diyAudio (
-   Tubes / Valves (
-   -   Suggest amp to drive mangnapan SMGa/MMG (

trondareo 2nd September 2011 11:06 AM

Suggest amp to drive mangnapan SMGa/MMG
Any suggestions for a push pull amp? Tubes and schematics in the 20-30W range? I will drive a pair of Magnepan SMGas

The Audioromy FU13 amp I previously used has died, and want to build a push pull tube amp in stead., I typically listen at 80dB, though my wife likes to turn it up even more. The room is 5m x 8m (16x26 feet) and I listen at 3 meters distance on the short axis of the room. Music preferences are a lot of jazz, some progrock and stoner rock, a bit of opera, a bit of soft pop and electronica, and not much classic. Program material is on MP3, FLAC, CD and LP
I don't like working with high voltages, like the FU13s 800v, I would prefer to work with something in the 300v area. The Magnepan SMGa is 90dB/2.83v/m @500Hz. An amp with 20-30watt should be enough. A nice and simple all tube amp. Cost wise I prefer the lower end of the scale. Id probably buy Edcor transformers or similar. Strange Russian tubes are just as welcome as the most popular types.

rock4016 2nd September 2011 01:30 PM

What about the DCPP? It's scale-able up to over 100W per channel.

BHD 2nd September 2011 02:59 PM

Back in the late 80's I drove a pair of SMGa's with a Conrad Johnson MV45 and it sounded incredible. The only time I heard them sound better was the one time I heard them with an Audio Research Classic 60 which was one of the best amps I've ever heard.

I don't know if that's helpful, but I think you're going in the right direction.

andyjevans 2nd September 2011 03:15 PM

I used to drive my SMGa with a modded Leak Stereo 20 in a room 16x12'. Was a bit marginal but it did sound better than a Conrad Johnson Premier 4 I bought for the purpose and then sold.

I wouldn't bother thinking anything over 30 watts. Quality is the thing here. If it were me I'd build a PP 300b amp. If you got 16 watts out of that it may be enough. There's also PPP which would enable you to use various triodes.


trondareo 2nd September 2011 06:53 PM

Interesting tips. Keep em coming!

I had allready been looking at the Engineer Amp. Its a nicely crafted idea, and I am definetly more on the TV tube end than on the 300B end of prices.
Havnt found any schematic on the Conrad Johnson MV45 though.

Im happy to hear of your experience Andy, that 20 good watts are all that is needed. I have the same experience from the Audioromy. It is easy to be lured into the myth of Magnepans-need-a-lot-of-power.

andyjevans 2nd September 2011 07:51 PM

Are you going to build an amp or buy one? Building an amp would give you loads of options. You don't need to go over 400v - maybe even 350v would be fine if you don't like high voltages.


trondareo 2nd September 2011 08:27 PM

I will be building one, and I dont like high voltages that jump out at you, so yes 350 and down is best.

andyjevans 2nd September 2011 10:02 PM

You may be able to get the quality in the first stages by using DHTs. Like 26 as a first stage, either in the amp or in a preamp - huge thread on "26 pre amp" tells you how to do this. And something like 46 or 2A3 as a driver. Point being with these 2.5v tubes that you can use AC.

You could then phase split with a Lundahl SE-PP interstage, like a LL1692A or LL1660. That would give you the possibility of using some cheaper indirectly heated triodes as finals - maybe in PPP.


Eli Duttman 3rd September 2011 01:03 AM

IMO, something along the lines of the Harman/Kardon Citation 5, using 6П3С-Е (6p3s-e) O/P tubes will be fine. No matter how you slice and dice, "Maggies" need some power. The Cit. 5 is a superb implementation of "classic" Mullard style circuitry and it will not leave you high and dry, when demanding material is played.

You can improve on the stock "5" by using an ECC99 (for its high gm), instead of a 6FQ7/6CG7, as the LTP splitter. CCS loading the LTP's tail is another good tweak.

trondareo 3rd September 2011 09:05 AM

I like you thinking Eli, The the 6s3p/6l6 types provide a wide range of similar tubes and a williamson style circuit is well proven.
Tjis is new teritory for me as i have been building spud sets so far. im reading as much as i can npw following your ideas

All times are GMT. The time now is 12:12 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 18.75%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio