) are 1/10 the physical size of round ceramic magnets found on most modern speakers but provide the same or higher field strength. Most of our speakers are true 8 ohm impedance and are fully compatible with 10 ohm Delco speakers. Many have whizzer cones for improved high frequency response and fabric or sanoprene rubber surround and larger spiders for improved low frequency response. They work exceptionally well with original Delco, Ford and Mopar radios made from the 40's through the mid 70's and will make your classic radio sound better than new. Available in most popular sizes used with car radios from the late 1930’s through the mid 1970’s. Most of our speakers can handle the added power produced by our AM/FM conversion radios and modern car radios.   Our speakers carry a 5 year warranty against manufacturing defects.

Compare our replica 4 x 10 speakers to original Delco slim line speakers used in many 1960's GM products. The original "Delco Special Rectangle"  is on the top left, our replacement speaker is on the top right. The bottom left speaker is our 4 x 10 Oval replacement. The 2 middle 4 x 10 oval speakers are original Delco 4 x 10 oval speakers. The lower right 4 x 10 is a common 4 ohm replacement speaker sold by many auto parts supply stores and restoration parts suppliers. The magnet on our speaker has more the twice the field strength of the ceramic magnet shown on the lower right speaker and 4 times the strength of the original alnico magnets used on the original Delco speakers.

                        Original Delco 4x10 Special Rectangle                           Our 4x10 Replacement

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             Our 4x10 Oval                           1964 - 67 Pontiac GTO                   1968-69 Corvette Kick Panel                 Generic 4 ohm speaker


Note: Many replacement speakers now sold by the discount stores, auto parts stores and mail order restoration parts houses are labeled as  "4 to 8 ohm compatible"  and are in fact 4 ohm speakers. These speakers can damage the older transistor radios. 4 ohm speakers will measure around 3.2 ohms with a DC ohmmeter. An 8 - 10 ohm speaker will measure around 7.4 ohms with a DC ohmmeter. The DC resistance is the critical number for the Delco radios as the output transistor is in series with the speaker. A properly operating Delco radio should have 1.5 volts DC across the speaker voice coil. A 4 ohm speaker will draw twice the current of an 8 ohm and cause the amplifier transistor (the half dollar size device mounted to the black finned heat sink on the back of a Delco radio) to run very hot. The speaker cone should be displaced in an upward (away from the magnet) direction about 1/8" when a Delco radio is turned on. If the cone moves down toward the magnet, the speaker leads need to be reversed.  Ford and Chrysler radios of the period used the same type of germanium output transistors as the Delco radios and also require 8 ohm speakers. However, Ford and Chrysler radios ran with 0 to 1 volt DC offset on the speaker depending on the radio model and vintage. Many will not deflect the cone when turned on like the Delco radios.

Warning: Never run 4 ohm speakers on any vintage car automobile radio using transistor output circuits.

If you don't know what type of output circuit your radio uses, call us.

Re-cone speakers: Many people call and ask if we can re-cone their original speaker. Sorry, but the answer is no. Many re-coned speakers do not sound good or function right.  The old alnico magnets are becoming weak with age and most re-coners do not have the equipment to re-magnetize the magnet. Also, in many cases the frame and voice coil gap cannot be cleaned and reconditioned for the speaker to perform well. After years of having original speakers re-coned with very mixed results, we decided to manufacture new speakers that would outperform the originals, fit in the original locations, and work with the original radios at a cost lower than recone.  

To order any of our speakers, just call us. We will be happy to help you in the selection of the proper speaker for your application. We accept all major credit cards for payment.

To contact us please call 1-763-780-2861 or email us at turnswitch@turnswitch.com.  We are open from 9:00 AM to 6:00 PM Monday thru Friday- Central Time.

Available Speaker sizes:

3 1/2"  Round - Used in late 60's and early 70's Cadillac, early 70's Olds, Pontiac, Buick and late 60's, early 70's Mopar front 3 speaker dash locations for stereo radio/tape applications. The mounting ears can be cut off and the speaker held in with the wire clips used on many GM applications(See photo below). We can supply a magnet filler block on request for cars using the Delco wire clip mount.

Note: When used with modern high power radios, this speaker should be connected with 50uf 50volt non-polar coupling capacitors in series to prevent over excursion of the cone at very low frequencies. Some factory GM and all Mopar applications using these speakers have the crossover capacitors installed in a box under the dash. It is even more important when installed with our conversion radios or modern after market radios with high power amplifiers. 


