It is currently Tue Mar 17, 2020 1:24 am

All times are UTC - 7 hours



Post new topic Reply to topic  [ 32 posts ]  Go to page Previous  1, 2, 3  Next
Go to page Previous  1, 2, 3  Next
Author Message
Post subject: Re: Weber Signature Series > or < reissue Jensens?
Posted: Tue Nov 06, 2012 3:39 pm
Offline
Aspiring Musician
Aspiring Musician
User avatar

Joined: Sun Jun 28, 2009 6:05 pm
Posts: 684
Location: Canada
Got the plate voltage by measuring off pin 3 to ground. 460 on one side, 462 on the other. Using the Weber bias calculator for a 6L6GC, that should be 45.4mA at 70% plate dissipation.

_________________
The ultimate Rolling Stones experience!
https://www.facebook.com/TheMainStreetExiles


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Weber Signature Series > or < reissue Jensens?
Posted: Tue Nov 06, 2012 3:41 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Bluesky, that's a pretty cool option on that bias probe. Too bad it doesn't read the screen (pin 6), too. I usually will read this one also --- just to be sure that its voltage is around 5 VDC less than the anode plates (usual value for amps with 470-ohm screen resistors).

Makes for a happier amp. :D


Top
Profile
Post subject: Re: Weber Signature Series > or < reissue Jensens?
Posted: Tue Nov 06, 2012 5:52 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
Powdered Toast Man wrote:
Got the plate voltage by measuring off pin 3 to ground. 460 on one side, 462 on the other. Using the Weber bias calculator for a 6L6GC, that should be 45.4mA at 70% plate dissipation.


That calculator gives you the plate current for 70% max plate dissipation for that plate voltage.

If you measured 75 mV (which equals 75 mA cathode current) at the Fender test point and 460 VDC plate voltage, then each tube is running at 37.5 mA cathode current (36 mA plate current) and gives you 17 watts at idle for each tube. That's only 57% max plate dissipation. You are still cold.

Note that Fender uses a 1 ohm, 5% tolerance resistor to measure cathode current. That means the actual cathode current could be anywhere between 71.25 mA and 78.25 mA. The bias probe uses precision 1 ohm, 1% tolerance resistors. I use it for both my BDRI and Weber 5F6A clone. The Weber does not have a 1 ohm resistor in the cathode circuit and I removed the 1 ohm resistor in the BDRI.

_________________
Bill

Image


Last edited by bluesky636 on Tue Nov 06, 2012 5:58 pm, edited 1 time in total.

Top
Profile
Post subject: Re: Weber Signature Series > or < reissue Jensens?
Posted: Tue Nov 06, 2012 5:54 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
BMW2002Ti wrote:
Bluesky, that's a pretty cool option on that bias probe. Too bad it doesn't read the screen (pin 6), too. I usually will read this one also --- just to be sure that its voltage is around 5 VDC less than the anode plates (usual value for amps with 470-ohm screen resistors).

Makes for a happier amp. :D


There are a number of probes that let you measure both cathode current and plate voltage. Never seen one that lets you measure screen grid voltage.

_________________
Bill

Image


Top
Profile
Post subject: Re: Weber Signature Series > or < reissue Jensens?
Posted: Tue Nov 06, 2012 6:54 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Bluesky, why does Fender use 5% tolerance resistors for the cathode-to-ground read position? It should be changed to a 1% tolerance one. I like Riken or Kiwame precision resistors. Sometimes, 10-ohms is better. Then you are reading in the 200-500mV range, which most meters are more precise.

Just a thought.


Top
Profile
Post subject: Re: Weber Signature Series > or < reissue Jensens?
Posted: Tue Nov 06, 2012 10:08 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
BMW2002Ti wrote:
Bluesky, why does Fender use 5% tolerance resistors for the cathode-to-ground read position? It should be changed to a 1% tolerance one. I like Riken or Kiwame precision resistors. Sometimes, 10-ohms is better. Then you are reading in the 200-500mV range, which most meters are more precise.

