Go Back   Home > Forums > > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Elekit News and products from Elekit

Reply
 
Thread Tools Search this Thread
Old 26th June 2020, 06:26 AM   #1
dkeath is offline dkeath  Australia
diyAudio Member
 
Join Date: Jun 2020
Location: Sydney
Default TU-8340VK Noisy in Right Channel

Hi All,


I have been getting an increasingly bad noise in the right channel of my ELEKIT 8340 for a while now. Just intermittent to start, but now there all the time. I have checked all the usual starting points, so not valves or external stuff, speakers, leads etc. Sounds like maybe a bad resistor/component or solder joint.

I need to lift the hood and start looking inside for the issue. I am going to go over everything and re-flow solder and check for dry joints etc, but any useful hints or potential component issues anyone else has found previously would be appreciated.

This has been my main stereo amp for over 3 years now and with the transformer upgrade is a fantastic amp. Getting lots of extra use due to COVID isolation time, and I have the time to tinker and fix.


Any help greatly appreciated.


DjK
  Reply With Quote
Old 26th June 2020, 07:35 AM   #2
vkung is offline vkung  Canada
diyAudio Member
 
Join Date: May 2005
Location: Vancouver BC Canada
please let me know the reference voltages

Last edited by vkung; 26th June 2020 at 07:37 AM.
  Reply With Quote
Old 30th June 2020, 12:37 AM   #3
Mancave62 is offline Mancave62  United States
diyAudio Member
 
Join Date: Jan 2016
Location: Baton Rouge
I had a bad solder pin on one of the pcb input connectors, was intermittent, but the unit would not bias on that channel. Re-flowed all the solder and bam everything was good. Was an easy fix, hope yours is also?
  Reply With Quote
Old 30th June 2020, 06:17 AM   #4
dkeath is offline dkeath  Australia
diyAudio Member
 
Join Date: Jun 2020
Location: Sydney
Thanks for responding.


I re-flowed all the solder, and especially around the solder bridges to the speaker jack boards.
I also checked all the test point voltages which was a good suggestion from VK.
All voltages plus or minus ok ranges.

Once reassembled, voila, no more noise. So yes, an easy fix as well, and back to just listening to music.


Cheers,


DjK
  Reply With Quote
Old 30th June 2020, 04:19 PM   #5
Mancave62 is offline Mancave62  United States
diyAudio Member
 
Join Date: Jan 2016
Location: Baton Rouge
Glad to hear it. Curious what tubes you are running? I haven't done any tube rolling yet, I'm using JJ 6ca7 for power, JJ 12AT7 for pre-amp. Thanks, Tom
  Reply With Quote
Old 2nd July 2020, 08:21 AM   #6
dkeath is offline dkeath  Australia
diyAudio Member
 
Join Date: Jun 2020
Location: Sydney
Hi Tom,



I am running NOS Phillips 7581 power and original Mullard ECC81/CV4024 pre valves.
I also have Triangle Esprit EZ and Comete speakers and a Doge 6 Valve preamp CD player hooked up to this.

The 7581 valves never sounded any good in guitar amps, so I tried them in the smaller TU-8200 ELEKIT amp and they tightened up the bottom end, gave more headroom/volume, and are very neutral in the mid-range. I had 4 so I put them in the 8340. With the VK mods/caps/transformer change, the 8340 can play any type of music with ease now. Even synthy super low bass stuff.

The Mullard CV4024 valves are a secret sauce. Still available at reasonable prices. I put them in the phase inverter position of any guitar amp that should have a 12AX7 there, and it improves tone and headroom every time. So I tried them in the 8340 and they are staying for good. I also have them in the Doge 6 pre amp. Just right, not too much gain or mush, and generally low noise. Lot's of microphonic ones about now though.

EL34/6CA7 valves never made me smile much in guitar amps. Barky mids and a weird low end. The best were the old Mullards, but they are unobtanium now. Probably all used up by 70's rock bands. Maybe ok for Marshall guitar amps in a band where there is a bass underpinning everything, but I found out 6V6 valves in a Marshall are killer. Lower volume for smaller gigs but with enough gain to bring road kill back to life.

I was going to try EL34 valves just for reference in the 8340, but do not have any handy and just never get around to it. Maybe I should just to see if I am missing some mojo.

But so happy with the 7581s that I just play music and enjoy the 8340. Unfortunately good 7581s are around 120 bucks each now. Ouch. I think I got my four for $150 years ago.

A few here by the looks. Not an ad for these guys, just a rough price reference for these types.



Power tubes
mullard cv4024



Cheers,


DjK
  Reply With Quote
Old 5th July 2020, 04:33 PM   #7
Steve Morley is offline Steve Morley  Canada
diyAudio Member
 
Join Date: Jan 2015
Location: Georgian Bay
Default My faves in the 8340

Genelex KT77 Russian reissue. Reissue Tungsol 12AT7 come close to the NOS Mullards to my ears. Cost less and are more reliable too.

A Mini Review of Three 12AT7 Tubes | Wall of Sound | Audio and Music Reviews

A Survey of Four Sets of Power Tubes in Two Push-Pull Amps | Wall of Sound | Audio and Music Reviews
 

Reply


TU-8340VK Noisy in Right ChannelHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Renkforce E-SA9 noisy on one channel jpcoetzee Chip Amps 7 25th May 2020 02:10 PM
Noisy left channel dnic77 Headphone Systems 0 12th September 2016 05:53 PM
Carver M-1.5t Noisy and weak one channel argonrepublic Solid State 9 21st January 2015 12:00 AM
Soundstream SA 245 noisy subwoofer channel Dr Zeus Car Audio 5 8th December 2010 03:57 PM
Noisy Channel in Hafler DH-200 neddyboy Solid State 9 15th September 2006 03:58 PM


New To Site? Need Help?

All times are GMT. The time now is 10:49 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki