Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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

Your thoughts please
Your thoughts please
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 30th October 2002, 06:57 AM   #31
fdegrove is offline fdegrove  Europe
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Default BALANCED

Jeff,

Quote:
I had this idea once. It was put to me that it was necessary to have a single ended stage *somewhere* in the signal path. I can't remember the exact reason, but I think it had to do with imbalances produced by the phono cartridge. Was this bad information?
While some catridges (mostly MM moving magnet) have a ground connection tied to one of the negative output pins and as such render them unbalanced,all MC cartridges are fully balanced and
should provide equal output on all four pins.

So it seems the information you got was incomplete at least.
Gain stages should include a way to balance differences in gain internally.

Best regards,
__________________
Frank
  Reply With Quote
Old 30th October 2002, 07:00 AM   #32
fdegrove is offline fdegrove  Europe
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Default TANGO

Hi,

Quote:
XE20-S, XE45-5 and XE45-8
Am I correct in thinking these are all SE OPT's?

Rgds,
__________________
Frank
  Reply With Quote
Old 31st October 2002, 01:04 AM   #33
dice45 is offline dice45  Germany
diyAudio Member
 
Join Date: Jan 2002
Location: Munich, Bavaria
Frank,
XE20-S is single ended & versatile for 2k5, 3k5, 5k primary and 4-8-16R secondary.

XE45-5 (5k primary) and XE45-8 (8k primary) are PP with 4-8-16R secondary and an additional separate FB secondary.

Lundahl only has 3k or 5k primary and 8R secondary. Which is to be preferred from the technical POV. No idle winding parts around, making the trannie inefficient. Just repeating what *any* Xfrmr expert said to that topic.
__________________
Regards,
Bernhard
  Reply With Quote
Old 31st October 2002, 03:10 AM   #34
Ken L is offline Ken L  United States
diyAudio Member
 
Join Date: Sep 2002
Location: deep south
To dice

Found the tango XE 45-8 for $201 each - didn't say anything about freight

Lundahl 1663 $94 - minimal freight

BFW tamura

http://www2.big.or.jp/~sunaudio/tamura/out1.html

F-685 for about $407 per pair including air freight

Was the Tamura ever a consideration?

Ken L
__________________
No longer powered by Linux - not enough apps and cross platform integration - but maybe one day
  Reply With Quote
Old 31st October 2002, 05:46 AM   #35
jeff mai is offline jeff mai  Australia
diyAudio Member
 
jeff mai's Avatar
 
Join Date: Aug 2002
Location: Melbourne
Quote:
Originally posted by Ken L
To dice

Was the Tamura ever a consideration?

Ken L
My Tamura OPTs are superb (model F-7002.)
  Reply With Quote
Old 31st October 2002, 10:19 AM   #36
fdegrove is offline fdegrove  Europe
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Default OPT

Hello Ken,

Here is a link to a European distributor specializing in audio xformers to allow you to have a look at the specs.:

http://www.trasformatoriaudio.com/tamura.html

On paper at least quite a few Tamura's outperform Tango's counterparts especially in bandwidth extension at freq. extremes.
I'm not going to discuss price differences since you may well find them a lot cheaper elsewhere.

Here is also an article that should be taken at face value:

http://www.studiomaudio.com/howto.html

There is also a handful of European manufacturers out there able to make excellent xformers but I fear importing those to the U.S.
will make these less attractive due to added taxes and shipping.

Hope this helps,
__________________
Frank
  Reply With Quote
Old 31st October 2002, 11:00 AM   #37
dice45 is offline dice45  Germany
diyAudio Member
 
Join Date: Jan 2002
Location: Munich, Bavaria
Ken,

not for me. Unreal as it sounds, i am dremaing of making my amp a product if sonics are satisfying me. And, thinking product, I am going to replace a $$$$ Tango with a $$ Lundahl if sonically possible; i am not going to display them on the top plate anyway.
i am not going to replace a $$$$ Tango with a $$$$ Tamura.

However, the Tamuras are reputed to have good to outstanding sonics, depending on the model and some hardcore Janaese audiophiles prefer Tamura to Tango.

Tango uses C-cores with 0.1mm thick sheetmetal; so does Lundahl. Just, Tango pots, Lundahl not. I tend to agree with Mike LaFevre's opinion on potting (see one early Sound Practises issue). Hate to admit it.
__________________
Regards,
Bernhard
  Reply With Quote
Old 31st October 2002, 02:23 PM   #38
fdegrove is offline fdegrove  Europe
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Default TO POT OR NOT TO POT....

