The "Ultimate Gem" SEP is here!

[CECAA850]

With a single, stereo, volume control there's no way to compensate for the usual imbalance in recordings, room acoustics, and our ears (unless the amp happens to have a balance control- a very rare presence in modern equipment).

 

And our EARS.  As we (I) age I notice that one of my ears has slightly better hearing than the other.  All my systems have either separate gain controls for either channel or a balance control.  I can move the sound stage right where I want it.

[CindyJarvis]

Thanks guys for the informative responses, it now makes complete sense.

Maynard, I see you have good 120Hz rectifier ripple smoothing! I was talking more about AC line noise. I was asking because i noticed you have a small cap from line to neautral but not line to ground and neautral to ground. We also use low pass filters in series with line and neautral. My thinking is that tube circuits arent as sensitive to noise as with most modern digital circuits. Advantage tubes so to say. I also just noticed a small cap to ground at signal input, is this for RF possibly being picked up?

-Cindy

[juniper]

 

With a single, stereo, volume control there's no way to compensate for the usual imbalance in recordings, room acoustics, and our ears (unless the amp happens to have a balance control- a very rare presence in modern equipment).

 

And our EARS.  As we (I) age I notice that one of my ears has slightly better hearing than the other.  All my systems have either separate gain controls for either channel or a balance control.  I can move the sound stage right where I want it.

 

Always a good idea to be careful with your car windows when they are open, often people have damage to one or their other ears, depending on which side of the pond you drive on.

[tube fanatic]

Thanks guys for the informative responses, it now makes complete sense.

Maynard, I see you have good 120Hz rectifier ripple smoothing! I was talking more about AC line noise. I was asking because i noticed you have a small cap from line to neautral but not line to ground and neautral to ground. We also use low pass filters in series with line and neautral. My thinking is that tube circuits arent as sensitive to noise as with most modern digital circuits. Advantage tubes so to say. I also just noticed a small cap to ground at signal input, is this for RF possibly being picked up?

-Cindy

You ask good questions Cindy!  The actual function of the suppression cap across the power xfmr primary, as I use it, is to prevent any audible pops or clicks from being reproduced by the speakers when the amp is turned on or off.  Not that they are loud, or can cause damage, but some folks simply don't like to hear anything!  Of course, it does provide some filtering of powerline grunge as a secondary benefit; but, as you stated, the ideal implementation for this would be 3 caps (for anyone who decides to do this, I advise using only Class Y caps.  Class X caps are not intended for any line to chassis connections, but rather for across the line use if preceded by a fuse).  When used this way in digital devices, the caps can also prevent "stuff" from going out into the powerline where it could cause issues in other devices.

The small cap across the input is to prevent ultrasonic garbage (often generated by digital sources to varying degrees) from getting into the amp.  I don't like anything which the amp is not intended to reproduce from coming in.  The value chosen is my personal preference based on using the 10k series pot for refinement of the amp's high frequency characteristics.  At maximum attenuation, response should be down around 12 db or so at 20 kHz.  For those who don't want to adjust the high frequency response, the 2200 pf cap can be replaced by a lower value if that results in a more pleasing sound.

Maynard

[CECAA850]

We also use low pass filters in series with line and neautral.

 

Who is we?

[CindyJarvis]

"We" was the group of engineers I worked with. I was in charge of quality control and testing of the boards.

-Cindy

Edited February 12, 2016 by CindyJarvis

[DaMuffinMan]

Maynard and anyone else who has built The Ultimate Gem, I have attached a breakdown of yhe parts needed to build it. (I think I got everything correct),

 

What I would like to know is if I have identified all of the parts correctly. If I did not let me know and I will update it or add anything that is missing. I am very close to pulling the trigger on purchasing the parts for this build and want to make sure I have them identified correctly.

Thanks

The Ultimate Jem.pdf

[tube fanatic]

Will try to review and check your parts list over the weekend.  Is Mark, the antique radio guy, going to help you with the build?  

 

Maynard

[DaMuffinMan]

Thanks Maynard. If you prefer I can give you my email or cell number.

