Primrose(SumR Audio) Toroid GB - Page 60 - diyAudio
Go Back   Home > Forums > Commercial Sector > Group Buys

Group Buys Members group buys

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 Search this Thread
Old 22nd January 2014, 11:07 AM   #591
diyAudio Member
 
Join Date: Oct 2009
Quote:
Originally Posted by alazira View Post
I have the ones for EUVL's F5X and, without a load, they are silent. Hopefully it will remain so as it would be a PITA to send these to Canada.
In my EUVL F5X under load the Sumr’s buzz.
Not excessively, I can only hear it from a couple of inches away.
I kind of expect this is normal, especially considering the current draw.

  Reply With Quote
Old 23rd January 2014, 12:30 AM   #592
BDP is offline BDP  United States
diyAudio Member
 
Join Date: Apr 2002
Location: SE Washington State
I would be satisfied if I couldn't hear it five feet away, but I can't accept hearing the buzz in the other room.
  Reply With Quote
Old 23rd January 2014, 12:40 AM   #593
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
It is obvious you have a bad one. Contact Richard and he will rectify the situation. He has handled this very professionally up to this point and I don't expect it to change.
__________________
...Shape the sound , Man!
  Reply With Quote
Old 4th February 2014, 12:18 AM   #594
labjr is offline labjr  United States
diyAudio Member
 
Join Date: Apr 2003
Location: MA
Quote:
Originally Posted by Tea-Bag View Post
How about someone in the know establish a basic loading test with minimal parts etc to test for mechanical noise. Something we can standardize on for in the cheap. If I have the parts already - I will do it and send it on to the next guy....
I'm wondering if someone has come up with a test procedure yet? Preferably something that doesn't need a variac as I don't have one.
  Reply With Quote
Old 4th February 2014, 01:34 AM   #595
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
Take your rail voltage and divide the bias current your amp will be set at. The number you get is the value of the resistor you should load your PSU with tied from each rail to ground. Just make sure you have adequate dissipation ratings. Probably easiest to parallel multiple 3W resistors. Light bulbs will also work, but will be more e expensive in the end. For most FW amps, which use 22V rails and about 1-2A bias, you are looking at about 10R. You could buy a large resistor or get 10-20 cheap 3w types.
__________________
...Shape the sound , Man!
  Reply With Quote
Old 4th February 2014, 02:05 AM   #596
labjr is offline labjr  United States
diyAudio Member
 
Join Date: Apr 2003
Location: MA
I have a bunch of 6 ohm 50 watt resistors and a power supply board built up. I'll try to wire it up when I have time. Thanks
  Reply With Quote
Old 6th February 2014, 08:04 AM   #597
diyAudio Member
 
ByronInPortland's Avatar
 
Join Date: Nov 2010
Location: Portland, Oregon
Thumbs up My Pimrose in Action

I forgot all about this thread, and was surprised to see it still alive. I finished my amp using my Pimrose transformer long ago. I'm very happy with this tranny. Thank you, Buzzforb for arranging this group buy!
Attached Images
File Type: jpg acryllic amp_side view.jpg (160.6 KB, 184 views)
File Type: jpg acryllic amp_done.jpg (398.3 KB, 185 views)
  Reply With Quote
Old 14th June 2014, 08:07 PM   #598
BDP is offline BDP  United States
diyAudio Member
 
Join Date: Apr 2002
Location: SE Washington State
Quote:
Originally Posted by BDP View Post
I finally installed the SumR transformer as part of the group buy (400VA, 22VAC) and it mechanically buzzes badly, not usable for my standards.

While I was waiting for the SumR transformer I was testing a single channel F4 with a 120VA, 22VAC Plitron and it was dead silent at full bias.

I would suggest everyone involved in the group buy test their transformers before too much time passes.

BDP
I wanted to report back that SumR exchanged both transformers and both are completely quite. Richard was very good to correspond with. I never heard what the problem was with the first batch, but these two units perform perfectly.

BDP
  Reply With Quote
Old 14th June 2014, 09:21 PM   #599
labjr is offline labjr  United States
diyAudio Member
 
Join Date: Apr 2003
Location: MA
Quote:
Originally Posted by BDP View Post
I wanted to report back that SumR exchanged both transformers and both are completely quite. Richard was very good to correspond with. I never heard what the problem was with the first batch, but these two units perform perfectly.

BDP
Who paid the shipping cost?
  Reply With Quote
Old 5th July 2014, 10:57 PM   #600
RKH is offline RKH  United States
diyAudio Member
 
Join Date: Sep 2002
Location: Colorado, USA
Default Testing

I finally got around to setting up a test rig for my SumR transformers.

- Variac supplying the transformer (so I can ramp the voltage slowly)
- Secondary output of transformer feeding a bipolar PSU ("+"-ground- "-")
- Output of PSU feeds load of 300-Watt light bulbs (up to 3) wired in parallel
-- I can change load by inserting or removing bulbs.

I am measuring the DC current through and the voltage across the load. Here is what it looks like. Quantitative report to follow, but in an initial test I can hear buzzing from about 3 feet away.

Cheers,
Ryan
Attached Images
File Type: jpg testRig1.jpg (453.4 KB, 52 views)
File Type: jpg testRig2.jpg (791.6 KB, 53 views)
__________________
Lighten up while you still can ...
  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
FS: F5X GB chassis and all GB parts Studley Swap Meet 6 21st May 2013 12:47 PM
Kits to start an audio electronics lab GB ashaw Group Buys 0 30th September 2011 02:28 PM
GB for R2R audio volume / input selection pcb danzup Group Buys 147 22nd May 2011 05:42 PM
1kva Toroid GB Sweden widerström Group Buys 0 18th March 2008 10:45 PM
Conrad Heatsinks GB in GB/EU bremen nacht Parts 1 1st February 2006 09:48 PM


New To Site? Need Help?

All times are GMT. The time now is 06:12 PM.


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