DIY Audio Projects Forum
 NEW  Matt presents bias and operation data for the 6V6 tube in SE operation - 6V6 Single-Ended (SE) Ultra Linear (UL) Bias Optimization.

DIY Audio Projects Forum

Welcome to the DIY Audio Projects Message Forum. Use these forums to discuss Hi-Fi audio and to share your DIY Audio Projects. Registration is free and required to post messages and view the file attachments. Registration will only take a minute and registered users do not see any advertisements. After you have completed the online registration process, check your email (including spam/junk folder) for the verification email to activate your account. New members are under moderation - so your posts will not be visible until approved by a moderator. See the Read Me 1st, Forum RULES and Forum FAQ to get started on the forum.

It is currently 12 Dec 2017, 07:28

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 1636 posts ]  Go to page Previous  1 ... 160, 161, 162, 163, 164  Next
Author Message
PostPosted: 09 Oct 2017, 09:34 
Offline

Joined: 20 Sep 2017, 08:08
Posts: 1
Made myself a networkplayer with this nice little amp:

Attachment:
P_20171008_143220s.jpg


Here is the amp-part:

Attachment:
P_20170920_201923s.jpg


It's battery powered and sounds really nice! The digital part consists of a raspberry pi and hifiberry plus, for those who might be interested.

It was a fun to build and I am really happy you shared it. Thank you!


This post has a file attachment. Please login or register to access it. Only Registered Members may view attached files.



Top
 Profile  
 
PostPosted: 12 Oct 2017, 07:00 
Offline

Joined: 19 Feb 2013, 05:16
Posts: 1
Just build this nice amp to a protoboard for testing but for some reason the other mosfet and R4 are warming quite a lot and the original 0.6W R4 was smoking. So I swapped 8.2ohm 5W in place for R4 and measured 520 mA through it. The other channel's R4 draws only 137 mA which i think is normal. Any tips for troubleshooting? I haven't noticed any mistakes in wiring and it's pretty much identical to the other channel.

The amp otherwise is working and I can hear both channels and they seem to in balance.


Top
 Profile  
 
PostPosted: 14 Oct 2017, 08:44 
Offline

Joined: 13 Oct 2017, 04:14
Posts: 1
Built this little amp a week ago and i just can´t get it to work... every voltage seems to be fine, the voltages on the pins, on the mosfet and the lm317. But no sound. I tried diffrent potentiometers, inputs, headphone jacks and no diffrence. Can the MOSFET´s be damaged if they put out the right voltages?

Thanks for replies! ;)


Top
 Profile  
 
PostPosted: 02 Nov 2017, 16:20 
Offline

Joined: 18 Oct 2011, 03:15
Posts: 14
Hi all, i am planning to start this weekend. Have soent about 30 pounds at conrad on parts and excited to build this with my son. Open question for me is how to check the 'dc offset'? I take it i turn on the amp, have no music playing and check potential difference between channel out and earth? What happens if it great than 10mv? An indication that something isnt right?
I am thinking of buying multiple resistors of the same values then measuring them with DMM and using as best matched pairs i can on each channel?
Thanks all, Richard

....ok, quick google and i think i have got the dc offset thing


Top
 Profile  
 
PostPosted: 03 Nov 2017, 03:50 
Offline
User avatar

Joined: 08 Aug 2009, 03:11
Posts: 2111
Location: Chilliwack, BC
It's coupled with a cap on the output. DC offset is moot unless you use a really leaky cap ;)

Cheers!

_________________
-= Gregg =-
* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
Work: Classic Valve Design


Top
 Profile  
 
PostPosted: 03 Nov 2017, 04:14 
Offline

Joined: 29 Oct 2017, 08:10
Posts: 1
Hey Guys

Shoo wow, 163 pages and a lot of time later I have finished reading the thread.

This is not my first amp build, built some small CMOYs and a O2 from JDS Labs.

This is my first Tube Amp build and I love it.
I was lucky enough to find a local guy who had had some really neat compact PCBs etched. The amp runs great although very hot so heat sinks are on the plans for the weekend. Was also lucky with power supply, the second one I pulled out my box of bits worked perfectly and is dead silent.

I have a Little Bear P1 Tube Amp and I think this new one sounds better. (I suppose there is the I built this myself factor that affects the sound).