Bernhard,

Thank you for the info on the Tango range.
From what I understand Tango are now restuctured internally and they made changes to the range of product.

All,

Quote:
I tend to agree with Mike LaFevre's opinion on potting (see one early Sound Practises issue). Hate to admit it.
I would hate to admit that too,so I don't.

I recall having read this article in SP years ago and I had found similar arguments against potting OPTs elsewhere.

However one can unnerve the arguments easily as well:

What they are afraid of is the stray capacitance caused by the potting resin and the metal can playing havoc with the freq. response of the transformer.
A good transformer however will have this calculated in before potting is applied and so far I haven't been able to observe freq. abberations with high q. brands.
And what about the added capacitance of the leadout wires?
Better not twist those pairs tightly together as I see some people do it.

What they don't tell the public either is that it is both cheaper and easier to design a non-potted transformer as opposed to a potted one.
All too often I see those unpotted transformers arrive with shifted laminations and that is something very undesirable.
I would not feel comfortable with that product when being told to untighten the bolts and to realign the laminations,knowing that these bolts should not be overtightened nor undertightened in the first place and will have a direct effect on its performance.

Another factor is that if windings and laminations are not properly isolated from structureborne and airborne vibrations,they will at some point start to resonate and therefore add distorsion all of their own.
This is especially the case when neither laminations nor windings have been impregnated with high temperature varnish.
Again a lenghty and time consuming process requiring industrial ovens.
In short it takes a lot more effort and time on the manufacturers' side to make a decent potted one then a non-potted OPT would.

Add to that that they want to penetrate an already very competitive niche market and it becomes all of a sudden understandable why they argue against potting anyway.

One way of reducing stray capacitance while still protecting the OPT from the elements is using tightly fitting pots and sealing them with good quality resin at the bottom,or,better still using ceramic end bells as they used to do in the distant past and use a counterfitting bottomplate which is spotwelded to the can.(remember UTC,Partridge and such?)
Now that would be molto expensive,right?

Another good practice is to isolate the OPT from the chassis by using rubber grommets and washers for example.

I am pretty sure that I missed some arguments so I don't claim the list is complete.
I just wanted to bring this point across.

Back to my bombshelter,

P.S.Don't even be tempted to remove the potting on your existing OPTs,please!
__________________
Frank
  Reply With Quote
Old 31st October 2002, 08:47 PM   #39
Ken L is offline Ken L  United States
diyAudio Member
 
Join Date: Sep 2002
Location: deep south
Default I'm not above going with Tamura instead of Tango

All too frequently, when a company that has been making a superb high dollar product goes under and reopens under new management - the reissued product may be beneath the previous standard -

I noticed the Tango was rated at 45 watts while the comparable impedance Tamura was about 30 watts -

Would that be a factor running 45's push-pull?

I would go Lundahl first choice if they had the 8K impedance - and may do it anyhow, depending on my cash position at the time of purchase.

Ken l
__________________
No longer powered by Linux - not enough apps and cross platform integration - but maybe one day
  Reply With Quote
Old 31st October 2002, 09:05 PM   #40
fdegrove is offline fdegrove  Europe
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Default WATTAGE RATING

Ken,

See you,
Quote:
I noticed the Tango was rated at 45 watts while the comparable impedance Tamura was about 30 watts -
In the case of the 45/2A3/6B4G/300B PP it wouldn't matter one bit,the 10 W margin won't play that much of a role.

I haven't run through the Lundahl range for your requirements yet but they have a very good rep.
According to Bernhard they don't carry the 8K you require and 5K is a bit of a mismatch.


Cheers,
__________________
Frank
  Reply With Quote

Reply


Your thoughts pleaseHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Any thoughts on this 108 cab? DaveCan Full Range 31 22nd May 2009 01:05 PM
813 Thoughts Steven-H Tubes / Valves 40 26th January 2008 03:24 AM
HT thoughts bjackson Multi-Way 5 8th February 2006 06:18 PM
Any thoughts on this Amp? ShinOBIWAN Solid State 8 3rd March 2005 02:43 AM
Some DAC thoughts Bernhard Digital Source 9 31st January 2005 03:54 PM


New To Site? Need Help?

All times are GMT. The time now is 09:13 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki