Anderton '64 reissue JTM145 - any info?

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odrpol
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Re: Anderton '64 reissue JTM145 - any info?

Post by odrpol »

Hi
I`m new on on this forum. Some days ago i was build this circuit.
But the amp not started. In attachment, diagram with the measurement of the voltage. Are this correct. All measurement to ground without valves.

Is somebody who make this amp and make the measurements of voltage
and can say that, they are correct or is some wrong.
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Thomas_H
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Re: Anderton '64 reissue JTM145 - any info?

Post by Thomas_H »

Hi,
some voltages look strange to me, but I didn't build this amp yet.

The first grid shouldn't have dc on it , is it really 8,7V?

The second cathode and the power tubes cathode shouldn't be 0V, unless they're grounded.

And the heater voltages?
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Matec
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Re: Anderton '64 reissue JTM145 - any info?

Post by Matec »

Hello odrpol

If you are really made these measurements without the valves, it is almost everything wrong.

If you did with the valves, it is still incorrect.

Within a few days I will make measurements on my amp, and post here for comparison.

Provide some pictures of your amp and post here.

Cheers

Matec.
odrpol
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Re: Anderton '64 reissue JTM145 - any info?

Post by odrpol »

HI
Thanks for replay. Tomorrow I will post the photos from amp inside
and the layout from wire of board.
odrpol
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Re: Anderton '64 reissue JTM145 - any info?

Post by odrpol »

The measurement I was made without valves.
I was verify the circuit same times with the layout and I think
layout is OK.
odrpol
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Re: Anderton '64 reissue JTM145 - any info?

Post by odrpol »

Hi
Here is the layout
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odrpol
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Re: Anderton '64 reissue JTM145 - any info?

Post by odrpol »

Hi
Here is the layout
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Matec
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Re: Anderton '64 reissue JTM145 - any info?

Post by Matec »

Hello odrpol

I have some questions:

As you had stated, these measurements were made without the valves.

No valves, no current consumption, then every source voltage would be close to the maximum in all the terminals of the anodes of the valves in the circuit. Approximately 295v there in your circuit.

How then appear lower voltages, as if current consumption?

Without valves there is no anode current, then there is no cathode voltage as well. All terminals of the cathodes would mark zero

The grids are connected directly to earth (except for V3B). Even so, the voltage measured on these six grids is close to zero. All without the valves.
-----------------------------------------------------------------------------------------------------------

In my opinion there is an error there in their assembly, maybe you have not connected all grounds of your circuit, or there is a lack of contact in any of them.

I do not know.
-------------------------------------------------------------------------------------------------------------
I noticed that in your layout, the numbering of the terminals of its valves are counter-clockwise. When one looks at the terminals of the valves, the number of these terminals follows the clockwise direction. I hope this has been corrected in the assembly.

In the layout also found that in V1 and V2 terminals 4 and 5 are connected, suggesting a 6.3V voltage to the heaters; V3 already, there is no such connection, which suggests a power 12,6V. What is the real tension of the heaters in your circuit?

You chose to connect the Output Transformer to the positive terminal of C5, and not to C3 terminal. I did not understand exactly why, but that's not a good choice. It will make the whole circuit works with voltages below 140vDC, and will make R7 heat to burn. Better get back to the original.

Cheers

Matec
cassoulet
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Re: Anderton '64 reissue JTM145 - any info?

Post by cassoulet »

Hi there,

Yes, as Matec said, something is definitely wrong about your measured voltages.

Aso, you should stick to Matec's original schematic or even use his HTM1 schematic which has best of both worlds.

The way your output transformer center tap is connected to a lower B+ is not correct to me. :roll:
odrpol
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Re: Anderton '64 reissue JTM145 - any info?

Post by odrpol »

Hi Matec

Unfortunately I haven’t possibility to log in to forum for some hours.
About the pins direction – I know there are counter clockwise, but all connections the valves are OK.
The reason is that I make the layout from right side to the left and then I get the chassis for this amp
and all wholes was inversely. I flip the layout in the computer to see that the board will match the chassis , dependent to other components like switch light , and others.

