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Old 9th March 2002, 01:17 AM   #21
PedroPO is offline PedroPO  Portugal
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I've made a AUDIONOTE KIT ONE, that is a 300B single ended, directly heated triode, valve rectification, Class A amplifier that delivers 9W per channel.

It is one of the best amps that I've listened so far, and I don't say it because I've made it, it really can compete( and win) with the big boys from Audionote like Oto Phono, Conquest or Conqueror and PM17 from Marantz (solid state).

It comes with one line input and volume control.
f you wan't more inputs or phono input, I suggest Creek obh-12 passive aplifier with remote! and a separate phono stage.

The price is a litle over your budget, but for a few pounds you can buy the plans. the kit is about 800.

see www.audionote.co.uk. You can buy online.

I've attached one picture of my baby with some cosmetic upgrade.

Pedro
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Old 9th March 2002, 01:24 AM   #22
PedroPO is offline PedroPO  Portugal
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here goes the picture
Attached Images
File Type: jpg an-kit-one.jpg (89.3 KB, 1000 views)
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Old 9th March 2002, 12:54 PM   #23
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Quote:
Originally posted by Mohan Varkey
Erik,

I just had a look at your speaker. Although it is 90dB/1W/1m, its nominal impedance is 4 ohms. Maximum power handling is 250W.

I am not familiar with your speakers. However, I suspect that you need a fairly stiff (read as damping factor) amp perhaps in the 20W-30W range. You are not looking at a simple beginners amp here. Perhaps you should be looking at a push-pull 6L6 or KT88 amp for a start. I could be wrong here. Someone else on this forum could comment on this speaker and amp compatibilities.

It is great that everyone on this forum is trying to help you get started. Do you have friends locally, who may be able to come over to your place with their tube amps for an audition or have you already auditioned a tube amp in your system?

I n the mid nineties, I had correspondence with a few friends over your way. But I have lost contact with most of them. This was through the Lowther Club. If you wish, I may be able to go through my old correspondence and dig out a name or two. Lowther people are diehard fanatics. It is rather difficult to get a neutral opinion from them. But they will have tube amps.

Perhaps you may be aware that there was a Swedish electron tube manufacturer. The name escapes me. I think? that this company was taken over by Outoucompu in the mid seventies.

Mohan
The amp Im strongly considering (read: almost decided to build) right now is the "Ella" from www.diyhifisupply.com

Its rated at 2x40W with the standard Valve Art EL34 tubes and 2x50W with optional KT88 tubes.

Do you think it will fit my needs well?

The guys over at www.audioasylum.com loves it.

/Erik
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Old 9th March 2002, 10:02 PM   #24
PassFan is offline PassFan  United States
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It looks like a fine amp Eric. Try to buy the best tubes you can. You might get them cheaper closer to home and save a little money. I hope you have looked at what it cost to ship one of those things to Europe. My jaw hit the ground when I read his shipping rates. You are going to spend a third of the amp price in shipping and that alone would prohibit me from listening to one. But, they do look good. If you are insistant on building your own chassis why not find a good design and just buy the parts. It would seem a whole lot cheaper and most of it could probably be found online as close as Great Britian or even Germany. Good luck and have fun whichever way you go.
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Old 9th March 2002, 10:29 PM   #25
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Quote:
Originally posted by PassFan
It looks like a fine amp Eric. Try to buy the best tubes you can. You might get them cheaper closer to home and save a little money. I hope you have looked at what it cost to ship one of those things to Europe. My jaw hit the ground when I read his shipping rates. You are going to spend a third of the amp price in shipping and that alone would prohibit me from listening to one. But, they do look good. If you are insistant on building your own chassis why not find a good design and just buy the parts. It would seem a whole lot cheaper and most of it could probably be found online as close as Great Britian or even Germany. Good luck and have fun whichever way you go.
Hey, they are also sold in Denmark and I live in Sweden. So I might just pop over to our western neighbors and buy one this summer.

/Erik
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Old 9th March 2002, 10:37 PM   #26
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Erik: With regard to the shipping rates diyhifi is going to have a US distributor soon. It is going to be announced at the Midwest Audio Meeting in Lima Ohio later this month. The new distributor is going to be Kevin at Diycable so maybe the shipping will go down when they get a US base. Maybe check w/ Kevin at www.diycable.com. They are going to have a forum for helpm with modifications there too.

With regard to the above concerns with damping the power in Watts of a tube amp does not have much to do with it. An amp's damping factor is related to its output impedance, not its watt power. Just the same, it is important to match your amps power with the sensitivity of your speakers. And the amp you are looking at has plenty of power for a 90db rated speaker.

I just read a decent overview of damping at the www.madisound.com site if you want a little info on damping. I suggest you go there and read it. It was posted by Tim Kolody on 2/28/2002 in a thread dealing with tubes vs Solid state.

You could also ask at the Asylum. Basically tubes are high impedance by nature and this effects the damping. Electromagnetic damping is caused by emf being reflected back to the amp and if the amp's impedance is too high it resists the reflected emf and there is less damping. No sense reinventing the wheel here. Read Tim's post at Madisound.

