hi there...Velly'amps....not cast iron reliability with time..that's what I've heard. Alot had/have problems with this amp esp.....o/p stage biassing.....and output load stability. These amps don't like electrostatic LS or complex loads. The suspect to load instability is a symptom of poorly thoughtout circuits.
I believe Maplin UK marketted this Dutch made amp, so they might have a update cum repair page on this model. ......
rich
I believe Maplin UK marketted this Dutch made amp, so they might have a update cum repair page on this model. ......
rich
I've owned a K4040 for years and now keep it as a spare amp. It sounded awful with the supplied Sovtek EL34's. It sounded very good with Golden Dragon EL34's and NOS Telefunken Driver tubes however the Golden Dragons started to fail after only a month. The K4040 basicly uses cathode resistors as fuses and whenever a EL34 shorts out you also have to replace the cathose resistor. Also, the mains fuse is in a holder soldered to the pc board and it gets so hot it melted the holder so I replaced it with an inline holder.I finally decided to do some mods on it and did most of the mods found on the page at the following link:
K4040 Mods Page
It now is very stable and I used it to drive my homebrew electrostats for over a year without failure.
Dave
K4040 Mods Page
It now is very stable and I used it to drive my homebrew electrostats for over a year without failure.
Dave
Hi,
Being no big fan of the Velleman amps and having learned through private e-mail that Brap is the proud owner of a set of KlipschHorns I recommend the following:
-SE 2A3 or 300B, WAD or some US made KIT....Couldn't think of any at the time of writing.
-Didn't mention it but 12B4A PP or 6S19P PP could be great too. No kits exist though to the best of my knowledge...IOW, a PP of small but linear little devils.
-Very compact small devils are most dissimilar triodes such as the 6EM7 etc.
Again, no kits I'm aware of.
Cheers,
Being no big fan of the Velleman amps and having learned through private e-mail that Brap is the proud owner of a set of KlipschHorns I recommend the following:
-SE 2A3 or 300B, WAD or some US made KIT....Couldn't think of any at the time of writing.
-Didn't mention it but 12B4A PP or 6S19P PP could be great too. No kits exist though to the best of my knowledge...IOW, a PP of small but linear little devils.
-Very compact small devils are most dissimilar triodes such as the 6EM7 etc.
Again, no kits I'm aware of.
Cheers,
Velleman k4040
I have had the k4040 for a few months now and have not had problems with it so far. It worked fine first time I tested it with excellent results.
I know a lot of people who criticise this for a number of reasons. I am one of the few who liked it a lot and have heard a number of other amps in comparison worth eight times as much and this was better both on the frequency range test (torroidal outputs) and on the output power (90w rms pc).
I am sure with a few very basic mods you can make this a killer amp surpassing the various ultra high end brands.
Remember to use svetlanas for el34, they are a few hundred times better than the next competitor (including mullards).
I have had the k4040 for a few months now and have not had problems with it so far. It worked fine first time I tested it with excellent results.
I know a lot of people who criticise this for a number of reasons. I am one of the few who liked it a lot and have heard a number of other amps in comparison worth eight times as much and this was better both on the frequency range test (torroidal outputs) and on the output power (90w rms pc).
I am sure with a few very basic mods you can make this a killer amp surpassing the various ultra high end brands.
Remember to use svetlanas for el34, they are a few hundred times better than the next competitor (including mullards).
Velleman
Thaks for all the input, it's really appreciated.
I am leaning towards the Bottlehead Paramour 2A3's with mod kit. I seems that for the price of two monos and the reviews they have on line ( one owner having Khorns like me) this is a good bargain.
Decisions, decisions -- contemplating the "Ella" also!
Anyone have comparisons of these two, or isn't that fair?
thanks!
Thaks for all the input, it's really appreciated.
I am leaning towards the Bottlehead Paramour 2A3's with mod kit. I seems that for the price of two monos and the reviews they have on line ( one owner having Khorns like me) this is a good bargain.
Decisions, decisions -- contemplating the "Ella" also!
Anyone have comparisons of these two, or isn't that fair?
thanks!
Don't know anything about the Ella. It "looks" reasonabe build quality, and seems to be running in "ultra linear"/"distributed load" (Pentode) mode, in class AB. This puts it in the same class as the WAD that you were considering.
I do know the Paramour's. They are sweet things, and (to my ears) sound surprisingly good for the cost and their simplicity.
