Filmosound 18Watt conversion, Help!

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LeifH
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Re: Filmosound 18Watt conversion, Help!

Post by LeifH »

JMPGuitars wrote:
Fri 03/26/21 5:54 pm
LeifH wrote:
Fri 03/26/21 5:47 pm
They are JJs
There's your first problem. JJs in general have become mediocre, but their EL84 tubes are just trash.

That may not be the source of the problem, but very well could be. This is an example of bad EL84 JJs I posted 7 years ago: https://www.youtube.com/watch?v=21G6TkukwY8

I typically bought tubes in bulk, and returned all of the JJs at the time. There wasn't a single pair that didn't have issues out of the lot.

While you're waiting for new tubes, you might want to unplug the amp, remove all the tubes and check for shorts between all the tube socket pins and such. Inspect the amp visually too, with a magnifying glass.

Thanks,
Josh
Josh, thanks!

Will triple check for shorts, and with a magnifying glass.

Any suggestions for EL84s?
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Re: Filmosound 18Watt conversion, Help!

Post by JMPGuitars »

LeifH wrote:
Fri 03/26/21 6:02 pm
Any suggestions for EL84s?
New production Mullard or TungSol are both good and reasonably priced.

TAD is good if you want to spend extra money for probably no reason.

If you really like spending extra money, I've been curious about Psvane tubes. ;)
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Re: Filmosound 18Watt conversion, Help!

Post by TriodeLuvr »

I've heard good things about the EL84M, available directly from eastern Europe. Not as cheap as they used to be though.

Jack
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Re: Filmosound 18Watt conversion, Help!

Post by JMPGuitars »

TriodeLuvr wrote:
Fri 03/26/21 11:39 pm
I've heard good things about the EL84M, available directly from eastern Europe. Not as cheap as they used to be though.

Jack
The Sovteks? Sovteks are better than JJ, but I haven't personally tried their EL84 varieties. I was pleasantly surprised by their 7025 series 12AX7WA and WB tubes. Their regular 12AX7s aren't exciting, but still better than JJ. I haven't A/B'd them with anything else though.
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Re: Filmosound 18Watt conversion, Help!

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JMPGuitars wrote:
Sat 03/27/21 7:06 am
TriodeLuvr wrote:
Fri 03/26/21 11:39 pm
I've heard good things about the EL84M, available directly from eastern Europe. Not as cheap as they used to be though.

Jack
The Sovteks? Sovteks are better than JJ, but I haven't personally tried their EL84 varieties. I was pleasantly surprised by their 7025 series 12AX7WA and WB tubes. Their regular 12AX7s aren't exciting, but still better than JJ. I haven't A/B'd them with anything else though.
I don't use them for V1 or V2. But they rule as reverb tube. The EL84 M is a really rugged tube. It's a real difference in glass thickness too..
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Re: Filmosound 18Watt conversion, Help!

Post by JMPGuitars »

Bieworm wrote:
Sat 03/27/21 7:39 am
I don't use them for V1 or V2. But they rule as reverb tube. The EL84 M is a really rugged tube. It's a real difference in glass thickness too..
I did. I used all Sovtek WAs and 1 WB in my 36W Trem TMB. I'm gonna try and finally record a demo with it this weekend. Cryoset TungSol EL34s for the power tubes. I don't usually buy into the cryo stuff, but I had a pair in my tube stash.
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Re: Filmosound 18Watt conversion, Help!

Post by TriodeLuvr »

Bieworm wrote:
Sat 03/27/21 7:39 am
JMPGuitars wrote:
Sat 03/27/21 7:06 am
TriodeLuvr wrote:
Fri 03/26/21 11:39 pm
I've heard good things about the EL84M, available directly from eastern Europe. Not as cheap as they used to be though.

Jack
The Sovteks? Sovteks are better than JJ, but I haven't personally tried their EL84 varieties. I was pleasantly surprised by their 7025 series 12AX7WA and WB tubes. Their regular 12AX7s aren't exciting, but still better than JJ. I haven't A/B'd them with anything else though.
I don't use them for V1 or V2. But they rule as reverb tube. The EL84 M is a really rugged tube. It's a real difference in glass thickness too..
Hi-fi builders use the EL84M to sub for the 7189, which is an up-rated EL84. Not sure I have a good copy of the exact specs, but a pair of 7189 can output 24W. I think the EL84M is probably the most reliable variant available at this time.

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Re: Filmosound 18Watt conversion, Help!

