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Old 20th April 2007, 01:56 PM   #411
schuhbu is offline schuhbu  Germany
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[QUOTE]Originally posted by cviller
Everytime I plug it into my system I'm startled on how wonderful it sounds and when I get all excited and want to turn up the volume, I get disappointed cos it won't go any higher. (well I just have to build myself a preamp)

Christian,
I completely agree with you - itīs really a wonderful sounding amp. Compared to the Babbelfish (which is the best amp I have had until now) it sounds "less romantic", more refined and has a firmer bottom end. Regarding the volume, although, I donīt share your doubts. Iīm using an Aleph P with two monoblock F4 amps in balanced mode to drive my Tannoy HPD 315s. Believe me - this goes really loud. The best is, its not only loud, it still sounds absolutely clean. There is absolutely no sign of stress or loss of details and control. Perhaps you should invest into another F4. You know: 2 amps play twice as loud as one amp
Thanks a lot to Mr. Pass, Veteran and of course you for sharing the schematics and PCBs of this amazing amp.
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Old 20th April 2007, 02:20 PM   #412
cviller is offline cviller  Denmark
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Quote:
Originally posted by schuhbu
I completely agree with you - itīs really a wonderful sounding amp. Compared to the Babbelfish (which is the best amp I have had until now) it sounds "less romantic", more refined and has a firmer bottom end. Regarding the volume, although, I donīt share your doubts. Iīm using an Aleph P with two monoblock F4 amps in balanced mode to drive my Tannoy HPD 315s. Believe me - this goes really loud. The best is, its not only loud, it still sounds absolutely clean. There is absolutely no sign of stress or loss of details and control. Perhaps you should invest into another F4.
Great, the European diy community is leading...
Do you have pictures of your new amps?

I have no doubts at all about the capability of F4 - it has enough power for me at least. My only doubts concern how consumers react to this new kid on the block.

Well, about my lacking volume - I have been trying to keep this a secret... I currently use a nad302 as preamp, which is why I cannot drive the voltage higher than line-level.
My speakers are also ordinary inefficient speakers, but still I get just about the volume I need.

I plan to use this attenuator: (I have calculated and bought resistors for a 48k load)
Constant impedance relay-resistor logarithmic attenuator

Now I just need to decide on the gain stage and find the time to build it.
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Old 20th April 2007, 06:00 PM   #413
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Quote:
Originally posted by veteran
Great work (like always) Mr Pass

Modifications added - I almost redesigned PCB. I will probably place sources in PDF format for a minute.

schematic f4_r0

Hi Veteran,
Great design. Are you going to offer boards?
Thanks!
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Old 20th April 2007, 09:15 PM   #414
schuhbu is offline schuhbu  Germany
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Quote:
Originally posted by cviller

Great, the European diy community is leading...
Do you have pictures of your new amps?
They are not yet completed and are still in their "skeleton phase". Still looks a bit like a spaghetti incident.
Next week Iīm going to complete the cabinets (I hope, I do so - my Aleph P looks this way since half a year now).

I used Veteranīs pdf for the boards. The transformer is 330VA, caps are Evox-Rifa and Sikorel, 152.000uF/amp.
Heatsinks are 325mm x 160mm x 40mm and get quite warm now, but I think they donīt get too hot. I can still touch them for several seconds without getting blisters.
The enclosure will be made of 8mm aluminum, the front panel of 15 mm aluminum silver anodised.

Quote:
Originally posted by cviller

I plan to use this attenuator: (I have calculated and bought resistors for a 48k load)
Constant impedance relay-resistor logarithmic attenuator
I hope you can read Cyrillic
Iīm using the Relvol of Dantimax. It works just fine for me.

Cheers
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File Type: jpg f4_1.jpg (58.0 KB, 1602 views)
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Old 20th April 2007, 09:16 PM   #415
schuhbu is offline schuhbu  Germany
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Some more details.
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File Type: jpg f4_2.jpg (85.4 KB, 1735 views)
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Old 20th April 2007, 09:34 PM   #416
cviller is offline cviller  Denmark
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Quote:
Originally posted by schuhbu

I used Veteranīs pdf for the boards. The transformer is 330VA, caps are Evox-Rifa and Sikorel, 152.000uF/amp.
Heatsinks are 325mm x 160mm x 40mm and get quite warm now, but I think they donīt get too hot. I can still touch them for several seconds without getting blisters.
The enclosure will be made of 8mm aluminum, the front panel of 15 mm aluminum silver anodised.
Looks really good, nice and solid! I think you have enough capacitance in your psu..

Are your heatsinks made of two square pieces? If so, you'll get better performance from them by rotating them so cold air can be "sucked" in in the bottom an blown out in the top. Placed horizontally makes them less efficient because the hot air cannot easily escape the fins.
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Old 20th April 2007, 10:25 PM   #417
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Just tip the whole thing on end. Problem solved. Looks great!
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Old 20th April 2007, 10:29 PM   #418
jleaman is offline jleaman  Belgium
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Quote:
Originally posted by ipolyakov



Hi Veteran,
Great design. Are you going to offer boards?
Thanks!

We are offering boards here >> http://www.diyaudio.com/forums/showt...80#post1189280
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Old 20th April 2007, 10:47 PM   #419
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Quote:
Originally posted by marsupialx
Just tip the whole thing on end. Problem solved. Looks great!
He can't, the RiFa electrolytic cans need to remain upright.
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Old 20th April 2007, 11:23 PM   #420
Magura is offline Magura  Denmark
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Quote:
Originally posted by jacco vermeulen


He can't, the RiFa electrolytic cans need to remain upright.

No, according to the application note the Rifa's can be horizontal as long at the vent is in the most upper position possible.


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