Price - $94.95 per pair               8 - 10 Ohm         Size: 3 3/8" dia.   1 1/2" deep.  3 3/4" to 4 1/4" mounting center.

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Cadillac spring clip mounting



3 1/2"  Square - Used in late 60's   Cadillac,  late 60's and early 70's Mopar front 3 speaker dash locations for stereo radio/tape applications.

Price - $94.95 per pair               8 - 10 Ohm         Size: 3 1/2" dia.   1 3/8" deep.   2 3/4" mounting centers.

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4 1/2" Pin cushion  - Used in Volkswagen Beetle, Porsche, some late 50's Lincoln applications.  Used in our Dual6x9HQ and Dual4 x10HQ "Special Rectangle" and Dual4x10HQ Mopar speakers.  This is a excellent speaker for use in concealed locations due to its small size, light weight, and excellent frequency response and power handling abilities. Power rating 40 watts RMS

Price - $55.95 each               Both  4  ohm and 8 ohm available           Size: 5" dia.  1 7/8" deep.  3 5/16" mounting centers.

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5 1/4" Pin cushion - Used in late 60's and early 70's Ford, Mercury, Lincoln MK III's rear speaker stereo applications. Companion to our 4 x 8 speaker used in the doors of these cars. Also used in some 60's Porsche 356's and VW Karmen Ghias.

Price - $55.95 each               8 - 10 Ohm       Size: 6" dia.  2 1/8" deep.  3 3/4" mounting centers.

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6 " Pin cushion - Used extensively in GM applications mounted in the center of the rear seat cushion, starting with the  1958 Impala , Pontiac, Oldsmobile, etc. This speaker will greatly improve the rear seat sound of your original GM Radio, especially if used with the Stereo radios or reverb units. This speaker is also correct for 1960's VW bus applications.

Price - $55.95 each              8 - 10 Ohm       Size: 6 1/8"dia. 2" deep. 4 3/8" mounting centers.

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7 " or 7 1/2" Pin Cushion - Used extensively in Mopar dash applications from 1946-1948, and various other years up through 1965. Also used inside 1940 & 41 Ford box radios. This speaker uses a 11ga laser cut steel mounting ring that matches the mounting pattern of the original 7" speaker exactly. Mounted on the ring is our high quality 6" pin cushion  speaker. We also install a fabric dust screen over the face of the entire assembly.

Price - $59.95 each              8   Ohm       Size: 7"dia.  2 1/8" deep.  Non-square mounting centers. 7" model - 4 1/4" x 5 3/4".   7 1/2" model - 4 5/8" x 6 3/16"

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Also available with 7 1/2"  ring size and mounting centers for early 1940's Cadillac box radios.




8" Pin cushion - Used with tube style radios in the 40's box radios and 50's Olds, Pontiac, and early Corvette through 1957.

Price - $55.95 each                  4   Ohm         Size: 7  1/2" Dia,  2  7/16" deep. Mounting centers 5 3/16"

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4 x 6" Oval - Used in the dash and kick panels of many GM cars with the factory "Stereo" radios from the mid 60's through the mid 70's. This speaker will directly replace the rare 65, 66, 67, etc.,  Chevrolet kick panel speakers and rare Chevelle dash pad speakers with the twisted magnet.

Price - $49.95 each      8 - 10 Ohm    Size: 4"W x 6 1/8"L.   1 1/2" deep. 3" x 5 1/4" mounting centers - other combinations.

Price - $109.90 per pair with Chevelle angle brackets installed. Does NOT include the stamped steel brackets that the speakers mount on.

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Our 4 x 6 speakers are available with angle brackets for direct bolt-in on 1970 - 72 Chevelle/El Camino/Monte Carlo dash applications.


Original Delco 4x6 dash speakers for Chevelle shown on top. Notice the difference in the magnet size and location between the left and right speakers for instrument panel clearance. If you look close, you will also notice the angle brackets are in different positions on the driver side verses the passenger side speaker.

The middle picture is our 4x6 speakers bolted to the dash speaker support brackets. (Stamped dash support brackets not included with our speakers.)

The bottom picture shows our 4x6 speakers with the angle brackets. We also sell our speakers with the angle brackets installed for Chevelle/Monte Carlo.

