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Home / Product Category / Whole House Audio / Volume Controls / 70V Volume Control, Speaker Selector, Transformer / OSD Audio 70V External Transmitter Tap 8 Ohms up to 20W (Single 70V Transformer EW70V External) 1, 3, 6, or 12 Pack

OSD Audio 70V External Transmitter Tap 8 Ohms up to 20W (Single 70V Transformer EW70V External) 1, 3, 6, or 12 Pack

Product code: EW70V

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Features & Specifications

Turn your standard in-ceiling or in-wall speakers into a 70-volt music or paging system with this high-quality adapter. It's designed for indoor and outdoor use, and all you need to do is plug in your 8-ohm speaker wire. It features an external burial in-line transformer switch with weatherproof design, and the input to output cable seals 8-ohm to 2.5, 5, 10, 15 and 20-watt taps. It comes in an ABS impact-resistant enclosure for maximum protection.


Other Product Info

Allows standard in-ceiling and in-wall speakers to be adapted for use with 70-volt music and paging systems. Plug and Play just plug your 8 ohms speaker wire and it is ready to go.



15 Questions & 17 Answers
from Harleysville, Pa asked:
June 1, 2019
Hi I have a 70v system with a Sonance DSP2-750mkii amplifier and 4 Sonance ls68 speakers. I am thinking of adding 2 TIC GS50 Subwoofers which are rated at 125w RMS. To do this I will need to use the 70v transformer, will I have less power to the subwoofers since the transformer only goes to 20w?


2 Answers
HI Dan:

I am a little confused regarding the SONANCE Amplifier and 4 Satellites you are using. The AMP 2-750 MKII shows it has 750 watts at 70V but not listed in its Owner's Manual. That withstanding you have a $1500 Amplifier and 4 Satellite speakers at roughly $550 each. The Speakers rated at 70V/50Watts each. If you add the Sonance 12" in Ground sub, it would cost $2,000 but does include an internal Transformer. I think that you paid over $3,000 for the AMP and Satellites from a SONANCE Dealer or you bought a house with the speakers already installed, or you just bought them on eBay at a lower price. So I am trying to figure out how you selected 2 TIC 8 inch outdoor subs at $114 each. Then I see they have an outdoor 70V step-up transformer just like our EW70V at $34.00 versus $14.99 for the OSD unit. And both are limited to 20W taps which will not do anything for your application. The SONANCE 12" In-Ground Sub has a 70V 300W step-up transformer more in line with the AMP and Satellites. I have a solution that might work for you and (2 solutions) behalf or 2/3 the cost of the SONANCE 12". One is an 8" In-Ground with internal 70V/150W tap or the 12" that features a 70V/300 watt tap much like the SONANCE 12". I am sending you information on the two Black Series In-Ground directly to your email. I can provide you more information and a quote on both of the Subs.

My contact email;


Submitted by: Tim Leahy on June 8, 2019
Hi Dan:

We have a newer High Power Step down transformer coming that has a high Tap setting of 100 Watts (SP70VT100W), but the TIC subwoofers are a strange match for the SONANCE. 


Submitted by: Tim Leahy on June 8, 2019

from GA asked:
July 25, 2018
When I attempt to daisy chain your weatherproof 70 v Transformers, the First speaker is very loud, but the next speaker in the chain has low volume..any idea what problem is? We have tested speakers, and they are fine If they are first in the chain
1 Answer
HI Keemit: Based upon your description are you daisy chaining the second speaker after the first Transformer or splitting the signal before it is wired to the transformer then connected to the respective speaker. If you were daisy chaining 70V speakers with built-in Transformers and you are taping in at the input side with the wires going to the next speaker you are splitting the signal before going through the transformer. So that is the question are you taping the second speaker after the Transformer? TL/5127
Submitted by: Tim Leahy on July 30, 2018

