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Premium Sweetie Build


henry4841
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55 minutes ago, henry4841 said:

I saw where Area51 posted he had the economy version of the Sweetie. It got me to thinking, all my previous builds were built pretty much the same as his amplifier. All the 22 or 23 ones I now have and probably 10 or more of the other ones I have built the last 10 years. I guess you could say all my amplifiers were economy builds. Not expecting anything earth shattering different in the sound though. Already sounds really good using parts I have always used in my personal Sweetie I have had for years. 

 

 Looking great! It'll be interesting to hear your impressions I'm sure it will sound at least a little different with part changes and being dual mono. Bob Carver proved over 40 years ago with the Carver challenge that it is not necessary for top shelf parts to deliver high end sound but at the minimum I'd think its worth it to a certain extent just for build quality- not just longevity but consistency and reliability throughout the years.  

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I bought grommets for my KT88 diy build, but didn't end up using them. The PT wouldn't sit flush with them in place and I didn't want to use spacers to raise the PT (ugly IMO), so I just opened the holes up with a step bit and put heat shrink tubing around the leads. The amp is just sitting on a shelf and I don't think the wires are going to move around.

 

YMMV, JMO, don't try this at home, etc.

Edited by 82 Cornwalls
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On 9/13/2022 at 10:49 PM, 82 Cornwalls said:

I bought grommets for my KT88 diy build, but didn't end up using them. The PT wouldn't sit flush with them in place and I didn't want to use spacers to raise the PT (ugly IMO), so I just opened the holes up with a step bit and put heat shrink tubing around the leads. The amp is just sitting on a shelf and I don't think the wires are going to move around.

 

YMMV, JMO, don't try this at home, etc.


Your method is equally effective since the object is solely to prevent the insulation from being cut.  An issue often encountered in 75-80+ year old radios is xfmr leads pulled across ungrommeted holes.  As the leads dried out with age, the insulation split.  Even some vintage audio amps have had a similar issue.

 

Maynard

 

 

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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. 

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And here are some pictures of the finished amplifier. Sounds great, good solid, quick bass. Possible has to do with the larger Hammond OPT's used in this build. Comparing the differences between Edcor or Hammond OPT's is just a mute point. Both build good transformers. Hammond just has been the standard for many years and I can see why now. No wait for them to be built as Edcor's are as well.  I just finished wrapping it up this morning so no extended listening has been done yet. Neither have I compared it to my Sweetie I have had for years. Right now I am just enjoying listening to my new tube SET amplifier. 

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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.. 

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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. 

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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. 

P1040078.JPG

P1040079.JPG

P1040080.JPG


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

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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. 

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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

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