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4 x 8" Oval - This is a very rare speaker size used in 1958 Cadillac, Studebakers, International Harvester, Lincoln Mark III's & IV's, Late 60's, early 70's  Mustangs and T-Birds door mount in stereo radio applications. Now with improved cone and suspension.

Price - $55.95 each        8 - 10 Ohm           Size: 4"W x 8" L.  1 11/16" Deep.         Mounting Centers: 3 1/8" x 5 1/2"

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4 x 8" Oval with Ford Spacer Ring - This is our 4 x 8  - 8 ohm speaker mounted on a ABS plastic 3D printed adapter that matches the size and bolt pattern used in early 70's vintage Ford Mustang and other Ford stereo radio door mount applications.

Price - $60.95 each        8 Ohm          Size: 4 1/2" W x 8 5/8"L x 1 3/4" Deep         Mounting Centers: Bottom 4 15/16"  Top: 6 7/8" x 3 5/8"

Front                                                   Rear



Comparison - Top is OEM, Bottom is our replacement.




4 x 10" Slimline Oval - Used extensively in many GM, Ford and Mopar products starting in 1959.  This is probably the most common car front dash  radio speaker size used in the 1960's by all manufacturers.   This speaker will fit in all 4 bolt oval 4x10 applications. Required for 1964-1967 GTO/Tempest and 1968/69 Corvette kick panel used with original Delco radios.

Fabric cover on all 4 x 10 speakers.

Price - $55.95                 8 - 10 Ohm             Size: 4 1/8"W x 10"L.  1 1/2" deep.  3 1/4" x 6 7/8" mounting centers

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                                                                                                                        Shown with original Delco 68-69 Corvette speaker on top.                                                                                                                                                                                                                                              Note the Corvette hanger hook opposite the terminals.



4" x 10" Delco Style Special Rectangle  -  This speaker is an exact replacement for original Delco speakers used starting in 1965 Chevrolet and Chevelle and by 1968 almost all GM cars. This speaker is correct for 1967 - 1972 Chevy pickup trucks as well. This speaker is very light weight and will mount with all original Delco/GM mounting brackets. The magnet cover block on the back of the speaker can be configured in either direction to match your original application and is user attached with an EDPM double backed tape ring.  Full installation instructions included. Fabric cover on all 4 x 10 speakers.

  Price - $69.95 each              10 Ohm           Size:   4 3/4"W x 10 1/2"L.   2 1/8" deep. No mounting centers - held in by bracket.

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Some of the GM speaker brackets used to install the above speaker. The brackets used are different on almost every model and year GM car and are NOT included with the speaker. You must have the original bracket to mount our 4 x 10 Special Rectangle speaker.

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NOTE: OEM Brackets are not reproduced. Must be sourced from original cars.



4 x 10" Oval Universal Frame - Used in many Ford and Chrysler products as a front dash speaker. This speaker uses a larger magnet structure, bigger diameter spider than our "Slim Line" and "Special Rectangle" speaker and has a cloth rolled suspension for improved bass response and better power handling capability. The extra ears on the end allow for mounting in Ford and Chrysler products that used the 2 hole mounting pattern. They can easily be cut off with a tin snips if needed for 4 bolt mounting clearance. Fabric dust cover installed on all speakers.

Price - $55.95 each               8 - 10 Ohm           Size: 4 1/8"W x 10"L.  2 5/8" deep.  3 1/4" x 6 7/8" mounting centers.

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4 x 10" Extended Range - Used in most 1984 - 1987 Buick Grand National's and Buick Regal's including the turbo models. These use a larger 3 1/4" diameter ceramic magnet that matches to the original factory speakers. If your car came equipped with the extended range speakers, check for the code U66 on the trunk ID Label.

Please Note: You must have the factory cages to secure this speaker to the deck.

Price - $55.95 each               10 Ohm           Size: 4"W x 10"L

5 x 7" Oval - Used in many Ford and Chrysler products as a rear deck speaker and in some cases, in the dash.

Price - $55.95 each               8 - 10 Ohm           Size: 5" W x 7 1/4"L.   2 1/8" deep.  4 3/8" mounting centers - both directions.

