Premium Sweetie Build

[Shakeydeal]

Looks good! 👍

[henry4841]

Thanks

[SonicSeeker]

Looks fantastic, great job.

I am anxious to hear your thoughts after some extended listening.

[henry4841]

54 minutes ago, SonicSeeker said:

Looks fantastic, great job.

I am anxious to hear your thoughts after some extended listening.

Thanks

[jjptkd]

Amp looks great man- this is your second build in about a months time, you're a machine! With the forum down I know I had to find things to do the last couple of days it's amazing how time can get lost in this place.. 

[henry4841]

This build went together much smoother than the previous one. The previous one was with a 2 or more year absents from building a tube amplifier. That is not to say it did not have a few issues to deal with after first completing the project but nothing that took a lot of time. Mostly joining together a few ground issues eliminating a tiny bit of hum. Dead silent now like my other Sweetie builds. Listened for a few more hours last night. Wonderful sounding SET amplifier with some better looks and parts than the previous Sweeties I have built. In my book Maynard hit a home run designing this amplifier. 

 

There has always been a lot of back and forth discussions on capacitors on the site. Being a relatively new member to this site I just tried to ignore all this audiophile talk not wanting to get involved in such things. Electronic engineers and just plain electronic geeks such as myself do not get caught up in such foolish conversations about the different sound of different brands of capacitors. Sure they sound different from each other but that can be said about any component in an amplifier if one has good enough hearing to hear the differences. At least to a certain degree. Called spitting frog hairs with a razor blade down here in the south. A cap is supposed to stop DC and let audio AC signals through. That is it's job period. Most all the film caps at Mouser will do this job without a hiccup. This kind of talk is audiophile language. Electronics is an entirely different language one must learn. The language of electronics. That is what a teacher at an electronic tech college I am currently watching calls the class of electronics. Learning a new language. I have been watching his class on youtube. Just passing the time. Electronic guys speak this language, some better than others and to  an outsider it may as well be Greek. I am just now, after 10 years or more since being retired studying the electronics, able to follow along with what sound engineers are saying on some of their videos. But remember I am now 73 years old and some new subject does not come easy at my age. The thing I like about electronics is there is always more to be learned. Always changing and advancing. 

 

On this build I ordered the film caps that are made with polypropylene but the input polypropylene cap I ordered was one of those ones made to be placed on a circuit board. Short leads. It's value is .1uf and it is a common cap used in audio repairs of which I keep a number of them in stock. I have a number of .1uf caps bought at Mouser made by Panasonic with the dielectric film of polyester. Spec sheet says it does a great job as a film cap and it is an axial cap made just for a point to point build. I used it for my input cap. Sounds great, no problem. 

 

This talk of capacitors has caused a lot of friction on this site from what little I have seen the last couple of years I have been a member. I think it is about time Roy put an end to it and now with Klipsch making and marketing their own film caps for crossover networks we have a Klipsch authorized capacitor picked by their audio engineers to bring ones crossovers back to the sound Klipsch thinks one should hear from their old speakers. I am curious about  the sound of of their capacitor they have chosen. Certainly an audio engineer should know more about picking a capacitor than a layman without any formal training in the field of electronics. 

 

Us good old boys down here where I live would want an original part for their Harley and not some after market brand. They would probably save their money and buy a stripped down Harley and every time they saved enough money they would go back to the Harley dealer and buy an authorized Harley part. Much the same with your new GM vehicle. If you keep it long enough to need repairs the part you will want is an original GM part to replace the one that went bad if given the choice. Makes sense does it not. Klipsch owners should want the same thing with their Klipsch speakers. 

 

Enough rambling this morning. Your thoughts are welcome. 

[tube fanatic]

23 hours ago, henry4841 said:

While the website was down I finished the Premium Sweetie build. Here are some pictures of my work. Maynard thinks I used too much solder and he is probably right for a point to point build of a tube amplifier but for the PCB board builds and repairs I do it is what the solder joint is supposed to look like. Trust me I always flow my solder and look for a little whiff of smoke telling me the flux has burned off. Maynard was taught the 3 second rule of soldering. Finish the solder joint then hold an additional 3 seconds. Excellent advice. If you watch some of the professional repairers of SS gear it will shock you how much heat and for how long they hold the iron to the parts they are soldering together. That and the amount of solder added. With a tube build such as this there is a mechanical attachment of all the connections whereas in a board build the only thing holding the part in place is the amount of solder one uses. Many problems can be solved in those old 70's receivers by reflowing the solder joints and adding more solder. Especially pay attention to those big parts on the board that get warm or hot. The steady expansion and contraction of the component leads will crack the solder and will prevent a good connection. Fixed by re-soldering the connection. 

