prodj101 Posted September 29, 2002 Share Posted September 29, 2002 this is the status of my home made amp so far. Got all the heaters for the tubes wired up, and I'm gonna start on the transformers tomorow. Thats basicaly how it will look, except with one more input tube, the power switch, and a blue LED. Quote Link to comment Share on other sites More sharing options...
prodj101 Posted September 29, 2002 Author Share Posted September 29, 2002 n/m, just click on my avatar, for some reason it won't load to the topic. Quote Link to comment Share on other sites More sharing options...
Deang Posted September 29, 2002 Share Posted September 29, 2002 Welcome back! Pretty kewl. Did you build it from scratch or is it a kit? What's the tube complement? Do you have a preamp for it? Nice job. Quote Link to comment Share on other sites More sharing options...
prodj101 Posted September 29, 2002 Author Share Posted September 29, 2002 Hey, no hard feelings dean. Its a scratch kit. I used Magnequest transofermers and the higher end Svetlana tubes here. The input tubes are Tesla. 100 watts RMS when done. Quote Link to comment Share on other sites More sharing options...
John Warren Posted September 30, 2002 Share Posted September 30, 2002 I don't think the transformers are mounted right. they should be 90 degrees relative to nearest neighbors otherwise they will interact. this is a *basic* concept in amp building, how did you miss it? Quote Link to comment Share on other sites More sharing options...
leok Posted September 30, 2002 Share Posted September 30, 2002 Hello prodj101, Your amp looks great. Can you tell us a little about your design? I think I see KT88s and 6SN7s. What circuit will you use for phase splitting? Will this be class A or A/B? Will you use global feedback? Also, what is the output transformer? I may not be particlarly resourceful, but the best readily available 10W transformer(I'm using KT66, pp, no feedback) I could find is the Hammond 1608. I checked Magnequest but couldn't find any pp transformer at all, only SET style. I'm sure your amp will be smooth with the RF-7s. By the way .. if you use the 4 Ohm transformer tap and place an 8 Ohm (power, 10W) resistor in parallel with the speakers, the amp will be loaded properly, see a more constant impedance vs freq., and the speakers will see a lower impedance drive. With those KT88s and RF7s you'll be able to spare the power. leok Quote Link to comment Share on other sites More sharing options...
justin_tx_16 Posted September 30, 2002 Share Posted September 30, 2002 Prog101, glad you stayed around. Sweet amp! Wanna make me a tube headphone amp hehe Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted September 30, 2002 Share Posted September 30, 2002 Proj, Nice to have you back...and CALMER!! See how nice things are when you keep your cool? You are doing nice work with that tube amp. May I suggest you rotate the mounting of those transformers 90 degrees? Quote Link to comment Share on other sites More sharing options...
Deang Posted September 30, 2002 Share Posted September 30, 2002 Hey John, everything's "basic" to you! Maybe you should change your avatar - you seem a little *****y today:) 101 - man, 100 watts. It must be class A/B push-pull. Did you base your amp on another amp's design -- or is it like "scratch" scratch? Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted September 30, 2002 Share Posted September 30, 2002 I think he used a schematic online as I remember. I must have missed the big flameup everyone is alluding to or have lost my mind; perhaps a combination of the two. Hey Dean, does that John Warren post surprise you? The fact that he is talking to someone in high school doing his first tube amp from a schematic is of no concern. John is a curmudgeon without the amusing wit of someone like a Mencken or Dorothy Parker. He cant help it. Quote Link to comment Share on other sites More sharing options...
Deang Posted September 30, 2002 Share Posted September 30, 2002 Apparently, 101 is in good company. Check out this transformer layout. http://cgi.audiogon.com/cgi-bin/cl.pl?ampstube&1037552926&class&3&4& Quote Link to comment Share on other sites More sharing options...
prodj101 Posted September 30, 2002 Author Share Posted September 30, 2002 thanks for the comments, about the 90 deggree thing, I'll look into it more, but my dad has never mentioned it. He built about 6 amps when he was back in jamaica, so I figured he would know. Maybe he forgot though, either way, I think it will turn on fine. I was thinking about painting the chassis but I think it will look cool with everything done and with the blue LED. power is 100 watts in class A/B, thought about lower in A, but liked the other option more. And besides, I'm thinking about using it to power a home made sub I'm planning, so class A won't be important. And yes, those are KT88 Svetlana power tubes, the rectifiers are sovtek 5AR4's, and the input tubes are Tesla ECC83's and 84's. The output transformer is Magnequest, and the power transformer is Hammond. I would havel iked to use a Mag for the power too, but they didn't make one big enough, at least not at a decent price ! Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted September 30, 2002 Share Posted September 30, 2002 Ummmm...the last thing you want to power a sub with is your new tube amp. If anything, you would power the sub with the SS power house with the tubes doing speaker detail. Tubes have a MUCH better midrange with more transparency and openness than solid state but are NOT known for their stygian BOTTOM octaves. So using a tube amp to power a sub is a real waste of resources. Indeed, that is why most sub amps are simply powerful plate amps; you dont need top notch amplification to run subs, at least not comparatively. Good job on the amps. I personally am partial to the brass, steel, copper top plate with a wood chassis; it looks VERY classic and works well with easy soldering using the plate and then installing in the wood frame. There is something to alternating the trans mounting and even MORE important when close together. At least you have the power and output pretty far apart. The only problem with Hammond power transformers is they have a tendency to buzz and hum a bit. Hope your turns out better. You are making monoblocks, right? kh Quote Link to comment Share on other sites More sharing options...