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JMPGuitars wrote:
Sat 03/27/21 11:14 am
Bieworm wrote:
Sat 03/27/21 7:39 am
I don't use them for V1 or V2. But they rule as reverb tube. The EL84 M is a really rugged tube. It's a real difference in glass thickness too..
I did. I used all Sovtek WAs and 1 WB in my 36W Trem TMB. I'm gonna try and finally record a demo with it this weekend. Cryoset TungSol EL34s for the power tubes. I don't usually buy into the cryo stuff, but I had a pair in my tube stash.
To my ears the EHX 12ax7 is the nicer V1. I actually like the sound of a JJ ECC83S but I just don't trust them anymore...
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Re: Filmosound 18Watt conversion, Help!

Post by LeifH »

I'm as an experiment, I've ordered some 6P14P mil spec soviet made tubes from ebay.
8 for $20, gives me spares in case. First bit of reading, some claim that they are what the tube store label their preferred 7189s?

It gives me spares, which is what I'm missing.

As a back up if the 6P14P sound terrible a set of Tung Sol new production from the Tube Store, I needed some other parts, so I thought I'd try these as well.

In the mean time, I checked with a meter, I'm not getting any shorts between pins on the output sockets, looks like it was just the tube going bad, crap.
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Re: Filmosound 18Watt conversion, Help!

Post by JMPGuitars »

Bieworm wrote:
Sat 03/27/21 12:00 pm
To my ears the EHX 12ax7 is the nicer V1. I actually like the sound of a JJ ECC83S but I just don't trust them anymore...
Mullard's probably my favorite, followed by Tung Sol. I don't know where these Sovteks rank yet (to me), and I haven't tried the EHX in a while, though I think I have an EHX 7025 in my stash. Maybe on the next build I try some V1 tube swapping and see what sounds best.
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Re: Filmosound 18Watt conversion, Help!

Post by TriodeLuvr »

LeifH wrote:
Sat 03/27/21 1:01 pm
I'm as an experiment, I've ordered some 6P14P mil spec soviet made tubes from ebay.
8 for $20, gives me spares in case. First bit of reading, some claim that they are what the tube store label their preferred 7189s?

It gives me spares, which is what I'm missing.

As a back up if the 6P14P sound terrible a set of Tung Sol new production from the Tube Store, I needed some other parts, so I thought I'd try these as well.

In the mean time, I checked with a meter, I'm not getting any shorts between pins on the output sockets, looks like it was just the tube going bad, crap.
The audio guys say the 6P14P is a good choice, suitable for anode voltages up to at least +400V. A number of them have also apparently used it to replace the 7189. Just have to be sure not to exceed the 12W anode rating. Wow, $2.50 each?? I might have to buy some myself, just to keep around.

Jack
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Re: Filmosound 18Watt conversion, Help!

Post by Bieworm »

LeifH wrote:
Sat 03/27/21 1:01 pm
I'm as an experiment, I've ordered some 6P14P mil spec soviet made tubes from ebay.
8 for $20, gives me spares in case. First bit of reading, some claim that they are what the tube store label their preferred 7189s?

It gives me spares, which is what I'm missing.

As a back up if the 6P14P sound terrible a set of Tung Sol new production from the Tube Store, I needed some other parts, so I thought I'd try these as well.

In the mean time, I checked with a meter, I'm not getting any shorts between pins on the output sockets, looks like it was just the tube going bad, crap.
I have those 6p14p too on my 18 watts. One pair has gone microphonic... not bad, but rattly a little... so there goes military spec BS... they sound great though.. really great
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Re: Filmosound 18Watt conversion, Help!

Post by LeifH »

Bieworm wrote:
Sat 03/27/21 3:25 pm
LeifH wrote:
Sat 03/27/21 1:01 pm
I'm as an experiment, I've ordered some 6P14P mil spec soviet made tubes from ebay.
8 for $20, gives me spares in case. First bit of reading, some claim that they are what the tube store label their preferred 7189s?

It gives me spares, which is what I'm missing.

As a back up if the 6P14P sound terrible a set of Tung Sol new production from the Tube Store, I needed some other parts, so I thought I'd try these as well.

In the mean time, I checked with a meter, I'm not getting any shorts between pins on the output sockets, looks like it was just the tube going bad, crap.
I have those 6p14p too on my 18 watts. One pair has gone microphonic... not bad, but rattly a little... so there goes military spec BS... they sound great though.. really great
LMAO

I guess the mil spec should have the accompanying binder with the name of the janitor who cleaned up before and after production as well as the days lunch menu.

Or it was made on a Wednesday ?

Thanks to all for the input, hope to have tubes by Wednesday, I would like my next post to be a clip of the wee beast in action.
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Re: Filmosound 18Watt conversion, Help!

