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Little Sweetie Forum amplifier project


henry4841

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This is an old project of Maynard's years ago and before I posted this project I checked with him to get his permission to do so being it is his design. He gave me his blessing. This is going go to be a stereo version and not mono's like Maynard built keeping the cost down. I have already ordered all the parts. At least I hope so but most of the time I will have to order something I forget paying the high shipping cost these days. This is truly an amazing sounding little amplifier using NOS tubes that are still reasonably priced. The output tube is the 6Y6 which went out favor years ago for the 6V6 having to do with the power needed for the filaments being less. Some say the sound is much the same. I have never heard a 6V6 amplifier so I cannot comment on that. This tube has some of the best vocals I have ever heard. Very lush sound. Listening to a Connie Francis LP I can imagine her standing in front of one of those old rectangular microphones. The sound reminds me of the old tube radios and juke boxes of the 50's and 60's. The tube was used in the old console radios of yesterday with speaker much less efficient than our Klipsch speakers. I measured almost 1 watt before clipping. So close I would call it a 1 watt amplifier. It plays as loud as I care to listen with it without distorting. At least to my ears. Never runs out of power with my LaScala's. One has to remember that LaScala's are 100db and that is very loud. This amplifier should be good with any of the Klipsch line of speakers for reasonable people at responsible listening levels. Trust me it does and this is from someone that has 150 watt per channel A/B amplifiers. Sure the bass is going to better with a more powerful amplifier but that does not mean this little amplifier does not have good bass. If real deep strong bass is what you love this is not going to be the amplifier for you. This amplifiers shines with vocals and midrange. Enough said about it now. One can do some research on this site when Maynard posted his build for more info. Below is my personal Little Sweetie which is not for sale to give you an idea of what it will look like. This project will have a single volume control instead of two in the picture. There are ways to dress it up with a wooden stand for it to sit in. For that reason I am going to put the controls input and outputs high on the chassis so one can build their own stand of wood and make it pretty. Pardon the dust, cleaning lady did not come this week. 

P1030962.JPG

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I just want to add for those that turn their nose up at 1 watt of power that a high in demand amplifier called the Decware Zen is all the rage on youtube right now with all of it's 1 watt of power. I have one that I built from an earlier design that is published. It does sound really good but I prefer the sound of Maynard's Little Sweetie better. 

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8 minutes ago, Curious_George said:

If you are frugale and / or have some parts on hand, I would say $375 for a stereo unit, but this is using Edcor iron. If you can get output transformers that are cheap and perform well, then the cost could remain low(er). Cheap & good output transformers don't usually go hand in hand. $400 would probably be more realistic. 

 

Using a 6Y6G/GT you should be able to get 2.5 ~ 3 watts out @ 3~5% THD+N. That is 2A3 territory (kinda).

I guess the original Little Sweetie was designed for 1 watt or so output. Technically, since the plate dissipation of the 6Y6G/GT is 12.5 watts, you can get 1/4 of that dissipation in output power, which would be 3.125 watts. 

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This Little Sweetie Forum Amplifier Project is absolutely the best news I have stumbled into recently. Discouraged, I had come to the conclusion that a quality SET amp is something I would simply have to live without. I just don't have the budget so I thought I would be going back to solid state to power my recently acquired Klipsch Belles. I keep reading about this so called "tube magic" but it's not going to work for me. Or, is it? 

Thanks for this ray of sunshine!

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51 minutes ago, Curious_George said:

If you are frugale and / or have some parts on hand, I would say $375 for a stereo unit, but this is using Edcor iron. If you can get output transformers that are cheap and perform well, then the cost could remain low(er). Cheap & good output transformers don't usually go hand in hand. $400 would probably be more realistic. 

 

Using a 6Y6G/GT you should be able to get 2.5 ~ 3 watts out @ 3~5% THD+N. That is 2A3 territory (kinda).

Yes I could have waited and still can wait on an exact price.

Just ballparking.

Also, wanted to see if price anywhere near where the other forum amp budget price started at yet kept rising out of range newbies to tubes would be tempted to try.

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There is some truth in what jimjimbo said in that one will be putting down their hard earned money for a forum member designed amplifier, built by a forum member at his home in his spare time. One should consider what he said but for the ones willing to take a risk and your taste in music and sound is what I like you might like this little amplifier.