About the heater – the power TX have the 200 V secondary without CT, and the heater is 6,3 V without CT

About the connection of OT transformer – I have read in the datasheet of 12AU7, that the maximum rating of anode voltage is 300 V, at main 294 V I’m afraid that is to nearest from maximum, following datasheet, and I connect the OT to lower tension to get about 250V at the anode this valve.
At datasheet it stay that 250 V is typical operation voltage for 12AU7.

Could You be so kindly and make the Voltage measurement of Your amp, and post it on forum?

I have a question. Maybe You have a working bridge wiring layout that I can to assemble
that the amp is working. Otherwise I have no ideas what can be wrong, I was checked all contact
for cold solder joint on mine mind there are OK, The all ground are connected, I was checked several times. The last thing maybe the valves are damaged .
Is it possibly to check the valves without the valve tester

Regards

Odrpol
odrpol
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Re: Anderton '64 reissue JTM145 - any info?

Post by odrpol »

Hi Matec

My question was about "board wiring layout"

Odrpol
cassoulet
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Re: Anderton '64 reissue JTM145 - any info?

Post by cassoulet »

odrpol wrote:About the connection of OT transformer – I have read in the datasheet of 12AU7, that the maximum rating of anode voltage is 300 V, at main 294 V I’m afraid that is to nearest from maximum, following datasheet, and I connect the OT to lower tension to get about 250V at the anode this valve.
At datasheet it stay that 250 V is typical operation voltage for 12AU7.
Don't worry about getting 294V at plates. You are measuring voltages without tubes, right? Once you plug in all valves, you will hardly get 250V or 260V at plates because of current drawn.

And if you really get a too high voltage at 12AU7 plates, just insert a 100R or 150R (or even 180R) before C3 and that will drop all your B+ voltages.
But don't connect the way you have done it. This is wrong.
odrpol
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Re: Anderton '64 reissue JTM145 - any info?

Post by odrpol »

Hi
Thanks for answer I will make the OT connection like You said cassoulet.

Regards
odrpol
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Matec
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Re: Anderton '64 reissue JTM145 - any info?

Post by Matec »

Hello odrpol

I got explanations about the layout.

Talking about the heaters.

If your transformer has 6.3V for the heaters, the V1 and V2 valves are with the right connections; V3 is already wrong, because it should also be with the pin 4 and pin 5 connected. In case the connection between the pin 9 and the cathodes of V3 must be undone. In its place the voltage swing of the heaters should be done with two 100R resistors connected to V3 cathode.

About the Output Transformer Ct connection, explaining Cassoulet is perfect. If you do it this way, you will have no problems.

I can take measurements for my amp as few in the middle of next week. Once you do, I'll post.

I believe that soon we will have solved the problems in your amp. I do not think you need to disassemble your, and start over.

I have an experimental layout, which I published for HTM1 circuit, (my version of JTM1). It is designed to 12,6v voltage of the heaters.

It has not been tested. Here it is:

[img:1279:848]http://s26.postimg.org/fhwquobrd/HTM1_3 ... OUT_01.png[/img]

Cheers

Matec
odrpol
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Re: Anderton '64 reissue JTM145 - any info?

Post by odrpol »

Hi Matec
Thanks for replay.
About heater - I was made like You said. Connected pin 4 and pin 5 together, and unconnected the pin 9 from cathode 3 and 8, and connected to pin 9 to the other side the heater.
Follow Your`s and cassoulet suggestions I was changed
the OT transformer CT connection from C5 to C3.

Switch on the amp with valves.
The V1 and V2 was OK but the V3 was immediately very hot, and started to little sparkling at pin 5 leg. It was visible from the chassis side. From the valve side i don't watch any sparkling or strange behavior except it was very hot. The soldering is OK

All the time I`m afraid that the V3 is damaged.
Maybe You have any idea how to check the valve without valve tester.

Thanks that You make the voltage measurement Your`s amp next week.
I`m waiting for this data.

Regards

odrpol
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