NOSValves Posted September 30, 2002 Share Posted September 30, 2002 prodj101, Nice looking amp !! What suprises me is how small the Power transformer is compared to the output tranformers. Must be the 100W per channel. If you feel like it let us know what it cost you to build these when its all said and done . Of coarse let us know how they sound also. I'm thinking of building a couple mono amps myself this winter. Craig Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted September 30, 2002 Share Posted September 30, 2002 Ummm.... I dont think that little trans in the center is a power trans; if it is, it would be the smallest I have ever seen for an amp that size. I assumed this was a monoblock with the power and output at opposite ends of the chassis. kh Quote Link to comment Share on other sites More sharing options...
John Warren Posted September 30, 2002 Share Posted September 30, 2002 Hey Dean, does that John Warren post surprise you? The fact that he is talking to someone in high school doing his first tube amp from a schematic is of no concern. John is a curmudgeon without the amusing wit of someone like a Mencken or Dorothy Parker. He cant help it. Mobile- You keep coming back for more. Mencken (repeat 3X) Now there's a name you don't see every day unless of course your taking a literary class at Bennington or studying for the SAT or, in your case, the GED (don't despair mobile, I heard third/forth time the *charm*). Ever noticed that you resort to *Prose and Poetry* references OR "wine tasting" OR "colored vinyl" when you feel the need prove to us that you are complicated? Where do you get your Hairshirts pressed? John Warren Quote Link to comment Share on other sites More sharing options...
prodj101 Posted September 30, 2002 Author Share Posted September 30, 2002 the total cost for everything so far is upwards of 700, and yes, they are monoblocks, which means I'm gonna have to save up for awhile to build the second. I'm pretty happy with how this one looks so far, but it would be nice for future models to head down to the chassis shop and have them make one out of 1/4 inch stainless steel, than send it into stereophile for a review, lol. Never know, could happen. And yeah, as you can see I'm working with limited chassi space, so I can't have everything spaced as well as I would like. The thing in the middle is a 12h choke, basicaly a filter. Hopin to get some good results sense the schematic called for only a 2h choke, lol, and 100 uf capacitors where as I'm using 200. Oh well, we'll see in the end, maybe Ican start up a company, lol. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted September 30, 2002 Share Posted September 30, 2002 Funny.....about the choke I just assumed you were building a stereo amp from previous posts about 100W RMA per channel. To tell you the truth I guess I thought you were bonkers with the little choke I thought might be your PS trans LOL !!! I guess I should of looked closer. Anyway now I got it Craig Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted September 30, 2002 Share Posted September 30, 2002 John, that GED retort was the most pathetic comeback since the issue of this new forum and deserves a special place in the EDIT section, now responding to multiple tries (something to consider in your case). While HL Mencken might only be someone you read while "studying" for your SAT, a pretty sad admission in and of itself, others might read his columns and essays more often, especially since he is quite humorous and pretty on target even today. Actually, I only listed those two because they are relatively noted curmudgeons. Too bad the Dorothy Parker sailed over your head despite the availability of google. Your Round Table is pretty oblong... You finish your post off with a more adventurous challenge although coming back from that "GED" comment entailed some serious virtual mountain climbing. Interesting how you attack the usage of those references while dropping "Bennington" like lead shot on fly fishing line. Before making any more vitriolic and unnecessary posts, as evidenced with the comment to the young lad building his first tube amp, a post that was an attempt to both discredit and discourage curiosity, something that has left your possession long before your Barcalounger days, I would sit back and take in a few more sub 25hz organ notes and hit the cheap sherry for good measure. kh Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted September 30, 2002 Share Posted September 30, 2002 As an aside, although I didnt agree with John Warren's tone, it is more advisable to rotate that choke 90 if that close to the power trans. kh Quote Link to comment Share on other sites More sharing options...
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