 

So far if my math is correct I have spent $241.47 for parts with a few more parts to buy. I am going to estimate $35 more is going to be the extra cost for parts bringing the total parts cost to $276.47. I would hope anyone interested in me putting the parts together making a working amplifier will be willing to pay me $100 for this service bringing the cost to $376.47. It figures at 10 hours at $10 an hour. About what McDonalds is paying now. I would not call this fee extravagant and far less than what I made when I was working. One hundred dollars does not go far these days with eggs at almost $5 dozen where I live.  There will still be an added shipping cost to send it any one wanting to try this amplifier. This is with those Chinese OPT's which might not suit me raising the cost buying Edcors with a long waiting period to get them. OPT's are just wire wrapped around a steel core. If the wire is sufficient size for the current going to them they should not fail. That and if they are built to the correct specs. I honestly expect them to sound really good keeping the cost down but I will see. This is not a secret design and possible other members with an electronic background will build and sell one themselves making this a true forum amplifier. That is if they like the sound as much as I do. Just search on this forum for Little Sweetie for schematic. I think Maynard did an excellent job designing this amplifier from the ground up. 

 

I am only doing this fun and I have built over 30 amplifiers the last 10 years having many to compare this amplifier to. I also have 6 or 8 working receivers that I have restored and repaired. Most are the ones offered on Ebay as not working only taking my time and a few parts to get to going again. I few others are waiting for me to take on for a project along with a few I have gave to friends and kinfolks.  I am only using parts from Tubedepot and Mouser to build this amplifier. The tubes are NOS ones from Tubedepot. Not off of Ebay. I can find very little history on the 6Y6 tube only that it was built for audio many years ago. Radios of yesteryear. Obviously if Maynard used them he had them in his stash of tubes when he designed an amplifier around them. Trusted sources so I would not call the parts cheap. If no one wants it I will just add it to my collection having fun building another amplifier. I am only doing this for fun hoping others might have some fun following me along on this build. I plan on taking pictures of the progress. 

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If I am not mistaken RCA invented the 6Y6 tube. Tube Depot sells them as NOS various brands. My personal amp has RCA 6Y6 tubes. I like the nostalgia of this old tube. Probably your grandfather or great grandfather listened to a radio with a 6Y6 tube at some time in his life. From what little I have found the 6Y6 lost popularity to the 6V6 which needed less power for the filaments. The 6V6 made it cheaper to build a radio or amplifier with. 

 

Those with an electronic background of amplifier circuits know that a 2 stage SET amplifier is the easiest to build needing very few parts. This Little Sweetie has only 7 resistors and 4 capacitors in each amplification channel.  Just be careful to place them in the correct spot and you have a working amplifier stage. It has a SS rectification stage which I have come to favor over a tube one as sounding just as good. Debate on that subject I do not wish to get into here. Much like LP's vs CD's. Rectifier, 3 caps and 3 resistors in that portion of the amplifier. The most labor intensive part of building a tube amplifier like this is chassis work, drilling holes and installing the hardware. I am lucky to have a drill press making that chore easier but still work. 

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Let me be clear, I am not doing this to make money. If someone wants to try this amplifier and does not like it you can send it back to me and I will refund the price of the amplifier but not the shipping charge to or from you for lets say a week. That should be a sufficient time. I will not lose money on something that has no significant profit. I just want to contribute to this forum a project I enjoy having fun building and talking about the progress with other members. Let's keep this thread positive and have some enjoyment with it.  

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34 minutes ago, henry4841 said:

If I am not mistaken RCA invented the 6Y6 tube. Tube Depot sells them as NOS various brands. My personal amp has RCA 6Y6 tubes. I like the nostalgia of this old tube. Probably your grandfather or great grandfather listened to a radio with a 6Y6 tube at some time in his life. From what little I have found the 6Y6 lost popularity to the 6V6 which needed less power for the filaments. The 6V6 made it cheaper to build a radio or amplifier with. 

 

Those with an electronic background of amplifier circuits know that a 2 stage SET amplifier is the easiest to build needing very few parts. This Little Sweetie has only 7 resistors and 4 capacitors in each amplification channel.  Just be careful to place them in the correct spot and you have a working amplifier stage. It has a SS rectification stage which I have come to favor over a tube one as sounding just as good. Debate on that subject I do not wish to get into here. Much like LP's vs CD's. Rectifier, 3 caps and 3 resistors in that portion of the amplifier. The most labor intensive part of building a tube amplifier like this is chassis work, drilling holes and installing the hardware. I am lucky to have a drill press making that chore easier but still work. 

