Go Back   Home > Forums > >

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Boyuu EL34 A9 Tube Amp
Boyuu EL34 A9 Tube Amp
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools
Old 23rd October 2020, 07:20 AM   #1331
Tubby23 is offline Tubby23  United Kingdom
diyAudio Member
 
Join Date: May 2020
Location: London
You have crackling on both channels?
If only one, try swapping the power tubes and then the drivers to find out which is/are bad.
__________________
What Hi-fi?!
I can only hear up to 13K!
  Reply With Quote
Old 23rd October 2020, 08:30 AM   #1332
pelanj is offline pelanj  Czech Republic
diyAudio Member
 
Join Date: Jul 2008
Boyuu EL34 A9 Tube Amp
Russian tubes are actually very good. I bet you could get EL34 from some online musician shop easily, these are the most common tubes in guitar amps.
  Reply With Quote
Old 23rd October 2020, 10:08 AM   #1333
DIYBobbie is offline DIYBobbie  Australia
diyAudio Member
 
Join Date: Aug 2019
Location: NSW Australia
Boyuu EL34 A9 Tube Amp
Default Crackling problem

Quote:
Originally Posted by Tubby23 View Post
You have crackling on both channels?
If only one, try swapping the power tubes and then the drivers to find out which is/are bad.
Hi Tubby, Thanks for your reply.

The crackling is actually more prominent in the right channel. However, if I change the tubes right to left the crackling is still more evident in the right BUT it is also heard in the left channel to some extent.

This made me think the rectifier tube was at fault. However, on changing that tube nothing changes. Still crackles as before. I have some new tubes in the post and we will see if they fix the problem. I hope that they do and the problem is not more deep rooted.

Cheers.
Bobbie
  Reply With Quote
Old 23rd October 2020, 11:25 AM   #1334
Tubby23 is offline Tubby23  United Kingdom
diyAudio Member
 
Join Date: May 2020
Location: London
Hmm.. I'd start off by checking the RCA input plug connections and solder joints, then the sheathed signal cables themselves and where they solder into the driver tubes.
Have you modded the original design?
Added caps and negative feedback to the drivers?
__________________
What Hi-fi?!
I can only hear up to 13K!
  Reply With Quote
Old 23rd October 2020, 11:56 AM   #1335
DIYBobbie is offline DIYBobbie  Australia
diyAudio Member
 
Join Date: Aug 2019
Location: NSW Australia
Boyuu EL34 A9 Tube Amp
Default Crackling amp

I run the input thru a bluetooth setup. Your suggestion of checking the inputs may be a another good place to investigate.

Cheers,
Bobbie
  Reply With Quote
Old 24th October 2020, 06:20 PM   #1336
OldHector is offline OldHector  Sweden
diyAudio Member
 
Join Date: Jun 2018
Location: Täby, Sweden
I've seen some people recommend using an insulated pointer, and tap around the PCB and connections, to see if the noise is triggered that way, highlighting a potential dry joint or loose connection.
  Reply With Quote
Old 25th October 2020, 08:20 AM   #1337
Tubby23 is offline Tubby23  United Kingdom
diyAudio Member
 
Join Date: May 2020
Location: London
Another way of investigating is turning on the amp with the, left, then right, then both driver tubes removed while listening out for the noises. This method helped me determine a few "bugs". Good luck and keep us posted.
__________________
What Hi-fi?!
I can only hear up to 13K!
  Reply With Quote
Old 27th October 2020, 05:37 AM   #1338
DIYBobbie is offline DIYBobbie  Australia
diyAudio Member
 
Join Date: Aug 2019
Location: NSW Australia
Boyuu EL34 A9 Tube Amp
Default Crackling Amp

Hi Tubby23 and all who suggested remedies,

Found the cause of the crackling. As I have mentioned previously I run the amp thru an el cheapo tone control pre-amp with input from from a bluetooth setup. The el cheapo tone control uses a 6k4 tube per channel and simply reseating these valves fixed the problem.

Thanks to all who had suggestions, much appreciated,

DIYBobbie

PS: Some may scoff at the use of this pre-amp. However, I can assure that it works well especially in the bass department
  Reply With Quote
Old 28th October 2020, 05:18 PM   #1339
Tubby23 is offline Tubby23  United Kingdom
diyAudio Member
 
Join Date: May 2020
Location: London
Just thought I'd share my latest upgrade.
I just swapped out my Tung-Sol SL7GT s for NOS Sylvania JAN-CHS-6SL7GT s and, oh my, what a difference they make!
The amp is noticeably brighter, with clearer treble and bass. The soundstage appears wider too.
Can't say if this will have the same effect on stock A9s - I added bypass caps and local negative feedback to my driver stage but I think it's worth a try - it certainly won't get any worst..
Attached Images
File Type: jpg IMG_20201028_161243.jpg (644.2 KB, 83 views)
File Type: jpg IMG_20201028_161257.jpg (587.8 KB, 79 views)
__________________
What Hi-fi?!
I can only hear up to 13K!

Last edited by Tubby23; 28th October 2020 at 05:19 PM. Reason: Politeness
  Reply With Quote
Old 28th October 2020, 05:30 PM   #1340
IlikeTech is offline IlikeTech  United States
diyAudio Member
 
Join Date: Apr 2020
Location: Maine
Is it just me or has that Sylvania gone to air. The white getter flash isn't generally a good sign.
  Reply With Quote

Reply


Boyuu EL34 A9 Tube AmpHide this!Advertise here!
Thread Tools

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
Boyuu hifi Equis A10 EL34B+6N2 SE Tube Amplifier with 5Z4P rectifier: review and mod ygg-it Tubes / Valves 84 31st October 2020 05:21 AM
My new el34 + 12ax7 VCT amp. (Need Ideas For my first headphone vacuum tube amp Too~) briansune Tubes / Valves 10 12th July 2013 06:33 PM
FS: DIY EL34 / 6SN7 Tube Amp john65b Swap Meet 2 12th March 2012 03:02 AM
EL34 tube amp that needs work on el34ecc88 Tubes / Valves 0 17th December 2008 09:05 AM
EL34 vs. 6L6GC for 1ST DIY Tube Amp? pjkunz Tubes / Valves 4 17th December 2001 03:51 AM


New To Site? Need Help?

All times are GMT. The time now is 05:48 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki