[eichlerera1]

The end of an era.
I’ve owned my VTL 225 MonoBlocks for almost 30 yrs.
Over the last year they have been blowing tubes and shorting out at an unacceptable rate. They have no soft start capability which stresses the circuit and tubes at startup.
The 525 Volt rail doesn’t help. I actually had an internal fire which torched some resistors.
It was time for a change.

Being a fervent ModWright fan, I decided to call Dan Wright for some advice.
I own a tube modified Pioneer CD player and a tube preamp made by him.
He has always been a believer of using tubes for the front end while using a Solid State Amp for the back end.

Since he knew I was an avid Tube fan he suggested that a Mosfet SS Amp would be a good choice as they tend to be a tad more gentle in nature soundwise.
He had a demo of a KWA 100SE which he would let go at a great price.
Roughly 100 Watts into 8 ohms and 200 Watts into 4 ohms.
Since my Hales Signature Twos are 4 ohms with a sensitivity of 90dB, I figured this would be a fine match. (Especially since I utilize 3 powered subwoofers)
Normally I would have to audition a product before committing to a purchase but I have grown to trust Dan over the years from a design and integrity POV.

So I went for it and received it about a month ago.
Dan suggested that it should be burned in for around 450 hrs (actually less because it was a demo).

So for the past few weeks I’ve been trying to get the sound I want by using various tweaks. Due to the nature of the Transformer design and input circuit the Amp cannot be floated.
It must use the hot, return and ground. Therefore, it has become the single point ground for my system with all other components floating. (otherwise I get ground loops and hum)

The sound of this Amp was quite different than the VTL and I wasn’t sure I could accept the differences at first.
I knew from the outset that the midrange of the VTL could not be duplicated as that is the main strength of a good tube amp.
The KWA 100’s midrange was detailed, crisp and had body. It was slightly lacking (I thought) in it’s harmonic content. (odd vs even order stuff).
The VTL was stomped in the treble presentation by the SS Amp (again, expected).
The bass was pretty close but the KWA 100 won out due to it’s precise rendering of pitch. No one note bass here. All the slightly different, fast paced notes were clearly differentiated from each other. Plus the bass was a little tighter.
The dynamics and transient responses were identical. Both great.

So, apparently, the main bugaboo was the KWA’s midrange.
I utilized every tweak in my arsenal to try and get that midrange “bloom” common with tube amps. Mostly power input tweaks using filters, parallel capacitance and various Quantum Products. I sweetened the midrange quite a bit and got a tad more bloom.
Over the past few weeks, by playing cuts I was really familiar with, I came to realize how euphonic my VTL was in the midrange. It wasn’t entirely accurate but was sure pleasant to listen to.

So at the moment, I’ve come to appreciate the more accurate rendition of my KWA amp and am quite pleased with it. The sound appears to be evolving with additional break in hrs for the better. After I feel it has run it’s break in course, there’s a possibility for some tube rolling in the front end to give me a touch more second order stuff.
I have a dream to try the legendary Bendix 6900 tube in my Pre Amp. Although it may not help in the Bloom Dept.

Right now, the KWA uses a single input transformer. I suggested to Dan that an additional one could be added for channel separation and perhaps a partitioning within the amp isolating the two channels. What do you think Dan?

[eichlerera1]

The Amp continues to evolve.
Did the following tweaks:
1) Placed a Quantum Symphony directly over the back of the top cover.
2) Placed a Shakti Stone directly over the front of the top cover (over the transformer).
The midrange was starting to sweeten up (especially the upper midrange)

I continued on:
3) Purchased Blue Jeans subwoofer cables (for my three subs) (a REAL bargain).
4) Purchased a Magnan Signature Power Cord for the Power Amp. (stole it on EBAY)
This is certainly the "John Holmes" of the cable world with a diameter of over two inches!
5) Rearranged my power cord location by plugging my PreAmp and Power Amp into the same outlet.
Bang! The soundstage REALLY snapped into place.
When several instruments played at the same time, they were clearly discernible from each other. Real depth and separation! And the bass and highs are as good as it gets.

So I am now really pleased with the sound.
But I'm not quite done yet.
Planning on treating every unit with sound dampening sheets on the walls, top and bottom.
Surrounding the massive KWA 100 transformer with Stillpoint ERS Sheet material.
Will do that and report back.

Short to medium term plan.
I've been using a Straightwire Maestro Speaker Cable for close to 30 yrs.
Got my eye on the new SilverSmith Fidelium Cable.

[eichlerera1]

Lined the top, sides and bottom (as much as possible) with stick-on sound dampening material.
Covered input transformer with ERS paper.
Bought some Herbies RCA plug dampers on EBAY on the cheap and installed them everywhere.

Results:
1) A darker background.
2) Tighter and more distinct bass.
3) Improved soundstage and instrument separation.
All of these were not slight in nature.

