Radii Tube Electronics

Wayne1 · « **on:** 27 Feb 2003, 05:01 pm »

After a very long time of evaluation and negotiation, The BOLDER Cable Company will be offering selected models of tube electronics from Radii Audio.

This is a company that is based in Hong Kong and has their products hand assembled in China. I believe they use the same plant as ASL.

These products will be available by prepaid order only. I will not be stocking any of them, at least at first. Each item will be hand built when the order is placed. This requires a lead time of 4-6 weeks.

So why would anyone pay upfront for a product built in China and then wait for it for a month and a half?

Because they sound so damn good for the money

These products both feature all aluminum chassis, a 10 mm thick front plate, TRT and MIT coupling caps, JJ power supply caps on the Preamp. IEC connectors upgraded gold RCAs and binding posts.

The power amp uses 4) EL-34s per channel and is rated at 78 WPc running in Class A. It includes a digital bias meter and controls for each output tube. The pricing should come in around $1750.00 including shipping to the US. Upgraded tubes and dampers are available for extra charge

The preamp is available with or without a phono section. It uses a ALP pot and a 5AR4 for rectification. The price on this item should be in the $800.00 ball park without phono section including shipping. Dampers are extra.

I should firm up the details this week and add these items to the website early next week.

These pieces will be used for our booth at the Midwest Audio Fest, if you wish to take a listen to them.

I do want to thank Jason Wong for the VERY nice photos. I didn't know you had it in you, Jason

Brad · « **Reply #1 on:** 27 Feb 2003, 07:11 pm »

Nice looking amp/preamp!
The tube dampers give it kind of a supernatural look
What are the rest of the tubes in the preamp?

Does Radii offer any SET's?

Wayne1 · « **Reply #2 on:** 27 Feb 2003, 07:56 pm »

Hello Brad,

The tube compliment for the pre-amp is:

4 x 12AX7, 2 x 12AU7, 1 x 6BM8, 1 x 5AR4

Radii does offer quite a lot of designs using SETs.

What are you looking for?

A stereo amp using 300Bs?

A mono block with an 845?

A mono block using an 805?

or maybe a mono block using the 2A3?

All of the power amps can be ordered with input switches and a volume control so you can have an integrated amp.

JayS has one one these based on the 300B stereo amp.

I do believe he is happy with it

Brad · « **Reply #3 on:** 27 Feb 2003, 09:00 pm »

Thanks for the quick reply, Wayne.

Nice looking gear.

I'm going to see how it goes with the Fi X and the M.A.D. Ultra 4m preamp for a while.

A 45-based stereo amp would probably be what I'd be interested in.

Jabba · « **Reply #4 on:** 27 Feb 2003, 10:32 pm »

Picking up on Wayne's comment about the fact that these are likely made at the same place as ASL ... the Radii preamp bears a striking resemblance to the ASL model ... are these in fact the same?

see http://www.tubehifi.com/amp/amp/aq2002dt.html

Wayne1 · « **Reply #5 on:** 28 Feb 2003, 12:45 am »

The circuit design is similar. The Radii uses a 6BM8. The ASL uses a 6V6. The ASL uses a steel chassis and this Radii is Aluminum. The coupling caps in the Radii are TRT and MIT, as I stated above. I also spec'ed the JJ filter caps and Alps attenuator.

The Radii is designed by Mr. Santa Man. The ASL is designed by Mr. Joseph Lau.

This particular preamp has been compared to quite a few more expensive preamps and easily held it's own.

The only pre-amp that was better sounding in the DAM comparisons was the Symphonic Line, multi-kilobuck "Der Erleuchtung".

Jay S · « **Reply #6 on:** 28 Feb 2003, 12:48 am »

Yup, I've got the 300B tube amp. Mine has some parts upgrades that Wayne specified, as well as an Alps volume pot. I use mine as a 1-input integrated.

