Amp/Preamp Asylum: REVIEW: VTA M-125 amp KIT Amplifier (Tube) by cirwin1

Model:	M-125 amp KIT
Category:	Amplifier (Tube)
Suggested Retail Price:	$869 in KIT form
Description:	VTA M-125 tube monoblock amplifier
Manufacturer URL:	VTA
Model Picture:	View

Review by cirwin1 on April 23, 2014 at 18:23:17
IP Address: 75.62.16.39 Add Your Review
for the M-125 amp KIT

After researching many vacuum tube amps in forums and looking at performance data sheets on line for about six months, I called Bob Latino with tubes 4 hifi, web site http://www.tubes4hifi.com/bob.htm. I decided to purchase two M-125 monoblock kits and do the assembly myself.
The kits arrived solidly packed in one heavy duty box (70 lbs.), with transformers and other components individually boxed and wrapped. Each component is individually zip locked bagged and clearly labeled. No need to read resistor color codes or capacitance values. The instructions are clear, to the point and there was no question as to exactly what to do next. Also included is a detailed color photograph of the assembled wiring. There is also a color drawing clearly showing all of the point to point wiring connections. I never felt lost during the assembly. I am using KT120’s for the output and 12BH7’s for the drivers. A Weber WZ68 copper cap rectifier looks great.
Immediately after completing assembly, I hooked up the Tyler Acoustics Linbrook System II’s, and plugged in a shorted RCA connector in the input for setting the bias. Next, I sent audio to the amp. In pentode mode, I had a distortion issue, but the sound was great in triode mode. I contacted Bob and he had me send him a photo of my wiring. He noticed I had not installed a wire from the negative speaker post to ground. Note that if you check off each step as completed on the instructions as advised, this will not happen. I added the missing wire and, wow, what a great sound. Good bass and crisp highs. I put in a bass track and the sound rattled the windows with clean smooth bass. Cymbals are crisp and clear. I run the units in pentode ultra linear mode. This seems to give more authority to the speakers resulting in more solid highs and lows. I probably have 10 or more hours on the amps at a fairly high gain and I think the sound is somehow improving. I have enjoyed several high end Yamaha A/V receivers in the past and still using a four year old unit, but none have compared to the two channel sound quality from the M-125’s. I had forgotten how two speakers can generate a wall of sound.
Even if you have never built a kit or soldered, this kit, as it is configured with an excellent instruction manual, photograph, drawing, and clearly labeled parts, you should have no problem putting this kit together. If you have a problem, as I did, you will find that Bob has the expertise to quickly resolve the issue and he is readily accessible by phone and/or email, from 9 AM to 9 PM, eastern. If you have never soldered before, you can find someone to teach you in about 5 minutes. I find it very rewarding to build anything, but when you can flip a switch and it comes to life, it’s a real thrill!

Product Weakness:	None - Don't expect any.
Product Strengths:	Easy Assembly<br>Good Directions and Assembly Graphics<br>Smooth Solid Bass and Crisp Highs<br>Dead Silent with No Input - No Hum At All <br>Accessible Knowledgeable Technical Support

Associated Equipment for this Review:

Amplifier: VTA M-125
Preamplifier (or None if Integrated): Tisbury Audio Passive Preamp
Sources (CDP/Turntable): I-Phone via Blu-Tooth, CD
Speakers: Tyler Acoustics Linbrook System II
Cables/Interconnects: Monster
Music Used (Genre/Selections): Various
Room Size (LxWxH): 12 ft x 16 ft x 8 ft
Room Comments/Treatments: Sliding Glass Wall, Tile/rug floor
Time Period/Length of Audition: 10+ Hours
Type of Audition/Review: Product Owner

Amplifier:	VTA M-125
Preamplifier (or None if Integrated):	Tisbury Audio Passive Preamp
Sources (CDP/Turntable):	I-Phone via Blu-Tooth, CD
Speakers:	Tyler Acoustics Linbrook System II
Cables/Interconnects:	Monster
Music Used (Genre/Selections):	Various
Room Size (LxWxH):	12 ft x 16 ft x 8 ft
Room Comments/Treatments:	Sliding Glass Wall, Tile/rug floor
Time Period/Length of Audition:	10+ Hours
Type of Audition/Review:	Product Owner