Mark Scholten Antique farm Power Club
from West Michigan fairgrounds setting asked:
January 4, 2018
I have many 8 ohm speakers. I need at least 10 for coverage. The speakers are Radio Shack 8 ohm 50 watt horn speakers. I purchased the transformers but someone asked if i set the transformer to 8 ohm because I am powering an 8 ohm speaker. I said i think i use the voltage that gives me the required volume I need at that speaker. Am i wrong? Running a 70 volt 240 watt system for announcements and background music.
1 Answer
Hi Mark: Typically all the speakers you connect the Transformer to are 8 ohm, 6 ohm or even 4 ohm. But you need to set the tap setting based upon the available wattage (you said 240 watts so you need to calculate 80% which is 196 watts). So you have 10 speakers where you can set to the highest output 20 W so you are using 200 watts close enough to the 196 to work. Note: You do not need to set all the speakers at the same Tap level. Maybe you wanted 4 of the 10 speakers to play at a lower volume level so you could set them to 15 W or even 10W. I would set all to 20 W and see if you need to make any additional adjustments. Checkout our SS2V70 2 zone Mono 70V speaker selector with 2 internal 100W volume controls and on off switch for both zones. Good luck TL/4728
Submitted by: Customer Service - Q&A on January 4, 2018

from Mexico asked:
September 8, 2016
Hi can I use this transformer for 4 ohm speakers?
1 Answer
HI Francisco: Yes you can use 4 ohm speakers but you then double the values of the tap settings. So if you are using 100 watt amplifier and have 4 speakers. If the speakers were 8 ohm then you could set the tap at 20W x 4 speakers would be 80 watts which would fall at 80% of the available power as recommended. With 4 ohm speakers you would need to set the taps to 10 ohm which would double the tap value to 20 watts times 4 speakers (80 watts as well) that would work. Note if you wire two speakers in series then you are back to an 8 ohm setting and standard tap settings apply. I hope that helps TL/4058 Note: Checkout ProSoundWeb / Forums, see JR; John Roberts comments on the same question
Submitted by: Customer Service - Q&A on September 22, 2016

from Pa asked:
June 6, 2016
Similar question I have a 70v amp going to 8 ohm speakers, is my amp connecting to the input side and speaker to output? Or vise versa?
1 Answer
Hi Rm from PA: You connect the Power Amplifier to the Input side so signal is coming into the transformer and coming out on the output side to the 8 ohm speaker. Good luck TL/3916
Submitted by: Customer Service - Q&A on June 6, 2016

from PA asked:
February 25, 2017
I have TIC GS3 Omni garden speakers with up to 100w power, will this really limit the volume of my speakers because the highest tap is 20w??
1 Answer
HI Matt: Problem answering the question with out finding out what is the rest of the story. Are you attempting to connect your TIC speaker to a 70V system (amplifier/Mixer)? The EW70V is used to convert your speaker to a 70V speaker used in a seventy volt setup where you have available power from your amplifier. Are you designing a 70V system and if so how many watts are available to you. Unlike 4 and 8 ohm system where we have to deal with Impedance Matching a 70V system depends on how many watts are available say 100 watts. So the total wattage available for your group of speakers is 80% of the rated power of the Amplifier (100 watts in this case). So if you have 4 speakers each with a transformer with the following 70V taps choices; 2.5W, 5W, 10W, 15W and 20W. You would set each at 20W x 4 would equal 80 watts which is perfect. But lets say you want to add 2 more speakers with the same transformers. You could set all speakers to 10W or 60 total and be within the 80 watt range. But all speakers do not have to be equal or set to the same output. You could set four speakers to 15W and the two new speakers to 10W. You have the ability of adjusting the output of each speaker in the system. The higher the setting the more output. These speakers could be daisy chained together (in parallel). Sorry to ramble on, I am assuming you are doing a 70V system otherwise this transformer would not be for your application... let me know if I can be of additional assistance TL/4233
Submitted by: Customer Service - Q&A on March 1, 2017

from Miami, fl asked:
May 16, 2016
Hello: I need to install 36 speakers in a garden, and are in two channels, each have 18 units, How I do to make a daisy chained using this transformer, because have not enough space to make the connection inside the sealed clamp?
1 Answer
Hi Gustavo: This transformer is used per each speaker in order to convert an 8 ohm speaker to 70V. You would need 36 of these if you are trying to use 8 ohm speakers for your 70V system. Now if you are already using 70V speakers with built in Transformers then you do not need this component. So maybe you can contact me directly and explain to me more about you system including what speakers and amplification you are using. My contact info is I would be more than happy to try and help you out. It sounds like an interesting challenge. TL/3885
Submitted by: Customer Service - Q&A on May 16, 2016