Sent from my SM-N910T3 using Tapatalk

[tube fanatic]

Had a few moments to start looking over your list.  R3/4 need to be 10 megohms (you can use 1/4 watt if you prefer, although 1/2 watt is readily available), R5/6 should be audio taper (you can use the linear taper pots you specified, but the volume adjustment characteristics will be a bit different), R7/8 need to be 1/2 watt resistors as opposed to trimmer pots, R9/10 must be 1 watt minimum as opposed to 1/4 watt, and R11/12 need to be 1/2 watt resistors and not trimmer pots.  When you set up the search, be sure to specify through hole, axial leads, and the required wattage.  You should then see a selection from which you can make your choices.  Mouser's navigation menu can be tricky until you get the hang of it.  If Mark is available to help you with this, or generate a BOM, it will save you a lot of time.  Or if you don't mind waiting until spring, when my build/restoration season ends, I can try to do it for you then.  Please give more consideration to starting out with a kit to gain some familiarity with the various parts and components involved in doing an amp project.  I don't want you to wind up with as little hair as I have!  Will try to continue checking over the list during the weekend, and have a safe new year's eve.  

 

Maynard   

[DaMuffinMan]

Thanks for the update Maynard that helps alot. You have a happy n safe one also. HNY!

[Rjk1972]

So after going through a few tube amps and still sorting out my most recent purchase, I have come to the conclusion that I really need to become compitant at repairing, restoring, and ultimately building my own amp. 

 

So basically I am looking for some recommendations for the equipment I need, like a soldering station, multimeter and other tools and equipment and a good amp kit to start off with. I'm looking to get into doing this for the long haul. I'd also like to be able to make my own interconnects, re cap speaker crossovers and ultimately build a first class tube amp with top notch parts and iron. So I'd like start out with some decent equipment that I wouldn't need to upgrade for awhile.

 

Any and all suggestions and help would be appreciated. My speakers are a pair of 1985 Cornwall 1s. I would love to start out with one of Maynard's designs if it's possible to buy as a kit with a chassis. Are there any other popular kits here that would be a good learning experience? 

 

Thanks in advance. 

[tube fanatic]

4 hours ago, Rjk1972 said:

So after going through a few tube amps and still sorting out my most recent purchase, I have come to the conclusion that I really need to become compitant at repairing, restoring, and ultimately building my own amp. 

 

So basically I am looking for some recommendations for the equipment I need, like a soldering station, multimeter and other tools and equipment and a good amp kit to start off with. I'm looking to get into doing this for the long haul. I'd also like to be able to make my own interconnects, re cap speaker crossovers and ultimately build a first class tube amp with top notch parts and iron. So I'd like start out with some decent equipment that I wouldn't need to upgrade for awhile.

 

Any and all suggestions and help would be appreciated. My speakers are a pair of 1985 Cornwall 1s. I would love to start out with one of Maynard's designs if it's possible to buy as a kit with a chassis. Are there any other popular kits here that would be a good learning experience? 

 

Thanks in advance. 

Unfortunately, I don't have any amps available as kits.  You may want to check out the Spudkit which was featured in another thread very recently. Either that, or the Bottlehead S.E.X. amplifier.  As to setting up a basic shop, if you have the time to do some reading, log onto the American Radio History site and start reading Popular Electronics beginning with the first issue in October '54.  You will find many articles about basic electronics, testing, tools, setting up a beginner's shop, and just about anything else you would want to know. Back in the day, many newcomers to electronics learned from those magazines.  

 

http://www.americanradiohistory.com/Popular-Electronics-Guide.htm

 

Maynard

[Rjk1972]

4 hours ago, tube fanatic said:

Unfortunately, I don't have any amps available as kits.  You may want to check out the Spudkit which was featured in another thread very recently. Either that, or the Bottlehead S.E.X. amplifier.  As to setting up a basic shop, if you have the time to do some reading, log onto the American Radio History site and start reading Popular Electronics beginning with the first issue in October '54.  You will find many articles about basic electronics, testing, tools, setting up a beginner's shop, and just about anything else you would want to know. Back in the day, many newcomers to electronics learned from those magazines.  

