Author Topic: USB audio DAC, bluetooth reciver and shielded relays for tube amplifier  (Read 1330 times)

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Offline WildMOSFETTopic starter

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Guys, I'm designing a vacumm tube audio amplifier.
Configuration: push-pull ultralinear class B of EL34 8)

But I need some opinions :-//.

In addition to the analog line entry, I would also like to put a couple of modules:
1) DAC composed of USB input, analogue line output.
2) Bluetooth audio receiver, always with line out.

Can you recommend ready-made and tested modules?  :-BROKE
Can you also advise me on shielded relays for input selection? (old school method)  :-/O

Thanks for the attention  :-DMM

This is the 3D model of amplifier:
« Last Edit: March 17, 2019, 08:45:25 pm by WildMOSFET »
 

Offline jmelson

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Hmm, monolithic ICs, vacuum tubes and RELAYS?  Gee, think you can fit a Diesel engine in there, too?  Just to make sure you have all the major technologies covered in one project. ;)

Jon
 

Offline WildMOSFETTopic starter

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I think I have all the skills needed to bring these different technologies together.  :-DMM
I just need to find these two modules.  :-//
Ah, I see the diesel engine well anyway.  :-DD

Probably the beginner section is not very suitable for this thread...
 

Offline Audioguru

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Why are you designing an antique vacuum tubes amplifier that is 60 years old?
Where will you find the vacuum tubes and output transformers today?
 

Offline floobydust

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You are better off asking your questions at the diyaudio.com forums.
There is support there for whatever technology or circuit you want to build and listen to.
 

Online Gyro

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@Audioguru:

There are still plenty of audio transformer manufacturers (not sure about Canadian suppliers, but certainly US and Europe) and vacuum tubes are still readily available. As for the reason, builder's choice.

@WildMOSFET:

Looking at your images, the mains transformer and output transformer are not in the ideal orientation (windings all vertical) you are running some risk of induced hum.
« Last Edit: March 17, 2019, 10:46:57 pm by Gyro »
Best Regards, Chris
 
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Offline WildMOSFETTopic starter

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@Audioguru:

There are still plenty of audio transformer manufacturers (not sure about Canadian suppliers, but certainly US and Europe) and vacuum tubes are still readily available. As for the reason, builder's choice.

@WildMOSFET:

Looking at your images, the mains transformer and output transformer are not in the ideal orientation (windings all vertical) you are running some risk of induced hum.

I agree, as far as the material is concerned, you can find everything, just search on ebay to get an idea.

@Gyro, you're right, the power transformer must be placed horizontally and the cores must not be aligned. I missed this detail.

I think I found everything:

USB-DAC -> Line output:

https://it.aliexpress.com/item/Lusya-XMOS-U8-AK4490-Modulo-NE5532-DAC-USB-Decoder-Scheda-Audio-Supporto-per-16-32bit-192/32880205812.html?spm=a2g0y.search0104.3.63.60e1497fC73gt8&ws_ab_test=searchweb0_0%2Csearchweb201602_7_10065_10068_10890_319_10546_317_10548_10696_10084_453_454_10083_10618_10304_10307_10820_537_536_10902_10843_10059_10884_10887_321_322_10103%2Csearchweb201603_51%2CppcSwitch_0&algo_pvid=d72ff831-4e2d-40db-b39c-97785c5e06da&algo_expid=d72ff831-4e2d-40db-b39c-97785c5e06da-9

Bluetooth receiver -> Line output:

https://it.aliexpress.com/item/Lusya-CSR8675-Bluetooth-5-0-Senza-Fili-a-Bordo-del-Ricevitore-PCM5102A-I2S-DAC-scheda-di/32889060488.html?spm=a2g0y.10010108.1000023.14.299013e3edP6bo
« Last Edit: March 18, 2019, 11:20:08 am by WildMOSFET »
 

Online Gyro

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Bluetooth receiver -> Line output:

https://it.aliexpress.com/item/Lusya-CSR8675-Bluetooth-5-0-Senza-Fili-a-Bordo-del-Ricevitore-PCM5102A-I2S-DAC-scheda-di/32889060488.html?spm=a2g0y.10010108.1000023.14.299013e3edP6bo

The PCM5102A sounds very nice in the Arcam miniBlink. Of course implementation is everything, with much more impact than the devices used.
Best Regards, Chris
 

Offline DimitriP

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Why are you designing an antique vacuum tubes amplifier that is 60 years old?
Where will you find the vacuum tubes and output transformers today?

Transformers are easy. He can order from "next door"   http://www.antoniadis.com/   if he can't find anyting locally.


   If three 100  Ohm resistors are connected in parallel, and in series with a 200 Ohm resistor, how many resistors do you have? 
 

Offline WildMOSFETTopic starter

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Bluetooth receiver -> Line output:

https://it.aliexpress.com/item/Lusya-CSR8675-Bluetooth-5-0-Senza-Fili-a-Bordo-del-Ricevitore-PCM5102A-I2S-DAC-scheda-di/32889060488.html?spm=a2g0y.10010108.1000023.14.299013e3edP6bo

The PCM5102A sounds very nice in the Arcam miniBlink. Of course implementation is everything, with much more impact than the devices used.

I was looking at the datasheet of the components and they seem to have good features.:-DMM

@Gyro: Thanks for the feedback on PCM5102A. I agree on the implementation.

Instead regarding the relays for the selection of the inputs, I think they go well with the simple miniaturized relays.
If the contact area is small and the positioning is correct, they should not absorb many electrical disturbances.
If it works badly I can add a shield around (obviously connected to the ground). :-/O

If anyone is interested, I put the datsheets below. :bullshit:

USB-DAC:

https://www.akm.com/akm/en/file/datasheet/AK4490EQ.pdf
http://www.ti.com/lit/ds/symlink/ne5532.pdf

Bluetooth reciver:

https://www.qualcomm.com/media/documents/files/csr8675-product-brief.pdf
http://www.ti.com/lit/ds/symlink/pcm5102a.pdf
« Last Edit: March 19, 2019, 10:31:58 am by WildMOSFET »
 


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