The 6Y6G was designed as an "Beam Tetrode". This would indicate that it was designed for audio service, but could also be used in TV sets as well for video. The 6Y6G was used in a lot of table top radios or where only a few watts were needed for audio. The 6V6 was the successor which is also a great tube for a low power SET amp.

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I got those Chinese OPT's today and I do not like what I see. Too small in my opinion to have any bass. I found some Hammond OPT's for $131 and that is what I am going to use. I want this project to sound it's best and not be low cost without having quality as well. Adding around $90 to the build but I think worth it. Hammonds known for quality built transformers so the little amplifier should sound it's best. The parts cost is now $369 and adding $100 assembling fee totals $469 plus shipping. I was really trying hard to keep the cost close to what a Chinese SET amplifier is selling for on Amazon. With the price increases this is the cheapest I see for building a decent quality amplifier. As for as $100 assembling fee, as my uncle use to say "If you don't feed your bird dog he want hunt." If no one is interested I will have me another amplifier which is alright with me. I like amplifiers. Have since I was just a kid. 

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5 minutes ago, henry4841 said:

I got those Chinese OPT's today and I do not like what I see. Too small in my opinion to have any bass. I found some Hammond OPT's for $131 and that is what I am going to use. I want this project to sound it's best and not be low cost without having quality as well. Adding around $90 to the build but I think worth it. Hammonds known for quality built transformers so the little amplifier should sound it's best. The parts cost is now $369 and adding $100 assembling fee totals $469 plus shipping. I was really trying hard to keep the cost close to what a Chinese SET amplifier is selling for on Amazon. With the price increases this is the cheapest I see for building a decent quality amplifier. As for as $100 assembling fee, as my uncle use to say "If you don't feed your bird dog he want hunt." If no one is interested I will have me another amplifier which is alright with me. I like amplifiers. Have since I was just a kid. 

I think we should encourage members to build it themselves as well. It is a simple amp and parts count is fairly low comparatively. @rmlowzhas already reached out to me to build him a Little Sweetie this fall/winter when I have time. 

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1 hour ago, henry4841 said:

I got those Chinese OPT's today and I do not like what I see. Too small in my opinion to have any bass. I found some Hammond OPT's for $131 and that is what I am going to use. I want this project to sound it's best and not be low cost without having quality as well. Adding around $90 to the build but I think worth it. Hammonds known for quality built transformers so the little amplifier should sound it's best. The parts cost is now $369 and adding $100 assembling fee totals $469 plus shipping. I was really trying hard to keep the cost close to what a Chinese SET amplifier is selling for on Amazon. With the price increases this is the cheapest I see for building a decent quality amplifier. As for as $100 assembling fee, as my uncle use to say "If you don't feed your bird dog he want hunt." If no one is interested I will have me another amplifier which is alright with me. I like amplifiers. Have since I was just a kid. 


I hate to say it, but anyone averse to paying 500.00 for a custom amp should probably take up needle point instead…

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Maybe newbies could find another forum member to build along with them so they could commiserate. Then one wouldn't feel so alone and it might provide a little incentive to plod along.  Misery loves company.  Just a thought....

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3 hours ago, Racer X said:

Maybe newbies could find another forum member to build along with them so they could commiserate. Then one wouldn't feel so alone and it might provide a little incentive to plod along.  Misery loves company.  Just a thought....

I’m only happy when it rains…

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I was very disappointed with those Chinese OPT's I bought on Amazon. I have two Chinese kit amplifiers I put together and both of them have really decent iron. These look to me like they were built to sell but not to use. I am going to use an Antek toroidal PS transformer along with the Hammond OPT's. Just the iron cost is $182 for this amplifier. Maynard, the designer, uses Hammond OPT's for his builds so I will for this build as well. He likes the sound of them. 

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1 hour ago, Edgar said:

I don't know if anyone here has tried any of these. I have a pair to use in a PP EL84 amp that I haven't built, yet, so I cannot comment about sound quality.

I have seen them on eBay, but didn't know the specs... don't look too bad. I think I'll order and pair and try them out. 

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7 hours ago, Curious_George said:

I have seen them on eBay, but didn't know the specs... don't look too bad. I think I'll order and pair and try them out. 

Good George. I would love for someone to use them and publish their findings about how they compare to Edcors. I love Edcors but hate waiting 2 months to get them. Just not a realistic shipping for those without a lot of patience. 

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