 

http://www.americanradiohistory.com/Popular-Electronics-Guide.htm

 

Maynard

Great. Those old magazines are amazing. Lol loved the smoke alarm with vacuum tubes. 

 

Just wondering. Have you ever designed a no holds barred tube amp?

[mkane]

keeping an eye on this 

[mojomc]

6 hours ago, tube fanatic said:

As to setting up a basic shop, if you have the time to do some reading, log onto the American Radio History site and start reading Popular Electronics beginning with the first issue in October '54.  You will find many articles about basic electronics, testing, tools, setting up a beginner's shop, and just about anything else you would want to know. Back in the day, many newcomers to electronics learned from those magazines.  

 

http://www.americanradiohistory.com/Popular-Electronics-Guide.htm

 

Maynard

 

I can confirm there is a lot of information in PE. Maynard pointed me towards it a while back. Navigation takes some getting used to but is worth it. I'm taking my sweet time since it'll be a while before I do any DIY. My current residence, complete with a 3 and 6 year old and an understanding wife up until I commandeer the dining room, which is what it would take, won't allow it and I have too many other priorities right now. I'm slowly going through and learning where I can so that when the time comes, ie 'we move', I'll be ready. Hoping to see a build thread from someone. Who's it gonna be? 

 

[Rjk1972]

1 hour ago, mojomc said:

 

I can confirm there is a lot of information in PE. Maynard pointed me towards it a while back. Navigation takes some getting used to but is worth it. I'm taking my sweet time since it'll be a while before I do any DIY. My current residence, complete with a 3 and 6 year old and an understanding wife up until I commandeer the dining room, which is what it would take, won't allow it and I have too many other priorities right now. I'm slowly going through and learning where I can so that when the time comes, ie 'we move', I'll be ready. Hoping to see a build thread from someone. Who's it gonna be? 

 

I feel your pain. It took awhile to find a spot to set up. Luckily I have a patio room that come the end of March will be getting a work bench to go in front of a large screened window with a fan in it doing exhaust duties. As for a build. Well I spent a few hours yesterday and today watching some pretty cool soldering videos on YouTube and in one of them the guy was demonstrating how to solder and desolder resistors and caps on the circuit boards. So now I am in possession of three decent boards with a dozen and a half components to desolder and solder. Right now I'm looking for a soldering station and the tools I'll need and a good multimeter and of course doing a lot of reading. Also just sent an email to the guy behind the Spudkit. So hopefully I'll have everything I need and be practiced enough to to start the build in March. Then if all goes well I'd like to move on to the amp in this thread. Maybe with some uprated transformers. Then do a good rebuild on a Fisher x100 I have. Should be a fun year.

[davesans]

18 hours ago, tube fanatic said:

Unfortunately, I don't have any amps available as kits.  You may want to check out the Spudkit which was featured in another thread very recently. Either that, or the Bottlehead S.E.X. amplifier.  As to setting up a basic shop, if you have the time to do some reading, log onto the American Radio History site and start reading Popular Electronics beginning with the first issue in October '54.  You will find many articles about basic electronics, testing, tools, setting up a beginner's shop, and just about anything else you would want to know. Back in the day, many newcomers to electronics learned from those magazines.  

 

http://www.americanradiohistory.com/Popular-Electronics-Guide.htm

 

Maynard

 

Thanks for the link Maynard I will defiantly be reading through those myself I still have a lot to learn. 

[Pdlu]

This interesting thread has been sitting idle for three years too long!   Yesterday I ordered parts for the "Ultimate Gem" from Mouser... hopefully I didn't miss anything and will not need to re-order.  This should be fun!  ...Will be ordering tubes and sockets this week.  

 

Pete

[tube fanatic]

Good news Pete!  You won't be disappointed with this amp (in my opinion of course!).  Don't hesitate to post, or PM, any questions.  Use the photos as a guide for the layout.  What speakers will you be using it with?

 

Maynard