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 Post subject: First tube amp
PostPosted: January 23rd, 2015, 8:31 am 
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Joined: July 3rd, 2014, 7:47 am
Posts: 89
I am in the consideration stages of trying a tube amp. In making my decision I am thinking about a lot of different things. I am listing my biggest concerns and goals for the project to see peoples opinions, feasibility etc. Hopefully it will be a fun project for me, I will learn alot, and get to listen to some speakers that I will need to build lol.

1. I want to assemble it. I am more than fine with a kit, and don't really care if it comes from China. My soldering skills are pretty decent so I think I can handle this.

2. The transformer aspect worries me. Have heard of people getting nastily shocked.

3. Would like it to be stereo, have volume control.

4. Cost- I would really like to keep the cost to a bare minimum. This is for me to get my feet wet, so while I may be able to do this or that better for another 100 dollars, I would like to avoid those tangents. I understand there will have to be trade-offs to accomplish this goal at a low cost, but that's just part of my process. Honestly I would like to have the entire thing built for less than 250.00. This would not include the chassis, finishing etc.

5. Power output I would like would be 5 watts or so, maybe 8 watts.

6. Would like to build a kit that has great documentation so I can really follow it step by step. I have seen quite a few times where an obscure design is amazing, but the lack of documentation or readily available parts stalls things.

What does everyone think? Are my goals achievable? Any obvious problems with my ideas?

Thanks

Jeff


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 Post subject: Re: First tube amp
PostPosted: January 23rd, 2015, 10:32 am 
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Joined: February 28th, 2013, 10:38 am
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This is about the only thing I could find that comes close to your requirements: http://www.ebay.com/itm/6L6-SE-Valve-Tu ... 4ac8d4505b

By the time you add power & output transformers and a volume pot, you'll probably be in the $250-275 range.... No idea how it sounds....

Of course, one of us could whip up a design you could build, but then you'd have to source all the parts yourself, which can be a pain in the butt....

Roscoe

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 Post subject: Re: First tube amp
PostPosted: January 23rd, 2015, 10:42 am 
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Joined: January 14th, 2015, 11:15 pm
Posts: 499
Since I mostly build inexpensive amps, I may be of help to you.

1 - Building a kit is a very good way for a beginner to start. A good kit will have a good design that is known to work well and be safe. Along the way you will learn important lessons on how to lay out the various parts. Also worth considering is the support you will receive if you run into problems.

The Bottlehead company http://bottlehead.com/bottlehead-products/ based near Seattle is renowned as a producer of good kit amps. They are worth checking out, both the kits and also their forum http://www.bottlehead.com/smf/ which is a great source of support if you run into problems. I got into this hobby by building a Foreplay line stage many years ago. Unfortunately their amps are more expensive than your $250 limit but remember you are paying for a learning experience.

2 - There is a lot of advice out there for working safely with the high voltage of tube amps. This article http://tubelab.com/safety/electrical-safety/ from the Tubelab website is very useful. I have been using his idea of using several cheap digital multimeters from Harbor Freight for many years. Even so, I still get sweaty armpits when I fire up a new amp for the first time.

3 - should not be a problem with an inexpensive amp.

4 - Building a low powered amp for less than $250 can be done. Go to this link http://bottlenecksaudio.blogspot.com/2012/02/6v6-competition.html and scroll down to photos of a 6V6 competition held a few years back at Sterling VA a few years back where the amps had to cost less than $200 and the cases had to come from Ikea. The winning entry actually cost less than $150. Most builders had trouble staying below $200. Since you have no building experience, you are not going to be able to build any of these without help.

5 - Your power output needs will depend on the efficiency of your speakers and room size. To get an idea of power requirements, read this post by Paul Joppa http://www.audioasylum.com/scripts/d.pl?audio/faq/sets.html. Paul is the principal designer of the Bottlehead kits.

6 - It really helps to have help on your first build. Depending on where you live, you might be able to find somebody local who might be able to help you.

Finally, the initial cost of entry into this DIY hobby might be low, but it can become much more expensive if you really get into it. But it is fun and there is nothing like listening to an amplifier that you built.

ray


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 Post subject: Re: First tube amp
PostPosted: January 23rd, 2015, 4:58 pm 
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Joined: July 3rd, 2014, 7:47 am
Posts: 89
Has anyone had any experiences with this company? In my research I kept finding an amp called "el Cheapo" and another called SE. Neither seem to be available anymore as kits, but this company was apparently involved in el cheapo. Barely over my initial budget, but seems like it comes with everything except the case.

http://s5electronics.com/l16stereo.html

Should I be looking for a specific style? Push/Pull, Single End, Triode, etc. From what I have read pp amps will be out of my budget.


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 Post subject: Re: First tube amp
PostPosted: January 23rd, 2015, 5:25 pm 
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Joined: March 12th, 2013, 11:12 am
Posts: 738
The type of amp you should build will depend in large part on the efficiency and load of your speakers. The first amp I actually built from scratch was a simple 2 stage(12AX7>EL84), cap coupled stereo amp with a volume pot using old console OT, PT and chassis. It cost me virtually nothing (got the console amp for next to nothing and had most of the parts sitting around) until the PT fried itself and I purchased a Hammond PT to replace it. Sound is pretty bad and the PS is bare bones which results in some noise on my 100db efficient horns. But I did learn how to calculate load lines and other basic design considerations.