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6 x 9" Oval - Our 6x9 speaker uses our large NEO magnet, treated fabric accordion surround edge suspension, added whizzer cone for improved high frequency response and a much larger spider than OEM speakers. All this makes our speaker out perform any OEM 6x9 used on classic cars. The 6x9 is the most popular size speaker used by all car manufacturers starting in the late 40's and still in use today. A common dash and rear deck speaker for most cars. Available in both 4 ohm and 8 ohm impedance.  As a rule, if your radio is all tube operation with a vibrator, it uses a 4 ohm speaker. If your radio is a hi-bred ( part tube, part transistor ) or all transistor ( 1962 or later ) it will require an 8 - 10 ohm speaker.

Note: 4 ohm speakers do not have the whizzer cone as many applications like the 1955, 1956 Chevrolet full size factory radio applications. Due to the compact NEO magnet, this speaker will fit in the 1946, 47, 48 Fords, 50, 51 Mercurys, 55, 56 Chevy and other applications that require small magnets. 

Black fabric dust screen installed on all 8-10 ohm speakers (optional on 4 ohm at no extra charge).

Price - $55.95 each               4 & 8 Ohm available.      Size: 9 1/16"L x 6  5/16"W.   2 11/16" deep.  4 5/8" x 6 5/8" mounting centers.

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1958 - 1967 Corvette Speaker

6 x 9" Oval with correct Delco Load Coil - Used in 1957 & 1958 full size Chevrolet front speaker applications and Corvettes from 1958 through 1967.  We have gone to great length to reproduce the correct load coil and mounting bracket used on the C2 Corvettes. This speaker will make your original Corvette radio sound better than new, with improved bass and treble response and can achieve higher volume levels than an original speaker.    The Neo magnet used on our speaker provides more than twice the magnetic field strength of the ceramic magnet on the speaker shown below ours. As with all Delco radios of this vintage, this speaker is designed to run with 1.5 volts DC across the speaker terminals.

Warning: There are many copies of this speaker available from other sources that have the wrong value load coil and 4 ohm speakers. Many we have seen have a DC resistance as low as 1/4 ohm. Load coils with this low resistance will appear to be a short circuit to the radio and can destroy the output transistor or amplifier circuits. 

Price - $74.95 each      8 - 10 Ohm with correct 1.5 ohm 26 millihenry load coil.  Black fabric face dust cover on all speakers.

Size: 9 1/16"L x 6  5/16"W.    2 11/16" deep.  4 5/8" x 6 5/8" mounting centers.

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Our 8-10 ohm speaker with correct 1.5 ohm, 26 millihenry coil.




Incorrect common replacement speaker

sold for 1958 - 1967 Corvettes


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This is a 4 ohm speaker with 1/4 ohm, 1 millihenry load coil.  Way to low a value for proper operation. You cannot get the bias voltage above 1/2 volt DC using this speaker.

This speaker will not sound good and can damage your Delco radio.




1970 - 1982 Corvette 4x6 Speaker

High Performance 4 x 6" Oval  As the original Delco 4x6 for the C3 series Corvettes have become harder to find, we have had increased requests for a speaker that will work in this application.  We wanted a speaker that would outperform the original OEM and have come up with a speaker that far surpasses the Delco unit. Thanks to our NEO magnet, sanoprene rubber surround, larger spider, composite cone with whizzer, this little speaker has far better bass response and   high frequency response out beyond the FM band limit of 15kHz. We have cut a custom cork gasket for this speaker for proper fit in the factory speaker mounting frame. This speaker is the same depth as the original Delco speaker and is the correct 10 ohm impedance to function with all Delco radios. This speaker will also give excellent performance when used with modern radios and can handle up to 40 watts RMS. This speakers comes with installed cork face gasket, mounting nut spacers and complete instructions.

Price - $98.95 per pair            8 - 10 Ohm         Size: 4"W x 6 1/8"L x 2 1/8" Deep.   Gasket mounting centers match C3 Corvette - many other combinations.

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Original Delco (left) and our 4x6 (right) shown on Corvette cast speaker mounting frame.

4x6 Speaker shown with cork gasket and dust cover.



Special Application High Performance Speakers


SX69 Coaxial 6 x 9" Oval - Our customers kept asking for a high end coaxial 6 x 9 speaker for use with our AM/FM conversion radios. This 6 x 9 utilizes a special titanium /fiber composite woofer cone, rubber surround, and a high energy mylar film tweeter with built in crossover. Unlike our other speakers, this speaker uses a 20 oz ceramic magnet and is only suitable for rear package tray mounting. It will fit in most of the 1970-1972 GM A body convertibles behind the rear seat in the factory locations. This speaker is of 4 ohm impedance and cannot be used with original factory radios. A speaker of similar quality would cost twice this amount from the national electronics retailers.

