AudioNervosa

Self Medicating => General DIY => Topic started by: seadogs on December 11, 2014, 10:46:31 AM

Title: DIY 2A3 or 300b kit
Post by: seadogs on December 11, 2014, 10:46:31 AM
Hi, all

I am looking to build my own 2A3 or 300b Mono block amps, and matching tube pre-amp and need advise.  It is my first venture into amp building.  Can, i buy a complete kit or is it better/ cheaper to buy it all individual. read something about the Moondog 2A3 Monoblock Amplifiers and  Laurel II 300B Monoblock Amplifiers     any advise will be greatly appreciated, thanks   
Title: Re: DIY 2A3 or 300b kit
Post by: Brap on December 11, 2014, 11:31:33 AM
You may want to check out Transcendent Audio. I built the SOB kit and am contemplating their Masterpiece Pre-amp. They have a great forum too.  The SOB OTL amp rocks big time with efficient speakers.
Title: Re: DIY 2A3 or 300b kit
Post by: BobM on December 11, 2014, 11:32:24 AM
The adventure of building something yourself is always a great one. You will likely learn a lot. Just be careful, make sure your solder joins are good, test along the way, power it up slowly with a varistor.

Basically, a decent kit will also have decent instructions. Read a few on-line articles on DIY tube amp building before you start to see what you are up against. Tube amps have high voltage, and can be dangerous. Can't emphasize that enough. But to me, DIY is a whole 'nother end to this hobby that many people don't explore, and it can be very rewarding.


Title: Re: DIY 2A3 or 300b kit
Post by: shadowlight on December 11, 2014, 01:35:35 PM
Once I get comfortable in reading schematics and working with tubes.  I plan to build 6CB5A based amp based on Thomas Mayer.  Link to articles on where he lays out everything and does a pretty good job of explaining.

http://www.diyaudio.com/forums/tubes-valves/235980-schematic-learn.html#post3490993
Title: Re: DIY 2A3 or 300b kit
Post by: richidoo on December 11, 2014, 04:35:18 PM
Welcome to AudioNervosa seadogs!!

Since it is your first amp project, I would strongly recommend to buy a complete kit with all parts included, and which also provides good tech support. When you make a goof you will be very glad you picked a kit with good support.

Welborne Labs doesn't make the Moondog kit anymore. I don't see any kits for sale there, only assembly manuals. Do they still sell kits?

TubeLab offers proven designs as PCB only. http://tubelab.com/

Tubedepot imports tube amp kits: https://www.tubedepot.com/t/diy-central/kits-tube-amp/hifi-tube-amp-kits

Oddwatt: http://www.oddwattaudio.com/

Bottlehead: http://bottlehead.com/

Transcendent Sound: http://www.transcendentsound.com/

Vacuum Tube Audio: http://www.tubes4hifi.com/

Triode Electronics: http://www.triodeelectronics.com/hifikits.html


For preamp, most of the above offer preamps also, but one brand offers excellent preamp kits but no amps.  Glassware Audio: http://glass-ware.stores.yahoo.net/index.html

Look at their Aikido preamp kits. They are well loved among the DIy community, many MANY have been built successfully and they sound very good.
Title: Re: DIY 2A3 or 300b kit
Post by: sleepyguy24 on December 11, 2014, 05:18:54 PM
I would give Bottlehead a try. I'm happy with their BeePre 300B preamp.

This is their amplifier kits.

http://bottlehead.com/product/paramount-v1-1-300b2a3-monoblocks-pair-kit/

Good luck and welcome.
Title: Re: DIY 2A3 or 300b kit
Post by: seadogs on December 12, 2014, 05:44:01 AM
WoW   Thanks guys for the input, I will go thru all the links and take a look at them.  Just wondering how i know what is good/great parts or just crap.  Should i look at other well known amp manf  and see what parts they use, and adjust accordingly  thnaks for your help and will keep you posted :-)
Title: Re: DIY 2A3 or 300b kit
Post by: tmazz on December 12, 2014, 07:49:21 AM
Welcome aboard seadogs! Good luck on your adventure. The first amp I bought when I started to dbble in high end audio was a Hafler DH-220 that I built from a kit. It was a fun thing and I have been actually beeen thinging abouttrying my hand at building a tube amp in the near futre (although I would need more power than a 300B set am can provide. There are a few guys out there selling kit based on old Dynaco designs that looked like they could be fun to play with.)

