The Other Side: Tube HiFi Stereos

[bcmatt]

I've been thinking of extending my love of tubes into an amplifier for my home stereo. Actually, my father seems interested in one, finally a cabinet he can use his woodworking skills for that he actually can use himself. And he's old, so it boosts his ego to think that the stereos he listened to in his youth are "better" than stuff today. So, I'm pretty sure i can get him to fund the parts for my first tube HiFi attempt.

Any recommendations out there for designs? He's not much of a rocker like me and doesn't need the volume to shake the house like I do.

I was thinking he might be happy with something like a dual push-pull EL84 design. So, a quad of EL84s and the two OTs. I'm not sure though; any suggestions?

Who has built their own Home stereos?

[tictac]

here's one I'd like to try someday...

[Cygnus X1]

Just like AX84 drawings.
When they do the layout why don't they just put the friggin' values in, instead of component numbers?

I'd like a simple circuit also.

[bcmatt]

What do you guys think of these projects?:
http://diyaudioprojects.com/Tubes/tubes.htm

I'm thinking easily found tubes might be a good idea... although this might be a good time to try to use a tube that abundant but not commonly used in modern guitar amps. Never looked into those for good deals...

Anyways, the other option my dad was excited about was the whole idea of a vintage style little radio. He want to make an old looking think with some really fine wood working and a little internal speaker in one unit.

I've been considering the idea of it not actually needing to be stereo. Could go with the whole "monoblock" idea and add a second one later if ever necessary. So many choices; I don't know where to begin. I just want to get into it now so that I know what I will eventually want for myself.

[Cygnus X1]

Old radios are still around, just have to look.
I have a 1940's RCA tabletop that still works!

[bcmatt]

Old radios are still around, just have to look.
I have a 1940's RCA tabletop that still works!

Ya, I'm not sure where to look exactly. The town I live in is only 40 years old. My band has been hired to play the celebration next month. I don't run into a lot of vintage electronics in my travels. I need to go further I guess. That would be cool to find an original though.

[Cantplay]

I'm using a pair of Dynaco Mk III, and a pair of Fisher 80-AZ monoblocks that I've restored.

A Dynaco ST-35 sounds like it would fit your description.

John

[briane]

I've looked into build a couple of macintosh's for my home stereo....They were the bomb back in the day, and the schematics are out there.

Its a lot of parts...you need to bi-amp, left & right, yes, plus those home stereos have to push without distortion, which == massive wattage....I think I was consider a dual 300 watter (ie 600 watts), which was the schematic I have somewhere. Its basically a big bass amp with even(er) frequency response.

I would suggest 6550's, or something along those lines....(kt88, ST100?)

Its a good idea, just have not gotten around to it myself.

[David Root]

The McIntosh is still the bomb in tube amps to a lot of old hifi types. Old Brits like the Quad II monoblocs that used Genalex/MOV KT66s. Both excellent designs, especially the McIntosh but it needs very special C-core OTs.

In the US or Canada it would be easier to find components and to build the Dynaco ST-35. www.triodeel.com for repro iron. Maybe chassis too, not sure of that. Great iron in the originals, the rest so-so, needs upgrading.

[martin manning]

I have Frank McIntosh's RDH4... is that a good start?

[passfan]

Here's a circuit based on the Magnavox EL84 console chassis. I have built and sold a number of these. It's a great sounding amp. I use the hammond OT's for 7.6k at around 10 to 20 watts.
http://gabevee.tripod.com/maggie.html

[bcmatt]

I'm using a pair of Dynaco Mk III, and a pair of Fisher 80-AZ monoblocks that I've restored.

A Dynaco ST-35 sounds like it would fit your description.

John

So Dynaco is a good way to go? Do you like the sound of your Mk IIIs? Your right that the ST-35 does seem to be what I was describing. I'm not stuck on EL84s though. I wonder if I should try a MkIII. Did you build yours from kits or did you acquire them and restore them?

I've looked into build a couple of macintosh's for my home stereo....They were the bomb back in the day, and the schematics are out there.