It powers a pair of Acoustic Reality Avinci 1 2-way bookshelf speakers. They are only 85.5 db/watt efficient, but I get more than enough volume in my bedroom... from just 8 (9?) watts of power! Source is a humble Pioneer dvd player but sound quality is fine. IC is a norh silver cable, speaker cables are Wayne's now discontinued cross-connected speaker cables. Tubes are Full Music mesh plates that I got from Brian Cherry at www.diyhifisupply.com. I've got a couple of Halo tube dampeners on the 2 small tubes, but not yet on the 300Bs.

I especially enjoy vocal music and jazz as the system doesn't have the dynamics for pop/rock. Bass performance is surprisingly good, extending down to the midbass, with enough tightness for this application.

Pez · « **Reply #7 on:** 28 Feb 2003, 01:11 am »

I own the two pieces that are in the pictures Wayne posted up top. And I have compared it to everything (just think of all the amps the memebers of DAM have had their hands on and currently own) and I prefer it to everything I have heard. The pre-amp is the best damn pre-amp I have heard short of the Symphonic line pre-amp Tyson had at 5x the price.

The tube amp is, hands down more musical in my system than a lot of the highly regarded amps commonly mentioned on this website. If you own the 626s do yourself a favor and buy this amp. Although it has many of the common tube attributes such as warm midrange and smooth highs, it does not have the common tube downfalls of rolled off highs, bloated midrange and weak bass, at least in my system. All in all I have not found a better sounding amp in my system and have tried many. Biasing is simple and can be done on the fly. Volume is not an issue as it outputs 78 watts per channel.

I thought I would never go tubed, but once I heard the neutrality and resolution the Radii is capable of I will never go back.

Pez · « **Reply #8 on:** 28 Feb 2003, 01:12 am »

BTW if you want to see more pictures of the Radii equipment, I took a bunch more and will be posting my favorites in my gallery.

ABEX · « **Reply #9 on:** 28 Feb 2003, 05:28 am »

I have been intrested in amps and will be trying to determine what to use a question I have is what determines when you can use a SET amp with a particular set of speaker's?

My new speaker's will have a sensitivity of 90db@1m.I would imagine room size would matter and I do not forsee having a Sadaam Palace anytime soon.(never know though!)

Please advise as to what might be applicable

TIA

ABEX · « **Reply #10 on:** 28 Feb 2003, 05:44 am »

BTW-Nice looking equiptment!

Wayne1 · « **Reply #11 on:** 28 Feb 2003, 02:30 pm »

Here is some information from over on Audio Asylum that I think might help with your question:

Quote

Posted by Paul Joppa on August 05, 1999 at 21:08:11:

While I certainly don't want to suggest that science is everything, there are two points about SET amps that are highly predictable:

1) They are usually low power. You want typically 102dB capability for fully satisfactory sound.

The amp adds 10*log(watts) dB to the speaker sensitivity. (base 10 logarithm) Some examples:

45 tube 2 watts = 3dB wants 99dB speaker
2A3 tube 3.5 watts = 5dB wants 97dB speaker
300B amp 8 watts = 9dB wants 93dB speaker
88dB speaker wants 14dB = 25 watts
90dB speaker wants 12dB = 16 watts

You can have lots of fun with less power, if your room is tiny and/or you like chamber music or little-girl-with-acoustic-guitar music, but this is the standard minimum.
2) Most SET amps are without feedback. Triode amps without feedback, SE or push-pull, have a damping factor of 2 or so, not the 50-1000 of heaviily fed-back sand amps. This means the bass resonances of the speaker are "loosened up" a little - expect the bass to change! Speakers whose bass is a little too quick and tight with a feedback amp are likely to come alive with a no-feedback amp, while flabby bass will just get worse.

Brad · « **Reply #12 on:** 28 Feb 2003, 03:33 pm »

In addition, you need to check some other specs on your 90db sensitive speakers:

Is the impedance 8 ohms?
Is it relatively flat across the frequency range?
Is the crossover fairly simple?

