details on Matsushita tube
Darryl Lock
audio amp that I have - it came from a small record player. The
numbering is very smeared but it looks like EDEH5 . The last three
letters are clear, the first two are not. It could be FDEH5 or EOEH5 .
It may be asking the impossible, but does anyone have pinouts and/or
data on these? I'm thinking of making a small headphone amp with
them.
Darryl
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* dar...@ozemail.com.au (Darryl Lock) *
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Harvey Axlerod
My guess is these are 50EH6 tubes. They are listed in the RCA tube manual
as equivalent to 6EH5, except the heater. Single ended, it is listed as 1.4W
at 7% distortion. It is a power pentode with the following pinout:
1 = K, G3 2 = G1 3,4 = H 5 = G1 6 = G2 7 = P
Hope this helps. I do have some NIB if you need them. Contact me directly
via e-mail if you need more details.. Harvey
In article <4fff5u$8...@oznet11.ozemail.com.au>,
--
/-------------------------------------------------------------------------\
| Harvey Axlerod, Chief Programmer Analyst, University at Buffalo |
| email: axL...@acsu.buffalo.edu voice: 716-645-3570 Fax: 716-645-3734 |
\-------------------------------------------------------------------------/
Scott Dorsey
>Two of these tubes (one each channel) make up a flea power (<1 watt)
>audio amp that I have - it came from a small record player. The
>numbering is very smeared but it looks like EDEH5 . The last three
>letters are clear, the first two are not. It could be FDEH5 or EOEH5 .
Sure it's not 60EH5? Two tubes with 60V filaments would be perfect for
120V power.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
John Botari
Lock) writes:
> Two of these tubes (one each channel) make up a flea power (<1 watt)
> audio amp that I have - it came from a small record player. The
> numbering is very smeared but it looks like EDEH5 . The last three
> letters are clear, the first two are not. It could be FDEH5 or EOEH5 .
>
> data on these? I'm thinking of making a small headphone amp with
> them.
Darryl:
Sorry it's taken so long to get back to you on this ... your posting
arrived at my news server only to-day. The tubes are, almost without
a doubt, of type 50EH5 -- a small power pentode used in phonos be-
cause of its high power sensitivity. The output of the crystal or
ceramic cartridge was connected directly to the grid of the 50EH5,
which was used in a straight Class A configuration.
By the sound of it, the amplifier of which you speak was from a stereo
phono -- one tube per channel. Output in this configuration was about
1.4W per channel at 7% THD (not exactly high fidelity!). Characteris-
tics of the tubes are as follows:
Plate supply voltage .............. 110 Volts
Screen (G2) supply voltage ........ 115 Volts
Cathode-Bias resistor ............. 62 Ohms
Peak AF Grid (G1) Voltage ......... 3 Volts
Zero Signal Anode Current ......... 42 mA
Zero Signal Screen (G2) Current ... 11 mA
Anode Resistance ............... 11000 Ohms
Transconductance ............... 14600 uMhos
Load Resistance ................ 3000 Ohms
Heater Voltage .................... 50 Volts
Heater Current ................... 150 mA
If you look at the way things are wired, the heaters of the two 50EH5
tubes are likely wired in series, and the whole thing was likely in
series with the phono motor -- providing the necessary voltage drop
to get the Australian mains voltage (220 VAC, as I recall) down to
the 100 volts or so needed to run the amplifier. There will likely
be a small solid-state or selenium half-wave rectifier to produce
the DC needed, along with a capacitive-input filter. Don't expect
stellar results ... this stuff was fairly typical of inexpensive
equipment.
Pinouts are as follows:
Pin Electrode
=== =========
1 Cathode (K), Suppressor (G3)
2 Control Grid (G1)
3 Heater
4 Heater
5 Control Grid (G1) -- second connection
6 Screen (G2)
7 Plate (Anode)
Information is from the RCA Receiving Tube Manual, edition RC-25 (1966).
Hope this helps you out!
jb
--
John Botari Environment Canada - Informatics Saskatoon, SK, Canada
E-mail: j...@desoto.wxe.sk.doe.ca
Voice: +1 306 975 6918 Fax: +1 306 975 6929
Darryl Lock
>Darryll...
> My guess is these are 50EH6 tubes. They are listed in the RCA tube manual
>as equivalent to 6EH5, except the heater. Single ended, it is listed as 1.4W
>at 7% distortion. It is a power pentode with the following pinout:
> 1 = K, G3 2 = G1 3,4 = H 5 = G1 6 = G2 7 = P
> Hope this helps. I do have some NIB if you need them. Contact me directly
>via e-mail if you need more details.. Harvey
Thanks, and I think you are correct. Someone else emailed me with
full details on a 50EH5. I had never heard of 50 volt heaters, so I
didn't guess that there might be a 6EH5 equivalent to 50EH5 !
Darryl Lock
>In article <4fff5u$8...@oznet11.ozemail.com.au> dar...@ozemail.com.au (Darryl Lock) writes:
>>Two of these tubes (one each channel) make up a flea power (<1 watt)
>>audio amp that I have - it came from a small record player. The
>>numbering is very smeared but it looks like EDEH5 . The last three
>>letters are clear, the first two are not. It could be FDEH5 or EOEH5 .
>Sure it's not 60EH5? Two tubes with 60V filaments would be perfect for
>120V power.
>--scott
>--
>"C'est un Nagra. C'est suisse, et tres, tres precis."
Others suggested 50EH5, and sure enough, the two filaments are in
series across a 110v transformer secondary, so I have the solution.
Thanks to all who helped.