[FullRangeMan]

Just see a Tango trafo to 6C33 for sale:
http://www.ebay.com/itm/Tango-XE-20-600S-600ohm-Single-End-Output-Transformers-For-6C33C-Tube-/121527105619?pt=Vintage_Electronics_R2&hash=item1c4b947853

[S Clark]

Gustavo, you are much more knowledgeable than I am about electronics.  What is it about these that makes them better than other vintage transformers?

[FullRangeMan]

They sound good, however expensive.
I also not expert. The Tango are very well made in Japan, the sound quality are very good as reported by many users.

However various parameters are poor(*), except the Freq response, that show a nice treble to 100Khz.
Primary impedance: 600Ω
Secondary impedance: 4, 8, 16  Ω
Frequency Response: 30Hz - 100kHz (-2dB)
* Power output: 20w
Inductance: 2.2H - 3.3H (270mA)
* Max Allowable Current: 320mA
Dimensions: 83L x 75W x 104H mm
* Weight: 2.3 kg each

[FullRangeMan]

Gustavo, you are much more knowledgeable than I am about electronics.  What is it about these that makes them better than other vintage transformers?

Maybe you would like a more technical answer, then as a matter of fact, verily the factor that most influences the sound quality of an OPT is the balance of the pri/sec layers.

OPTs pri/sec windings are a compromise between capacitance/inductance:
Too few interleave layers=Too much capacitance.
Too much pri/sec layers= Too much Inductance.

If I remember well:
Too much capacitance= attenuated bass.
Too much Inductance= Attenuated Treble.

A great OPT have a good interleave balance.
Others minor built secrets are the wire, the paper or cloth insulation, annealing, cryogenics, encapsulation if used, chassis placement etc...
Regards

[FullRangeMan]

From $8,599.00 to $2,999.95
http://www.partsconnexion.com/product27252.html
It yet looks expensive to me, Oh price its per mono pair!

[FullRangeMan]

Wow this offer is indeed hot $300 for a small tube.
They have 6H30P-DR Reflector but at this price.
http://www.partsconnexion.com/tube_nos_6h30.html?utm_source=getresponse&utm_medium=email&utm_campaign=1express&utm_content=pcX%E2%80%99s+BULK+BUY+Sale+-+Expanded%3A+20%25+Off+6H30P-DR+Supertube%3B+87%25+Off+HP+6552A+Power+Supply%3B+20%25+Off+Reflektor+6P14P-EV%2FEL84%3B+20%25+Off+CONNEX+4x30uf+600V+Cap%3B+20%25+Off+Voskkod+6N1P-EV%3B+Dozens+More...

[JoshK]

If that is cheap, I am glad I got my 6H30P-DRs back back when I paid $20-25/ea. 

[FullRangeMan]

This price is absurdly expensive, Gstubes still have 6H30n-EB at $13 each.
The EB difference over DR is minimal.

[FullRangeMan]

Nice GM70 SE amp for $2600 from Croatia:
http://www.had-audiolab.com/products/power/cyclone-gm70-se-integrated

[E55l2]

For me this transformer have to weak bass, -2dB  at 30Hz isn't really a good performance.
Secondly the distortion would be a little high too because induction is to low.

I guess this transformer sounds airy but not balance enough. Any square waves to see if there is no ringing?

I saw better Tango's.

They sound good, however expensive.
I also not expert. The Tango are very well made in Japan, the sound quality are very good as reported by many users.

However various parameters are poor(*), except the Freq response, that show a nice treble to 100Khz.
Primary impedance: 600Ω
Secondary impedance: 4, 8, 16  Ω
Frequency Response: 30Hz - 100kHz (-2dB)
* Power output: 20w
Inductance: 2.2H - 3.3H (270mA)
* Max Allowable Current: 320mA
Dimensions: 83L x 75W x 104H mm
* Weight: 2.3 kg each

[FullRangeMan]

Any square waves to see if there is no ringing?

No that I know, but it may be there in the internet.

[bladesmith]

When a tube was produced is important and from what factory is was produced in, is very important.

It's like saying, " my 67" Pontiac GTO is the same as a 2000 Chevy GTO. 

[FullRangeMan]

When a tube was produced is important and from what factory is was produced in, is very important.

It's like saying, " my 67" Pontiac GTO is the same as a 2000 Chevy GTO. 

In the case of GM70 graphite plate tubes are all from Ulianov factory.

[E55l2]

To much interleaving , to much induction...

It dosn't matter, what counts is the frequency response and if there are any resonance problems. Secondly how low is the copper loss and at last how low is the core loss. A good balance would be 10Hz - 80kHz at -3dB, 1Watt with the tube as a sourse and not more then 0,3dB copper loss. EI core are worse then C-cores specially at low volume settings (EI sounds  worse because of the higher core loss,permeabilty problems at low exitation

Frequency respons is a matter of how much distorion is allowed at low frequencies and how good (how airy ) the top end must be..... Resonance problems must be avoid at any time. Distortion at low frequencies sounds "warm"  or a bulb in the low frequancies ( lack of control at the low frequancies).
The easiest way to detect the resonance problems is to look at the frequency respons at 50kHz to 1 MHz or the square wave response at 10kHz or 20kHz.

Not many transformer companies like to give data. It is difficult to understand what excactly the data will mean for the performanance but specially  many transformer companies want to hide that the transformer they make are not so good. Probebly they will say that the sound is special or something like that....

Maybe you would like a more technical answer, then as a matter of fact, verily the factor that most influences the sound quality of an OPT is the balance of the pri/sec layers.

OPTs pri/sec windings are a compromise between capacitance/inductance:
Too few interleave layers=Too much capacitance.
Too much pri/sec layers= Too much Inductance.

If I remember well:
Too much capacitance= attenuated bass.
Too much Inductance= Attenuated Treble.

A great OPT have a good interleave balance.
Others minor built secrets are the wire, the paper or cloth insulation, annealing, cryogenics, encapsulation if used, chassis placement etc...
Regards

[FullRangeMan]

Hi E55l2,
What you would say about this OPT??
EI 120/73 0,3mm annaeled
+- 1dB: 20Hz 25kHz
+- 3dB: 10Hz-45kHz
Primary 7K ohms
Copper wiring
Output 100W
weight 7kg

[E55l2]

You not give information if it is a SE or a PP.

EI is always second best (my personal opionion is : stupid, no need for EI because there are c-cores)

Look for the frequency respons after 50kHz. A good transformer has no resonance probles after this frequency.
Or look at the 10kHz square wave. No ringing/ overshoot. It dosn't mean anything just to tell the -3dB point at the high frequency point.

-3dB at what output? Specially EI have so much loss that at low levels the -3dB point at low frequencies will be totally different then at high or max level.

100W? Sounds as advertising bullshit.......

Hi E55l2,
What you would say about this OPT??
EI 120/73 0,3mm annaeled
+- 1dB: 20Hz 25kHz
+- 3dB: 10Hz-45kHz
Primary 7K ohms
Copper wiring
Output 100W
weight 7kg

[FullRangeMan]

Its SE.

[E55l2]

If this is all the information you have, not even the dc current then the transformer is very bad documented.
If it cost €50,- you can give it a try but probebly even this is a waste of money (7kg/100W/SE.....pfff)

Its SE.

[E55l2]

@ fullrangeman

Is this for a gm70 tube?

I hope to have some time to develop a propper SE transformer for this tube. I have some gm70 at home but i want to use the SV572-10 because i think this is even a more interesting tube. I made a 12K transformer for a 211 and i think i can make a very nice transformer for the gm70 too.

[FullRangeMan]

With 12K you use EI or C core?