Actually, I consider it better to use a little more solder than not enough.  As far as the “3 second rule,” it was used at the power supply company when training new workers who had never soldered before.  Heat the joint, flow the solder, keep the iron on the joint for 3 seconds.  They taught it that way to avoid cold solder joints.  My method is different and has been cultivated over the past 66 years.  I was originally taught by old timer ham operators whose work was exemplary.  More on that some other time!

 

Maynard

[Area 51]

On 9/16/2022 at 2:13 PM, henry4841 said:

While the website was down I finished the Premium Sweetie build.

Looks good and I'll bet it sounds as good as it looks!

[Curious_George]

JJ - How are you doing after your fall? Hope you have recovered. 

[jjptkd]

1 hour ago, Curious_George said:

JJ - How are you doing after your fall? Hope you have recovered. 

 

Thanks man! I started PT on Thursday had a full torso brace on for 5 weeks and was on bed rest the whole time now dealing with weak core support muscles luckily I was in decent shape before hand looking at probably another 6 weeks before fully recovered PT twice a week until I don't need it any more. 

[henry4841]

I ran a few test of this Sweetie yesterday and found 8.64W and 8.62W dissipation on the 6Y6 tubes. Well below the 12.5W max. Should give long tube life running at these numbers. Output to the speakers was over 1W. My new generator did not give enough output V to check the wattage out at clipping. Ordered another generator. Way it goes sometime. The one I ordered this time is this one. Should be adequate for some distortion analysis using Arta as well.  

 https://www.amazon.com/gp/product/B08PQ9R131/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

[henry4841]

I am undecided on what to build next. I have been discussing this over with Maynard getting his opinion. I have mentioned a SET 2A3 build but not really wanting to deal with a pure triode cathode heating again. I have two of them now, my SET  300B and SET 45 tube. Watching one of Modjeski's videos, https://www.youtube.com/watch?v=7qg9ot20EdA , he is saying one of the EM7 tubes is a modern built and sounding 2A3. I believe an EM7 SET amplifier was my first tube build. If not one of my first. I took it apart for no reason other than to use the OPT's on another build to satisfy my build passion at the time. And it was not Modjeski's design. I may have to revisit this tube. I already have a PS transformer and tubes I could use. The cost of building will not be that great if I decide to build an EM7 amplifier. 

 

A little discussion of OPT's. For the most part I have always used Edcor OPT's. Mainly because they were much cheaper than Hammonds. Not anymore so I have decided to use the ones Maynard likes the Hammonds. After building Area51's amp I thought the bass might have sounded better on his amp compared to mine. I did not do an A/B comparison between the two fearing I would hear an improvement and not wanting to know being that at that time I had not planned on building another Sweetie. Last night I decided to do a quick A/B comparison. Now there is no doubt in my mind that the bass is stronger and quicker with these Hammond OPT's on this build compared to the similar rated Edcors. Edcor GXSE10-5K - 10W, 5K are $62.36 with a few weeks wait against the Hammond 125DSE at Tubedepot for $61.95 with quick shipping. The Hammonds do need to be installed under the chassis for appearances, not the prettiest, but it should not be a problem if one chooses a big enough chassis.  

 

Yesterday I visited a neighborhood old audio gear dealer called Classic Audio in Prattville, Alabama. In it he has 3 sets of Klipsch speakers. A nice looking set of K-horns along with a nice looking set of Cornwalls and Heresy's. He has them stuck in with a bunch of other old speakers where I could not look them all over but from what I saw all three sets look really nice. I looked at the prices and they were inline with the prices on like speakers these days. The Heresy's looked nice and I do remember he was asking $600 for the pair of them. Also he has a tube tester on the showroom floor anyone can use to test their old tubes. That is something I am going to get some use out of. The owner also has an interest in seeing this Premium Sweetie amplifier I just built. Who knows he may be an outlet for selling a few Premium Sweeties helping us both out. That is if there is a market for a high end SET 1 watt amplifier in our vicinity. This kind of amplifier is not going to appeal to the mass market. It is going to only appeal to someone with efficient speakers and desires quality over quantity when it comes to sound. I wish we all had a store like this in our town. I could spend hours looking at all the old gear he has in there. 

 

[henry4841]

15 hours ago, tube fanatic said:

I was originally taught by old timer ham operators whose work was exemplary.  More on that some other time!

 

Maynard

I would certainly like to hear more about the old timers you were taught your craft by. That is the kind of subject I have an interest in. I have told you in private my threads are your threads as well so please tell us more. 

