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henry4841

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I've decided to let the aluminum show on my amplifier. I am going to spray some clear enamel over the tops of the plates though for protection.  Enamel paint sticks like glue and if I clean the panels well the enamel paint should stay on a long time. I really do not even want to sand them for better adhesion. I would not even spray enamel on the chassis if it were for my own use. What does it matter if it shows a smudge or stain later. That is what aluminum does. The Biltmore house in No Carolina has a copper roof that stains and streaks like crazy. Many consider the look eloquent.

I like the bare aluminum look over being painted. I want this amplifier to look like it belongs in a man cave and not in a ladies parlor. Look and feel like it was built like a tank. An instrument not looking too elegant but look more like a tool to produce music. 

Buying one of those ready to cut holes in cases on Ebay is a real temptation to get out of all the work I am doing on this chassis but I like working with my hands. There is pleasure to be enjoyed cutting dovetails by hand joining two pieces of fine hardwood together. It is a woodworkers kind of thing. A large majority of the furniture in my house was built by me over 20 years ago. When my ex left she took most everything with her so I had to get my furniture stick by stick. That is the way country boys describe getting furniture. If I were just starting to build tube amplifiers, and wanted to build one that looked good, I would probably go for the one above on Ebay. When first starting to build I was in a hurry to see if I could do it. Now after building 15 or so I just like enjoying the process. Taking my time enjoying every stage. Work an hour of two in the morning then quit and do something else or nothing at all. I am almost positive I could sell a chassis like this on Etsy for $300 real easy. There is a demand for hand built articles on Etsy. Years ago I sold some different kind of things in a store I had on Etsy. Sold really well as fast as I could make them. Nothing to do with audio amplifiers or speakers. 

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5 hours ago, henry4841 said:

How much does Front Panel Express charge for their services Seti?

 

 

I'm working on a piece for the museum. For a 12x17 large front panel with lots of features $125. Then another 14x17 with a ton of holes and engraving with infill around $145.

The size you have would be much less and once you have a parts list it is easier.

 

 

 

 

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On 9/3/2022 at 6:42 PM, captainbeefheart said:

 

Yes it's a good idea to use a metal primer with Aluminum.

 

I scuff the aluminum and then chemical clean it. A couple coats of metal primer and then you're ready to use the regular paints.

 

Thank for asking, I kinda expect that to be obvious part of the metal preparation process but many people that don't paint things might not know it.

 

Honestly for indoor usage like an amp as long as you scuff the Aluminum and clean it good enough I doubt there would be concerns, even in the long term because it's not a car or something marine outside and exposed to water and moisture regularly. Of course it's just worth the extra time to properly prep metal, which includes primer.

For aluminum, you want to use an acid etch primer. Regular primer will not adhere to the aluminum properly. 

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Forgot to drill some vent holes in the main plate. This little amplifier runs really cool for a tube amplifier with most of the heat is coming from the top mounted tubes but those voltage reducing power resistors do generate some heat doing their job. Not a worrisome amount but some heat. I will drill those vent holes first thing this morning.  

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Guys I appreciate each and everyone of ya'll that gave their opinion on how to finish the aluminum on this build and I gave some thought to each and every one of them. But this is the great thing about building your own amplifier, you can make it look exactly like you like. I am building this amplifier like I am building it for myself and the look I have chosen is what I like. If  decided to sell it after finishing it I guess I will just have to try to find someone that likes the look I like or I will just keep it for myself. This is the first for me on a couple of levels. This is the first tube amplifier I have built as mono's and the first with premium parts. There is a strong temptation for me to keep it but Lord knows I do not need another tube amplifier. Or the trouble it is building one this way, for looks as well as for sound. If I decide to sell it and no one else likes the look I will be perfectly happy keeping it for myself. I am not rich by no means of the imagination but nor am I broke. Always, like most everyone else, could use some extra money but I get by within my budget. For the time being that is. No one knows what is around the corner. 