They are definately good value for money, but I have 3 criticisms:
1. The build quality is poor: Jagged edges and surface marks on chassis plates. Transformers "nude", don't look good to my eyes. Mounting system for transformers is amateurish.
2. The instructions are wierd
. Since I was building these for a friend, I thought I owed it to him to build them the way they said. There were so many modifications, alternative parts and amendments that it was easier for me to ignore them.
3. The hum level on the output, with the hum balance pot optimised, and the CCS fitted was 7mV. I think that is too high for high efficiency speakers. Extra decoupling fixed it to an acceptable level.
But despite all of the above, when finished, I played them for a day and loved them!
The kind of music I played was orchestral, mandolin and female jazz vocal. I doubt (though I didn't try) they would hold up so well as they did on heavy rock or organ music.
I do know the Paramour's. They are sweet things, and (to my ears) sound surprisingly good for the cost and their simplicity.
They are definately good value for money, but I have 3 criticisms:
1. The build quality is poor: Jagged edges and surface marks on chassis plates. Transformers "nude", don't look good to my eyes. Mounting system for transformers is amateurish.
2. The instructions are wierd
. Since I was building these for a friend, I thought I owed it to him to build them the way they said. There were so many modifications, alternative parts and amendments that it was easier for me to ignore them.3. The hum level on the output, with the hum balance pot optimised, and the CCS fitted was 7mV. I think that is too high for high efficiency speakers. Extra decoupling fixed it to an acceptable level.
But despite all of the above, when finished, I played them for a day and loved them!
The kind of music I played was orchestral, mandolin and female jazz vocal. I doubt (though I didn't try) they would hold up so well as they did on heavy rock or organ music.
Hey Guys,
I cant mention on the Velleman, but I do own a WAD Kit34. This is a VERY similar amp to the Kit6550 you are interested in.
The WAD was my first "real" kit, and it was a great experience. I had little knowledge of electronics (General Physics in college) and was able to assemble this kit with relative ease. The bulletin board at WAD is excellent in terms of assistance, as is this board.
The build quality was very good, the instruction were good, and the customer service was equally as good. The WAD does not use printed circuit boards, and this may be of considderation should you desire to upgrade the amp in the future.
I would happily recomend the WAD kit, but you must considder the cost of shipping from the UK... not too cheap!
Hope this helps.
Bryan
I cant mention on the Velleman, but I do own a WAD Kit34. This is a VERY similar amp to the Kit6550 you are interested in.
The WAD was my first "real" kit, and it was a great experience. I had little knowledge of electronics (General Physics in college) and was able to assemble this kit with relative ease. The bulletin board at WAD is excellent in terms of assistance, as is this board.
The build quality was very good, the instruction were good, and the customer service was equally as good. The WAD does not use printed circuit boards, and this may be of considderation should you desire to upgrade the amp in the future.
I would happily recomend the WAD kit, but you must considder the cost of shipping from the UK... not too cheap!
Hope this helps.
Bryan
Velleman
WOW -- thanks for everyone's help. I think this post has reached it's useable life.
The Velleman is no longer in the running.
See my next posts on my direction based on all the valued expertise here on this forum!
Go patriots!!!
Brap
Khorns, Forte's, Carver C-1, 1.5T, Denon AVP 8000, Sony DVP7000
WOW -- thanks for everyone's help. I think this post has reached it's useable life.
The Velleman is no longer in the running.
See my next posts on my direction based on all the valued expertise here on this forum!
Go patriots!!!
Brap
Khorns, Forte's, Carver C-1, 1.5T, Denon AVP 8000, Sony DVP7000
K4040 Mods
I'm the developer and maintainer of the "K4040 Mods Page" mentioned above. Along with others, I have performed somewhat extensive analysis of and tweaks to the K4040.
The good news is that the basic components of the K4040 (output transformers) are really quite good and the entire setup has a lot of potential right out of the box. Additionally the amp is the DYIer's paradise because it needs a few mods to sound good.
I've had two of these in the past and still have my "Powerhouse II". I have it modified to the point now where it can easily compete with amps costing 4x what I've got into it which is about $2K. In fact it souds so good that I have sold my SET monoblocks! The thing really performs and is POWERFUL on top of that.
You ask what tweak made the most difference? The tubes. KT88s blow EL34s off the map for sonic quality as far as I'm concerned and lukily the transformers in the K4040 are beefy enough to handle them!
Additionally the selection of the three preamp tubes is very important too. The ones which came with the kits I got were quite horrible.
What tweaks am I planning? I'd like to figure out how to replace the 12AX7/ECC83 second preamp & phase splitters with 6SN7s. I think that would be a worthy next mod. If any of you tube circuit engineers want to lend a hand with that, I'd appreciate it.
Thanks!
I'm the developer and maintainer of the "K4040 Mods Page" mentioned above. Along with others, I have performed somewhat extensive analysis of and tweaks to the K4040.
The good news is that the basic components of the K4040 (output transformers) are really quite good and the entire setup has a lot of potential right out of the box. Additionally the amp is the DYIer's paradise because it needs a few mods to sound good.
I've had two of these in the past and still have my "Powerhouse II". I have it modified to the point now where it can easily compete with amps costing 4x what I've got into it which is about $2K. In fact it souds so good that I have sold my SET monoblocks! The thing really performs and is POWERFUL on top of that.
You ask what tweak made the most difference? The tubes. KT88s blow EL34s off the map for sonic quality as far as I'm concerned and lukily the transformers in the K4040 are beefy enough to handle them!
Additionally the selection of the three preamp tubes is very important too. The ones which came with the kits I got were quite horrible.
What tweaks am I planning? I'd like to figure out how to replace the 12AX7/ECC83 second preamp & phase splitters with 6SN7s. I think that would be a worthy next mod. If any of you tube circuit engineers want to lend a hand with that, I'd appreciate it.
Thanks!
Banned
Joined 2002
I've got a K4040, and from my experience, the phase inverter is the weakest point. The original concertina PI have very little, or no headroom at all. To expect a concertina PI to drive 4 x EL34 is a little bit optimistic - IMHO.
I have modified my K4040 PI to a paraphase variant, and with 55volts rms of headroom from the PI, the K4040 got a new life.
I’ve got some pictures here: http://www.veiset.net/K4040/k4040PImod01.html
(In Norwegian only, but pictures tells the story)
I have modified my K4040 PI to a paraphase variant, and with 55volts rms of headroom from the PI, the K4040 got a new life.
I’ve got some pictures here: http://www.veiset.net/K4040/k4040PImod01.html
(In Norwegian only, but pictures tells the story)
jleaman said:
Jleaman,
I couldn't help but be intrigued by your answer. I followed through your webpage and saw that it seems that you've done quite a bit of DIY and the Gainclone seems to be your thing.
I'm a beginner and trying to decide from where to start. I'm considering a variety of options so I'd appreciate your constructive feedback on why the Velleman sounds like 'junk' and what would you recommend instead.
Thanks,
tube.rico
Hi there.......I might be an old salt at tube amps but I often wonder why relatively newish manufacturers are so keen to sell stylish tube amps...and haven't learnt from previous design hallmarks from yesteryear. No critisism to enthusiasts....(it's our market).. I always say to newcomers, have a crack a time served design that has been proven to work. Mullard 5-10's 20s & loads of SE designs out there...
Recent lavish exotic designs which have to be up-ended on my bench for debug are a pain-in -the- butt.
I don't have a posh car....which (for some reason) the electronics is suspect for recall.... how about a well designed tube amp ? One should Never even think about a recall to fix a botch-up. .
richj
Recent lavish exotic designs which have to be up-ended on my bench for debug are a pain-in -the- butt.
I don't have a posh car....which (for some reason) the electronics is suspect for recall.... how about a well designed tube amp ? One should Never even think about a recall to fix a botch-up. .
richj
A word about Velleman K 4040
At the advice of another Velleman K4040 user I replaced the EL34 by Russian 6S3P tubes, which are equivalents to 6L6-tubes. The sound has improved,but at the expense of the 10Ohm/5W resistors blowing out after a few months. My wife is getting a bit jumpy over this. You are the expert on 'tweaks', can you recommend a way to solve this problem? Thanks, Maarten
(Where do I find your site?)
At the advice of another Velleman K4040 user I replaced the EL34 by Russian 6S3P tubes, which are equivalents to 6L6-tubes. The sound has improved,but at the expense of the 10Ohm/5W resistors blowing out after a few months. My wife is getting a bit jumpy over this. You are the expert on 'tweaks', can you recommend a way to solve this problem? Thanks, Maarten
(Where do I find your site?)
The original Ella's - the ones with the three big round tranny cans on top - are incredible values. Power tranny is way overbuilt so you can run 88's, 34's, 6550's or even 100's in them. Very open design and very easy to get inside and mod and improve. Built 4 of them - all performing flawlessly.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.