High Power Single Ended Amplifier: The NS-SEP20

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Niteshade

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High Power Single Ended Amplifier: The NS-SEP20
« on: 12 May 2010, 12:19 am »
NS-SEP20


Twenty watts per channel, pure Class A and single ended!

We have updated our finish process: That's a reflection of the surface it was sitting on. The finish is so deep and polished it looks like black chrome.

More will be posted about this amp soon!
« Last Edit: 11 Jan 2011, 02:17 pm by Niteshade »

Bill Baker

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Re: New Amplifier: NS-SEP20
« Reply #1 on: 12 May 2010, 02:58 am »
HI Blair,
 Are those 6L6/5881 tubes. Curious your thoughts on the KT66 compaired to the 6L6. The finish you describe sounds intriguing. Do you have pictures the better represent the true look of the chassis?
 One day I'll get to hear on of your amps!

Niteshade

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Re: New Amplifier: NS-SEP20
« Reply #2 on: 14 May 2010, 12:03 am »
Hey Bill,

Those are Russian 5881's. The amp sounds exceptionally good with them. More photos are on the way! Black is difficult to depict dimension and detail with. The color I chose is actually an extremely dark green metallic pearl. For all purposes it's black, but the highlights are spectacular in the right light.

drphoto

Re: New Amplifier: NS-SEP20
« Reply #3 on: 15 May 2010, 09:06 pm »
Blair, I'm a professional photographer and have a lot of experience shooting shiny painted things. (cars and trucks) If you want to ship me a mock up, I'd help a fellow AC'er and small business owner w/ a freebie beauty shot. Maybe you could make up some dummy trannies that would save shipping weight. Would be to 40206.

Of course, if you wanted the tubes to glow (which would be nice) it would have to at least power up.

LMK if interested.

(I could email you some photo tips too, if you want to try it yourself. My method requires one to be well versed in photoshop)

joe

Niteshade

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Re: New Amplifier: NS-SEP20
« Reply #4 on: 17 May 2010, 12:34 am »
Thanks! The above listed amp is for a customer, so I can't send it out. I'd like to take you up on your offer sometime. For now, any instructions on photo taking would be greatly appreciated. I use Photo Shop 7.

Blair, I'm a professional photographer and have a lot of experience shooting shiny painted things. (cars and trucks) If you want to ship me a mock up, I'd help a fellow AC'er and small business owner w/ a freebie beauty shot. Maybe you could make up some dummy trannies that would save shipping weight. Would be to 40206.

Of course, if you wanted the tubes to glow (which would be nice) it would have to at least power up.

LMK if interested.

(I could email you some photo tips too, if you want to try it yourself. My method requires one to be well versed in photoshop)

joe

Vulcan00

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Re: New Amplifier: NS-SEP20
« Reply #5 on: 18 May 2010, 01:33 am »
I really like the deep green!

Niteshade

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Re: New Amplifier: NS-SEP20
« Reply #6 on: 18 May 2010, 10:50 am »
That particular finish is one of the most unique I have ever used. Allot of pearl was used. It 'glows' and takes on the characteristics of its surroundings. It's really a green-based black. The green you see is being diffused through the enclosure by what it's sitting on. Direct sunlight will bring out a dark green hue as well. It's certainly exotic! I have to apologize: More photos were going to be taken, but I forgot and it's been sent to my customer already. Another amp has been finished and I've got a complete photo set of it- from the beginning of construction to the end.

I really like the deep green!

Niteshade

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Re: New Amplifier: NS-SEP20
« Reply #7 on: 20 May 2010, 10:37 am »
An introduction to the NS-SEP20:

A new customer really liked the idea of a high power single ended amplifier, but did not want to spend the money on a SEP30. Right then and there a new model was developed that's the most affordable high power SEP in the industry. I wanted a sub $2K amp that could easily go up against 20 watt amps costing much more.

Specifications:

Power output: 20 watts per channel into 4, 6 or 8 ohms.
Frequency response: 20-20,000hz
Feedback: Variable
Biasing: D.C., our easy-tune circuit
Rectification: Tube is standard, Diode or diode/tube combo on request
Power supply: Three stage filtering
Power socket: IEC
Tube compliment: 6L6x4, 6SN7 (or 12AU7 by request) x1, 5U4 or 5AR4 x1
Finish: Your choice or color and wood combination (wood trim is extra)
Integrated: Yes! This can be an integrated amplifier.

