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REVIEW: Velleman K4040 Amplifier (Tube)

I recently puchased a Velleman K4040 tube amp kit to drive my home brew ESL's. It lists for $999 kit and $1300 assembled. I've owned dozens of tube amps in the past and have always prefered the sound of a good tube amp over most solid state amps. The last tube amp I owned was a ARC D76a but I sold it because it didn't have the power to drive the Martin Logan CLSIIz's I owned at the time and replaced it with a (yetch!) Carver TFM75. I have since sold that also but I still have several other Carver TFM series amps for my home theater setup. I've been using a TFM35 to drive my homemade ESL's and decided I needed a tube amp again.
The Velleman is easy to build and the manual is mostlt well written though a bit sparce. An experienced kit builder should be able to easily build it in a weekend or less. The parts included (with exception of tubes) seem high quality for the price. It uses toriod transformers for power and output. The bias is easy to set as it has a built in LED bar meter and front panel adjustments. Bias can also be checked with a normal meter across test points. It came with all Sovtek tubes. 8 EL34's, 1 12ax7 (not even a lps version), and 2 - 12au7. Its rated at 90 wpc and 15 wpc Class A. With the Sovtek tubes the amp sounded a bit harsh during break in but got much better after a few days. However, the amp always sounded like the upper midrange had a bit to much presance that became a little annoying on loud passages and caused listening fatigue. Also, one channel sounded slightly different from each other do to the fact all 8 tubes were not matched, just the quartets. I decided to give the amp another chance with some new, better tubes. I bought 8 matched Golden Dragon EL34M's from Thor Audio and replaced the 12ax7 with a used Bugle Boy I had and replaced the 2 12au7's with NOS Telefunkens. I broke in the new tubes and then rechecked the bias and then started listening. Wow! What a difference! All the upper midrange harshness is gone. I played Enya at 110 db at 12 feet (Yes, ESL's will play that loud when you have 1440 square inches of panel a channel) with no fatugue at all, just nice and smooth sound. Acoustic guitar sounds life like as if they are playing right there. The Carver TFM35 actually sounded surprisingly good but sounded sterile and not life like and things like maracha's and tamborines and cymbols didn't sound right. They do now with the retubed Velleman. The bass is far superior to the ARC D76a and the midrange doesn't sound as veiled either. It's now smooth sounding without being overly sweet. I have to admit it still doesn't sound as good as I would like it but for the price I don't think there is much that would. I can easily live with it now until I can finish my 6C33-CB OTL tube amp project. With the Golden Dragon tubes the chrome trim rings that hide the sockets won't fit. Also the smaller chrome trim rings won't fit on the Telefunkens either. I feel its an excellent tube amp for the money but if you plan on building one the first thing to do is to sell the Sovteks and buy some better tubes. I think it would be a better deal if they sold it with better tubes even if they had to charge more to make up for it. I feel most people would be disapointed with the sound with the Sovteks. This would be a nice entry level tube amp especially for someone that needs the 90 wpc to drive ineffecient speakers.

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Topic - REVIEW: Velleman K4040 Amplifier (Tube) Review by DaveInVA at Audio Asylum - DaveInVA 18:20:23 07/07/01 (5)

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