I want to protect my headphones from the thump and know I need to put a delay circuit on the amp. I am looking at viewtopic.php?f=10&t=1480 for the details.

My question is, where in the amp circuit do I put this?
I assume it is between power and amp, but not sure at all.
(or does it make up part of a regulated supply)

Thanks a mill for a really fun and fantastic build.

Ross


Top
 Profile  
 
PostPosted: 05 Nov 2017, 13:53 
Offline

Joined: 18 Oct 2011, 03:15
Posts: 14
Yippie, built this over about 8 hours this weekend. Running off a wallwart, little hum, have 50k alps pot on input with gets noisy the higher the volume. Amp sounds bass heavy on cheap headphones and bass light on grado 325's. Currently using no name valve, cheapest conrad.ch had. Buying two GE JAN,s tonight, see how they fair. May try 1uF input cap see if bass improves? Want to build one as a pre amp? Any suggested changes when running as a pre amp?
Fantastic project. May build for friends and family and give as crimbo presents :-)


Top
 Profile  
 
PostPosted: 05 Nov 2017, 14:40 
Offline

Joined: 23 Feb 2017, 02:02
Posts: 52
mistamovie wrote:
Yippie, built this over about 8 hours this weekend. Running off a wallwart, little hum, have 50k alps pot on input with gets noisy the higher the volume. Amp sounds bass heavy on cheap headphones and bass light on grado 325's. Currently using no name valve, cheapest conrad.ch had. Buying two GE JAN,s tonight, see how they fair. May try 1uF input cap see if bass improves? Want to build one as a pre amp? Any suggested changes when running as a pre amp?
Fantastic project. May build for friends and family and give as crimbo presents :-)


Is your supply regulated or a switch mode? Normally non regualted supplies and these type of low ripple rejction circuits have allot of hum.

You are using a 0.1uF right now? what size is your output cap? is it 4700uF. If your already these values changing your 0.1uF would not increase bass however you can try. (0.22uF would be good as it will not distort your square as much while providing one times lower cutt of freq) (EDIT: I thought I was making a reply for MCA - Son of ZCA)

As a pre amp, your output cap would only need to be 2.2uF or higher, 1.5uF has a cut off of about 10hz with a 10k load. You can chose high quality metalised polypropene for better sound.


Last edited by KochiyaYamato on 05 Nov 2017, 19:16, edited 2 times in total.

Top
 Profile  
 
PostPosted: 05 Nov 2017, 14:59 
Offline

Joined: 18 Oct 2011, 03:15
Posts: 14
Hi KochiyaYamato,
Thanks for the reply. Currently running the amp stock, so 2.2uf on input and 470uF output.
Not sure about the wallwart, some little Phillips affair. Better that the laptop 12v I tried which was crazy noisy. Source tried so far is an iPod shuffle.... So what should I expect!!! Will hook up to my cd850mk2 after 12hours burn in. I've seen an additional cap to Earth on the input side could help with noise, and a 1000uF on the power supply could help. Will pick up a 12v pub battery tomorrow and see if that helps. Will definitely build more and try tinker a little to match better to my headphones. The thump worries me but can workaround with the right plugin order. Can't find a good schematic for the 12v thump delay. Missed out on the ge Jan valves :-( sure something else will come up. Am sure I will go higher voltage at some point but need to know what I am talking about first!!! I've also got the oatley low voltage headphone amp, has much more fun with this one so far


Top
 Profile  
 
PostPosted: 05 Nov 2017, 19:06 
Offline

Joined: 23 Feb 2017, 02:02
Posts: 52
With a calculation your cut off freq due to output cap is about 10hz (32ohm phones)


With calcualtion your cutt of freq would be about 7.7HZ with a 0.22UF input cap
http://sim.okawa-denshi.jp/en/CRhikeisan.htm


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 1636 posts ]  Go to page Previous  1 ... 160, 161, 162, 163, 164  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: Bing [Bot] and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
DIY Tube Projects :: DIY Tube Amp Kits :: DIY Speaker Projects :: DIY Solid State Projects :: DIY IC / Op-amp Projects :: DIY Phono Projects :: DIY Cable Projects :: Hi-Fi Audio Schematics
© diyAudioProjects.com - Terms of Service - Privacy Policy