Merren Audio

Send us your damaged speakers...We can diss-assemble them repair them and re-install them back into thier frames. Unfortunately many vintage speakers have been re-coned when repair could have restored the speaker to it's original working condition. Repairing will ensure your vintage speaker keeps it's original sound as well as maintain it's value and collectability.

Below is a photo of a 20W pre-Rola green back in for repair of blown voice coil. The speaker is carefully dissassembled. The voice coil is repaired re-varnished and re-assembled back into it's frame.This speaker has been fixed and placed back in service.

JENSEN

Rebuild of damaged voice coils

Below is a photo of a 30W greenback with a blown voice coil in for repair. As you can see the original cone and voice coil are carefully dissassembled. This speaker is now back in service functioning like it should and sounding like it should. Also in the photo backround you can spot a raw AC30 output transformer just wound. It still needs to be stacked with steel laminations and varnished.

Early Celestion voice coil

Typically found on 15W and 20W speakers with H1777 cones

Note the un-treated raw white paper with diagonal gap

Late 60's to early 70's Celestion voice coil

Typically found on 25W and 30W speakers with 003 or 014 cones

Note the heat treated brown paper with diagonal gap

Mid to Late 70's Celestion voice coil

Typically found on 25W and 30W Cream-back or Black-back speakers with 444 or 1777 cones

Note the heat treated brown paper with holes and straight gap

Merren Audio has over 20 years experience in saving many vintage speakers from going to the grave and becoming re-cones.

At one time many years ago RE-CONE was not a bad thing. You simply brought your speaker to an authorized service center and your speaker was re-coned with the OEM cone that came from the original factory. So your speaker was just like it was when it was new. After a break in period, your speaker tone was right back to where it was.

Those days are gone for many vintage speakers. In many cases the original re-cone kits are no longer available and or the replacement kits are now made from totally different materials. You may have a nice vintage frame with a modern re-cone kit installed but it may not sound vintage.

Many re-cone kits will use an aluminum voice coil former as opposed to the vintage paper ones. While this is great for heat dissipation, higher power capability and reduced warranty returns, it makes for an nasty sounding speaker a higher volumes and at higher frequencies. At low clean levels the aluminum voice coil is not so bad. At high volumes, guitar amps produce square waves that contain additional high frequency harmonic content, Fourier Series.

At higher audio frequencies normal speaker motion and operation will slow down instead of speed up, due to the limitations of the speakers mechanical compliance. There is a "turn-over" frequency at which the speaker can no longer follow the frequency and the cone will no longer move. It is at this frequency the speaker now becomes a resonator or for better terms a tweeter. Voice coil resonance peaks becomes the major player at this point. The glues, the paper, wire, mass, suspension..ect..ect...all play a role in this resonance.

The use of Cross-Over networks in speaker systems was intended to avoid theses issues. Using speakers and or tweeters in thier intended frequency range allows the speaker to function properly in thier intended bandwidth. When square waves from guitar amps are introduced to 12" mid range speakers at high volumes all sorts of affects occur. Many vintage speakers have a nice affect when cranked, in that they roll off some of the high frequency content.

MERREN AUDIO can repair your speaker in many cases.

Contact us for more details....