Erik Mandaville Posted April 8, 2006 Share Posted April 8, 2006 I built these amplifiers from scratch a few years ago. They are in perfect working order, and also have the ultrapath modification that is common to the DRD amplifiers offered by Welborne labs. These amps use an inexpensve but very good-sounding 5687 input/driver, and coupling capacitors between stages are brand new Jensen oils. These capacitors were sent to me from Dee in a sort of trade for some work I did for him. The main components of the amp: 2A3 plate and grid chokes, as well as the parafeed output transformers, are from MagneQuest. The design is generally based on J. Lessard's Horus, although there are some departures from the original schematic: I have bypassed the cathode resistor in the input stage with a good quality electrolytic capacitor, and also incorporated the DRD ultrapath out connection. I have used separate filament transformers for the 2A3s, and have installed MOVS (metal oxide varistors) in the power supply to prevent damage from sudden high voltage line transients, such as lightening. tube compliment input/driver: 5687 output: 2A3 (Sovteks) tube rectifier: 5AR4 *note: The chassis of this amplifier was entirely hand-punched, drilled, and filed, and as such have some fine hair-line scuffs. I am asking $1,500, shipping included, within the U.S. This price would include any maintenance needed for the life of the amplifier. Also: Please note that the output transformers are the MagneQuest EX0-36 with permalloy Core. MagneQuest also makes this transformer using cobalt, which these are not. More pictures are available upon request. but I will include a couple more below. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted April 8, 2006 Author Share Posted April 8, 2006 Front view: The front panel now has two stainless steel allen head machine screws in a horizontal orientation. These hold the terminal strips for the two coupling capacitors. Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted April 8, 2006 Share Posted April 8, 2006 Erik, whoa, what a sweet deal these will be for someone! I hope you will post some pics in this thread. They are very cool amps. edit: oops. Now that I've clicked on "post" the pics have appeared! You must have ESP! :-) Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted April 8, 2006 Author Share Posted April 8, 2006 Rear of amplifier: IEC connector and fuse. I keep all AC connections, including power switches, away from the signal input to the component. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted April 8, 2006 Author Share Posted April 8, 2006 I personally prefer heavy-duty metal switches, as is shown here: Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted April 8, 2006 Author Share Posted April 8, 2006 An arm workout! After the chassis plates were punched, drilled and filed (I would have loved to have owned a drill press!), they were completely polished using a 5-stage abrasive process. This is the final polishing back to a mirror finish, and this was not an easy job. It's important for me to point out that, I found that the Greenlee punch I found on ebay for the 2A3 socket to be...ugh....dull. The 2A3 holes were the first I did, and the punch started to pull slightly to the left as it dug its way through the 1/8" aluminum plate. The finished hole was finished by very careful hand filing, and fits the socket like a glove. However, if you look closely, it is slightly to the left of center on the chassis. I was subsequently obliged to also punch the rectifier socket slightly off center in order to line it up with the 2A3 hole. It's only a slight cosmetic issue, and of course has zero to do with peformance. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted April 8, 2006 Author Share Posted April 8, 2006 My little work bench, work in progress Quote Link to comment Share on other sites More sharing options...
Chris Robinson Posted April 8, 2006 Share Posted April 8, 2006 Erik, If these sound anywhere near as nice as mine, I think the price is waaaaaay more than fair and someone looking to experience the lush sound of SET for jazz and classical music should jump on them. I'm actually a little surprised you're selling them but I understand the liquidity issue [] Chris Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted April 8, 2006 Author Share Posted April 8, 2006 Chris: The Horus is a great SET amp, no doubt about that. I attribute a good bit of its basic sound to the input/driver stage, plus the grid choke, which is really nice. It sounds good with the more common grid leak resistor, but sounded somehow 'dry' (hard to put into words) without the grid choke. One of the chokes went south from some really strange reason, and Jeff replaced that at a fair discount for me. They lend a sort of richness that isn't there so much when absent from the circuit. As a buildier, a very significant part of the interest with this is the conceptual part, and construction process. I loved the amplifier when it was finished, and it is still an awesome amp. I'm using it right now for the main L/R amps in our system. I friend here in Houston was borrowing it for a bit, while I in turn did some some work and listening with his SE OTL pair from Transcendent Sound. He and I swap stuff all the time, just because its fun -- and because it's a blast to do origami with his two sons! Very, very nice family. I want to sell these to help fund some other audio 'wants' (like BEC tweeters -- hope he is ok....), and some other important things. I will admit the price is low. I'm charging nothing for the actual building, which always involves a ton of work when one with working with a blank chassis made out of thick metal. Erik Quote Link to comment Share on other sites More sharing options...
jt1stcav Posted April 8, 2006 Share Posted April 8, 2006 If only I had the spare cash... Seems a shame you're letting these go at all; I know just how important they are to you and Marie and the part they play in your overall musical enjoyment (I think your Klipschorns will miss 'em as well). Maybe I've missed a thread or post somewhere lately, but what amplification will you use in the interim? Good luck with their sale...some lucky person will own these very soon (wish it was me).[] PS - just noticed the above pic of your workbench...there's alot to be said about a person from his workspace environment, and yours was/is one very tidy, organized area! No mess, no clutter, and every tool has its place. Unless of course you just cleaned it up for the picture...heh! Quote Link to comment Share on other sites More sharing options...
leok Posted April 8, 2006 Share Posted April 8, 2006 Erik, Very nice amps and a great deal for he new owner. Leo Quote Link to comment Share on other sites More sharing options...
