April 23, 2013, 08:35 PM #1
A Velleman K4040 Tube amp odyssey ..
A Velleman K4040 Tube Amp Story
Well..about 10 months ago or so I got into my first tube amps. After a few that didn’t cut it for me I stumbled on the Velleman K4040 Tube Amp on a Bartertown in another audio site. The guy accepted an offer of $500, shipped (he was asking $800 plus shipping). Now this amp starts as a kit costing from $1900 to $2100. So already built, working and with tubes, this was a steal. It was also the start of an in-depth odyssey.
The seller advertised it as working perfectly and he did package it for shipment to Mars. When it arrived and I hooked it up, it had a BUZZZ in the left channel and an excessive HISS in the right. Thus began my odyssey and learning experience. In some cases it was fun but always frustrating. The BZZZ and HISS were low but I could hear them if the room was quiet and not the way they should be. Of course the seller said it never did that for him and it must be my power.
Well, I won’t drag this out but after searching the net, getting expert help and a lot of trial and error (not to mention experimentation with resistors, grounds, multi-meters, etc.) I found the right mix. I now had a beautiful 90wpc tube amp with no hums or buzzes or hiss…and the thing sounds so damn awesome.
Once working, I replaced the tubes he supplied (1 12AU7 for phase splitter, 2 GE 12AX7 input tubes and 8 – yes 8 SOVTEK Russian output tubes.
The 12AU7 was replaced with a GE blackplate, 12AX7’s with a very rare pair of Sylvania triple mica black plates with gold lettering and 8 NOS GE 6L6GC ‘s from 1962…
The sound and range is incredible. I did try other input tubes, I like the Mullard’s also. The RCA and GE blackplates are a little TOO detailed (painful) and the mids were not forward enough.
Anyway, that was a 2 month long journey and now my baby gives me pleasure every day…I leaned how to measure voltages, read resistors and solder like a champ. LOL Also leaned the difference between signal ground and earth ground and how a difference can cause issues if they are in the same loop.
Velleman K4040 Stereo Vacuum Tube Amplifier Kit
Last edited by ohbythebay; April 23, 2013 at 08:37 PM.MAIN RIG: Equipment: Marantz SR4023 as Pre / Velleman K4040 Tube Power Amp / Yamaha M65 Power Amp / Polk Monitor 70's with Polk Sub / ClearAudio Concept table with Musical Surroundings Phonomena II Phono Stage and ClearAudio Concept MC cart /Pioneer PL500 TT with AT440MLa
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