Its a lot of parts...you need to bi-amp, left & right, yes, plus those home stereos have to push without distortion, which == massive wattage....I think I was consider a dual 300 watter (ie 600 watts), which was the schematic I have somewhere. Its basically a big bass amp with even(er) frequency response.

I would suggest 6550's, or something along those lines....(kt88, ST100?)

Its a good idea, just have not gotten around to it myself.

To be honest, this is a new world to me. The only tube HiFi brand I have ever heard of was the McIntosh Stereos. I wonder if would be too ambitious to make a layout from online schematics out of Turretboard or something. Then find the appropriate transformers from Hammond or something. I'm probably the wrong guy to mess with that, but if someone paved the way, I'd be all over following in their footsteps. I don't think I would go anywhere near that kind of power you are describing for building for my dad. I'd be tempted down the road for myself though...

The McIntosh is still the bomb in tube amps to a lot of old hifi types. Old Brits like the Quad II monoblocs that used Genalex/MOV KT66s. Both excellent designs, especially the McIntosh but it needs very special C-core OTs.

In the US or Canada it would be easier to find components and to build the Dynaco ST-35. www.triodeel.com for repro iron. Maybe chassis too, not sure of that. Great iron in the originals, the rest so-so, needs upgrading.

Are you saying that the iron in these Dyanaco kits from Triode are fine? But you would get better components?
If you were to build a McIntosh what would you do for iron?

Here's a circuit based on the Magnavox EL84 console chassis. I have built and sold a number of these. It's a great sounding amp. I use the hammond OT's for 7.6k at around 10 to 20 watts.
http://gabevee.tripod.com/maggie.html

I like this article. I have to admit that it has me intrigued with that Magnavox model. Is that you that wrote it? Where do you get your information on it? Do you make your own layout from a schematic on turretboard, or go point to point or something else? So this is a favourate model of yours and people seem quite pleased with it? I'm going to see what else I can dig up about it online...

[Cantplay]

I'm using a pair of Dynaco Mk III, and a pair of Fisher 80-AZ monoblocks that I've restored.

A Dynaco ST-35 sounds like it would fit your description.

John

So Dynaco is a good way to go? Do you like the sound of your Mk IIIs? Your right that the ST-35 does seem to be what I was describing. I'm not stuck on EL84s though. I wonder if I should try a MkIII. Did you build yours from kits or did you acquire them and restore them?

I do like them. Mk III's are enough power for all but deaf speakers. Mine are the old cloth covered wire trafos, and new everything else. All the original ones need upgraded power supply.

[img:997:769]http://www.vehicross.info/gallery/data/ ... _MkIII.JPG[/img]

I'm not a fan of the Mc amps, they're more for the chrome and blue lights crowd. If I could have my choice it'd be RCA 845 theater amps, or on a more attainable level, Marantz monoblocks.

John

[bcmatt]

I do like them. Mk III's are enough power for all but deaf speakers. Mine are the old cloth covered wire trafos, and new everything else. All the original ones need upgraded power supply.

[img:997:769]http://www.vehicross.info/gallery/data/ ... _MkIII.JPG[/img]

I'm not a fan of the Mc amps, they're more for the chrome and blue lights crowd. If I could have my choice it'd be RCA 845 theater amps, or on a more attainable level, Marantz monoblocks.

John

Wow! Very Pretty! Shiny chassis and gold transformers!
So, I feel stupid asking this... do you need to use a separate preamp with these, or do you plug them directly from a CD player? How do you control volume?

[Cantplay]

I'm running a tube preamp. Mostly becausae I have several different inputs, PS3, Sonos, DAC, phono, etc.

If your input source has volume control you don't need a pre. You could also build the amp with a 500k trimmer on the input. In a home amp, the volume control is before any gain stage in the amp.

in the dining room its PS3-->amps-->speakers

[img:337:450]http://cgim.audiogon.com/i/vs/s/f/1218022697.jpg[/img]

In the bedroom its just Sonos-->amp-->speakers.

[img]http:600:400]http://cgim.audiogon.com/i/vs/s/f/1257218434.jpg[/img]



John[/img]