NOSValves Posted April 8, 2006 Share Posted April 8, 2006 Another excellent deal offered by Erik. If you want a taste of SET I for the darned me would not be able to figure why you wouldn't grab these up!! I personally think they are worth more like $2500 on the open SET market pricing structure. Craig Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted April 8, 2006 Author Share Posted April 8, 2006 $2,500 is precisely what I would ask if selling these on Audiogon or ebay, which would reflect the labor cost. Unlike the those Edmond got, the wood on the chassis on my pair is nothing out of the ordinary, and the look is more utilitarian I suppose -- maybe not, they look decent. I'm asking just under what I paid for parts, and the parts are a few years old by now. These also do not have the Cobalt OPTs which can really add to the cost, but sounded wonderful when I had the chance to hear them. Thanks, Leo! Erik Quote Link to comment Share on other sites More sharing options...
Kevmosmith Posted April 8, 2006 Share Posted April 8, 2006 Erik was kind enough to loan me these amps for an extended listen a while back and they are amazing amps. The sound, the finish and the design are first rate. With a life time service agreement to boot! I hope somone here snags them as they sound great with the horns. . Kevin Quote Link to comment Share on other sites More sharing options...
Spongeworthy Posted April 8, 2006 Share Posted April 8, 2006 What are the dimensions of these amps and how much power do they have? I would be using these with La Scalas. Also, do they run hot? Thanks. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted April 8, 2006 Author Share Posted April 8, 2006 Hey, Kevin: Thanks for that! I need to mention a small cosmetic issue on the front panel on one mono block. This is in the area just above the two allen head bolts, which can be seen if the light is just right. The wrench slipped out, and ..... a little scratch. I'm sorry, I forgot about this, but see picture below. The area is hard-anodized, unlike the top plate, which ismirror-finished polished aluminum. See here, and enlarge as needed for greater clarity: Quote Link to comment Share on other sites More sharing options...
steamer Posted April 8, 2006 Share Posted April 8, 2006 Eric, Great looking amps!If I hadnt purchased my Wavelength Geminis I would be all over them.They are a steal for the price.I cant say they sound like my Geminis but I bet they are very similar.Great amps for the Heritige line. I should buy them and set em up with my Geminis to biamp the Scala's.But I just recieved my Electriprint 300b DRD monos for that purpose. Greg Quote Link to comment Share on other sites More sharing options...
Chris Robinson Posted April 9, 2006 Share Posted April 9, 2006 What are the dimensions of these amps and how much power do they have? I would be using these with La Scalas. Also, do they run hot? Thanks. These amps are usually about 3W which would be plenty for the LaScalas under most listening conditions. My Klipschorns go very well with my own pair and I've never had any volume or bass issues. Of course, most SET owners go with this topography for the lush midrange. These amps don't run too hot, but the 2A3 will put out some heat. I have big AVVT mesh plates and they're comfortable to be around. If you have air conditioning, you'll never even know they're there. They're not like OTL amps or anything. Eric can give you the dimensions but they look to be about 10" x 12" or so. The biggest dimension to consider is the vertical dimension. Be sure you have adequate clearance above the tubes in your installation. Chris Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted April 9, 2006 Author Share Posted April 9, 2006 Thanks for the compliments! Sure, I'll measure the amps in a bit and post the dimensions a little later today. The rectifier also tends to get pretty warm, but these amps do not get nearly as hot as some OTLs I have had here. I totally agree. 3 watts with La Scalas or Klipshorns in the right room can sound very clean and really loud. I appreciate your bringing up the room issue, because it's important! I should have mentioned that myself. Another forum member once borrowed one of my Moondogs to use a center channel speaker, and let me know pretty quickly that he heard clipping distortion. The acoustic space was much larger than we have here, but someone interested in single-ended triode amps needs to understand the power limitations. I saw those Electra-print 300B DRDs! Very, very cool! Jack Eliano has done some really neat stuff, I think, and also builds outstanding transformers. I have Electraprint transformers in my Moth amp, too. Speaking of DRDs: I want to point out that, if someone might be considering this pair of monolbocks, another option in a very similar category and price would be the DRD SET factory built/kits from Welborne Labs. They are great in terms of both design and parts selection, and one also has the choice of different all-wood chassis. The fit and finish overall would be less DIY looking than my amps -- which as I mentioned have little nicks and stuff here and there. Erik Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted April 9, 2006 Author Share Posted April 9, 2006 FIY: Sale on these amps is pending. Erik Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.