Build Your Own Clone Message Board

It is currently Fri Aug 19, 2022 5:28 am

All times are UTC - 6 hours




Post new topic Reply to topic  [ 38 posts ]  Go to page Previous  1, 2
Author Message
 Post subject: Re: Tweed Royal Mods
PostPosted: Fri Mar 22, 2013 7:33 am 
Offline
User avatar

Joined: Wed Feb 27, 2013 11:46 am
Posts: 9
I’ve installed the Mini Watt into my newly built BYOC Tweed Royal, and for a few minutes it worked fine, scaling the overall volume of the amp perfectly. I did notice a slight delay in the volume changing after turning the knob, but I assume that’s normal as the valves take time to react.

However, at some point after switching between Single Ended and Push Pull modes a few times while I was testing the amp, I noticed that the overall volume of the amp was maxed out, and the Mini-Watt was having no effect. The SE/PP switch also crackles when I switch between modes and I can see a bright spark on the switch contacts as the connection is made. Apart from that the amp still works as I would expect.

Any ideas what might have gone wrong here, and where I should start looking to do any fault diagnosis ?


Top
 Profile  
 
 Post subject: Re: Tweed Royal Mods
PostPosted: Fri Mar 22, 2013 9:11 am 
Offline
User avatar

Joined: Wed Mar 04, 2009 6:36 pm
Posts: 1376
Location: Toronto, Canada.
Russell wrote:
I’ve installed the Mini Watt into my newly built BYOC Tweed Royal, and for a few minutes it worked fine, scaling the overall volume of the amp perfectly. I did notice a slight delay in the volume changing after turning the knob, but I assume that’s normal as the valves take time to react.

That's caused by the caps slowly charging/discharging. Normal

Russell wrote:
However, at some point after switching between Single Ended and Push Pull modes a few times while I was testing the amp, I noticed that the overall volume of the amp was maxed out, and the Mini-Watt was having no effect. The SE/PP switch also crackles when I switch between modes and I can see a bright spark on the switch contacts as the connection is made. Apart from that the amp still works as I would expect.

Any ideas what might have gone wrong here, and where I should start looking to do any fault diagnosis ?

The SE/PP switch is not the safest switching method to put it simply. I would put the amp in standby while switching modes.

_________________
http://www.pdfelectronics.com/


Top
 Profile  
 
 Post subject: Re: Tweed Royal Mods
PostPosted: Fri Mar 22, 2013 9:31 am 
Offline
Moderator
User avatar

Joined: Wed Apr 26, 2006 5:14 pm
Posts: 8657
Location: Truckee, CA
Chris - standby mode is the center position of the rotary switch, i.e. there is no separate standby switch and the amp goes to standby while switching from one mode to another.

Any suggestions for beefing up the SE to PP switching?

Russel - carefully inspect the wiring on your rotary switch and re-work the solder joints on the switch to ensure you don't have a bad connection. Actually, I'd prefer it if you would open a new support thread and post some photos of your rotary switch wiring and mini-watt installation.

_________________
MasterDelayer/Reverbrador/Ampaholic/TopJacker


Top
 Profile  
 
 Post subject: Re: Tweed Royal Mods
PostPosted: Fri Mar 22, 2013 9:37 am 
Offline
Moderator
User avatar

Joined: Tue Jan 02, 2007 1:24 pm
Posts: 15554
Location: Albany, NY
ChrisM wrote:
The SE/PP switch is not the safest switching method to put it simply. I would put the amp in standby while switching modes.

The middle position of the SE/PP switch IS standby, since the incoming DC voltage from the rectifier is disconnected. Keith's recommendation is to leave at the intermediate standby position for 3 seconds when switching between the SE and PP modes.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2


Top
 Profile  
 
 Post subject: Re: Tweed Royal Mods
PostPosted: Fri Mar 22, 2013 9:49 am 
Offline
User avatar

Joined: Wed Feb 27, 2013 11:46 am
Posts: 9
I have been leaving it a good 5 seconds in standby before selecting one of the output modes, but I still get a fair spark. I just wondered if this was normal.

