Another Simple SE builder - Page 10 - diyAudio
Go Back   Home > Forums > Commercial Sector > Vendor Forums > Tubelab

Tubelab Discussion and support of Tubelab products, prototypes and experiments

Reply
 
Thread Tools Search this Thread
Old 30th October 2008, 06:31 PM   #91
diyAudio Member
 
dsavitsk's Avatar
 
Join Date: Jan 2005
Location: Hartford
Quote:
Originally posted by n_maher
One other rectifier related question - I haven't looked into it all that closely yet but has anyone else looked at using a 5U4 in the power supply?
From Tubelab.com: "I have also tried about 6 different rectifier tubes 5U4, 5AR4, 5R4, ..."
  Reply With Quote
Old 30th October 2008, 06:47 PM   #92
n_maher is offline n_maher  United States
diyAudio Member
 
Join Date: Jul 2005
Location: Seacoast, NH
Quote:
Originally posted by dsavitsk


From Tubelab.com: "I have also tried about 6 different rectifier tubes 5U4, 5AR4, 5R4, ..."

You would have to read the instructions, Doug, wouldn't you.

That's good news since I have 5U4s, 5R4's and 5AR4s.
  Reply With Quote
Old 30th October 2008, 06:55 PM   #93
diyAudio Member
 
Ty_Bower's Avatar
 
Join Date: Mar 2007
Location: Newark, DE
I used a 5U4 for a short while. It works just fine, but I don't like how quickly it heats up. The rectifier is hot before the output tubes, and you get a relatively big surge on the supply caps. I prefer the 5AR4 with its nice, slow, gentle startup.
  Reply With Quote
Old 30th October 2008, 06:57 PM   #94
n_maher is offline n_maher  United States
diyAudio Member
 
Join Date: Jul 2005
Location: Seacoast, NH
Quote:
Originally posted by Ty_Bower
I used a 5U4 for a short while. It works just fine, but I don't like how quickly it heats up. The rectifier is hot before the output tubes, and you get a relatively big surge on the supply caps. I prefer the 5AR4 with its nice, slow, gentle startup.
That is one of the main differences yes. The 5AR4 certainly has a much more controlled rise time for the B+.
  Reply With Quote
Old 30th October 2008, 07:31 PM   #95
N1ESE is offline N1ESE  United States
diyAudio Member
 
Join Date: Oct 2008
Quote:
Originally posted by whitelabrat
They're beefier XSE's in a nutshell.
Exactly. They just have a little better low end frequency response and should be fine for our audio use.

XSE: 70~18,000 Hz
GXSE: 40~18,000 Hz

All other specs are the same. They also have CXSE's rated for 25W with 20~20,000 Hz response. However, these are $50 more than GXSE's and probably overkill for the Simple SE circuit.
  Reply With Quote
Old 30th October 2008, 10:17 PM   #96
diyAudio Member
 
tubelab.com's Avatar
 
Join Date: Jul 2005
Location: West Virginia panhandle
Quote:
CXSE's rated for 25W with 20~20,000 Hz response.
I bought a pair of the CXSE's for testing back when I was designing the Simple SE. I must admit that They tested out very good but I didn't really listen to them critically. Last year I got them out and connected them into a 300B amp. These have since become one of my favorite transformers. They sound really good. They are much larger than the XSE's and the GXSE's, about the size of the Hammond power transformer. If you have the space and the bucks, try them. If it were my amp, I would spring for the good transformers and start with lower cost output tubes. You can (and probably will) always upgrade the tubes but aren't likely to change the transformers. The transformers make the sound!

Quote:
I have also tried about 6 different rectifier tubes 5U4, 5AR4, 5R4,
I have indeed tried a bunch of different tubes. The 5AR4 and the 5V4 both warm up slow which is good. The others will start up faster than the output tubes which can cause problems, though they are still slower than the solid state diodes. The 5R4 requires a fairly small filter cap to avoid sparking out. For these reasons the 5AR4 is the preferred choice.