BTW - what kind of speakers areyou going to drive with this the 300B amp?
Title: Re: DIY 2A3 or 300b kit
Post by: richidoo on December 12, 2014, 09:44:26 AM
WoW   Thanks guys for the input, I will go thru all the links and take a look at them.  Just wondering how i know what is good/great parts or just crap.  Should i look at other well known amp manf  and see what parts they use, and adjust accordingly  thnaks for your help and will keep you posted :-)

Tube amps use expensive parts, so a kit with good quality parts will not be the cheapest choice, but it will be better designed and will sound better. The output transformer is the most expensive part. Big size makes it better, which means more iron and copper and thus more shipping weight. Transformers tend to be shortchanged in kits and low cost tube amps. As a DIYer you kinda have to use your faith, research and instinct to fess out a project before you commit. Read about the kit, other builders' experiences, preferably there is a builders' support forum. Search diyaudio.com for threads pertaining to your kit. Google the kit and the seller for dirt. In the end it's a leap of faith to do a DIY. even if the kit is quality and builders are happy, and you build it perfectly, it may not gel with your speakers.

Tom's question about your speakers is the most important one of all. 2A3 makes 3W? 300B makes 8W. Your speakers should be high efficiency types, with 95+ sensitivity for the 300B and 100dB sensitivity for a 2A3 in order to play music loud enough to get you moving.   :dj:
Title: Re: DIY 2A3 or 300b kit
Post by: tmazz on December 12, 2014, 12:09:36 PM
And of course any time you are dealing with their flea size output wattages typical of SET amps noise becomes a huge factor. Given the hyper efficient speaker designs that you need to use a SET even the slightest amount of noise will become instantly audible, and annoying.Think about is, with my big Thiel 6.0s and the 200 watt Audio Research amp if I had 2 or 3 mW of noise it was not that big of a deal compared tot the wattage being used to drive the speaker. However: if that same 203 mW of noise is present in an amp they only puts out 2 or 3 watts total, it quickly becomes very significant in comparison to the signal. (Just do the math and figure out what the acoustic outputs of 104 db and 87 db efficient speakers are and you will see what I mean.)

So not only do you need a well designed amp but you must be very careful in terms of wire routing and soldering when you assemble it. It is not easy to get right. There is a reason why those flea wattage SETs cost as much as they do.

That said, this doesn't mean it can't be done, just that you really need to take your time and pay extra attention to detail when you do it.
Title: Re: DIY 2A3 or 300b kit
Post by: richidoo on December 12, 2014, 12:23:17 PM
Another great point Tom.

The kind of details Tom is talking about are the reason why a beginner should use a well designed kit for the first build. Hopefully a wise and experienced engineer thought through all those subtle points and then engineered them into the kit.
Title: Re: DIY 2A3 or 300b kit
Post by: hogg on December 12, 2014, 07:39:12 PM
Here's another 300B kit that permits different power tube rolling.

http://www.vkmusic.ca/elekitnew.htm (http://www.vkmusic.ca/elekitnew.htm)


                                               Jim
Title: Re: DIY 2A3 or 300b kit
Post by: seadogs on December 15, 2014, 07:10:35 AM
Hi all

  I went thru all the amp kit website and some better than others and i came across this when i was looking at the 2A3 amps.
 http://www.finaleaudio.com/300b-set-mono-blocks-kit/ and have talked with the sale rep, and i am very impressed,  They are not pushy and he seems like he wants to  inform me, and make sure im getting the right match with my speakers and listening habbits over just selling me an amp/integrated.   Two thumbs up Finale/Triode Labs
 My speakers are Zu's  101 dB's   I will let everyone know if i go with the Mono's Kits or just buy the Mono's 2A3's   
Title: Re: DIY 2A3 or 300b kit
Post by: Response Audio on December 15, 2014, 08:18:23 AM
You may also want to look at Audio Note Kits. They have a few really good 2A3/300B kits available as well as preamps.

I have built dozens of these for customers and they are very nice for the money. You can always upgrade components later if (actually 'when') the urge gets ahold of you.

The manuals are very friendly to even the first time builder.

Just throwing another option on the table for you.
Title: Re: DIY 2A3 or 300b kit
Post by: shadowlight on December 15, 2014, 10:11:12 AM
Hi all

  I went thru all the amp kit website and some better than others and i came across this when i was looking at the 2A3 amps.
 http://www.finaleaudio.com/300b-set-mono-blocks-kit/ and have talked with the sale rep, and i am very impressed,  They are not pushy and he seems like he wants to  inform me, and make sure im getting the right match with my speakers and listening habbits over just selling me an amp/integrated.   Two thumbs up Finale/Triode Labs
 My speakers are Zu's  101 dB's   I will let everyone know if i go with the Mono's Kits or just buy the Mono's 2A3's   

Frank @ Triode Labs / Finale is easy to deal with.  He answered endless questions when I purchase the 2a3 amp.
Title: Re: DIY 2A3 or 300b kit
Post by: tmazz on December 15, 2014, 11:18:38 AM
You can always upgrade components later if (actually 'when') the urge gets ahold of you.


