Deluxe despair #2 - A hope...

[Fingerpicker]

Hello everyone

Thank you for all the answers. I tried to summarize them, and made a possible diagnosis. Please also comment this idea. I quote the more detailed amp-history:

- My Deluxe was not used for a long time, probably more than 20 years.
- When I bought it, the first week I used it only at home - at low volume (max5).
- The phase shift General Electric tube became microphonic in the first (!) rehearsal with my band. The amp went 3-4 hours quite loud volume (7-8).
- The technician replaced the tube, we tried at least 5 tube until we found an old RCA. Not the perfect substitute, but I resigned myself to it (that tone was still OK).
- There were no problem for one and a half month - until I borrowed a Morley A/B pedal. I connected the two channels with a Tube Screamer on the first channel and left the vibrato clean. It sounded great for a few hours or maximum 1-2 afternoons.
- Then the metallic, unnatural tone showed up. Deluxe got sick.
- I told my complain, so the technican checked the all the voltage-parts:
- Discovered that the power tubes drop some voltage after a while - so he replaced them.
- Discovered that some of the capacitors are leaking - so he replaced all of them.
- Nothing changed.

I this a possible diagnosis?: the heavy use (after decades of silence) killed the old "brown sound" of the preamp tubes.
We may just have to lower the B+ voltage and put in NOS vintage tubes.

Finally some important questions:

To MWJB:
How can I make contact with an internet vendor? Can you recommend a trustful one? I'm planning to order an American made NOS 5Y3 rectifier, as you said.

To jmaf:
Inserting a power resistor - isn't it too radical change? What about the previous idea: replacing the rectifier? Will it cause low enough +B voltage?

Once again: thank you for the comments.
Bye

[MWJB]

I use Watford Valves :: Watford valves is a U.K company that has become one of Europe's leading supliers of tested, graded and guaranteed valves to the professional music industry.

What power valves did the tech take out & what did he replace them with? Differing power tubes sound different too, what did he rebias the new power tubes to (bias should always be checked/adjusted on installation).

[jmaf]

Hello everyone

Thank you for all the answers. I tried to summarize them, and made a possible diagnosis. Please also comment this idea. I quote the more detailed amp-history:

- My Deluxe was not used for a long time, probably more than 20 years.
- When I bought it, the first week I used it only at home - at low volume (max5).
- The phase shift General Electric tube became microphonic in the first (!) rehearsal with my band. The amp went 3-4 hours quite loud volume (7-8).
- The technician replaced the tube, we tried at least 5 tube until we found an old RCA. Not the perfect substitute, but I resigned myself to it (that tone was still OK).
- There were no problem for one and a half month - until I borrowed a Morley A/B pedal. I connected the two channels with a Tube Screamer on the first channel and left the vibrato clean. It sounded great for a few hours or maximum 1-2 afternoons.
- Then the metallic, unnatural tone showed up. Deluxe got sick.
- I told my complain, so the technican checked the all the voltage-parts:
- Discovered that the power tubes drop some voltage after a while - so he replaced them.
- Discovered that some of the capacitors are leaking - so he replaced all of them.
- Nothing changed.

I this a possible diagnosis?: the heavy use (after decades of silence) killed the old "brown sound" of the preamp tubes.
We may just have to lower the B+ voltage and put in NOS vintage tubes.

Finally some important questions:

To MWJB:
How can I make contact with an internet vendor? Can you recommend a trustful one? I'm planning to order an American made NOS 5Y3 rectifier, as you said.

To jmaf:
Inserting a power resistor - isn't it too radical change? What about the previous idea: replacing the rectifier? Will it cause low enough +B voltage?

Once again: thank you for the comments.
Bye

It's a modification, yes, so it does change the stock amp to something else. It is a very easy to undo change, so it's not destructive or irreversible. Now, to keep the amp stock, MWJB's advise to add 5y3's is good advise, it'll lower the tensions, it has higher resistance and would have the similar effect to adding the resistors.

The brown sound comes from lower voltage or older tubes. The first thing an old tube loses is high end definition, so that's what you probably liked about the amp using the previous setup.

[Fingerpicker]

I use Watford Valves :: Watford valves is a U.K company that has become one of Europe's leading supliers of tested, graded and guaranteed valves to the professional music industry.

What power valves did the tech take out & what did he replace them with? Differing power tubes sound different too, what did he rebias the new power tubes to (bias should always be checked/adjusted on installation).

Hi

The power valves were the original Fender tubes, the tech replaced them with JJ's. It didn't change the soud basically.
I don't know what did he rebias the new power tubes to, he always says: "original values".
But: I found a new technican, who suggested to insert a power resistor - for trial.
The amp has a Miniwatt Gz34 rectifier. The tech says we shouldn't change this tube, because this was the original, when I fell in love the amp.
So first we'll begin to experiment with a power resistor, and If we fail, then comes the tube-replacement.

Anyway, the preamp tubes are:
1. RCA 12 AT7
2. General Electric 12AT7
3. 12AT7
4. Fender 7025

What does the third tube do? Isn't it a problem that it's not an AX7?

Thanks.

