Avalon VT 737 sp

[chrispbass]

Here u go, should i open the PSU ? didnt saw any burned transistors on 5600-737
Orange 11,6
Black 34,6
White 188
Red 34,5
T1 182
T2 ? 6
R34 = 0
R43 41

Yes, open up to give it a visual check. You can pull the connector (3rd pic down) to measure the voltages.
Be careful.

 

[punkt]

I already pulled the moltex connecter, as i wrote down the messaurements of the connector

Didnt saw any burnmarks in the PSU, but i might be wrong, whats next to check?

 

[pucho812]

Thanks for the photos.

From your measurements.
All is fine.
R34 shouldn’t get a measurement. 0v at R34 is correct.
Your voltages sound within tolerance.
Have you replaced tubes yet?
Have you replaced any of the 10uf and 100uf blue capacitors yet?

 

[punkt]

Thanks for the photos.

From your measurements.
All is fine.
R34 shouldn’t get a measurement. 0v at R34 is correct.
Your voltages sound within tolerance.
Have you replaced tubes yet?
Have you replaced any of the 10uf and 100uf blue capacitors yet?

I already replaced tubes, no i didnt replaced any of them, should i?
are these the right type of capacitors? i think bout 25 of each of them should be enough, let me know if u think otherwise
https://www.mouser.de/ProductDetail/594-2222-036-90109
https://www.mouser.de/ProductDetail/594-MAL214258109E3

thank you for your kindness

 

[pucho812]

Well let’s go back a minute before we do that.

What is the issue exactly?

Can we confirm the unit is passing signal properly?

 

[punkt]

Well let’s go back a minute before we do that.

What is the issue exactly?

Can we confirm the unit is passing signal properly?

So the problem is the following, I get only a very thin, very quit output, also its noisy neither the line or mic works properly

 

[pucho812]

So the problem is the following, I get only a very thin, very quit output, also its noisy neither the line or mic works properly

Show more photos how you have it connected and how you have it set up as far as the controls.

 

[punkt]

Show more photos how you have it connected and how you have it set up as far as the controls.

What do you mean exactly, i need to crank it up on max, max output,max gain, high gain to hear a just little bit

 

[aurt]

“Thin and low” as a description usually sends me looking for a single ended transformer first. Often as simple as a wire off on an XLR. Worth a check, anyway.

Can you get the meter to respond? For level and/or compression?

 

[pucho812]

What do you mean exactly, i need to crank it up on max, max output,max gain, high gain to hear a just little bit

I mean exactly that. The number of times I heard that complaint and they had the output connected to the stereo link vs output. Or they had the wrong input selected in the front

 

[punkt]

I mean exactly that. The number of times I heard that complaint and they had the output connected to the stereo link vs output. Or they had the wrong input selected in the front

nah i used the avalon 3 years before this happend, so its wired up properly^^ instrument set on mic, preamp gain on max, output on max

i bought the avalon used in 2019 after like 6 months this issue popped up the first time, but suddendly disapperead after using it again couple weeks afterwards, fast forward to summer 2023 the problem popped up again and persists to this day, so i was talking to the ceo of pms electronic service and he told me the repair will be bout 500€, couple weeks ago i decided to give it a shot and repair it myelf, because as an student i dont have that kind of money

 

[punkt]

“Thin and low” as a description usually sends me looking for a single ended transformer first. Often as simple as a wire off on an XLR. Worth a check, anyway.

Can you get the meter to respond? For level and/or compression?

Nope not at all, the meter doesnt respond

here is a picture fo the connector, maybe this will help

here is also a audiofile recorded with the avalon on max settings

 

[Egor Reshetnikov]

here is also a audiofile recorded with the avalon on max settings

sent you a message, i had very similar sounding fault with tube (trafo out) preamp. turn out to be bad connection. try different cables and patch channel

 

[punkt]

sent you a message, i had very similar sounding fault with tube (trafo out) preamp. turn out to be bad connection. try different cables and patch channel

HOLY MOLY it fired up!, i already tried different cables, but just now i used a completely new line cable and it works, and the meter also suddendly works, but didnt worked before, still strange behaviour imo

 

[pucho812]

Ok.
Whenever dealing with this type of action. I start with the line input, nothing engaged(no eq or compression) and I have the in and output pots at center detent. A +4 dBu signal at input should be +4 dBu at output. If it’s not, depending on how off it is could be a calibration issue or could be much more complex.
The fact you get some signal tells me the tube path is ok. I’d you changed all the tubes like you said and it’s still low signal, then the issue will be located in the 7372 I/O card. What makes the 737 unique is all of the parallel paths going on. It’s also what makes it super quiet.
If nothing has shorted on the 7372 card and no damage is visible, replace all the blue capacitors they will be values 10uF and 100uF. They are lytics so pay attention to polarity. Also use the specified voltages for each.
I usually replace them with Panasonics.