There have been several reports of sporadic bad quality from the octal JJ tubes, especially the EL34 and the 5AR4. Some users love them and some have had them instantly blow up. I have been using JJ EL34's in one of my Simple SE's for about 3 years without any problems. I have received a few emails from users that had JJ 5AR4's spark out on initial power up. One user had two tubes blow instantly and thought something was wrong with the amp. A Chinese 5AR4 worked perfectly.

Quote:
I buy all my tubes for my amateur radio projects from Jim McShane and he has some Chinese 5AR4's I will consider instead.
I have never bought tubes from him, but have never heard a bad thing from those who do. If he recommends a good Chinese 5AR4, try it.

Speaking of amateur radio, I am currently designing a monster transceiver for 902 MHz EME, about 600 watts. No tubes though
__________________
Too much power is almost enough! Turn it up till it explodes - then back up just a little.
  Reply With Quote
Old 30th October 2008, 11:01 PM   #97
N1ESE is offline N1ESE  United States
diyAudio Member
 
Join Date: Oct 2008
Quote:
Originally posted by N1ESE
They also have CXSE's rated for 25W with 20~20,000 Hz response. However, these are $50 more than GXSE's and probably overkill for the Simple SE circuit.
Well, shortly after I wrote this, I found some some audio curves on George's site of the CXSE's and now thinking of splurging on them.

Ty, sorry if I've hijacked your thread. Maybe I should start my own.
  Reply With Quote
Old 31st October 2008, 06:15 AM   #98
Zap is offline Zap  United States
diyAudio Member
 
Join Date: Jan 2006
Location: Milwaukee, WI
Quote:
Originally posted by N1ESE


Well, shortly after I wrote this, I found some some audio curves on George's site of the CXSE's and now thinking of splurging on them.

Ty, sorry if I've hijacked your thread. Maybe I should start my own.
I highly recommend the CXSE's as I'm running them on my Simple SE (using EH KT88, per your other thread no less) and they sound incredibly good. The power of the bass is nothing short of impressive even with inefficient speakers.

The one critique of bigger transformers is that they sometimes drop at higher frequencies, but as someone with better HF hearing than average I can definitely say I notice no deficiency with a pair of older Telefunken speakers that have good HF response due to the tweeters (at least in comparison to anything I've heard to date).

I would spring for the best iron and upgrade tubes as you go - I'm glad I decided to use the bigger transformers.
  Reply With Quote
Old 1st November 2008, 12:51 AM   #99
diyAudio Member
 
Join Date: Jun 2008
Quote:
Originally posted by tubelab.com


I bought a pair of the CXSE's for testing back when I was designing the Simple SE. I must admit that They tested out very good but I didn't really listen to them critically. Last year I got them out and connected them into a 300B amp. These have since become one of my favorite transformers. They sound really good. They are much larger than the XSE's and the GXSE's, about the size of the Hammond power transformer. If you have the space and the bucks, try them. If it were my amp, I would spring for the good transformers and start with lower cost output tubes. You can (and probably will) always upgrade the tubes but aren't likely to change the transformers. The transformers make the sound!
How would you compare the CXSE's with the Transcendars, George?
  Reply With Quote
Old 1st November 2008, 02:15 AM   #100
diyAudio Member
 
Ty_Bower's Avatar
 
Join Date: Mar 2007
Location: Newark, DE
George speaks on output transformers:

http://www.diyaudio.com/forums/showt...69#post1113169

Also be sure to follow the two links at the bottom of his post.
  Reply With Quote

Reply


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Zen V9 builder need help sandmarc Pass Labs 2 24th February 2008 08:02 PM
Looking for a BIB builder in either NC or VA Glowbug Full Range 3 9th July 2007 08:07 AM
Simple, SIMPLE Digital volume control -_nando-_ Digital Source 5 21st December 2006 02:20 PM
builder stuman69er Digital Source 0 3rd January 2006 07:55 AM
Simple answer required for a simple question... rabbitz Multi-Way 4 31st August 2003 11:05 AM


New To Site? Need Help?

All times are GMT. The time now is 06:33 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2