Coldamp

[tyee]

I have 3 amp modules and an SPS80 just waiting to be built when I have the time. Can't wait to hear it!!

[Bgt]

just did a test where I use a direct A/B switching on 2 stereo poweramps and found the mod of the 1 with the 4562 to give more 3D=depth than the 1 with the 5532. The latter is less stereo/wide than the 4562. The voice has more space with the 4562 chip. You need good speakers though to hear the sound widening with the 4562's.

[Erlend Sæterdal]

I have just received 2 x Sonora 750 and 2 x Sonora 250. I will use the Ad 8620 because it is the only opamp I can tolerate. Why on earth is there 10 ohm in series with the supply lines and only 100 nf. after them. I have very bad experience with this kind of design. I think I will short circuit those resistors. By the way the modules is still delivered with Ne 5532 why ?

[ssanmor]

Hi,
The RC configuration in the supplies of each opamp are there for filtering purposes (further removal of switching frequency in the supply of the signal stage), although given the good regulation of the aux voltages, it can be for sure removed and experimented with.
Regarding the input opamp, NE5532 has good price/performance balance. Some customers specifically ask for other opamps, and we usually exchange them at no additional cost (in any case we won't charge 20 euro more for a 3$ opamp). Next time, please ask first.

Hope to hear your experiences soon!

[Erlend Sæterdal]

Hi could it be possible to Change the opamp to a Discret single opamp ? I am not using the first stage . By the way my Coldamp is so good that a Tube entusiast think the concept ( including my very special mods ) must be something for the chinese market. None have ever seen anything like this. Every cap is plastic free and with silk isolation and oiled. Allmost all cables are silk isolated etc.

[ssanmor]

Hello, Erlend.
The second part of the input opamp is integrated into the control loop of the amplifier, so we don't recommend tweaking with it. You can, however, substitute the default NE5532 opamp with another dual opamp (pin compatible) of your taste. Some people have reported remarkable improvements with LM4562.
Congratulations for your superb mods and performance. Could you post photos here?

[Juhleren]

Hi ssanmor,

Would it be possible to use any of your amps as a current buffer (preferably no gain, or least possible gain) with a VAS design of own choice?

I am thinking of the possibility to build an amp with a VAS that I have the highest regards of, and then skipping its output current stage (that has no gain) for something else -maybe one of your sonora modules...

According to the data sheet the s450 seems to have connectivity for a potentiometer. Could this input for the power section be used as input for an external VAS?
- If so, what gain and circuitry follows this input?

Best,

[ssanmor]

Sorry for the delayed reply.
The gain of our amplifiers after the Potentiometer header is 45V/V. This can be modified to some extent but we don't recommend so. You can attenuate at the input to have a lower effective gain, but that depends on the noise characteristics of your preamp as well.
Hope this helps.