Bill you know us too well.  :rofl:
Title: Re: DIY 2A3 or 300b kit
Post by: Brap on December 16, 2014, 11:16:25 AM
Seadogs - I too have (will get them tonight) Zu's -- Druid version (101dB) and will be auditioning 3 different tube amps.  Prior speakers are Klipsch Fortes 98dB.  FYI - have been building kits for many years so I fully understand the complexity of tight tolerance components and solder technique.

1) Older 2A3 PP I build in 2005 from DIF Hi-Fi Supply. It is the Joplin amp with Alps volume option. Rigged it with Mundorf coupling caps. Roughly 9 watts.  2A3 not the best sounding tube and there was a bit of clipping at higher volumes.
2) Bob Latino ST-70 from tubesforhi-fi. VERY nice kit and easy to build. Also did Mundorf's. Wired for Pentode and Triode. 35w and 18W. Pretty much quiet unless I place my ear right up to the horn.
3) Transcendent Audio Son of Beast OTL.  Approx 20W with the Druids, 15 with the Fortes. DEAD quiet.  A bit more complex kit to build but I am hoping this will be the flavor of choice.  GREAT low end for an OTL amp.

All will be passed through a Parasound Halo P5 Oppo 105 source and vinyl.  I will try and post a decent review for all the above with the Druids after the Holidays.
Title: Re: DIY 2A3 or 300b kit
Post by: seadogs on December 17, 2014, 11:41:13 AM
Brap,

    Please keep informed on how the Druid's auditioning goes,  I think the druid's and essence's are close in sound.  I have the upgraded kits as well, so im at 101dB's  thanks
Title: Re: DIY 2A3 or 300b kit
Post by: Brap on December 17, 2014, 11:43:37 AM
Yes........................................... aa
Title: Re: DIY 2A3 or 300b kit
Post by: seadogs on December 17, 2014, 11:48:09 AM
The 2A3 is a PP or S.E.T?  an SET would have a more polished overall sound  VS the PP   yes?
Title: Re: DIY 2A3 or 300b kit
Post by: Brap on December 17, 2014, 11:52:13 AM
2A3 is PP and yes the SET is better sounding IMHO with Klipsch Fortes.  To the point I probably will not even try the 2A3 with my new babies (Druids  :yay2:).  I'll save the 2A3 for the Paradigm Studio V10's as a decent small system.  However, if you are local (Chgo) and are interested I would part with the 2A3 for a reasonable price :thumb:
Title: Re: DIY 2A3 or 300b kit
Post by: richidoo on December 19, 2014, 11:24:06 AM
Here's another 300B for you to consider, seadog. "Damn Good 300B," by Tom Christiansen, neurochrome.com.  I'm putting this one on my toodoo list. 
10Wpc, 6922 input and driver, solid design by professional engineer employed as analog audio design engineer at TI, PCBs and support available.

Homepage:
http://www.neurochrome.com/audio/?page_id=543

Development thread:
http://www.diyaudio.com/forums/tubes-valves/218217-deathtrap400-pretty-damn-good-300b-amp.html
Title: Re: DIY 2A3 or 300b kit
Post by: Triode Pete on December 19, 2014, 11:59:27 AM
I personally would not get any 2A3 or 300B SET that has circuit boards, especially with the tube sockets soldered onto a PCB... that's just looking for trouble...

I would find a real nice "point to point" wired design, since most SET's are relatively simple (remember the "KISS" principle; it really holds true here).

Also, don't get a cheap power supply, invest the money in the power supply, the more & bigger trannies (chokes, OPT's, filament, etc.) the better...

My $0.02,
Pete
Title: Re: DIY 2A3 or 300b kit
Post by: Response Audio on December 21, 2014, 06:23:21 PM
I am curious how hard they are running the 300Bs to get 10 watts with a 5k primary output transformer.As Pete mentioned, SET amps are relatively simple in regards to parts count so a hardwired setup would be recommended. Output transformers are crutial so dont skimp here. Same for the power supply.

Doing things right the first time around will make your life a lot easier when you are ready for a more complex design.