henry4841

Agree with Shu and Shakey. I just adjust by ear to what suits me best. Most of the time just enough to bring in more of the bass fiddle or guitar sound but when I listen to a more rock sound more sub. Too old to rock walls anymore but if good enough sub you can do that too.

After posting the original introduction Maynard presented of this amplifier I do not know much more I can add about the great sound of this design. Good place for me to fade into the sunset. The place for anyone building a Sweetie to post your build and results though. Not much I can say that Maynard did not say in the above post for me to say more. I will be posting results of my new build, the Premium Sweetie on another thread. See everyone there.

Below is a couple of video's Roy has done with Steve Guttenberg. They have already been posted numerous times at different places on this site but this thread may make it easier for newbies to find. Roy Delgado is the chief audio engineer that works for Klipsch. In other words the chief technical man.. About this thread: I thought why not. Diyaudio's biggest draw is the Pass topic thread on their site. They have one of the best amplifier guys in the business there. We have one of the best horn guys in the audio business here on this site. Right now he is more or less watching under a not so hidden handle as a moderator. I thought this may be a good spot to ask Klipsch audio information at. I have a first question perhaps someone can answer. I have not kept up with the advances in horn design for the last few years, decades even perhaps. What is the difference between the Klipsch Tractrix horn and let's say my 86 LS's horns. Is it something like what is called elsewhere as waveguides? Probably a simple question many on this forum can answer without Roy jumping in but if we keep this thread on Klipsch matters who knows he may speak up now and then.

Ask Dean. I have a Klipsch question but I am not going to ask it here out of respect for the focus of this thread is about Dean's new association with Klipsch. Dean is the one to ask about Klipsch crossovers now. That is if the big boss man does not answer your question first.

Heard good things about the AL-3's.

And little more this morning.

Making some progress.

Not on this one. This is another one from the bundle I recently bought. She has a good voice on this one and a good song selection. Probably better than some of the others ones by them I own.

Last night. I like it.

We are called greedy boyz on Nelson's thread. The ones looking for one more crumb.

Hey guys, lets all ask for his participation on this forum and perhaps he will feel sorry for us and throw us a bone every now and then. Right now he is mostly a referee of verbal fights. I would be happy for just a bone throwed my way. Hit the like button on this message and perhaps he will notice.

I like single ended amplifiers whether tube or SS. My preference for best sound is a tube single ended triode amplifier. For the technical minded below is an old article by Nelson Pass regarding single ended amplifiers. Lot of mentions of SET tube amplifiers in the article. https://firstwatt.com/pdf/art_se_classa.pdf

Not something to concern yourself about in my world. Klipsch speakers will sound wonderful right from the start and will only get better. 🙂

Thanks for the feedback. I'll try and remember that if I hear the same thing.

He was just an upstart then working for someone else. Since maturing he has published an number of different articles in audio circles sharing with electronic geeks some of his knowledge. Since 1977. https://firstwatt.com/articles.html But then he started his own company. It's helped make him super rich. Big ranch on the California seacoast. Roy may need to get Klipsch corporate to agree with the idea. I see it as a good selling point for Klipsch myself. Just a few crumbs, no classified top secrets.

I'm not so sure. It worked out well for Nelson Pass. It's made him a lot of money. I am not talking company secrets, just good old fashioned audio knowledge in general. He has more than he needs. I hope he shares a few crumbs with us. Good for us, good for Klipsch. Word gets out this forum has a great audio engineer sharing a few crumbs and good people will flock to this forum to hear what he has to say about Klipsch horns. Perhaps buy a few speakers. Keep our fingers crossed. Exactly what this forum needs to keep it on the right path, IMHO. A Roy Delgado thread.