Just a thought.


Because 5% tolerance resistors are cheaper than 1% tolerance resistors. :lol: :lol: :lol:

Like I said, when I built my 5F6A clone I didn't put a resistor in the cathode circuits since I had the bias probe. Removing the resistor in the BDRI and using the bias probe only resulted in a small but measurable difference in cathode current readings.

_________________
Bill

Image


Top
Profile
Post subject: Re: Weber Signature Series > or < reissue Jensens?
Posted: Wed Nov 07, 2012 4:23 pm
Offline
Aspiring Musician
Aspiring Musician
User avatar

Joined: Sun Jun 28, 2009 6:05 pm
Posts: 684
Location: Canada
I've now got it running right at 80mV (at the test point). I'd rather keep it under 70% simply for tube life. The tone is quite a bit warmer now. Although the speakers don't really do well at higher volumes. :? They just sort of get fuzzy and lose definition. Not a pleasing breakup tone.

I've got an Ampeg Scrambler on eBay right now that I'm waiting to sell. Once that goes I'll probably pull the trigger on the Weber combo. It's already a very loud amp, what's a few more db? *shrug*

_________________
The ultimate Rolling Stones experience!
https://www.facebook.com/TheMainStreetExiles


Top
Profile
Post subject: Re: Weber Signature Series > or < reissue Jensens?
Posted: Wed Nov 07, 2012 4:26 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
Powdered Toast Man wrote:
I've now got it running right at 80mV (at the test point). I'd rather keep it under 70% simply for tube life. The tone is quite a bit warmer now. Although the speakers don't really do well at higher volumes. :? They just sort of get fuzzy and lose definition. Not a pleasing breakup tone.


That's approximately 40 mA cathode current per tube. What is the measured plate voltage at that point?

_________________
Bill

Image


Top
Profile
Post subject: Re: Weber Signature Series > or < reissue Jensens?
Posted: Wed Nov 07, 2012 5:26 pm
Offline
Aspiring Musician
Aspiring Musician
User avatar

Joined: Sun Jun 28, 2009 6:05 pm
Posts: 684
Location: Canada
bluesky636 wrote:
Powdered Toast Man wrote:
I've now got it running right at 80mV (at the test point). I'd rather keep it under 70% simply for tube life. The tone is quite a bit warmer now. Although the speakers don't really do well at higher volumes. :? They just sort of get fuzzy and lose definition. Not a pleasing breakup tone.


That's approximately 40 mA cathode current per tube. What is the measured plate voltage at that point?


Still coming in at 460

_________________
The ultimate Rolling Stones experience!
https://www.facebook.com/TheMainStreetExiles


Top
Profile
Post subject: Re: Weber Signature Series > or < reissue Jensens?
Posted: Wed Nov 07, 2012 5:28 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Tue Mar 01, 2011 3:10 pm
Posts: 5646
Location: Gateway to the West
Not to muddy the waters so to speak, but if it were me and you wanted better tone from your speakers once the amp is properly biased and set to optimal specs...try Kendrick Black Frame 10's, a superior speaker to the Weber IMHO. Costs a little more but certainly worth it!

T2

_________________
-----------------------------------------------------------
What time is it? It's Fender Time.


Top
Profile
Post subject: Re: Weber Signature Series > or < reissue Jensens?
Posted: Wed Nov 07, 2012 5:35 pm
Offline
Aspiring Musician
Aspiring Musician
User avatar

Joined: Sun Jun 28, 2009 6:05 pm
Posts: 684
Location: Canada
T2Stratman wrote:
Not to muddy the waters so to speak, but if it were me and you wanted better tone from your speakers once the amp is properly biased and set to optimal specs...try Kendrick Black Frame 10's, a superior speaker to the Weber IMHO. Costs a little more but certainly worth it!

