Premium Sweetie Build

[jjptkd]

2 hours ago, henry4841 said:

 Just thought I would add I have decided to hang onto this build. Too pretty for me to sale just now. Let's just enjoy the building together.  

 

 It's great that you're able to keep such a sweet sweetie-- does this mean this going to be your last build for awhile then? 

[henry4841]

34 minutes ago, jjptkd said:

 

 It's great that you're able to keep such a sweet sweetie-- does this mean this going to be your last build for awhile then? 

I just take it one day at a time. 

[henry4841]

20 hours ago, jjptkd said:

 

 It's great that you're able to keep such a sweet sweetie-- does this mean this going to be your last build for awhile then? 

I do enjoy building more so than doing repairs of audio gear. The problem is nothing I want to build that I have not already built in a tube amplifier. At least this amplifier is a first in a couple of ways. First mono build and using what I think are really good parts. That and the first wood chassis that I have made using hand cut dovetails. Even if I want to build another one right after this one there is always the problem of waiting till I have the money it cost to build to throw away. I'll most likely start some other electronic project if not a tube amplifier. I still have the SS Aleph J to take out it's test chassis and put in a proper chassis that I have already bought just sitting waiting on me to get started. That and many other projects I started and I got tired of fooling with and started on another project that might not get finished either. It happens here in this house. 

[henry4841]

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. 

[henry4841]

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. 

 

 

[mike stehr]

On 9/1/2022 at 10:51 AM, henry4841 said:

No, I am going this time with what Maynard recommends for mono builds, the Hammond 269EX. Two of them.  

I notice the pair of 269EX you purchased only has two bolts for the end-bells.

 

I bought a pair of those the single-ended parallel pentode 6AQ5 amplifier I built. They also only had two bolts for the end-bells.

 

It may not be an issue with you to be of concern, but one of mine had a mechanical rattle/buzzing that was fixed by installing two more bolts in the end-bells.

[henry4841]

3 hours ago, mike stehr said:

I notice the pair of 269EX you purchased only has two bolts for the end-bells.

 

I bought a pair of those the single-ended parallel pentode 6AQ5 amplifier I built. They also only had two bolts for the end-bells.

 

It may not be an issue with you to be of concern, but one of mine had a mechanical rattle/buzzing that was fixed by installing two more bolts in the end-bells.

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

[Area 51]

On 9/9/2022 at 2:00 PM, tube fanatic said:

 Keep up the beautiful work.

Our mutual friend was kind enough to build and send the "economy version" of your design my way. I am grateful to both of you, thanks. 

[henry4841]

Making some progress. 

 

 

[henry4841]

And little more this morning. 

 

 

[Marvel]

Ace Hardware usually has a nice selection of black screws, nut, bolts, in metric or English.

[henry4841]

I am building this one a little different from my previous builds. Paying more attention to layout of parts by putting the big components in first. Putting them in the center under the PS transformers and putting the input and output signals on both of the sides keeping them as far away from the AC lines as possible. I actually did a little more yesterday afternoon, maybe 45 minutes. I like the way it is progressing along. This build is following the original schematic Maynard posted and not the one he make for me using a stereo PS. 

 

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. What can I say. I am a cheap diy'er. Mind you with quality parts from the likes of Mouser or Digi Key but generally the lowest priced parts available from them. Unless one wants to spend hours or days researching those data sheets you have to trust the electronic supply house that supports the electronic industry has only good parts, or at least they are tested to meet the data sheet before they handle them. On the online electronic course I took one lesson was devoted on how to pick parts on Mouser. Their site can be intimidating for someone not experienced in electronics. I find the part I am looking for and then see the options for the ones starting with the lowest cost graduating to the most expensive. Then I look to see if there is a name brand I know with the price in the low range. That is the way I have picked all the parts for all my builds. This build is different in that I am choosing parts from what I have learned over the last 10 years as being a somewhat better quality part. Not so much in an audio way but in a quality way. Such as 105C capacitors instead of my usually 85C ones I have used in the past. In the audio circuits I have chosen Nichicon audio grade 105C electrolytic capacitors and in the PS section Nichicon 105C electrolytic capacitors. There are two .22uf caps in this build. One the input and I am going to use a Jantzen Crosscap there and for the coupling cap my standard orange drops I have found I like on my other builds. I did order some extra Jantzen with the thought of possible using them for the coupling caps as well but have not decided if I want to experiment with a different coupling cap on this build or not. Later if I feel like playing I may change back and forth, the coupling caps, for my impression. I expect both to sound good but different. Some people have good enough hearing to tell when a resistor has been taken out of circuit. Nelson has done blind experiments with his favorite listener of his builds to verify this. His listener could tell the difference. Me, my ear is not trained for such experiments. For the volume pot I have chose the Alps brand. Expensive for me but considered better by many on the net. Personally I have not found anything wrong with the Alfa pots I have always used.  Well this is some of the changes in parts I have chosen. 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. 

 

Picture of my star ground. Like a star with all the rays coming from one place a star ground is all the grounds going to one place only in an amplifier. All my builds, SS and tube, are built using the star ground method. 

[jjptkd]

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.  

[henry4841]

Enough for one day. One circuit done, two more to go. 

 

 

[tube fanatic]

Prospective builders should take note of Henry’s use of grommets through which the power xfmr leads pass.  Costing only a few cents, this step will prevent a sharp edge of the hole from cutting into the insulation of a lead causing a possible short.

 

Maynard

[82 Cornwalls]

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 September 14, 2022 by 82 Cornwalls

[tube fanatic]

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

 

 

[CWelsh]

On 9/13/2022 at 4:30 PM, henry4841 said:

Enough for one day. One circuit done, two more to go. 

 

 

Looking GOOD!

[henry4841]

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. 

[henry4841]

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.