How good is the Tamura TamRadio iron?

I have a set of Akia M8 transformers and waiting for an old Sony TC-500 to turn up.
Will compare the two, as they seem to be the same size measurement wise .
The M8 are not Nickel, sanded off the surface corrosion and they are GOSS .
Will do the same to the Sony Tamradio
 
Will measure both with the Akai M8 and Sony TC500 Tamdario transformers for freq responce with the Tektronix .
Will also measure inductance ,but by the sheer size they are unlikely to produce any serious bass below 40Hz .
The Tamradio has a 600 ohm winding so maybe quite useful for a headphone amp
 
Will measure both with the Akai M8 and Sony TC500 Tamdario transformers for freq responce with the Tektronix .
Will also measure inductance ,but by the sheer size they are unlikely to produce any serious bass below 40Hz .
The Tamradio has a 600 ohm winding so maybe quite useful for a headphone amp


Thread '5K Tape Machine OTs Tested'
5K Tape Machine OTs Tested
 
Great , saves some work .
Sony 15H- 0mA DC
Akai 24H-0mA DC
quite a big difference for same size iron
 
Great , saves some work .
Sony 15H- 0mA DC
Akai 24H-0mA DC
quite a big difference for same size iron
The Akai doesn't have the 600 ohm winding, so there's more room for more copper on the primary. It also seemed to saturate more easily, so it may have an air gap that isn't quite as large, which will certainly help with primary inductance.
 
Well, if the speaker the Akia transformer is driving is rolled off anyway, maybe it doesn't matter?
 
Will measure the Sony Tamradio with a SE 6BL7 plates strapped together.
The metal is silver/ white and looks very much like Nickel - Permalloy probably accounts for the drop in inductance to 16H rather than the copper difference between the Akai and Sony Tamradio .
With some CFB should be able to push them out to 18kHz
 
Based on the size of the TC-500 iron and the application, it's not nickel. The transformer would need to be quite a bit larger to function properly with a nickel stack, and size matters a lot in something like a TC-500.
 
Generally Nickel is part layered with M6,the later Tamura permalloy were %38 Nickel.
Those small 5K Tamradio's aren't up for more than 3 watts anyway.
 
Generally Nickel is part layered with M6,the later Tamura permalloy were %38 Nickel.
Those small 5K Tamradio's aren't up for more than 3 watts anyway.
Based on Pauls’s tests, 2.8W at 1kHz, 10% distortion. Well suited to an inexpensive and nice sounding 45 amplifier.
 
I think you would get better results with a triode strapped 4P1L driven close to A2 2- 2.5 watts 1.2K Plate R in triode , far less distortion near full power than a 45.
A PSE 6BL7 can be driven much harder than the manual dictates at 12 watt max both plates max dissipation , which would be jammed in an old TV cabinet , but in free air ,15-16 watts both plates strapped , 2.5-3 watts output 1.1K Plate R , lower than a 45 !
 
The 6BL7 is not so linear compared to the DHTs. I would not recommend using it as an output tube if you can afford something like a 2A3 instead.
 
You'd really need to pull them apart to know. What you may be looking at is a keeper or something compressible in there for squeezing down on the channel frame.
1621360557514.jpg
These both look like nickel from the front, but the lower transformer is GOS. Inspecting both the Akai and Sony transformers, I see keeper E lams turned around with no matching I lam at each end of the stack. The Akai transformer I have here is not well saturated in varnish, and that will change the appearance of the lams.
 
One of the Sony Tamradio's I have is cooked so will pull it apart and have a look .
I did pop the bottom cover off and all the laminations appeared clean and the same colour .
 
Hi, I tore down the cooked Sony Tamradio output transformer .

The Laminations tested so far are soft shiny and easy to bend by hand as you would expect from Nickel / Permalloy , they are not Silicon steel .

Oddly some appear to have a copper coating very strange , don't think it's the wax , but hey the wax was melted after its mishap maybe when Frank Sinatra and Roy Orbison were laying down some wonderfull analogue recordings .
 

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