Price - $120.00 per pair including grilles.           4 Ohm                    Size:   9 1/4"W x 6 3/8"L.   3 1/2" deep.  4 5/8" x 6 5/8" mounting centers.

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Included grilles




6" x 9" Stereo High Output - While similar to our standard 6 x 9" stereo speaker, this dual speaker uses drivers with a response curve more tailored to open cars providing improved clarity in windy or noisy environments. With 4 ohm voice coils is only suitable for use with our AM/FM Stereo conversion or modern radios. With 8 ohm voice coils, this speaker can be used with original factory stereo radios from the mid 60's and early 70's. This speaker is very compact and light weight - about 1 pound. Compare to others using smaller drivers at over 2 1 /2 times the weight. Shown without included fabric dust screen for clarity.

Price - $119.95              Both  4 ohm and  8 ohm available.            Size:   9 1/4"W x 6 3/8"L.   2" deep.  4 5/8" x 6 5/8" mounting centers.


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4" x 10" Special Rectangle Stereo High Output - This speaker uses the same High-Q drivers used in our Dual6x9 HQ  stereo speaker, but mounted on an 11ga laser cut steel plate with a foam rubber gasket to match the mid 60's through early 70's Delco 4 x 10. This speaker will mount back in the car with the original bracket in most cases. It is very light, weighing just over 1 pound. Compare to others using smaller drivers at over 2 1 /2 times the weight. This dual speaker uses drivers with a response curve tailored to open cars providing improved clarity in windy or noisy environments. Available with 4 ohm voice coils suitable for use with our conversion and modern radios or with 8 ohm voice coils for those who wish to install original factory stereo radios in Chevrolet cars but do not wish to cut their kick panels for the original 4 x 6 speakers.  Shown without included fabric dust screen for clarity.

Price - $119.95        Both 4 ohm and 8 ohm available Size:   10 1/2"L x 4  3/4"W.    2 1/8" deep. No mounting centers - held in by bracket (not included - must use original).

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Our Dual 4x10 Special Rectangle speaker shown with Chevy, Pontiac, Buick style bracket above right and Oldsmobile bracket below.

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4" x 10" Mopar A and B Body Stereo High Output - This speaker uses the same High-Q drivers used in our Dual6x9HQ  stereo speaker, but mounted on an 11ga laser cut steel plate cut to match the original Mopar A & B body 4x10 center dash speaker mounting plate.  It is very light, weighing just over 1 pound. Compare to others using smaller drivers at over 2 1 /2 times the weight.  Available with 4 ohm voice coils suitable for use with our conversion or modern radios or with 8 ohm voice coils for those who wish to install original factory stereo radios in Mopar cars but do not wish to acquire the 3 speaker dash parts used with original Mopar stereo radios and tape players.  Note: No dust screen due to fitment.

Price - $119.95        Both 4 ohm and 8 ohm available Size:   10 1/2"L x 4  3/4"W.    2 1/8" deep.

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Dual speaker replaces original Mopar A & B body 4 x 10 Speaker and mounting bracket for conversion radios or modern radio applications.

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Stereo 4" x 10" Oval Dual 3 1/2" - These speakers use two of our 3 1/2" full range speakers mounted on 11ga laser cut steel mounting plate to replace a standard single 4 x 10 oval 4 bolt or football shape 2 bolt speaker for stereo radio applications. These speakers will fit anywhere an original 4 bolt or 2 bolt 4" x 10" was installed including the very shallow Delco applications such as the 1964 thru 1967 Tempest/GTO (4 bolt) or 1970 thru -73 Mopar E-body (2 bolt).  Both speakers have black dust screen installed. Due to lack of low frequency response of the small speakers, this speaker should not be used as the only speaker in a sound system. It is meant as a fill-in speaker and should be used with a larger rear or underseat mount speaker system for full range sound.

Price - $119.95         8 ohm available Size:   10 1/2"L x 4  3/4"W.    1 1/2" deep.   3 1/4" x 6 7/8" mounting centers.

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Note: As 3 1/2" speakers cannot handle high power low frequency signals without distortion, our speakers have "Bass Blocker" capacitors installed to prevent overload from low frequency signals. These are the blue components shown installed on the back side view.

Note: To order any of our products, you must email us. Thank you.



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Last modified: November 09, 2022