Electrohome / Viking Console Tube Amp

[ssouci]

I just picked up this tube amplifier, which was pulled from an Eatons "Viking" brand stereo console (see photo of the faceplate)

my research shows it to most likely be made by Electrohome, in Kitchener, Canada

the tuner section has been removed, hence the big hole (tuner will not be replaced)

would appreciate any info on this unit, especially the exact name, so I can hopefully find a schematic somewhere

also, any advice as to what must and what should be done to this would be appreciated

it does work, it plays music in stereo, and I will post my findings once I listen more

this is my first foray into tube audio, so please go easy on me!... hope to get it cleaned up and into good/safe operating order

thank you!

 

[Patrice B]

Replace can caps, replace coupling caps, test tubes and resistors, clean pots and tube sockets with De-oxit and enjoy!

Electrohome is like the US Motorola or Magnavox. I have three Electrohome SE 6bq5 amps and love them.

 

[Patrice B]

Maybe you'll find the right schematic here: http://pacifictv.ca/wanted.htm

 

[ssouci]

OK!... I've found a schematic and more info for my unit (pics posted below)... looks like it's an RCS-450 or RCS-451 (same amplifier anyway)

*** FOR FULL-SIZE IMAGES, CLICK HERE ***

 

[ssouci]

I’ve listened a lot to this amp now, and in general, sounds really great and it’s amazing the detail it produces, especially at the very high end, and low end... I run treble flat, but have to turn bass way down to only ~20%

the pwr transformer definitely gets darned hot, and I will see if this continues after I do a thorough parts check and some parts replacements... if so, maybe I will rig up a heatsink to it, and/or even a small fan(???)... I can’t see how all that heat won’t eventually take a toll

Q1. previous owner replaced 2 coupling caps with large orange squarish films, value 0.1 mfd / 630V... apparently these caps are quite a good... the specs say to use 0.047mfd / 400V... is it OK to go up in capacitance like that?... what will the effect on sound be, and could it explain my excess bass?... I can get .047s, would it be good to put those in?... would it be worthwhile to upgrade these?

Q2: based on schematic, are there any particular locations where I should put in "audiophile grade" parts to have an actual audible effect on sound quality? (especially the caps and maybe resistors)... I don’t mind investing a few $ if it’s actually worth it, and while I’m in there with a soldering iron

Q3: when I use the “balance” control, it seems to act like no other balance I’ve ever used... it does not simply move sound on/off from left to right, with center position being an equal balance... seems somehow more complicated than that, and can even cause distortion at the extremes... do you think this control is acting normally, ie., has anyone ever experienced a balance control like this?... here’s how the specs describe it (which perhaps sounds like a “fancy” balance control?): http://screencast.com/t/qcKifxNaxtF

Q4: when I replace death cap with a safety cap, should I use basic blue ceramic disc version, or the square type that also includes filtering?... also, I assume death cap goes on hot lead from wall power? (I will probably swap in a new 2-prong *polarized* cord)

Q5: should I use carbon comp resistors to preserve sound quality?... or do other resistor types sound the same and are quieter and more robust?

would love to hear your any thoughts one the above, thank you!

 

[Patrice B]

Ok, I've gone mad myself and recapped one my three Electrohome with Solens. Ditto for a Clairtone and a Nordmende console: not worth the money in my opinion and my ears could not hear the difference. Any yellow or orange cap will do the job.

As for resistors, replace them if they're off values. I use metal films here.

For the safety cap, use one rated for the job.

About the balance control, it's only a dual-gang volume pot so throwing one side full is in fact just putting volume to max on this side, hence the distortion.

Others will probable chime in but you're better to put 0.047 instead of 0.1. Ah, and don't forget to replace the big cans.

The excessive bass could also be explained by the original design: this amp was built circuit-wise to be paired with the internal speakers and the console design.

All the Electrohomes I have sports the same specs: 20 Hz to 50 kHz, quite amazing IMO.

 

[Tom Bavis]

The volume control has loudness compensation, will boost bass at lower volume settings. Ceramic or film safety caps are fine, I can't read the value, but reduce it to .01 uF if it's more than than that. Changing values of caps inside a negative feedback loop is usually not recommended. In this case, gain is low and I doubt it makes any difference (output transformer limits the low end more than this cap does).

 

[MacNoob]

Hmmm just found a Viking console with exactly this receiver and a Garrard 210 table at the local estate reseller. It's sure tempting me.

What kind of speakers can be connected to this? Modern 6 ohm-ish units? How about my Magneplanars

 

[cptnCanada]

I have this amp and have used a variety of different speakers. I rebuilt the amp with new caps and used Russian pio for the couplers and very much enjoy the sound. Very easy to work on. It doesn't go that loud, so efficient speakers are better. Nice single ended sound. I converted the unit to a standalone.

Here is my thread in it. http://audiokarma.org/forums/index.php?threads/scored-a-viking-console-from-gw.635817/

 

[doctor fuse]

Hmmm just found a Viking console with exactly this receiver and a Garrard 210 table at the local estate reseller. It's sure tempting me.

What kind of speakers can be connected to this? Modern 6 ohm-ish units? How about my Magneplanars

I have an Electrohome SET receiver from a 1962 Montego console, and have run my Tannoy 609 dual-concentrics (8 ohm) and Audio Pro A2.14 Live bookshelves (4 ohm) through it. Both sound great. Here are the specs:

Tannoy 609:
Peak Power: 200 watts
Recommended Amplifier: 10 - 120 watts
Frequency Response: 46Hz - 36kHz
Nominal Impedance: 8 ohms
Sensitivity: 89dB
Crossover Frequency: 2.5kHz

Audio Pro A2.14:
Frequency range: 34-22.000 Hz
Sensitivity (1W/m): 90 dB
Impedance: 4 ohm
Crossover frequency: 3.200 Hz Amplifier: 10-100W