Have fun,
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Old 9th March 2002, 10:45 PM   #27
hifi is offline hifi  Sweden
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i believe i got the schemes for practicaly all audionote kits...if you are interessted..

i shall cheack my library...

/micke
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Old 9th March 2002, 10:52 PM   #28
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Quote:
Originally posted by Ryder
Erik: With regard to the shipping rates diyhifi is going to have a US distributor soon. It is going to be announced at the Midwest Audio Meeting in Lima Ohio later this month. The new distributor is going to be Kevin at Diycable so maybe the shipping will go down when they get a US base. Maybe check w/ Kevin at www.diycable.com. They are going to have a forum for helpm with modifications there too.

With regard to the above concerns with damping the power in Watts of a tube amp does not have much to do with it. An amp's damping factor is related to its output impedance, not its watt power. Just the same, it is important to match your amps power with the sensitivity of your speakers. And the amp you are looking at has plenty of power for a 90db rated speaker.

I just read a decent overview of damping at the www.madisound.com site if you want a little info on damping. I suggest you go there and read it. It was posted by Tim Kolody on 2/28/2002 in a thread dealing with tubes vs Solid state.

You could also ask at the Asylum. Basically tubes are high impedance by nature and this effects the damping. Electromagnetic damping is caused by emf being reflected back to the amp and if the amp's impedance is too high it resists the reflected emf and there is less damping. No sense reinventing the wheel here. Read Tim's post at Madisound.

Have fun,
I dont really have the time right now to check the post at madisound, will do it another day.

Anyway, do you think the amp will suit me well? I mean I really want that amp! Its lovely!

/Erik
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Old 9th March 2002, 11:42 PM   #29
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Erik,
Power wise your selection seems adequate. However, I am not able to comment further because I could not find even the topology (like a flow chart for a computer program) at the site.

Are you able to buy the kit without transformers? If so, take Skippys advice and consider whether you could save money on freight and use this money to purchase locally available Lundahl Transformers. They have a good reputation amongst serious audiophiles. Check out the costs involved.

In a standard KT88 application, you will need minimum 5K primary. A higher primary load will have a more linear output at the expense of a small reduction in power output. Make sure that you have option for 4 ohm secondary.

I have used both types of KT88 (shown in the photograph) in a wide variety of amps and I prefer the metal base ones. The China factory used to call them KT88R, the suffix meaning Retro (i.e. copy of GEC KT88). Labelling is just a marketing exercise these days.

Power supply is like the engine in a car and is the heart of your amplifier. Output transformer is like the gear box that transfers the torque. Once you have these two components in order, then you can switch and change the circuitry in between.

Mohan
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Old 10th March 2002, 06:10 AM   #30
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I'm Kevin from DIYCable and I thought I'd answer some of the questions about the Ella.

The goal of the Ella was cost effective amplification using a proven design. Nothing about the Ella is cutting edge technology, just well proven classic PP tube audio design and implemented with quality parts. Nothing exotic as far as parts but noting cheap either.

The biggest factor in getting good performance out of tube amp design is the circuit design and the iron (transformers) used. The Ella uses a classic design with a Sovetk 6922 as the first SRPP stage, followed by a 6SN7 driver stage and a choice of EL-34, 6550 or KT-88 output in push-pull Class A/B configuration.

This design is probably 50-60 years old and has been tweaked and played with but the biggest factor in performance outside of the basic circuit design is the quality of the output transformers. The iron used is once again classic in design with EI cores and oil paper insulation. This is how the iron of yore was made and many people subjectively still prefer classic iron. They are monsters on this amp and have both 4 and 8 Ohm taps.

[IMG]
http://www.diycable.com/images/Aucti...r.RIM00041.JPG[/IMG]

The power transformer is a huge toroidal unit.

I think a lot of people who just want good amplification without the bells and whistles will really be happy with the Ella. It is a lot of amplifier for the money and should drive most speakers, except for the most difficult loads. It is relatively easy to build, attractive, flexible and inexpensive. Tube rolling options are many and there are tweaks that we will be publishing that allow you to get even more out of the design/kit. One other benefit is that it is reasonably sensitive and comes with a volume pot so you can use it as a stand-alone integrated of sorts and then later on add an active line stage. I think a lot of people will like this as it allows you to start enjoying music right away.

A few short months ago when I was thinking about offering tube kits I looked into what I considered to be common sense designs and tried to source all the parts in volume to offer a line of tube kits. After doing the research I found that there was no way I could compete with the kit amps that Brian Cherry of DIYHIFISupply was offering. Just looking at what the chassis and transformers would cost put my prices over what the entire Ella kit price would be. My motto became "if you cannot beat them, join em" and I started talking with Brian about handling his products in North America. Soon we will have the kits on our web site and we are working on updating instructions, offering tweaks, upgrades and other options that we think are lots of fun, a good bargain and fill a niche in the market. I think the Ella does that and it is a great introduction to tube audio.

http://www.diycable.com/images/Aucti...r.RIM00043.JPG
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