[henry4841]

After a discussion with Maynard he seems to think a 2A3 SET amplifier is going to sound much the same as this Sweetie. At least judging by the curves in the tube data sheets. I have to agree with him.

 

I dug out 2 pair of the 6EM7 tubes from my stash and just looking at the tubes I am not too impressed. Not near the size of the 6Y6. From looking at the prices of new production tubes has anyone but myself noticed that it seems the bigger the tube the bigger the price? Could be the larger plate surface area catching the electrons has an very profound effect on tube performance. I think one is going to be hard pressed to find a 2 watt or less tube for SET use that will sound as good as the 6Y6 tube. 

[henry4841]

I did some more testing of this amplifier. I measure 8.64W and 8.62W of plate dissipation on the tubes. Well below the 12.5W maximum rating of the 6Y6 tube which means the tubes should have a long and happy life. My voltage from cathode to plate was 201V and 196V along with 41.3ma and 44ma of current. The amplifier clips at 1.3W the same as Maynard tested. These figures are subject to change slightly as the tubes settle in some more. At least they have changed some from when I first fired it up and did some test. 

[CWelsh]

@henry4841 I know you've only got a few hours on the new amp, but I wondered if you've been able to discern any appreciable difference in sound between this one with premium components and the standard version. I saw your comments on the Hammond vs. Edcor OPTs. Do you feel that difference is all related to the transformers, or do you think the other components contribute.

 

Unless I misunderstood your earlier post about the difference in cost between the standard and premium components, the added cost is quite small.

[henry4841]

I've been meaning to post my thoughts after giving it some more thought. It very well could be that the better parts along with Hammond transformers has raised this build over my previous 3 Sweeties I have built. All I can defiantly say is boy this amp delivers with our Klipsch speakers. This one is a keeper. This one cost more than $100 more, just a good estimate over the components of the previous Sweetie. At my age I just do not care to keep up with cost like an accountant for an amp I decided to keep. A good estimate though is getting close to $500 for parts alone. I have not priced what the solid cherry boards cost these days for an chassis like this. That and the aluminum sheets have gone up in price as well. A used a grade better hardware such as input and output jacks along with a premium potentiometer among other parts. That does not include the higher cost electronic parts. 

 

Is it worth it? Let me put it this way. I do not want to build myself another amplifier any other way. That being said the previous one Area51 bought sounds great as well. Absolutely nothing wrong with the way it sounds. The focus of that build was to build a good sounding SET amplifier using good parts as low a priced as I could. The way most of my other amplifiers have been built. This one just seems to be a bit better but that is what one would expect when spending more money. Does not always work that way but one expects it to be that way on any purchase. If you throw in looks, I do like the looks of this one better but I am not one to look at an amplifier when listening to music. Looks of an amplifier has nothing to do with what you hear. Then there is always the factor that most everyone that builds amplifiers favors the last one finished. At least that is the way it was when I first started this hobby. Now I am more picky. The last SS project I did was very disappointing for me. It was one of Nelson Pass' projects and it did not impress me the way I thought it would. A little bit disappointed in it. Nothing wrong with the sound, it is a SE V-Fet amplifier. The problem for me was the cost and I have many SET tube amplifiers that sound much better. Maybe I was just expecting more from it. 

[henry4841]

I failed to mention the biggest single difference between what I have been building and this amplifier is it is a mono build. Probably has more to do with what I am hearing than anything else. Having never built mono's before I really did not know what to expect. Imaging is as Maynard said dead center. My stereo Sweetie has center imaging but not as precise. Definitely an improvement in bass that could be contributed to the better electronic components or the different iron. When listening to Area51's Sweetie I did noticed the bass seemed mighty good, better than I remembered my Sweetie sounding. I did not do an A/B comparison between my Sweetie and Area51. I wanted to put some hours on Area51's before shipping it to be sure no unexpected problems showed themselves. I am now convinced, for a Sweetie build, the Hammond iron does have something to do with mine and Area51's amplifier having great bass for such a little amplifier and being a SET. Maynard said as much about the bass when first introducing the Sweetie. 

