Motorola EL84

[TomBig58]

These are great survivors of an era gone by...The amps make sweet sounding music. Neither the lowest lows or highest highs will have the highest fidelity, but sonically worthwhile for certain. I had a copper plated chassis stereo amp with passive controls, probably from a larger record player, which now resides with my daughter, sonny and granddaughters in their home. My son in law crafted a cool open top, painted wooden case, then mounted its' golden fascia plate in front. Functional and sounding sweet with corner mounted, small full range Philips speakers...

They plug their phones/digital files into a small hybrid headphone amp/preamp, then connected to the Moto and speakers, often for adorable "dance with the kiddies" listening sessions...

Finally had my first grandbaby. Little Audrey is 3 mos now. Since the daughter and son-in-law ( who ironically both really love their music) are more interested in sound bars, ipod docks, and bluetooth speakers I said the first "real" stereo in the house is going in the baby's room. Conscious of their lack of media I set up a little Lepai with USB, bluetooth, FM, and analog inputs with a set of pure white Cambridge Soundworks "New Ensemble" satellites and woofer kit. Perfect for a baby girl's room.

 

[TomBig58]

I never checked the specs but my KEF 103.2 are obviously more efficient than the Nova 7's and really sound great with the tube amp. Honest, they sound great with anything! I found I really have to play with those old tone controls to dial in the proper sound. I've only done nearfield listening so far. I find that as I increase the volume I need to roll off both bass and treble and for the most part it sounds best rolling down from flat except at the lowest volumes where I might cheat to the boost. It takes some fiddling but once I'm dialed in I get sort of mesmerized with the right material. Today it was Brandi Carlile "The Joke" and U2 "Until the End of the World" to name a couple.

 

[macgolf]

Congrats on your 1st tube gear! I run 103.2's with my tube units and my findings are similar to yours. Sharp looking unit for sure and glad you're enjoying it.

 

[fxer1982]

i just picked the same amp up with MULLARD el-84's in it i found it to be a Motorola sh-12E. but i didn't get the tone controls with it. i have a separate tube pre amp for that. anyone tell me if i can hook up RCA connectors without much trouble. thank you. cant wait to hear it sing.
you did a great job of cleaning up the chassis did you use never dull. that what im planing on useing. looks great.

 

[primosounds]

Yeah, just make sure your ground is not going to cause a loop and hum.

 

[fxer1982]

Yeah, just make sure your ground is not going to cause a loop and hum.

If you have more info. I look at schematic ID the area of the what I'm missing. The large connector the signal for the controls for high freq and low freq go preamp control recept # 1 to pin 2 of v1B and preamp control recept #8 to pin 2 of v3B of the 12ax7 since I don't have controls do I just forget those connects or do you have knowledge of what is correct. I love tube equipment but have zero knowledge of anything beyond listening and very simple circuit. Thank you if you can help.

 

[primosounds]

If you have more info. I look at schematic ID the area of the what I'm missing. The large connector the signal for the controls for high freq and low freq go preamp control recept # 1 to pin 2 of v1B and preamp control recept #8 to pin 2 of v3B of the 12ax7 since I don't have controls do I just forget those connects or do you have knowledge of what is correct. I love tube equipment but have zero knowledge of anything beyond listening and very simple circuit. Thank you if you can help.

If you are going to not use the original connector for the umbilical cord all the connections there can be deleted. That is if you are turning your amp into a stand alone power amp then the connections from the preamp are not needed. If that molex connector is the same size as the one on my model, i removed it and installed a nice on/off rocker switch in the hole. It was almost a perfect fit. Be sure to delete the wire at the source not at the connector. Wires can act as antennas so you don't want any loose wires hanging around.
I am not sure what your grounding scheme is like in your amp. It is a good idea to make a ground bus and have everything grounded to the bus, except some prefer to have the input and output jack grounds on their own separate ground connection. I have done both ways every ground on the bus and the other way and both methods seem to be good. A lot of highly regarded vintage amps have grounds scattered throughout the amp on convenient rivets or hold down screws. This may have been fine when the amp and the hardware were all brand new. but over 50 and 60+ years those rivet and screw connections may have developed some corrosion which can introduce a more than low resistance ground. When rebuilding an amp it is not wise to neglect refurbishing the grounds, and outdo the original and install the ground bus.

 

[fxer1982]

If you are going to not use the original connector for the umbilical cord all the connections there can be deleted. That is if you are turning your amp into a stand alone power amp then the connections from the preamp are not needed. If that molex connector is the same size as the one on my model, i removed it and installed a nice on/off rocker switch in the hole. It was almost a perfect fit. Be sure to delete the wire at the source not at the connector. Wires can act as antennas so you don't want any loose wires hanging around.
I am not sure what your grounding scheme is like in your amp. It is a good idea to make a ground bus and have everything grounded to the bus, except some prefer to have the input and output jack grounds on their own separate ground connection. I have done both ways every ground on the bus and the other way and both methods seem to be good. A lot of highly regarded vintage amps have grounds scattered throughout the amp on convenient rivets or hold down screws. This may have been fine when the amp and the hardware were all brand new. but over 50 and 60+ years those rivet and screw connections may have developed some corrosion which can introduce a more than low resistance ground. When rebuilding an amp it is not wise to neglect refurbishing the grounds, and outdo the original and install the ground bus.

thank you on your directions very easy to understand. i agree with the grounding used in RCA input and output to be separated from other grounds used within the circuits through the tubes bla bla bla.... i thank you .