I am new to your group and I don't know why I'm here, I do not belong in an asylum (don't ask my wife). I am contemplating making a DIY amp (Don't ask me why, I just am) to go with the Rhythm speakers (North Creek) I made 4 years ago. The speaker is very similiar to Lynn Olson's Ariel project but with more bass (this whole thing started after innocently reading his articles - http://www.aloha-audio.com/Ariel.html ) and is rated at approximately 89 dB. I started out by buying a Chinese EL34 integrated amp which actually sounds pretty good to me (the company is out of business). I recently bought a Dynaco ST 70 which is also alright but I know the sound can be improved for a more -you are there- sound. I am waiting to receive a HK Citation V to try because I wanted to avoid the time "wasted" to make a DIY amp, I have a family to attend to.

I have been following Lynn Olson's Amity amp project and I know I will eventually be compelled to make an amp using the 300B. A 300B SET will give 9 watts and I will be using the system in a 300 sq ft room. The Amity uses 2 300B's in a PP cofiguration with an interstage and choke for a very linear gridline and Class A operation. It's best to see his website at- http://www.aloha-audio.com/triode1.html . I added up the costs and the parts will be approximately $2000 not including the hospital bill (I know since I tried to "fix" my parents Zenith tube TV when I was a kid; I was "shocked" to learn how much voltage can build up in an unplugged appliance- don't worry, no permanent damage, again, don't ask my wife.)

The questions I have are:

1) Has anyone build the Amity/Raven or Aurora amp and how does it sound?
2) Will a SET+DHT+tube rectifier+choke sound just as good or better for half the price? Something like the "Billie" http://www.diyhifisupply.com/page/m500.htm . Is 9 watts enough vs. 18 for the Amity?
3) Do I belong in this asylum.

Any input will be greatly appreciated.

Sincerely,

Vince Tso

• Amity website

 Re: Amity PP 300B vs. SET - nl 04:29:33 11/01/01 (1)
 Check out Susumu Sakuma - nl 04:34:24 11/01/01 (0)
 Re: Amity PP 300B vs. SET - Walter Mitty 10:12:46 10/29/01 (0)

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 Re: Amity PP 300B vs. SET - nl 04:29:33 11/01/01 (1)
 Check out Susumu Sakuma - nl 04:34:24 11/01/01 (0)
 Re: Amity PP 300B vs. SET - Walter Mitty 10:12:46 10/29/01 (0)
 Re: Amity PP 300B vs. SET - Anand 07:18:51 10/29/01 (4)
 Re: Amity PP 300B vs. SET - tsotjbn 00:23:45 10/30/01 (2)
 BTW, your speakers look GORGEOUS (nt). - Anand 07:40:48 10/30/01 (0)
 Re: Amity PP 300B vs. SET - Anand 07:37:37 10/30/01 (0)
 And don't forget Allen Wrights fully differential amp kits, www.vacuumstate.com - Anand 07:45:16 10/29/01 (0)
 Re: Amity PP 300B vs. SET - Scholl 06:21:36 10/29/01 (0)
 Re: Amity PP 300B vs. SET - David McGown 19:14:59 10/28/01 (0)

That being said, and given your novice status with regard to DIY tube construction, I would really recommend either a kit, or working a bit with your current stable of EL34 amps, just to get the hang of working with tube circuits. One thing you may want to try is a triode conversion of the output stage, and experiment with different driver stages, parts, and power supply tweaks. Building an amp from scratch, particularily a more complicated design, may be moving too quickly. There is alot to learn, about soldering, parts selection, component layout, etc. After that, it is hard to beat building a SET amp (probably a 300B amp given your speakers, don't even think about an 845) as a first scratch project. Getting that together and working well will teach you alot, and will give you the confidence to plan and complete a more complicated design. The old adage, "you must walk before you run" is *very* applicable to tube amp construction.

Just some simple words of advice from someone else on the path.

If the chinese amp is P-P you might be able to convert it to a similar deisgn using 6B4Gs.

Fantastic speakers by the way. On the state of the art side with a pair of subs if you can swing it. Anyway, I also have built the North Creek Okara II's and use them with some modified Paramours from Bottlehead. One thing is for sure, your room size will make a difference. My room is rather small (9 by 9 by 7 feet) so I can get away with a mere 3.5 watts easily although at least 10 watts will be ideal, and according to Lynn, 60 watts would be more than ideal. Remember, I have heard that Lynn does have a large, large room compared to others and he likes to listen his music clear with non truncated dynamic peaks. We all want that I'm sure. We just need to adjust our demands/needs/wives/money.

So how big is your room? If its reasonable, say 12 by 15, I would *try* Doc Bottleheads Parabees and see where that takes you. I know it will work but at what volumes do you listen to? Lynn's Amity PushPull's will undoubtedly work, but they are expensive to build and nobody is holding your hand through the process. A Parabee is conservatively rated at 8 watts, is plenty gutsy, and can be modded to your delight. You can even build a separate power supply chassis and experiment with tube rectification easily, after building it stock first and listening to it. I know Ron Welborne is also coming out with his new 15-20 watt monoblocks he once had (the Apollo's) but a cheaper version of it. You might want to look into that too. Transcendent has a kit out right now that is an OTL with 15-40 watts depending on configuration ranging in price from $1K to $2K.

Those are a couple options for you...
www.bottlehead.com
www.welbornelabs.com
www.transcendentsound.com
www.aloha-audio.com
Anand.

-Henry

• 30 Watt Push-Pull with Svetlana SV300Bs

Thanks for the input. The speakers and amps I now have are in my office as my wife was complaining a little about all the "junk" in the house (you can see the speaker pictures at: http://www.prosthodontic.net/images/Dynaco.htm in case you're interested.)

The room I will eventually put this is approx. 16x20x7 but I usually listen at low to moderate volume. I may need more power just because of the size of the room, but the speakers are relatively efficient at 89dB.

BTW, how do your speakers sound? NorthCreek did not have the Okara when I built the Rhythm but it looks nice and small. I can barely lift the Rhythm's I made because I think I poured too much concrete in the base but it does sound pretty good.

Thanks again.

Sincerely,

Vince

Anand.
P.S. the floor standing picture on the website are my Okara's filled with sand/leadshot.

A PP amp will tend to produce 4-5 times the power of a SET. Two 300Bs should get you 25-40 watts.

If cost is a factor consider designing your own amp or using cheaper parts. For the output tubes, especially, there are cheaper alternatives to an $800 pair of WE 300Bs. For example, you could use a pair of VV32B ($200 a pair at Welbornelabs), which when biased up will deliver probably 70 watts. Pair that with some Plitron toroidial OPTs. And so forth.

http://www10.big.or.jp/~dh/work/power.html

Sakuma goes wild for tons of expensive iron and likes high voltage tubes like the 845, but it should at least give you an idea of the options.