This is long overdue and something I should have posted at the beginning of this project. Maynard's original presenting of his design of this amplifier in 2015 to the Klipsch community. Jason ("thesloth") originally proposed developing a number of low power diy tube amplifiers for the new forum section with two goals in mind: 1) easy to construct by those with enough experience to work with high, potentially lethal, voltages in a safe manner, and 2) to provide a level of sound quality, when used with Klipsch speakers, which rivals that of very costly amps. I thought it was an excellent idea. Of course, neither of us expected William ("wdecho") to bag the first entry award!!! And now he is getting ready for yet another amp project! In thinking about what I wanted to offer, a number of goals came to mind: 1) use of inexpensive, readily available, tubes which were originally designed for radio service, and which offer extreme long-term reliability. 2) a design which offers no compromises (to me, that means at least 1 watt/channel, which is more than enough for 90% of the users of both Heritage and Reference Series speakers with whom I'm acquainted), and very low distortion. 3) crosstalk limited to that of the source device to allow the speakers, which are capable of breathtaking imaging and a huge soundstage, to deliver the goods. 4) built like a tank with very cool operation, allowing use all day every day if desired. 5) low parts cost to be comparable with the imported offerings seen on Amazon and elsewhere. 6) ability to shape the high frequency response to suit individual taste and room characteristics. The first two goals are easily met by more tubes than you can imagine. I've always believed that the finest sounding audio tubes were developed for use in radio service. So, it was a matter of choosing a driver and output tube which provide very low distortion. The 6Y6, which was originally registered by Raytheon in July, 1937 is a very tough "battleship" of a tube with a 12.5 watt plate dissipation based on the extremely conservative design-center criteria. It also happens to be very linear when used as a triode (since SETS are unsurpassed for creating an enormous soundstage and pinpoint imaging, there was no decision to be made about using that mode of operation). It's only limitation is requiring a lot of drive to achieve full output (approx. 21 volts rms in this design), so a pentode driver was needed to effortlessly provide the tube with what it needs. The latter function is filled by the 6SJ7, which can drive the output stage fully with only about 200 millivolts of input signal, while its distortion stays very low (approx. 1% thd per published specs). In this design, 2nd harmonic distortion of the 6Y6 is only 2% at full output into the calculated 5k plate load (corresponding to a speaker impedance of 8 ohms when connected to the amp's 8 ohm tap). When the plate load drops to 2.5k, which corresponds with the typical minimum impedance of most Klipsch speakers of 3.5-4 ohms, the distortion rises to only 5%! Remember that the latter figure represents 1/400 of the total output power- quite insignificant. Speaker impedances greater than 8 ohms will reduce the distortion to well below 2%. Power output is approx. 1.3 watts at the onset of clipping into an 8 ohm resistive load. I know many of you are laughing at this figure. Well, don't! Unless you have experienced just how loudly and cleanly even half that amount of power can drive the speakers in a majority of installations you will remain skeptical. To eliminate soundstage reducing crosstalk issues (typically encountered when both channels share a common high voltage supply), these are constructed as individual mono amps. That can be done on a single chassis, if desired. Cool operation is no problem at all. The specified power xfmr is used well below its rating, and only gets mildly warm after extended use. Little heat is developed under the chassis as well. Longevity of the 6Y6 should not be an issue at all since the quiescent plate dissipation is about 10 watts, a very comfortable margin of safety for the tube. In addition, as noted on the schematic, filament voltage is going to be set not to exceed 6.3 under typical operating conditions. Excessive filament voltage is a common cause of premature tube failure. The 6SJ7 is unlikely to ever need replacement. Parts cost for the amps, as constructed, is in the low $300 range depending on the source you choose. Hammond output xfmrs tend to be a bit on the expensive side- going with Edcor can save some money. I have never heard the latter; however William, and others, has reported that they sound wonderful. Lastly, the amp incorporates the variable low pass filter which has become a standard feature in all of my designs. R1, the 10k pot on the schematic, allows the user to shape the high frequency characteristics of the amps to individual taste. I install it as an under-the-chassis control which is set once and then forgotten (until the amps are used with different speakers, or in a different room, etc.). You can just as easily panel mount the control if you plan on using it regularly, or simply eliminate it along with C1 if you don't want that capability. Lastly, the parts ratings are, in some cases, much higher than needed for this circuit. Since the higher rated parts are often only a few cents more than those with a lower rating, there's no reason not to over-build. Capacitors, in particular, last much longer if run well below their rated operating voltage and internal temperature. The amps are totally silent with an ear at the front of the speaker. The sound is silky smooth, definition (tested with vocal and choral music) is as real as if the performers were in the room, and bass output is very potent and approaches that of a well constructed SEP amp. I can't understand why some claim that SETs provide anemic, mushy bass. It isn't true. As expected, the imaging is precise and the soundstage is positively huge with my RF-15s. The amps will be tested with CWs as soon as I can get hold of "the guy down the road" (a professional musician and music teacher who auditions all of my creations with very critical ears!). From past experience we have found that when voiced for my speakers, we rarely have to change anything when used with CWs. The same voicing usually applies to K-horns and LSs as well, based on my own experiences. I've attached pics which should be useful for anyone who wants to use a similar format. Most importantly, star grounding (bringing all grounds to a single chassis point), and keeping all AC wiring as far from the driver as possible is critical for keeping the amps hum free. If you use a different layout, I suggest cutting a sheet of paper to the size of the chassis you will use and placing out the xfmrs, sockets, and so on to get the arrangement you desire. Then, mark up the chassis and re-check the component placement a couple of times before drilling. So, who's going to build a pair of these? If you do, you are likely to question why you ever spent a large sum on an amplifier! These could easily be the last amps you will want to own! If anyone notices something in the schematic which doesn't seem correct, please let me know asap! DO NOT ATTEMPT TO CONSTRUCT THESE AMPS IF YOU ARE NOT SKILLED IN WORKING WITH POTENTIALLY LETHAL VOLTAGES!

Guys I am late to the party. I did not know we had an audio engineer participating on this forum in some capacity. Not just any sound engineer but the Roy Delgado who works for Klipsch. I hope he throws us some crumbs of his audio knowledge like Nelson Pass does on the diyaudio forum.

I agree but I have noticed an upswing in the price of used LaScala's with the increase in cost of a new pair. Covid raised the price of most everything. Does not appear he has been using those speakers having them photographed in the middle of the room.

I have a question for Roy, Chief bone head. You are a sound engineer so I am asking if what I was taught correct by my instructor about how engineers pick an electronic part for a circuit with the electronic class I took? Who better to ask such a question than the Chief Klipsch engineer himself. I look forward to hearing your response. I just found the interview you did with Guttenberg on youtube. Good way to meet the Chief bone head at Klipsch as a real person.

Neither Lowe's or Home Depot had the black screws I wanted so I just did as someone already suggested and made my own black screws.

More country sounding than some of the others I bought in the package deal but recorded good.

It appears the black screws I bought and was expecting to arrive today from Amazon has not even been shipped yet. There goes my plan on working on this build tomorrow. That is unless I take a trip to the local hardware shops and see if I can find them there. I think they will improve the look and I do not want to start installing more parts underneath with the screws I have just to remove and replace them with black ones another day.

Thanks Area. I do honestly think you have a well built amplifier, that is what I would like to think, with really good decent parts that should last a lifetime or at least a few decades before needing a freshening up. NOS tubes as well. And it sounds really good to boot.