Hypex UCD400 poweramp (with tube preamp)

[carrejans]

Hi,

I want to make a hybrid amplifier for bass guitar. I want to make the preamp of an "Ampeg Classic". (I have a thread of this in the "tubes" subforum.
For the poweramp, I want to use the UCD400 module from Hypex.

I have some questions about this hypex stuff; I hope you can help me out a bit.


- What do you think. Should I go with the UCD400ST or the UCD400HG? Is the big price difference worth it? I'm thinking for using the ST version.

- So, it doesn't matter which output impedance I use? So I can connect 4Ohm, 8Ohm, ... speakers? Without using an output transformer?

- For the mono supply, the rating is: 25V min and 42V max. The rating of the hypex transformer TR400 is 40VAC. Isn't this a bit too much?

- I think it is better for me to buy just one transformer for both preamp as poweramp? So my transformer should have these outputs:
* +/- 400 V (for the tubes)
* 6.3V (for the heaters of the tubes)
* 40V (for the hypex power supply)
(* 13V (if I go for the HG version with aux 12V output; or to use for a fan)

- I think such a transformer doesn't exist like that in a shop. Where can I get me one of these made? (I prefer Europe) What will be the cost, you think?

- The input of the UCD is differential. How do I connect my tube preamp?


Sorry, for so much questions. I will be very gratefull if some of these will get answered.

Jan



schematic of the preamp:
http://members.lycos.nl/carrejans/temp/AmpegPreamp.jpg

[Koifarm]

I want to make a hybrid amplifier for bass guitar. I want to make the preamp of an "Ampeg Classic". (I have a thread of this in the "tubes" subforum.
For the poweramp, I want to use the UCD400 module from Hypex.

I have some questions about this hypex stuff; I hope you can help me out a bit.


- What do you think. Should I go with the UCD400ST or the UCD400HG? Is the big price difference worth it? I'm thinking for using the ST version.]

Take the UCD700 for live instrument amp you can not have enough power.

- So, it doesn't matter which output impedance I use? So I can connect 4Ohm, 8Ohm, ... speakers? Without using an output transformer?]

Yes.

- For the mono supply, the rating is: 25V min and 42V max. The rating of the hypex transformer TR400 is 40VAC. Isn't this a bit too much?]

You have the wrong data for the UCD400 it is between 45 and 65V. For the UCD700 it is between 75 and 95V

- I think it is better for me to buy just one transformer for both preamp as poweramp? So my transformer should have these outputs:
* +/- 400 V (for the tubes)
* 6.3V (for the heaters of the tubes)
* 40V (for the hypex power supply)
(* 13V (if I go for the HG version with aux 12V output; or to use for a fan)]

Do use two transformers one for the UCD and one for the preamp. The UCD produces noise on the powersupply with one supply it will disturb the preamp.

- I think such a transformer doesn't exist like that in a shop. Where can I get me one of these made? (I prefer Europe) What will be the cost, you think?

Use this for the UCD700:

http://www.redrocksaudio.es/files/SMPS6060PFCen.pdf

And a separate transformer for the preamp.

- The input of the UCD is differential. How do I connect my tube preamp?]

This is also on the hypex site.

Signal from preamp goes on + sig. of the UCD.
Massa from preamp goes on massa of the UCD and on the - sig. of the UCD.

Ronny

[carrejans]

Originally posted by Koifarm


Take the UCD700 for live instrument amp you can not have enough power.



Yes.



You have the wrong data for the UCD400 it is between 45 and 65V. For the UCD700 it is between 75 and 95V



Do use two transformers one for the UCD and one for the preamp. The UCD produces noise on the powersupply with one supply it will disturb the preamp.



Use this for the UCD700:

http://www.redrocksaudio.es/files/SMPS6060PFCen.pdf

And a separate transformer for the preamp.



This is also on the hypex site.

Signal from preamp goes on + sig. of the UCD.
Massa from preamp goes on massa of the UCD and on the - sig. of the UCD.

Ronny

Hi,

Thank you very much for your answers.

- I'm not going for the UCD700; 400W is enough for me. (is also a bit less expensive)

- I just read the rating of the input of the supply, from the datasheet from the Hypex website. I think that will be correct, no?

- Ok, so I will have to use two transformers. I think it is best to use the one from Hypex for the ucd.

- I see there are other threads about hypex modules on this board. Will check them out.



Thank you