I've finished the tweaking on this KWA 100SE Amp. REAL pleased with the improvements!
I must say that this Amp responds quite readily to tweaks!

I still have to add more sound dampening to my CD Player and Pre Amp.
And that Fidelium Speaker cable is callin' my name!!!!

[Sailorboy]

Hi I have the same preamp (9.0 AE) and power amp (100SE) and have been interested in your activities to improve the sound.
I am curious, which single change would you say made the biggest improvement?

I think I will first move the power cords to run from the same outlet as you did, and see what difference that makes before doing any further tweaking.

I am still using stock tubes which I have been very happy with but I am itching to try some others, so that might be the next move.

Tweaking is one change at a time to ensure SQ does not go backwards.

Regards
Colin

[eichlerera1]

Hi I have the same preamp (9.0 AE) and power amp (100SE) and have been interested in your activities to improve the sound.
I am curious, which single change would you say made the biggest improvement?

I think I will first move the power cords to run from the same outlet as you did, and see what difference that makes before doing any further tweaking.

I am still using stock tubes which I have been very happy with but I am itching to try some others, so that might be the next move.

Tweaking is one change at a time to ensure SQ does not go backwards.

Regards
Colin

First, a question. Do you own a ModWright tube altered CD Player?

The use of a common outlet for the Amp and Pre Amp was more of a configuration setup necessitated by my recent purchase of the KWA 100SE Amp. It wasn't intended to be a possible improvement in the sound. But I encourage you to try it!

I added the ERS Paper and Noico Dampening material at the same time.
I CAN tell you that the difference was significant. I would do both at the same time.
And please, don't forget to mass load all your components. The effects are not subtle!

I can absolutely recommend that you tube roll on your Pre Amp.
I use Amperex tubes on both my ModWright Pre Amp and CD Player.
These are highly resolving, vivid tubes. Almost Solid State sounding.
Depending on what speaker you use and the various interconnects within your system, these tubes may be too analytic for you.

Let me know what speaker, interconnects and speaker cables you utilize.

Finally, one of the greatest differences I've ever encountered was when I procured a set of Silversmith Fidelium Cables. These suckers are truly SOTA!!!

[Sailorboy]

My source is dual Antipodes digital streamers, one for the Roon server, one for the renderer; and very happy with this setup.
They feed a T+A DAC and then into the 9.0AE preamp.  My speakers are Dynaudio C1 Platinums.
Cables are a combination of Nordost IC's and power cables and Antipodes Komako speaker cables.

What do you mean by mass-loading, what are you using to do that?

I have heard that the Tungsol 5687's are the ones to get.  However I find the stock JAN5687WB's actually very good, very even across the frequency range.  If anything the mid-range could do with a bit more density/weight.

Cheers
Colin

[eichlerera1]

My source is dual Antipodes digital streamers, one for the Roon server, one for the renderer; and very happy with this setup.
They feed a T+A DAC and then into the 9.0AE preamp.  My speakers are Dynaudio C1 Platinums.
Cables are a combination of Nordost IC's and power cables and Antipodes Komako speaker cables.

What do you mean by mass-loading, what are you using to do that?

I have heard that the Tungsol 5687's are the ones to get.  However I find the stock JAN5687WB's actually very good, very even across the frequency range.  If anything the mid-range could do with a bit more density/weight.

Cheers
Colin

Quite an impressive system!
I assume you don't utilize sub woofers.

Mass loading is simply placing heavy weights (typically lead and brass in my case) on top of all your components.
See this discussion: https://www.audiocircle.com/index.php?topic=172466.msg1823908#msg1823908

I have some Tungsol 5687s. Dan Wright used to sell these until he ran out.
They are indeed a fine tube. But, IMO, there are better alternatives....
I actually use the Amperex 7119, D Getter, Pinched Waist (Late 1950s). This is a variant of the 5687.
Check out these descriptions. Scroll to find them (near the bottom of the page)
http://www.audiotubes.com/audtube.htm

[eichlerera1]

During the end of a listening session, I inadvertently failed to turn off my KWA-100SE Amp.
Two days later, I discovered my "mistake".
Decided it was an excellent opportunity to audition the Amp with an extended warm up time.

EVERY parameter you care to verify improved.
Now that I let the Genie out of the bottle, she's not going back in!

Discussed the 24/7 on time with Dan.
I was concerned about the possibility of a power failure with a resulting hard turn on by the Power Company.
In my area, this turn on is full on with a resultant power surge.
This burned out a circuit in my washing machine causing me to put an inline surge protector.
Luckily, when the KWA 100SE loses power, it turns off completely.
Upon resumption of power, one has to press the hidden on switch to let juice flow to the Amp.

Of course, if I leave town for a few days, I would turn it off.
Also, in case of Lightning in the forecast, I would turn it off. (as well as the stereo system's circuit breakers)

With all that determined, Dan gave me his blessings to leave it on 24/7.

I HIGHLY recommend this Amp be left on.
The improvements are well worth it!