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PostPosted: 11 Apr 2019, 21:14 
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Joined: 11 Apr 2019, 21:08
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I have a MENG Music Angel with 4 6AQ5s and 2 6N2s and want/NEED to upgrade to 6BQ5/EL84s and 12AD7s...Can anyone point me in the right direction please?
I am very new at schematics and wiring etc...I am a guitarist and artist...have been working with custom wiring my six string electric and repairing a couple of solid state amps successfully.


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PostPosted: 12 Apr 2019, 14:18 
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Joined: 19 May 2011, 05:38
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6N2 is a 6ax7 you will probably have to rewire the filament.
6aq5 is a 7 pin tube and the 6bq5 is a nine pin tube. Socket change will be necessary. you will have to resize the cathode resistors. (half of original value)

Schematics and pics would be a big help


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PostPosted: 12 Apr 2019, 14:47 
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Joined: 02 Mar 2009, 12:41
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Location: Vänersborg, Sweden
Why do you NEED to upgrade? You will propably not double the OP power (3dB) and propably the mains transformer will not cope with the higher demans of voltages and currents.

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PostPosted: 12 Apr 2019, 18:11 
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The chinese 6n2 is a 12ax7 but with changed heater pinouts.
Q means long life type and J means military use and M means for citizen use and T means special quality


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PostPosted: 12 Apr 2019, 19:44 
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At closer inspection. The MENG Music Angel MiniP (I believe) is labelled and advertised as 4 x 6AQ5 and 2 x 6N2. However. I noticed that the tubes in the amp are indeed 9 pin...so they can't be 6AQ5. Correct? And the reason I want the EL84 and 12AD7 is that I have read that it is a better set up for guitar amp...I really need it to be a preamp. I cannot find schematics YET...Been searching for days. If it is ok...I will send pics of the tubes (can't read the print at all) and also a picture of the board...both sides and of course...the entire amp. I popped a cap trying the EL84s...and replaced it. It is back up and running. The tubes are to a similar amp...and belong to a friend...we purchased them together. He got the tubes. I have only several EL84 (6BQ5) and 12AD7s another reason for the modification. Thank you all for replying. I will take pics as soon as I disassemble the amp. Thank you again. David


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PostPosted: 13 Apr 2019, 08:38 
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They are 6P1 or (in Russian) 6P1P, which is a nothing bot 6AQ5 in a noval package.

No direct Western equivalents.

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PostPosted: 13 Apr 2019, 17:39 
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Quote:
"I noticed that the tubes in the amp are indeed 9 pin...so they can't be 6AQ5. Correct?"

Theres 6aq8 (ecc85)


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PostPosted: 14 Apr 2019, 01:19 
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https://en.wikipedia.org/wiki/6P1P

https://www.revolvy.com/page/6P1P

http://www.mif.pg.gda.pl/homepages/frank/sheets/113/6/6P1P.pdf

You will se loads of 6P1, as the Chinese call them in 3W SE-amps and 10W PP-amps, bot as kits and as RTR.

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PostPosted: 20 Apr 2019, 08:03 
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Yes I have verified they are 6P1/6P1P x 4 and 6N2 x 2... How could I go about modifying the circuit for EL84/6BQ5 x 4 and 12AX7 or 12AD7 x 2??? Or should I just be patient and order some of the original types? IF I can find them. Thank you much.
David


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PostPosted: 20 Apr 2019, 08:32 
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To modify, you have to be assured that the power transformer can supply the extra power/voltage/current needed.
The 6AQ5 has specified heater requirements of 6,3V @ 0,45A whereas 6BQ5 require 6,3V @ 0,76A.
Using these figures for 4 tubes means that 6AQ5 will draw 1,8A and 6BQ5 3,54A.

The output power ratings differ also - 6AQ5 deliver 4,5W (SE) and 6BQ5 deliver 6W (SE), will the output transformer deal with that higer power/current?

And again I question if it is reasonable to do a (major?) modification just to increase OP power from 9-10W to 12-14W.

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