Listening notes:
This amp is rich sounding and the tone is well balanced. I drove speakers from 88db to 94db without issue. We're using a streamlined circuit that is exceptionally fast and provides instruments accurate placement within a forward sound-stage. Vocals are accurate and well placed as well. The amps's additional power over standard single ended types shows up in the form of providing space around instruments and superb bass delivery. Complex passages are not challenging, a non-issue. There is enough power for a well balanced delivery and transient response performance is exceptionally good. The amp's variable feedback control is used to perfectly integrate the amp to your existing speaker and room characteristics. Tunable biasing makes tube rolling a joy and actually makes biasing fun, not challenging in the slightest.

Price: $1650.00

For a limited time: Receive the DC filament upgrade for FREE and the 1940's power supply upgrade for 50% off!

Additional sale option: Receive a SEP20 and Beacon Two preamplifier for $2300.00

Niteshade

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Re: New Amplifier: NS-SEP20
« Reply #8 on: 2 Jun 2010, 04:39 pm »
I guess you can call this a mini review. Our DC filament upgrade was the only upgrade purchased with the amp being reviewed.

_________________________

Thought I would give you my opinion about the 6L6 SEP now that its been in use for some 200 hours.
At first I believed that a moderate amount of feedback was necessary because everything was too sharp and bright. However after about 60-70 hours of break-in I found myself slowing turning down the feedback each day so that now, there is no feedback used.
The sound stage is large and deep; instruments appear to have correct tonality; very high pitches on the violin are sweet, yet they sound extended and not rolled off.
The bass is quick enough and has authority.
There is a very slight tube rush when standing within 3 feet of my Klipsch Forte I speakers, but this is not heard in my listening position.
After a moderate amount of tube rolling, I have come to these conclusions: the best rectifier is a Mullard GZ33. The best driver tube - after 6 different 6SN7's and several 6SL7's - is a Sylvania 6F8-G with an adapter. I'm really quite happy with this combination. While I have several different quads of 6L6 tubes, I have not changed the Russian 6n3c-e  tubes since I liked them so much in another amp.
All in all, I am very happy with the amp.

nunhgrader

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Re: New Amplifier: NS-SEP20
« Reply #9 on: 6 Jun 2010, 07:40 am »
I'm drooling  :drool:

I think I'm going to have to try one of your preamps with my Will Vincent rebuild - Dynaco ST-70!

Niteshade

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Re: New Amplifier: NS-SEP20
« Reply #10 on: 6 Jun 2010, 09:51 pm »
I have not had a chance to comment on this review yet. Klipsch Forte I speakers are over 100db sensitive. Given that, a little tube rush from three feet away is not bad! Remember, the amp is being used with zero loop feedback. That means there are absolutely no noise countermeasures. Using a regulated DC filament source and a triple-filtered high current power supply significantly reduces noise. Nothing is more difficult to make quiet than high power single ended amplifiers. When they are done right- it's quite a treat. More is written about SEP's on our web site.

The transformers we chose are exceptionally well balanced and wide banded. That feature plus a lower output impedance from ganged output tubes greatly improves performance over standard single ended amplifiers.

6F8-G tubes: Never used them! Sounds like it would be interesting to try.

Berndt

Re: New Amplifier: NS-SEP20
« Reply #11 on: 7 Jun 2010, 03:50 am »
What are you using for OPT's?
(If you don't mind me asking)

Niteshade

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Re: New Amplifier: NS-SEP20
« Reply #12 on: 7 Jun 2010, 10:05 am »
Power and output transformers are made by Edcor for this model.

Niteshade

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Re: High Power Single Ended Amplifier: The NS-SEP20
« Reply #13 on: 14 Mar 2012, 11:00 pm »
Long, overdue update for the SEP20:

An early model came back for some upgrades and I went 'all out' regarding ways to improve this amp.

What it received:
1] Mark III circuit
2] New biasing circuit
3] Additional SEP power supply updates

Improvements: ABSOLUTELY, without a doubt 100% QUIET with 100db speakers! That's the tip of the iceberg.  Next, imaging was improved by modifying the screen and biasing supplies. Low end response and high frequencies are dead-on with incredible realism. This amp is ungodly good.

The new biasing circuit will be part of the Mark III upgrades for no additional cost and will obviously be part of all new builds. The update/upgrade was designed yesterday. So- if I'm working on your order, consider yourself lucky.

Forgot to add: When I say 100% quiet, that is precisely what I mean. No hum or hiss! It is so quiet that the slight hiss that was noticeable went away after my Dynaco preamp was turned off. That preamp is considered quiet, though not as quiet as a Beacon Two.