My recommendation is to hard wire your project and stay away from boards. You WILL want to modify the PS and signal path and a cheap circuit board will be a pain in the ass. Hard wiring your project will allow you to switch components, change design, reuse parts etc.




JDCrae wrote:
Has anyone had any experiences with this company? In my research I kept finding an amp called "el Cheapo" and another called SE. Neither seem to be available anymore as kits, but this company was apparently involved in el cheapo. Barely over my initial budget, but seems like it comes with everything except the case.

http://s5electronics.com/l16stereo.html

Should I be looking for a specific style? Push/Pull, Single End, Triode, etc. From what I have read pp amps will be out of my budget.


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 Post subject: Re: First tube amp
PostPosted: January 24th, 2015, 11:55 am 
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Joined: March 12th, 2013, 1:49 pm
Posts: 214
JDCrae wrote:
Has anyone had any experiences with this company? In my research I kept finding an amp called "el Cheapo" and another called SE. Neither seem to be available anymore as kits, but this company was apparently involved in el cheapo. Barely over my initial budget, but seems like it comes with everything except the case.

http://s5electronics.com/l16stereo.html

Should I be looking for a specific style? Push/Pull, Single End, Triode, etc. From what I have read pp amps will be out of my budget.


the el cheapo has been discussed many times on AA, from what I have heard its supposed to be a killer little amp, I believe that Eli Duttman had something to do with it. You can get the schematic and do a p-p scatter project, but being new I would just go for the board and eliminate the probabilities of miswiring, especially for someone new at this. Go on AA and research it, a lot of good and knowledgeable folks there.

I just picked this little jewel up for $300, working, probably right up your alley...


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 Post subject: Re: First tube amp
PostPosted: January 24th, 2015, 5:30 pm 
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JDCrae wrote:
From what I have read pp amps will be out of my budget.


I dunno why. Yeah, you need twice as many output tubes, but you can save quite a bit on the PS and the output transformers compared to single-ended, so it oughta be a wash...

Roscoe

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 Post subject: Re: First tube amp
PostPosted: January 24th, 2015, 5:36 pm 
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Joined: December 14th, 2013, 2:19 pm
Posts: 948
How about Pete Millett's Engineers. amp? Its an amp on one $50 Red PCB. Very versatile and future upgradeable. Tubes will be a big part of your expenses and this amp uses very cheap TV tubes. Originally. Desigbed for 30WPC, can be less or over 150Wpc. Read about it on diyaudio.


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 Post subject: Re: First tube amp
PostPosted: January 24th, 2015, 7:09 pm 
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Joined: April 22nd, 2013, 12:58 pm
Posts: 285
For a first amp, I think the 6B4G P-P amp on Pete's page is a better bet. Point-to-point, a lot less parts, and limited contribution from silicon parts.
http://www.pmillett.com/6B4G_push-pull_amp.htm

If lower power is acceptable, and a good headphone amp is in your future, the Jonokuchi is even simpler and cheaper. Easier to build with the PCB,, if you are planning to leave it alone after you build it. Most of us can't, which is why TubeDriver advised sticking with point-to-point.
http://www.pmillett.com/Jonokuchi.htm

FWIW, my philosophy is, "There is no BEST first amp. There is only YOUR first amp."
http://lesswrong.com/lw/53e/just_try_it_quantity_trumps_quality/

Stuart Polansky wrote:
How about Pete Millett's Engineers. amp? Its an amp on one $50 Red PCB. Very versatile and future upgradeable. Tubes will be a big part of your expenses and this amp uses very cheap TV tubes. Originally. Desigbed for 30WPC, can be less or over 150Wpc. Read about it on diyaudio.


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 Post subject: Re: First tube amp
PostPosted: January 24th, 2015, 10:16 pm 
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Joined: July 3rd, 2014, 7:47 am
Posts: 89
randy warren wrote:
JDCrae wrote:
Has anyone had any experiences with this company? In my research I kept finding an amp called "el Cheapo" and another called SE. Neither seem to be available anymore as kits, but this company was apparently involved in el cheapo. Barely over my initial budget, but seems like it comes with everything except the case.

http://s5electronics.com/l16stereo.html

Should I be looking for a specific style? Push/Pull, Single End, Triode, etc. From what I have read pp amps will be out of my budget.


the el cheapo has been discussed many times on AA, from what I have heard its supposed to be a killer little amp, I believe that Eli Duttman had something to do with it. You can get the schematic and do a p-p scatter project, but being new I would just go for the board and eliminate the probabilities of miswiring, especially for someone new at this. Go on AA and research it, a lot of good and knowledgeable folks there.

I just picked this little jewel up for $300, working, probably right up your alley...


That's a really cool looking amp. Where did you pick that up?



"How about Pete Millett's Engineers. amp? Its an amp on one $50 Red PCB. Very versatile and future upgradeable. Tubes will be a big part of your expenses and this amp uses very cheap TV tubes. Originally. Desigbed for 30WPC, can be less or over 150Wpc. Read about it on diyaudio."

I looked at that one, very promising. It's a bit over my budget, but perhaps I need to expand that. Something to think about definitely.


"I dunno why. Yeah, you need twice as many output tubes, but you can save quite a bit on the PS and the output transformers compared to single-ended, so it oughta be a wash...

Roscoe"

In reading a bunch of sites regarding first time diy tube amps, that seemed to be a common thought. Could be completely wrong, I simply assumed based on the number of times I read it.


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