[Fingerpicker]

It's a modification, yes, so it does change the stock amp to something else. It is a very easy to undo change, so it's not destructive or irreversible. Now, to keep the amp stock, MWJB's advise to add 5y3's is good advise, it'll lower the tensions, it has higher resistance and would have the similar effect to adding the resistors.

The brown sound comes from lower voltage or older tubes. The first thing an old tube loses is high end definition, so that's what you probably liked about the amp using the previous setup.

Hi

I found a new technician, he also eased my anxiety: inserting a power resistor is not destructive or irreversible.
We won't change the rectifier (Miniwatt GZ34) yet. The present theory is the following: when I began to use the amp (after 20 years of silence) the caps weren't work properly. This caused the "brown sound". Then they got their power back - and ruined my beloved tone.
The new tech says: first we try to insert a power resistor. I'll check the sound and decide that is this change enough or we need to replace some tubes too.

What power resistor do you suggest?
Will the resistor need some kind of cooling?

Thanks. Bye.

[MWJB]

Why have you got 3x 12aT7in there? V1 & V2 should be good quality, low noise but good gain 12AX7, V3 should just be a working 12AX7, V4 is a 12AT7. I am counting V1 to V4 from right to left, the tube farthest from the power tubes is V1.

There is no "stock value" for idle bias current. With the GZ34 you will HAVE to run the power tubes at very high dissipations, change the rectifier, to change the sound you need to change a part, may as well make it a part that plugs in & out. New caps did not hurt the tone, they made the amp work properly. If you like the the squashy sound of shot caps, try a squashier, low voltage rectifier...like a 5Y3.

[riz]

Hi


Anyway, the preamp tubes are:
1. RCA 12 AT7
2. General Electric 12AT7
3. 12AT7
4. Fender 7025

And there you have it.

[Fingerpicker]

Why have you got 3x 12aT7in there? V1 & V2 should be good quality, low noise but good gain 12AX7, V3 should just be a working 12AX7, V4 is a 12AT7. I am counting V1 to V4 from right to left, the tube farthest from the power tubes is V1.

There is no "stock value" for idle bias current. With the GZ34 you will HAVE to run the power tubes at very high dissipations, change the rectifier, to change the sound you need to change a part, may as well make it a part that plugs in & out. New caps did not hurt the tone, they made the amp work properly. If you like the the squashy sound of shot caps, try a squashier, low voltage rectifier...like a 5Y3.

Hi

Me and my new tech decided - the latest strategy is this: first we change the rectifier to a 5Y3, as you suggested.
And then we put 12AX7 and 12AT7 in the right places.

I've found a NOS rectifier at Watford's page: 5Y3WGTA/SYLVANIA-CRYO
(https://www.watfordvalves.com/product_detail.asp?id=106)
What do you think - is it good quality?

Although a site scared me. This is their opinion about 5Y3:
"This tube should probably not be used in anything other than what it came in where Fenders are concerned. Putting it in a 6L6 amp will give it a very short life and possibly cause it to arc, not good! Leave these in the Champs and whatever else they came stock in."
(The Rectifier Tube)
Is this a real danger? Even the Fender Amp Guide says: GZ34...
Are the 5Y3 and GZ34 tubes OK for substitution?

Thanks.

[MWJB]

6L6 draw more current through the rectifier, you don't run 6L6, you run 6V6s which draw less current & certainly will when you have the 5Y3 installed. Bias to ~25mA per tube.

[Fingerpicker]

Thanks.
And the other question: is the 5Y3WGTA/SYLVANIA-CRYO a good choice for rectifier?
I'm ready to order one.

[MWJB]

Yes, as is the non cryo version.

[Fingerpicker]

Yes, as is the non cryo version.

Hello again

My tech have just sent a link of 5Y3:
5Y3GT/WGT/WGTB/GTA NOS USA - Tubes: Odd Ball

He often orders tubes from this german company (Tube Amp Doctor) - this would be the easier way.

Which brand do you suggest? The description says, they have: 5Y3GT/WGT/WGTB/GTA

And we would also get 12AX7 from here: JAN 5751 NOS/USA
JAN 5751 NOS/USA - NOS Rare & Vintage

How about these tubes?
They are non cyro version, aren't they? (Actually, I don't know what it is, but I accept your warning.)

Thanks.

[jmaf]

Fingerpicker, you should be ok ordering any new 5Y3. You are in Europe, so I guess I can't help much with the tubes here from the Americas, but I've bought from these folks without issues: 5Y3 / 5Z3 Tube Types

You don't need to go into too much detail with rectifiers, as long as they're not catching on fire they are ok. The Sovtek ones at 15 bucks will solve your problem IMO.

[MWJB]

The Sovtek 5Y3 does not have the same voltage drop as a NOS 5Y3, closer to a 5V4, somewhat defeats the purpose of changing rectifiers to reduce B+.

[Wittgenstein]

The Sovtek 5Y3 does not have the same voltage drop as a NOS 5Y3, closer to a 5V4, somewhat defeats the purpose of changing rectifiers to reduce B+.

I just tested that last night on my 5F1 & 5E3. The Sovtek 5Y3 put out between 20-25V more than the NOS RCA & GE 5Y3. The 5E3 for example has 370VAC coming of the PT secondary, and it gets bumped up to 422VDC at the first filter cap with the Sovtek, as opposed to 396VDC with the NOS rectifiers.