 

Still undecided on what to build next. When I get started building I like to keep the ball rolling. I have a number of tube builds that I could improve on. Some of them were built years ago and I like to think I know more now than when they were built. One of them is the George Anderson SSE amplifier. It is an SET that can be used with many different tubes by changing the cathode resistor. I mentioned previously about using different tubes from the EL34 family and also said that it is not the optimal way of doing it which it is not. My Tubelab SSE was built for the EL34 tube and it was optimized for it. The best sounding tube I have tried with it is one of the Russian 6L6 substitutes, the 6N3C. I did some checking on this tube in my amplifier yesterday and I am running this tube way too hot. It must be a well built tube not to have the plate glowing red hot the way it is being run in this amplifier. Might have something to do with the best sound I have been hearing from it as well. Typically the hotter you run a tube, or a transistor for that matter, the better it is going to sound. That is until it burns itself up. I am considering taking all the hardware and putting everything in a chassis like the one I just built using Hammond iron and better electronic components along with making it a mono build. There are so many excellent tubes one can use in a SET EL-34 amplifier. But the tubes I want to use have gotten really expensive. I would really like to use some NOS EL-34 tubes. Those Russian 6N3C's are being sold as NOS on Ebay which makes me believe that they truly was a tube built years ago for audiophiles in Russia as a 6L6. In other words a Russian version of the 6L6. Here is the schematic of the Tubelab SSE.

 

http://www.tubelab.com/images/AssemblyManualSimpleSE/Simple_SE_Amp_Sch_11-08.jpg

 

Some purist tube builders will not like the idea of a SS component in the audio circuits but they need to realize that the 10M45 is only being used as a constant current source and just like a tube constant current source has no or very little influence on the sound. It is just a CCS and nothing more. Used frequently in SS A/B amplifiers and Nelson has stated many times really does not effect the sound character of an amp. It's job is much like a SS PS in a tube build being it's job is to provide good clean voltage for the tubes. The CCS job is to provide a constant current for the preamp tube just like the circuit is called. Many if not most SET's just use a resistor in that spot where the 10M45 is. A CCS is just better way to do the job a resistor can do it. Other than using a SS CCS in the preamp circuit the amplifier is a pretty standard SET amplifier. Another option is a PP amplifier built by Eico years ago I bought on Ebay. I put off restoring it a few years back not having a tube tester to check and see if the tubes were still in good shape. A set of tubes for that amplifier gets really expensive, for me that is. I took the tubes to Classic Audio yesterday and tested all of them and they all were almost new or at least little used. Instead of restoring that old amplifier I could just build it in chassis like the one I previously built. The problem of a PP vs a SET is it is much more complicated. You have many more circuits to build than the 3 circuits in the Sweetie build. A rough count in my head for a PP build is 9 circuits. Most will not build a PP amplifier point to point but use a PCB board made for the PP amplifier in question. The Tubelab SSE is just two more circuits to build. At least now I have a few things I need to think about before starting another build. 

[Area 51]

7 hours ago, henry4841 said:

When listening to Area51's Sweetie I did noticed the bass seemed mighty good

and I have to agree Sweetie sounds pretty darn good on my HIP Heresies without a sub. But there was something almost undefinable nagging at me. It didn't sound bad. It just wasn't lighting me up like I was hoping it would. I think adding a sub might be one of those things you don't miss until you have it. Then you realize you needed it. We'll get to that later but for now why wasn't I more enthusiastic about the overall sound? Again, it didn't sound bad but there was something I couldn't put my finger on that just wasn't there. At this point I should tell you I used to be something of a cable denier or skeptic. I didn't think interconnecting cables could make a big difference once you reach a level of competence and you're using "adequate" quality cables. I realize that, like so much around audio equipment, terms like "adequate" are highly subjective and I'm  opening myself up to criticism. In fact, I'll probably be excoriated-if not excommunicated-because I will soon be offering some cables for sale in the Garage Sale section but in my humble, admittedly biased opinion upgrading from my entry level cheapos to some good quality Audioquest interconnects delivered an immediately discernible improvement in bass on my Heresies without a sub so I can now confirm Sweetie's bass is "mighty good". 

 

8 hours ago, henry4841 said:

Maynard said as much about the bass when first introducing the Sweetie. 

 

[henry4841]

The Sweetie amp of mine, the personal one I built years ago before this one, was one I always liked the sound of but not one I played that often for a number of years but it was in my regular rotation of amplifiers. There was always something drawing me in to wanting to hear it again. It is the lovely vocals this amplifier makes. None no better of any of my amplifiers. Many of my amplifiers sound as good  in the mids but none any better. The sound it makes just grew on me the more and more I listened to it. I figured for what was required for a low cost forum build the Sweetie was the one and I still do believe that. Dollar for dollar it is a design that meets that requirement, low cost, great sound, better than any amplifier I have built. I believe the more you listen to it the more you will like it. That is for anyone that likes the SET sound. Many do not. My preferred sound is a SET tube amplifier.

 

This Premium Sweetie has over $250 in cost just in the iron once you add shipping more than that. Each one of the transformers were roughly $63 apiece and there are 4 of them, OPT's and PS transformers. Then two PS sections using Nichicon 105C caps adds up as well. I do believe it helped improve an already good sounding amplifier.