T2


The Webers are already a total of $380 (plus shipping). The Kendricks are $150 a piece x 4 = $600! :shock: That's a bit more than a "little". I could buy a used DRRI for that!

_________________
The ultimate Rolling Stones experience!
https://www.facebook.com/TheMainStreetExiles


Top
Profile
Post subject: Re: Weber Signature Series > or < reissue Jensens?
Posted: Wed Nov 07, 2012 5:40 pm
Offline
Rock Star
Rock Star

Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
Powdered Toast Man wrote:
bluesky636 wrote:
Powdered Toast Man wrote:
I've now got it running right at 80mV (at the test point). I'd rather keep it under 70% simply for tube life. The tone is quite a bit warmer now. Although the speakers don't really do well at higher volumes. :? They just sort of get fuzzy and lose definition. Not a pleasing breakup tone.


That's approximately 40 mA cathode current per tube. What is the measured plate voltage at that point?


Still coming in at 460


Still cold.

Using the Weber bias calculator, the plate current is about 38 mA. At a plate voltage of 460 VDC, that's a plate dissipation at idle of 17 watts. 17/30 = 56% of max plate dissipation.

_________________
Bill

Image


Top
Profile
Post subject: Re: Weber Signature Series > or < reissue Jensens?
Posted: Wed Nov 07, 2012 7:06 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Tue Mar 01, 2011 3:10 pm
Posts: 5646
Location: Gateway to the West
Powdered Toast Man wrote:
T2Stratman wrote:
Not to muddy the waters so to speak, but if it were me and you wanted better tone from your speakers once the amp is properly biased and set to optimal specs...try Kendrick Black Frame 10's, a superior speaker to the Weber IMHO. Costs a little more but certainly worth it!

T2


The Webers are already a total of $380 (plus shipping). The Kendricks are $150 a piece x 4 = $600! :shock: That's a bit more than a "little". I could buy a used DRRI for that!


You get what you pay for in this case :!: Or you could find a set of CTS 10 Alnico's...another great speaker for this application. I just think the webers are a bit over rated for my ears...YMMV of course.

T2

_________________
-----------------------------------------------------------
What time is it? It's Fender Time.


Top
Profile
Post subject: Re: Weber Signature Series > or < reissue Jensens?
Posted: Wed Nov 07, 2012 8:00 pm
Offline
Aspiring Musician
Aspiring Musician
User avatar

Joined: Sun Jun 28, 2009 6:05 pm
Posts: 684
Location: Canada
T2Stratman wrote:
Powdered Toast Man wrote:
T2Stratman wrote:
Not to muddy the waters so to speak, but if it were me and you wanted better tone from your speakers once the amp is properly biased and set to optimal specs...try Kendrick Black Frame 10's, a superior speaker to the Weber IMHO. Costs a little more but certainly worth it!

T2


The Webers are already a total of $380 (plus shipping). The Kendricks are $150 a piece x 4 = $600! :shock: That's a bit more than a "little". I could buy a used DRRI for that!


You get what you pay for in this case :!: Or you could find a set of CTS 10 Alnico's...another great speaker for this application. I just think the webers are a bit over rated for my ears...YMMV of course.

T2


I have no doubt the Kendricks are good. But am I really going to hear the extra $220?

_________________
The ultimate Rolling Stones experience!
https://www.facebook.com/TheMainStreetExiles


Top
Profile
Post subject: Re: Weber Signature Series > or < reissue Jensens?
Posted: Thu Nov 08, 2012 5:16 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Tue Mar 01, 2011 3:10 pm
Posts: 5646
Location: Gateway to the West
That will depend on your ears :wink:

T2

_________________
-----------------------------------------------------------
What time is it? It's Fender Time.


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 32 posts ]  Go to page Previous  1, 2, 3  Next
Go to page Previous  1, 2, 3  Next

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 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

Search for:
Jump to: