Hi John,
I have been using the D402 since 2 weeks now and I am quite happy. Neutral but pure sound, I use it with mp3/4 streaming over my sound system, DVD, turntables and CD, it sounds great.
On the building process it's properly explained but a few more small step to step pictures might be good.
About the Hypex modules, I noticed some hacking on the SMD resistors, are these improvements from the regular UcD-180?
The background noise [sounds like 60Hz] is affected by the potentiometer position. The middle position gives me the lowest noise when no signal is present on the Line input.
I might have some common mode noise issue as the modulation cable are close to the transformer.
All in all it's a very good DIY audio product, with which I am very pleased.
Pierre
San Jose, USA
Answer:
Nice to hear you're enjoying the D-402. And yes we alter some things on the Hypex modules. The most important change is in the feed back where the input sensitivity is altered in a way so you can connect any sound source giving ample amplification.
If the noise (or hum) gets more notecable when turning the volume knob down it looks like a kind of ground loop. Therefore control if the cinch inputs (without the attached wires) are isolated and free from the chassis (rear panel).
D-402
(received 4-4-2008)
Dear Mr.Sluis,
I have finished the construction of the D-402 amplfier. I am testing it and my first impression was amazing. The distortion is very low and the response is very fast. It is worth to have this sound quality with this low price.
Best regards,
Ka Hing Wong
Hong Kong
P-12 + A-60's
The sound of this set is more then impressive. Last weekend I enjoyed more hours listening then over the last few months. This is apalling. Thanks for this wonderful product.
Kind Regards
Jelle
Sleeuwijk, Netherlands
D-702-HG
(received 3-20-2008)
Hoi John,
Because of the intended (loud!) listening level I had to postpone my try outs. Last saturday I gave it a first try.
From the first moment it was clear that the sound (character) of my guitar and pre-amp is more clearly pronounced. Differences between the channels is better discernable. The sound is bright but less shrill, giving a warmer impression. Also the dynamics are far better pronounced then with my previous amp. Not only the sound is bigger, but it's also better predictable and that's why I have more control when playing the guitar ( The dynamic attacks are better "translated").
Last night I played a bit and also accompanied some music from CD. It became clear that the sound was integrated into the music, it simply went fluently into the music. This was a big surprise, I never experienced this. Not even with the pre-amp directly connected to the mixer.
In short, my set from guitar to loudspeaker at last gives me the feeling of a complete instrument, with which - as far as my capabilities go - I can articulate and intone. This way I can express my feelings.
All this is very nice. In my opinion this type of amplifier is extremely useful for the amplification of instruments and PA.
Regards
Mischa
Heerhugowaard, Netherlands
Reaction:
This D-702 has been offered by us for a very short time and nowadays we only deliver the mono-type D-701 model.
Our amplifiers are designed for use at home in a common stereo or surround set up. So, in principle, they are not intended for the use of instrument amplification. It's nice to hear that our amps also satisfy in this application.
There's a big difference with common instrument amplifiers in that sector in the sense that our amps are "colorless". Also the control over the loudspeaker behaviour is much better then with most "professional" amplifiers.
John