Post by LeifH »

I got the new tubes from the Tube Store today.
As I'm now a little paranoid about this. I had added screen resistors to my 5E3 when I built it on what seemed like everyone's recommendation as a little protection and to limit blocking distortion.

Is this a good idea on the lite iib? And, what size and wattage are preferred?

Again, thanks.
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Re: Filmosound 18Watt conversion, Help!

Post by JMPGuitars »

LeifH wrote:
Wed 03/31/21 5:08 pm
I got the new tubes from the Tube Store today.
As I'm now a little paranoid about this. I had added screen resistors to my 5E3 when I built it on what seemed like everyone's recommendation as a little protection and to limit blocking distortion.

Is this a good idea on the lite iib? And, what size and wattage are preferred?

Again, thanks.
The lite 2b already has screen resistors. If you're following my docs: files/JMPGuitars_18_Watt_Lite_2b_Schematic.pdf

...then it is sharing a 1K 3W screen resistor. You could use 2 separate 1K 3W resistors instead if you prefer.

The old doc versions had 100Ω screen resistors, but they should really be 1K.

Thanks,
Josh
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Re: Filmosound 18Watt conversion, Help!

Post by LeifH »

JMPGuitars wrote:
Wed 03/31/21 5:30 pm
LeifH wrote:
Wed 03/31/21 5:08 pm
I got the new tubes from the Tube Store today.
As I'm now a little paranoid about this. I had added screen resistors to my 5E3 when I built it on what seemed like everyone's recommendation as a little protection and to limit blocking distortion.

Is this a good idea on the lite iib? And, what size and wattage are preferred?

Again, thanks.
The lite 2b already has screen resistors. If you're following my docs: files/JMPGuitars_18_Watt_Lite_2b_Schematic.pdf

...then it is sharing a 1K 3W screen resistor. You could use 2 separate 1K 3W resistors instead if you prefer.

The old doc versions had 100Ω screen resistors, but they should really be 1K.

Thanks,
Josh
Thanks Josh, I'm not good at my words today.
Yes, I meant individual, for each tube. And does that provide better protection as well as blocking the isolation?
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Re: Filmosound 18Watt conversion, Help!

Post by JMPGuitars »

LeifH wrote:
Wed 03/31/21 6:06 pm
Thanks Josh, I'm not good at my words today.
Yes, I meant individual, for each tube. And does that provide better protection as well as blocking the isolation?
Words are hard sometimes, I hear ya. ;)

It's maybe better protection. Like if a resistor fails, then only one of the tubes will be directly affected, but I've never actually had that happen. I don't know what you mean by "blocking the isolation." I wouldn't overthink it. Either use two or use one, as long as you use 1K 3W, you're good.

Thanks,
Josh
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Re: Filmosound 18Watt conversion, Help!

Post by LeifH »

Sorry, that time I swear it was my stupidity. Not auto correct.

When I built my 5E3, as I recall, I was advised to put individual resistors on each tube to both prevent blocking distortion and help protect the tubes from each other. What i meant by isolation.

I wasn't sure about just one shared resistor both protecting the screens and helping to prevent blocking distortion.
I thought the blocking distortion was one tube pushing when it was supposed to be pulling or vice versa, ( out of phase) into the other tube via the screens?
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Re: Filmosound 18Watt conversion, Help!

Post by JMPGuitars »

LeifH wrote:
Thu 04/01/21 6:00 pm
Sorry, that time I swear it was my stupidity. Not auto correct.

When I built my 5E3, as I recall, I was advised to put individual resistors on each tube to both prevent blocking distortion and help protect the tubes from each other. What i meant by isolation.

I wasn't sure about just one shared resistor both protecting the screens and helping to prevent blocking distortion.
I thought the blocking distortion was one tube pushing when it was supposed to be pulling or vice versa, ( out of phase) into the other tube via the screens?
Read the maestro: https://www.aikenamps.com/index.php/wha ... distortion
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Re: Filmosound 18Watt conversion, Help!

Post by LeifH »

JMPGuitars wrote:
Thu 04/01/21 6:08 pm
LeifH wrote:
Thu 04/01/21 6:00 pm
Sorry, that time I swear it was my stupidity. Not auto correct.

When I built my 5E3, as I recall, I was advised to put individual resistors on each tube to both prevent blocking distortion and help protect the tubes from each other. What i meant by isolation.

I wasn't sure about just one shared resistor both protecting the screens and helping to prevent blocking distortion.
I thought the blocking distortion was one tube pushing when it was supposed to be pulling or vice versa, ( out of phase) into the other tube via the screens?
Read the maestro: https://www.aikenamps.com/index.php/wha ... distortion
He sure is, that was an explanation and a half. Thanks!
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