tpg

Have you had a look over at the tube section of www.diyaudio.com? They are very helpful over there, though they prefer "build it yourself" to kits, mostly. They always have tons of circuits, parts lists, etc. posted and available for use.

So, did it not hold up to your expectations? Any negative comments about it as a whole? I've been eyeing these for a while and would be interested in hearing some comparisons. Thanks!

I sent you a PM with my email address. Sorry I didn't spot this thread earlier- I thought it had almost totally disappeared a few pages into the 2-channel forums. Thanks!

I finally did a little testing after the setting became quieter and the right channel is very quiet. The left has a slight buzz that is only audible up close. So, I should have no problems at listening position. The CD-player does not have a grounded plug, and it is actually plugged into a totally separate power strip connected to a different wall outlet. The amp does use a grounded plug. The volume control doesn't plug into the wall. I am running it off of a battery supply. It requires +5V, so I am using a regulator and 9V battery (though I think I'll switch to two of my 4V SLA batteries in series sooner of later). I am currently keeping the analog signal grounds and the digital ground totally separate. I think this is the best way to run things, but am not totally sure. Funny thing about the volume control... I had to use around 80k series resistance between the input jacks and input of the digital pot before it would quit clipping when my CD-player is at full output. So, my 45k pot is actually now 130k or so, I guess. This is probably adversely affecting my amplifier in some way, but it sounds tons better than running it from my computer (even with a CD as a source in the computer instead of mp3's). I still have yet to get a serious listen in, though. Lots of homework and projects to do this weekend!

Yes... sorry, the Forte Audio 1A is a 50 WPC pure Class A power amp desined by Nelson Pass. I am guessing it is really sensitive, but my CD-player also does put out a whole lot of voltage, I believe. I don't have any specs on this amp, other than it is 50 WPC Class A. [:S] Anyway, I rebuilt the digital pot last night a little tighter with a different input/output scheme and it seems to sound fine now (though I cannot get a good listen because there is a LOT of background noise from elsewhere right now). I couldn't hear any hiss/buzz/hum with my ear up to the speaker, but, as I said, it's noisy in here right now. So, I'll check it out a little later to be sure. I have read Nelson Pass' article about ground loops and took care not to run into this issue, which is why I was so perplexed by the problem. It seems to be working... so I am afraid to touch anything. [] EDIT: On a second close listen, I think I detect a small amount of buzz, but I don't think this will be audible at listening position (unless it is dead quiet in here, which is extremely rare).

My CDP does have a variable output, but it only attenuates 20dB, which is not quite enough. It is still horrendously loud at -20. I have previously tried the -20dB setting with a resistor divider, but it hummed... I am a little sad about the digital potentiometer. It really should have worked. I tested it with my PC speakers (Klipsch ProMedia) and it worked wonderfully without any hum, hiss, or buzz. I hooked it up to my CDP and immediately noted a horrible channel imbalance (one channel was much quieter). I have heard that the DS1802 (the digital pot I used) can easily be clipped by some CD-players (apparently mine). This was even on the -20dB setting. The digital pot is 45k with push-button volume control. I had to add about 30k in resistors before the pot so it wouldn't clip. I tried various configurations, layouts, and cables, but all hummed or buzzed at variable levels. The right channel seems to buzz more than the left (though if I switch the cable leads around, the left channel then becomes the major-buzzer, so it is not an amp issue). I find it funny why this amp would be so much trouble. The digital pot didn't hum or anything when connected from my PC to my PC speakers. And, I've previously used the same RCA cables that I used to go from the digital pot to the amp to go from my CDP to receiver. So they shouldn't be the issue either. I am not sure if we have any dimmer switches or anything like that laying around unused... I'll check around tomorrow. Something about this amp just doesn't agree with me for some reason. It leaves me continually fearing for the safety of my speakers.

No matter what I do, I have a hum or a buzz or a hiss when I connect my Forte Audio 1A to anything (and I mean anything). When unhooked, it is dead silent. I've tried my computer (which is the best, by far), my CD-player (which has been a REAL chore), and my portable CDP (which hisses like crazy and continually distorts everything). My luck hasn't been running well with this amp, and I am getting frustrated enough to sell it (typically this is what happens to me). I built a digital potentiometer that somehow has a ground loop even though it probably shouldn't. The right channel ALWAYS buzzes, and quite loudly. It is very distracting. The left channel has a slight hum that is inaudible unless right up next to the speaker. It really took some hooking up to get my CD-player in the chain. Apparently it has a really strong output, as it clipped my digital pot and made it malfunction (even when set to -20dB on the fader). My computer produces a very mild buzz, but some hiss that is slightly audible at listening position. But, it is really far away and not convenient for hookup. The sad part is that I hooked my speakers back up to my receiver and started listening to music... and it sounds just as good as the Forte when at its best (so far anyway- I've not been able to get its best out). The thing is, my receiver is so much easier to hook up. And, EVERYTHING WORKS! I've never had any trouble from it- no hisses, buzzes, hums, nothing. If hum and other problems come with real high end audio components, I think I am going to go back to the "ignorant" side.

