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 19 Aug 2019, 04:02

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 276 posts ]  Go to page Previous  1 ... 24, 25, 26, 27, 28
Author Message
 Post subject: Re: MCA - Son of ZCA
PostPosted: 07 Feb 2018, 22:07 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 18:23
Posts: 5125
Location: Australia
Provide some images and listening notes. Did you stick 100% to the component suggestions?

_________________
Projects:"retro2308" - chip based headphone amp | ”Calibre 834” - tube phono MM preamp | ”najah” - Raw 180W Tripath Class D power amp | "Icon" - Shuguang CV-181Z preamp


Top
 Profile  
 
 Post subject: Re: MCA - Son of ZCA
PostPosted: 27 Feb 2018, 04:49 
Offline

Joined: 23 Feb 2017, 02:02
Posts: 517
bugeyes wrote:
with an 8 ohm 10w resistor across the binding post I get 0.0mv :wine:
thanks so much for the help, onto stabilizing the bias
cheers!

Wihout load seeing 14v at outpu is normal.
The proper way of fixing this is to connect a resistor 1M ohm at the output. I would recomend any 1/4w resistor or larger with 100k to 1m resisance.

Without any resistors connected to ground at the output, the output is floating and the voltage will be unkown.

I've seen this plorbem with one of my pre amps, during testing no resistors are connected at input, the input goes through capactor to amp. I was seeing a few volts I thought something was wrong.
Once I connected a 470k at intput instantly fixed the plorbem


Top
 Profile  
 
PostPosted: 20 Jun 2019, 13:15 
Offline

Joined: 25 Dec 2018, 08:41
Posts: 7
Today I tried to convert my ZCA to MCA.
All worked well, voltage adjusted at 12V, speaker hooked up and:

The hearing impression was terrible.

I switched between the the 3055 and the 2sk1058 for 5-6 times (Fixing screws, voltage adj............)
Nothing got better, harsh cymbals, harsh saxophone.
The smoothness, softness of the ZCA was lost.

I added some images of the parts u use.
Do they look counterfeit? The 3050 sideview looks mysterious...

I have no idea what is happening here.


Gerti


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



Top
 Profile  
 
 Post subject: Re: MCA - Son of ZCA
PostPosted: 20 Jun 2019, 18:43 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 18:23
Posts: 5125
Location: Australia
Not sure what the problem is here. I only made a rough prototype and thought it sounded OK. I don’t think that even if the parts were counterfeit that it would explain the poor performance.

Did you put it on the CRO to see if the signal is clean?

_________________
Projects:"retro2308" - chip based headphone amp | ”Calibre 834” - tube phono MM preamp | ”najah” - Raw 180W Tripath Class D power amp | "Icon" - Shuguang CV-181Z preamp


Top
 Profile  
 
 Post subject: Re: MCA - Son of ZCA
PostPosted: 21 Jun 2019, 04:52 
Offline

Joined: 25 Dec 2018, 08:41
Posts: 7
Monday at work I have access to a CRO.
Otherwise I would buy 3055 from different sources and have a try...........
Only the 2sk170 was difficult to get.
Any Ideas for a replacement?

Gerti


Top
 Profile  
 
 Post subject: Re: MCA - Son of ZCA
PostPosted: 21 Jun 2019, 04:54 
Offline

Joined: 23 Feb 2017, 02:02
Posts: 517
Fake transitors don't make any diffrence. Not enough for you to say "smoothness, softness of the ZCA was lost"

RS components only sells 100% geniune components all the time and gaurnanteed. They also offer free shipping even if you buy a single 1/4w resistor.
The k170 looks very geniune don't waste your time


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 276 posts ]  Go to page Previous  1 ... 24, 25, 26, 27, 28

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 8 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