Hi
I have a little headphone amp running Mullard EF80's or EF184 (much quieter).
Last night I found a nice pair of E180F tubes in my stock, would these be a straight swap
seems the only pin out difference is that the screen is connected to Grid 3, all other specs seem close.
Any thoughts would be great, as I would like to build another as a preamp and have heard the E180F is a good choice
Cheers
I have a little headphone amp running Mullard EF80's or EF184 (much quieter).
Last night I found a nice pair of E180F tubes in my stock, would these be a straight swap
seems the only pin out difference is that the screen is connected to Grid 3, all other specs seem close.Any thoughts would be great, as I would like to build another as a preamp and have heard the E180F is a good choice
Cheers
Can you share your schematic of the E180F and 2a3? I have a pair of Philips 6688 with gold pins.
You can't directly replace EF184 with E180F, whithout rewiring the screen connection. -pin 9 from EF184 to pin 8 from E180F -pin 8 from EF184 to pin 9 from E180F -Cut wire from pin 6 (EF184) to ground, and leave te connection free. By the way, the Russian equivalent to E180F is 6J9P (6ж9п). These are very unexpensive and very good tubes. It's worth a trial.
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Hi Blaireau
Thanks for that, It might pay for me to just use these on the preamp rather than trying to mod the headphone amp.
I guess my question was also aimed at the compatibility and people thoughts of the E180F?
I just had a look on Ebay for the 6J9P, your right at only $1.50 USD a piece!! Might try a few.
Cheers
Thanks for that, It might pay for me to just use these on the preamp rather than trying to mod the headphone amp.
I guess my question was also aimed at the compatibility and people thoughts of the E180F?
I just had a look on Ebay for the 6J9P, your right at only $1.50 USD a piece!! Might try a few.
Cheers
They are the same....., but sounding is some different, I have and I don't like 6J9P /close is 6J11P/.
Alexg, This is my SE 2A3-RCA. Plate resistor E180F now is 13 kohm /not 33 kohm/ and upper
resistor 12 kohm now is 3 kohm/:
https://picasaweb.google.com/109570777566485968551/KVM#5413313827582447474
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E180f 6j9p
I have seen many times that use the E180F - 6j5p (Too 6e5p -D3a ) but dont understand how is possible to obtain the 180Vpp of swing voltagge that need for 2a3 - 300b - 6c33 in these tubes the bias are over -70V to -90V
I think that is mandatory to have at less 170vpp ( 200vpp is my target ) and in this case the optimum valves could be EF184 - 6485 - 6j5p - 6ah6
I am upgrading my amp that use 6ac7 driver and 6c33 running at 240v 130ma -90v bias, is why I am studing many tubes. The 6ac7 do 180vpp but the sound is not great.
Opinions and ideas are welcome.
I have seen many times that use the E180F - 6j5p (Too 6e5p -D3a ) but dont understand how is possible to obtain the 180Vpp of swing voltagge that need for 2a3 - 300b - 6c33 in these tubes the bias are over -70V to -90V
I think that is mandatory to have at less 170vpp ( 200vpp is my target ) and in this case the optimum valves could be EF184 - 6485 - 6j5p - 6ah6
I am upgrading my amp that use 6ac7 driver and 6c33 running at 240v 130ma -90v bias, is why I am studing many tubes. The 6ac7 do 180vpp but the sound is not great.
Opinions and ideas are welcome.
By using a CCS as anode resistor, it is possible to get more than 200 Vpp with low distortion.
As an example from my memos:
Triode connected 6J9P with CCS and 100k load resistance.
+Ub = 350 V, Ik = 12 mA, Ua = 220 V, Uout 80 Vrms (=226 Vpp), THD = 0,58 %, G = 32 dB
Below is a schematic showing the basic idea of such high voltage driver (but with different tube...)
An externally hosted image should be here but it was not working when we last tested it.
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Here you have the schematic of an amp I built (E180F driving 6C4C) - more see http://www.diyaudio.com/forums/tubes-valves/175429-yagoolars-tube-amp-projects-8.html
An inductor load will also allow for greater voltage swing on output of the driver tube.
He has 1.7V bias on the E180F.
There is 1.7V (D106) minus VbeQ1 (0.6V) =1.1V
This is across the two 68R resistors in series for a bias current of about 14.5mA.
Find the intersect of these on the plate curve and yous should find the anode voltage.
Unfortunately I don't have a datasheet with triode strapped curves.
6688 curve is here, and looks like around 140Vak.
http://www.triodeguy.com/Triodeguy PDF files/6688 Triode Curves RFS Measurements.pdf
He has 1.7V bias on the E180F.
There is 1.7V (D106) minus VbeQ1 (0.6V) =1.1V
This is across the two 68R resistors in series for a bias current of about 14.5mA.
Find the intersect of these on the plate curve and yous should find the anode voltage.
Unfortunately I don't have a datasheet with triode strapped curves.
6688 curve is here, and looks like around 140Vak.
http://www.triodeguy.com/Triodeguy PDF files/6688 Triode Curves RFS Measurements.pdf
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Measured
Ug1(E180F) = -1.9V
Ua = 145 V
I have not optimised the amp towards minimum distortion. Neither driver nor driver/output tube.
145V and -1.9 V bias .... from E180F (triode mode) data sheet, Ik must be 6mA!!
Really very far from optimal for this excellent tube.
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