Well, people do spend lots of money to get that "smooth" sound. $3000 for a tube amp is a little pricey, in my opinion, but to others, it is a bargain. It all depends on your tastes, I suppose... You have a lot more dynamic headroom with your current SS amp than you would have with the tube amp. And, if you absolutely love the sound of your SS amp, you may not like tubes. Or, you may love tubes even more. Tubes often seem to breathe life into lifeless, analytical recordings. That being said, $3000 is a pretty hefty entry price for someone who isn't familiar with tubes. I'd probably try to find something in the mid to lower hundreds for a starter, and if you fall in love with the sound, then spring for something more pricey. Regarding how much power you currently use for "rocking", you'll need to define what that means to you. To some "LOUD" is about 80dB. To others, 80dB is quiet. If 110dB is loud to you, then you'd probably be using about 4 watts to achieve this level with K-horns (note: just in case my math is wrong, it's bee a LONG day...). Looking at it this way, your 600W seems a little bit much. That being the case, you'd probably be ok with a lower-wattage tube amp, provided you enjoy the sound. Also note that tube choice will affect the sound of the amp... As will choosing single-ended or push-pull. You can further subdivide into running output tubes triode, pentode, ultralinear... Anyway... good luck. It's a confusing business. []

I looked on the AudioXpress site to find out when they did the write up about modifying the Forte Audio 1A. Turns out it was done over two issues - the May and June issues of 2003 (I think those were the ones). Does anyone here have these issues? They sell them on the website, but for $40. Thanks all

For that price, just buy them and enjoy!

Unless the damage is major, there is usually no sound difference, I think. I've seen many Reference speakers for sale with dented and wrinkled cones, but everyone says they sound just the same and are only hurt cosmetically. Whether this is 100% true, I am unsure. All cones on my Reference are still perfect (I keep the grills on at ALL TIMES because of other people and cats in the house). Is the price $350 for the whole set or just the RF-3's? If for just the RF-3's it is still a pretty good deal. If for everything (Rf-3's, surrounds, and center), it is a darned good deal.

The Cerametallic woofers of the Reference series are very delicate. Often people keep the grill off of their Reference speakers because the copper cones are so pretty to look at. But, if you accidentally bump the cone, it may show a spot (dent). Occasionally the cones wrinkle from contact as well. This could be caused by over-excursion, I suppose. Often it is from bumping up against the cone. Either way, $350 for the entire Reference 3 set is a good deal. Usually, just the RF-3's alone go for that price.

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I think many people liked the idea of a floorstander with a built in powered sub, until they heard them. Or so I've heard. Most do not like their sound much because the bass is supposed to be over-exaggerated and flabby. And, you lose a little efficiency because of the single-woofer only design. But then again, if properly setup, they probably sound great. Just do note, it is a Synergy sub in there, not a Reference sub. That is probably the main cause for grief. My local ex-Klipsch dealer (they went to M&K, B&W, and Boston instead) still has a pair of RP-3's. They either wanted $1100 for the pair or $1100 each (the latter would be MUCH undesirable). If you were interested, I may be able to talk the guy down some (it's worked for me in the past). I heard them hooked up at the dealer's place and they didn't sound all that bad, but I wasn't seriously listening as I was on my way out with their other pair of Klipsch speakers... []

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Yes... replacing the resistors may help (and may bring it back to life completely). Just because the PCB is blackened doesn't mean anything is damaged. Find the correct value and go up a wattage step or two. If they are 3W, get 5W. If they are 5W, maybe get two 5W of double the value and put them in parallel. And, most importantly, mount them above the board about a centimeter or so to allow the heat to go somewhere other than the board, as was mentioned above. Hopefully the burned out resistors didn't cause any of the transistors to go out.

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Oh my... that is a lot of links. Added to favorites... Good find!

I know exactly what you mean. I've been trying to sell a few of my spare drivers and such, but no one wants them for a "decent" price. They only want dirt cheap.

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Oh my, those look nice. My favorite Klipsch speakers (and, of course, I don't have any)... Maybe if I have my massive sale because of extreme frustration I'd be able to afford them. But, it is unlikely that will happen. A good deal, too... If only I had the cash...