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49 minutes ago, KT88 said:

 

Henry, it sounds like a very fantastic project to me. I don't like to interfere, the components are your choice and your decision. But I would be very interested in your opinion and listening impression on your choice of 0.5 watt resistors (in the signal path or from signal to ground). I came up with this because a few weeks ago I had installed new resistors in a transistor preamp, Quad 34, at the output, the voltage divider. I wanted to increase the output voltage according to the manual, but for other reasons I went back to the original values. Unfortunately the brittle leads of the resistors broke and I needed a replacement. The pre amp is 35 years old and uses brown carbon film resistors. I had also bought Vishay metal film for the two lst Rs in the circuit, but I like the sound of carbon film better. For example, Mouser has these carbon film types from KOA, 0.25 or 0.5 watts.

 

https://www.mouser.de/ProductDetail/KOA-Speer/CF1-4CR50J?qs=JFoMzux4TxpPn4ppyPaeyg%3D%3D

 

I would be very interested to hear how your amp sounds with different types of resistors e.g. Vishay vs. KOA. But really don't bother if you are convinced of your choice. I didn't want to complain and just make a suggestion because you are in the building phase anyway.

 

Some very good points. I have talked to Maynard about the subject of carbon film vs mf resistors years ago and he just said no difference in his opinion. I built one tube amp with carbon resistors just to see for myself. I could really not tell any significant difference. The only way to run a real test is to build two identical amps, one with carbon and the other with mf and then compare the sound with some significant time listening to both of them with the same source of music. Personally I think either way will sound just fine. The one advantage of mf is they do not drift from stated ohms over time like a carbon resistor does. But an amp such as this one is real tolerate of drifting value parts. Nor does carbon have some other properties not wanted as does mf, inductance, reactance etc. You can make a carbon resistor at home with just a lead pencil and a piece of paper. Scratch yourself a good thick line of lead pencil on a piece of paper and then measure with an ohmmeter to verify yourself. I have done it. 

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Did a little this morning, very little but necessary. Drilled the ventilation holes and lightly sanded the enamel clear and put another coat of enamel on the top plate. Attached the small plates to have a look. I like the look I have achieved. Just what I imagined and was going for. This is what diy is all about. More so in a tube amplifier than a SS one. Took my own personality and put it in a tube chassis. This is the look I was after. A serious looking no frill amplifier. 

 

 

 

 

P1040057.JPG

 

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27 minutes ago, jjptkd said:

Looking sweet man! 

Many thanks, I like the look and yes the metal plates have some scratches as if it were a piece of old equipment. I like that kind of look myself. Certainly not a pretty vase in the wife's parlor but more for a mans room. Serious looking. I could have sanded the aluminum down and applied a pretty colored paint and made it glass smooth. Did as much with custom car work in the past but that is just not me at this stage in my life. I like this look. There is something called surface primer that fills in surface imperfections in the metal of cars. Works real well for minor imperfections. This is pretty solid wood hand built with hand cut dovetails and heavy solid aluminum plate not covered over with pretty paint. I am satisfied with how the chassis turned out. Pleases me. What do you guys think? Lurkers that never post as well. 

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Guys I want to thank ya'll for your input on this chassis build. I still like the way it turned out. It is me and my personality. I did listen and sprayed a coat of clear enamel on the aluminum for protection against stains. Something I have not and would not do for a amplifier I was building solely for myself. Wood and bare aluminum look is what I like. Nothing frilly about the look of this amplifier. Now I will see if I can still build an amplifier to go along with this case. At least I did last month. At 73 one never really knows what the day may bring.   

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32 minutes ago, tube fanatic said:

Well, Henry, your chassis work sure puts mine to shame!  Keep up the beautiful work.

 

Maynard

I am proud you like it Maynard. You builds though always look better than mine on the inside. If we can talk Maynard into building a Sweetie someone will have a excellent amplifier they can be proud of for many years. I have been twisting his arm a little bit. 

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I decided to stop right here for now and order some black screws to hold the parts underneath the top plate instead of the shiny ones I started using. I think it will more attractive that way. Ordered on Amazon expected Sunday with Prime. Be just in time to start again Monday morning. 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.  

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