from NM asked:
April 23, 2016
Hi Guys, I'm using the transformer to connect an 8 ohm amp and subwoofer to a 70v system. Do I set the switch on top to the source (5 watt/70v) or the output, 8 ohm? I'm assuming the Input side will be the 70v feed and the output will go to my sub amp. Thanks
1 Answer
Hi William: I have been trying to figure out what you are trying to accomplish. The first problem is that the EW70V has speaker level input and output. It connects a two conductor speaker wire (+/-) from the amplifier then out to the 8 ohm speaker (mono signal). You are wanting to interface with your sub amplifier which would need signal level then speaker level output to your sub-woofer. The EW70V is mainly used to add an 8 ohm speaker to a 70V system. What is the Sub-woofer Amplifier and Sub woofer your are trying to connect. And what is the 70V amplifier. Most 70 Volt amplifiers have high cut filter that limits the low frequencies making the 70V system more efficient. Maybe check to see if your 70V amplifier/Receiver might have a pre amp output that you could connect to your Sub Amplifier. Good Luck TL/3831
Submitted by: Customer Service - Q&A on April 23, 2016

Duane M Langlois
from Muskegon MI asked:
May 24, 2015
When hooking up the wire to the Amp I use the Common and 70v terminals and run them to the input side of the transformer. What line from the amp goes to the + side and what line to the - side.
1 Answer
Hi, The common will be the black (negative) and the 70v will go to the red (positive).
Submitted by: Customer Service - Q&A on June 2, 2015

from California asked:
November 17, 2014
When hooking up the speaker wire to this 70v transformers u have a input and a output. So the wire coming from the amplifier goes into the input or output of this specific transformer? Thanks
2 Answers
Hi Wes, Correct. Are you running a 70v amp to 8ohm speakers or the opposite?
Submitted by: Customer Service - Q&A on November 26, 2014
Hi Wes, Correct. Are you running a 70v amp to 8ohm speakers or the opposite?
Submitted by: Customer Service - Q&A on November 26, 2014

from arizona asked:
June 5, 2014
Does the impeadance of the speakers you add to a 70V system with this unit matter?, and if so how does it apply ?
1 Answer
Hi Ross, As long as the speakers are between 4-8ohms you will be good. What speakers are you running? BM 2735
Submitted by: Customer Service - Q&A on June 10, 2014

from NE New Mexico asked:
August 28, 2012
How do I mount the transformer? I do not see any clips or brackets on the item. This is going to be mounted outside. Thanks.
1 Answer
Hi Miguel, Typically the transformers are buried with the speaker cable underground. We do not carry a bracket for them at this time. You should be able to retro-fit your own mount if necessary. CL/MA 1259
Submitted by: Customer Service - Q&A on August 29, 2012

from L.A. asked:
June 30, 2012
what are the dimensions- length, height, depth?
1 Answer
Hi Eugene: H: 2 7/8" L: 6" with end caps, 3" without D: 2 5/8" TL
Submitted by: Customer Service - Q&A on July 2, 2012

from Ann Arbor, Michigan asked:
April 11, 2012
What is the frequency range of this transformer
1 Answer
Hi George: We are assuming this is the Frqency Range...65Hz - 20kHz. We are trying to verify that with our manufacturer. TL
Submitted by: Customer Service - Q&A on April 12, 2012

from Tampa , Florida asked:
February 15, 2012
Is this connector available in a passive format without the transformer for use with you 8 ohm rock speakers? If , not can this be used simply to weatherproof 8ohm rock speaker connections?
1 Answer
Hi Greg: Have you checked out our AquaBlue Direct Burial connectors, I believethey would be your better choice. The outdoor 70V Transformer is rather big and bulky and three times the cost of a pair of the AquaBlues. TL
Submitted by: Customer Service - Q&A on February 15, 2012

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