For best results with SET, you want a high, flat impedance and no x-over or a very simple one.

The 845 tube makes 22-23 watts in SET mode, btw.

ABEX · « **Reply #13 on:** 1 Mar 2003, 08:43 pm »

Thanks for the help!Will save info for reference.

davehg · « **Reply #14 on:** 2 Mar 2003, 07:32 am »

Quote from: Wayne1

The circuit design is similar. The Radii uses a 6BM8. The ASL uses a 6V6. The ASL uses a steel chassis and this Radii is Aluminum. The coupling caps in the Radii are TRT and MIT, as I stated above. I also spec'ed the JJ filter caps and Alps attenuator.

I haven't heard the Radii, but I originally auditioned several ASL products; nice for the price but not killer. I did buy a Passion integrated (www.rotac.com). Like the Radii, it was from the same factory as ASL but came with upgraded caps, volume pot, and output transformers. I owned this amp for over a year and used it with demanding Totem Model 1's and easier Merlin TSM's. The amp held its own against many others I auditioned, so I would suspect the Radii would really shine against its competition. The parts quality is nice for the price.

(It was only recently that I replaced with a used VAC avatar which is simply much better. It should be at 5.5 times the retail price of the Passion).

The pix show EI input driver tubes. Mine came with EI's and JJ output tubes. I find them to be merely acceptable; I suspect most will want to roll better tubes in. I had great luck with Tesla input tubes, and EH and Valve Art output tubes. I hear Sovteks work well too.

It's nice to see quality gear coming out of China. The ASL factory really does make nice components with good parts and exceptional value for the money.

Bwanagreg · « **Reply #15 on:** 2 Mar 2003, 03:42 pm »

That 805-based amp is seriously cool! The ASL 805 amp puts out about 45 watts if I recall correctly - is that about right for this one?

Given that these amps are special ordered, would it be possible to oder a set of (for example) 3 monoblocks for L-C-R in a multichannel system?

Its a good time to be a tube lover.

Wayne1 · « **Reply #16 on:** 2 Mar 2003, 04:57 pm »

Here is the information on the 805 mono block.

Yes, you can order 3 of them no problem. You can have you choice of Chassis finish: Black, Natural, or Chrome. You can also upgrade the coupling caps and power supply caps

GS-805SE:

R.M.S. Power: 50 Watts continuous
Output Resistance: 4,8,16ohm
Frequency Response: 10Hz to 30,000Hz
Harmonic Distortion: less than 0.3% at 1W
Sensitivity: 2V input for 50W output
Tube Complement : 1 x 12AX7, 1 x 6L6, 1 x 805
S/N Ratio: -96dB
Power Consumption: 250W
Dimension(W x D x H): 385 x 460 x 200mm
Weight: 23Kg
Chassis Finish: Full aluminum with powder painting
Remarks: Bias index meter, hum level control

The price for EACH mono-block with shipping should be around $800.00 in stock form. Shipping might be more, depending where you live.

Bwanagreg · « **Reply #17 on:** 2 Mar 2003, 11:59 pm »

The 805 looks like an awesome package, including the price!

Are 805's still manufactured, or all they all NOS? I checked a few of my usual online tube suppliers and came up empty wrt 805's.

Thanks for bringing these amps to the states. I thought I was having a hard time making a decision before

Mathew_M · « **Reply #18 on:** 3 Mar 2003, 01:20 am »

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2162084189&category=29833

There's a couple of auctions on ebay right now. Not sure if they are still in production or not. Having an amp that used out of production tubes would scare me a bit. I'm having a hard enough time finding decent NOS 12ax7 tubes for my Jolida cdp, and even harder time still for my AI preamp. Why don't companies like sovtek produce audiophile grade tubes anymore that compare to their NOS? It seems that there is still enough of a market with high end stereo and guitar amps.

Anyway that 805 tube does look pretty bad ass. I bet you can really impress your friends with that amp though they'd probably ask where the Jacob's Ladder is at.