I'll test the voltages out tonight...

Sorry, I missed the comment about opening a new thread, I'll do that when I have some pictures to upload :)


Top
 Profile  
 
 Post subject: Re: Tweed Royal Mods
PostPosted: Sat May 11, 2013 9:27 pm 
Offline

Joined: Sat Apr 27, 2013 10:22 pm
Posts: 58
Location: marseille, france
A video showing different mods I did on the Tweed Royal.
Enjoy (I hope :) )

http://maz18nrdiary.webs.com/apps/video ... royal-mods


Top
 Profile  
 
 Post subject: Re: Tweed Royal Mods
PostPosted: Thu May 23, 2013 10:38 am 
Offline
Moderator
User avatar

Joined: Tue Jan 02, 2007 1:24 pm
Posts: 15554
Location: Albany, NY
The Ampbooks gain calculator shows pretty clearly that the effect of the cathode resistor rating is swamped by the large bypass cap. So if you don't want to hassle with adding switchable values for the bypass cap and the cathode resistor, I'd suggest a simple on-off switch for the cap and pick whichever resistor value that corresponds to the desired magnitude of gain drop you'll get from switching the cap off. Using a 12AX7 at V1, you'll get the following gain differences with the bypass cap in or out:

2.2K - 7.7 dB
1.5K - 5.9 dB
820R - 3.7 dB

With a lower gain preamp tube, the differences won't be quite as large. You can calculate them from the gain vs. frequency curves I posted links for.

Also, if you're going for "max 5E3 character", maybe you want to go with a 12AY7 at V1, to mimic that circuit more closely. You'll lose some gain (somewhere in the 2.3 - 4.7 dB range, depending upon resistor rating and having the cap in or out), but you can probably just make that up by running the volume a bit higher. Your Champ single-ended setting will definitely lose some gain, as well, but back off on the negative feedback and you can get that back.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2


Top
 Profile  
 
 Post subject: Re: Tweed Royal Mods
PostPosted: Sun Mar 08, 2015 5:08 am 
Offline

Joined: Fri Mar 06, 2015 2:08 am
Posts: 5
Well im joining in on the Mini-watt mod. The only question I have since the instructions for installation are very straight forward is what value/kind of diodes are connected to 1-3 of the power tubes.


Top
 Profile  
 
 Post subject: Re: Tweed Royal Mods
PostPosted: Mon Mar 09, 2015 1:07 pm 
Offline
Moderator
User avatar

Joined: Tue Jan 02, 2007 1:24 pm
Posts: 15554
Location: Albany, NY
A 1N4007 will certainly do the job and is rated for voltage way above anything it would ever see in the TR.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2


Top
 Profile  
 
 Post subject: Re: Tweed Royal Mods
PostPosted: Mon Mar 09, 2015 7:09 pm 
Offline

Joined: Fri Mar 06, 2015 2:08 am
Posts: 5
Thanks. I order it today.


Top
 Profile  
 
 Post subject: Re: Tweed Royal Mods
PostPosted: Fri May 06, 2022 8:51 am 
Offline

Joined: Sat Apr 16, 2022 9:46 am
Posts: 1
How was your experience after ordering? IF someone like to share plz.

_________________
Check my blog https://alvenda.com/phenq-amazon/


Top
 Profile  
 
 Post subject: Re: Tweed Royal Mods
PostPosted: Fri May 06, 2022 3:03 pm 
Offline
Moderator
User avatar

Joined: Tue Jan 02, 2007 1:24 pm
Posts: 15554
Location: Albany, NY
This amp kit is no longer offered.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 38 posts ]  Go to page Previous  1, 2

All times are UTC - 6 hours


Who is online

Users browsing this forum: No registered users and 1 guest


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

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group