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nishant's β24+α10 integrated amp build log

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Re: nishant's β24+α10 integrated amp build log

Postby dsolodov » March 5th, 2013, 8:14 pm

Resistors 1/4W 0.1% for D1 (0.5dB, Zatt=25KOhm, Zload=1000.475KOhm))
http://www.mouser.com/ProjectManager/Pr ... 83baea6464
Completed AMB projects: M³, σ11, σ25, ε24, γ1, γ2, LCDuino
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Re: nishant's β24+α10 integrated amp build log

Postby tommarra » March 6th, 2013, 10:51 pm

Day 7:

After a week of after work soldering, I am pleased to document that all electronic components of A10 are now complete!

This means in 7 days I have somehow managed to complete 6 AMB Labs projects! (S25, S22, D1, D2, LCDunio, A20)...whew!

A20 board.jpg

David vs Goliath.jpg



Now for the next phase - B24. I did some cost estimates and created more Mouser projects and more spreadsheets and looks like that the parts alone would cost about $800.

For the enclosure I am toying between ordering them from HiFi or buying heatsinks from Heatsink USA or Rapid LED, Aluminium sheets from Homedepot and building my own.

With the shipping across the pond the price for two enclosure for my design from HiFi is a hefty 400 Eur or about 520 USD.


Question:

How warm should the output transistors for A20 get during setup. When i was setting them up, they became noticeable warm - not even remotely hot, but the heatsinks were warm to touch. Should I get bigger heatsinks to have them run really cool?

The S22 supply with the 2 inch heatsinks did not even feel warm.
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AMB Projects built: B22 (Active ground), S22, S25, LCDunio, D1, D2, A20
AMB Projects in progress: A10+B24 integrated amplifier
http://www.amb.org/forum/nishants-beta24-alpha10-integrated-amp-build-log-t2193.html
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Re: nishant's β24+α10 integrated amp build log

Postby amb » March 6th, 2013, 10:58 pm

tommarra wrote:How warm should the output transistors for A20 get during setup. When i was setting them up, they became noticeable warm - not even remotely hot, but the heatsinks were warm to touch. Should I get bigger heatsinks to have them run really cool?

It's normal for them to get slightly warm, but not hot (unless you bias them really heavily). There is no need to get bigger heatsinks.

The S22 supply with the 2 inch heatsinks did not even feel warm.

If that σ22 is intended to power only the α20s, you could have used much smaller heatsinks because the current draw is low. I used 1" tall small footprint heatsinks for the σ22 in my reference α10 preamp, and they don't even get much temperature.
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Re: nishant's β24+α10 integrated amp build log

Postby Pinnocchio » March 7th, 2013, 7:20 am

Nice build. Keep on going! :D
Ciao!
Do
PREAMPs : AMB α10 + JC-80 | Balanced DCB1 | Mirand | Tortuga LDR
AMPs: β24 | NX Amp | Telos 390 Clone | ExtremA | USSA
DACs : TPA Buffalo II + NTD1 I/V | Mirand AK4490
Speakers : Astasia SD | Sagwee LT | ATS-4 in progress
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Re: nishant's β24+α10 integrated amp build log

Postby tommarra » March 7th, 2013, 10:17 pm

amb wrote:It's normal for them to get slightly warm, but not hot (unless you bias them really heavily). There is no need to get bigger heatsinks.


Great. I noticed while playing some music that the output transistors stay lukewarm almost all the time.


amb wrote:If that σ22 is intended to power only the α20s, you could have used much smaller heatsinks because the current draw is low. I used 1" tall small footprint heatsinks for the σ22 in my reference α10 preamp, and they don't even get much temperature.


It was an ordering error on mouser - I was ordering 2 inch heatsinks for a S22 power supply for B22s and ended up ordering them for A20s as well :-)

Pinnocchio wrote:Nice build. Keep on going! :D
Ciao!
Do


Thanks --- BTW i noticed from your signature that you built Jim Holtz Statememts - those are next on my DIY to-do list. Could you comment on their synergies with the B24 and overall sound impressions?
Also for a total noob to wood working (except a few workshops during my engineering school days long ago) is it a doable project?


______________________

Quick comment on the audio quality of A20 (unbalanced stereo)- they are outstanding!
I guess one word to descibe them would be 'transparent'. What you hear is what was recorded...or in my case encoded. Bad over compressed recordings come out bad and good recordings really shine.

Now these are obviously not B22s and thus dont have the same oomph or sense of limitless power in driving my Beyer T1s but for a line stage I think they will work perfectly fine.

Also, just like B22 they take a few minutes to start sounding their best - when I first turned them on there was a lifeless quality to the sound. So I just let them play for sometime without listening. WHen I put on the cans after about 10 minutes the bass was noticeably deeper and as a result the highs not as sharp.

I wonder if that is because the output semiconductors heat up and are biased optimally only after a few minutes of warm up.

All in all I am pleased with choosing A20 and not B22 for the line stage.

_______________________________________________

Also now I am wondering if I wrongly chose 5x gain on my build - I am not even 1/2 way on my source volume and already T1s are too loud. On an iPod I have to turn it all the way up to get decent audio.

Should I change the resistors and choose 1x or 2x gain for them to work neatly with B4?


Finally, Ti, could you please comment on whether the following capacitors would be good enough for the B24 power supply and/or if there are any recommended caps?

Mouser part # 647-LGU1J103MELC
http://www.mouser.com/Search/ProductDet ... U1J103MELC

I havent yet decided how to mount them so I am okay with any style.
AMB Projects built: B22 (Active ground), S22, S25, LCDunio, D1, D2, A20
AMB Projects in progress: A10+B24 integrated amplifier
http://www.amb.org/forum/nishants-beta24-alpha10-integrated-amp-build-log-t2193.html
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Re: nishant's β24+α10 integrated amp build log

Postby amb » March 7th, 2013, 10:42 pm

tommarra wrote:Also, just like B22 they take a few minutes to start sounding their best - when I first turned them on there was a lifeless quality to the sound. So I just let them play for sometime without listening. WHen I put on the cans after about 10 minutes the bass was noticeably deeper and as a result the highs not as sharp.

I wonder if that is because the output semiconductors heat up and are biased optimally only after a few minutes of warm up.

Indeed. As most amplifiers, these will sound their best when warmed up.

Also now I am wondering if I wrongly chose 5x gain on my build - I am not even 1/2 way on my source volume and already T1s are too loud. On an iPod I have to turn it all the way up to get decent audio.

Should I change the resistors and choose 1x or 2x gain for them to work neatly with B4?

If "B4" is β24, then I suggest not jumping to any conclusions yet. What you hear now with headphones is not related to how it will ultimately be (with β24 and speakers).

Finally, Ti, could you please comment on whether the following capacitors would be good enough for the B24 power supply and/or if there are any recommended caps?

Mouser part # 647-LGU1J103MELC
http://www.mouser.com/Search/ProductDet ... U1J103MELC

I havent yet decided how to mount them so I am okay with any style.

Yes, this one is fine. Get capacitor mounting clamps and fabricate a plate on which to mount them, similar to what I did with my reference β24.
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Re: nishant's β24+α10 integrated amp build log

Postby tommarra » March 7th, 2013, 10:54 pm

amb wrote:If "B4" is β24, then I suggest not jumping to any conclusions yet. What you hear now with headphones is not related to how it will ultimately be (with β24 and speakers).


Indeed I meant β24, and I hear you, too early to make any conclusions.

BTW how do you type greek characters, I have to make do with B and A :-(

amb wrote:Yes, this one is fine. Get capacitor mounting clamps and fabricate a plate on which to mount them, similar to what I did with my reference β24.


Thanks - I was planning to order parts on Mouser and from AMB shop for β24 over the weekend so this clarification helps
AMB Projects built: B22 (Active ground), S22, S25, LCDunio, D1, D2, A20
AMB Projects in progress: A10+B24 integrated amplifier
http://www.amb.org/forum/nishants-beta24-alpha10-integrated-amp-build-log-t2193.html
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Re: nishant's β24+α10 integrated amp build log

Postby amb » March 7th, 2013, 11:28 pm

tommarra wrote:BTW how do you type greek characters, I have to make do with B and A :-(

Easiest way is to copy and paste! :)
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Re: nishant's β24+α10 integrated amp build log

Postby Pinnocchio » March 8th, 2013, 6:27 am

Pinnocchio wrote:Nice build. Keep on going! :D
Ciao!
Do


Thanks --- BTW i noticed from your signature that you built Jim Holtz Statememts - those are next on my DIY to-do list. Could you comment on their synergies with the B24 and overall sound impressions?
Also for a total noob to wood working (except a few workshops during my engineering school days long ago) is it a doable project?


Hi Tommarra,

The Statements are great speakers but I compared them to two other pairs I have Tubasson Mark 2 and Astasia SD (those two are designed by my friend which is a sound engineer and speaker designer) and there is obviously some caveat with the Statements. I like them but the Dayton RS-225 bass drivers are not the best and there seem to be a something missing in the lower mids. It could also be the 100uF MKP in the mid section of the XO that is not good and I will change this to a Obbligato Oil capacitor. I have seen that those do a great job on the mids and open things up quite nicely. As far as "doability" building the speakers well... It is not the easiest build and will require lots of clamps. I had over 12 clamps when gluing pieces together. It is a fun build but a large one.

I have a B24 and a balanced a10 in my arsenal and it does sound REALLY good. Now I'm waiting for Ti's new DAC! :D

Ciao!
Do
PREAMPs : AMB α10 + JC-80 | Balanced DCB1 | Mirand | Tortuga LDR
AMPs: β24 | NX Amp | Telos 390 Clone | ExtremA | USSA
DACs : TPA Buffalo II + NTD1 I/V | Mirand AK4490
Speakers : Astasia SD | Sagwee LT | ATS-4 in progress
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Re: nishant's β24+α10 integrated amp build log

Postby MisterX » March 8th, 2013, 8:38 am

alt 224 = α
alt 225 = ß
1352.5 and counting.
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