Traynor YGM-3 (early) - Selmer cab

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Phil_S
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Re: Traynor YGM-3 (early) - Selmer cab

Post by Phil_S »

This is just a wild hair. There is a thing over at 18watt.com called the Paul Ruby zener fix or something like that to address buzz or fizz. It involves a couple of zener diodes on the PI. My recall on this is fuzzy. There is some crossover membership between TAG and 18watt, so maybe someone else here has the details and will see this. Or you can try to search 18watt. I just tried and had no luck getting to the specifics, but it is just 2 zeners across 2 of the PI resistors. This fix treats the symptoms, not the cause. If it works, it works. If not, you probably haven't lost much.
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sonicmojo
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Re: Traynor YGM-3 (early) - Selmer cab

Post by sonicmojo »

I'm really late to this party but I had fizz going on in my highly modified (gained up) Traynor until I swapped out the older vintage preamp tubes for some new JJs with an ECC803S in the PI position. You've probably tried a bunch of different tubes over time but maybe worth experimenting with the tubes again to rule out??
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Bryan
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Barks
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Re: Traynor YGM-3 (early) - Selmer cab

Post by Barks »

I bypassed the mid circuit.

It wasn't initially happy after that with some HF squeals if I had the treble below 6 on the dial - so I may have disturbed something.
However - the fizz is still in there!

I've put it all back and it's happy again.

Looking at two versions of the schematics for the 3 input model one has two 10k resistors going to ground (as mine did - though with the mid boost they are connected together and not ground) and the another version does not.
Why is that?

Also no sign or indication of what the capacitor is in series with one of the 10k in the earlier scheme. It does not seem to be in my amp.

On mine I did correctly tie the two 10k to ground when I disconnected the mid boost btw
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Barks
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Re: Traynor YGM-3 (early) - Selmer cab

Post by Barks »

For general info, I've traced the mid boost circuit and how it is implemented.
I have no idea what value the inductor is.
The mid boost pot is a stacked pot but one of them seems only to be used as a handy connector point.
IMG_0583.JPG
When the switch is OFF the mid boost is additive to the circuit as shown in the diagram.
You can vary the mid boost by turning the added stacked 500k pot.
Most of the action happens at the last 25% of travel

When the Switch is ON, it disables the two 10k resistors to ground leaving just the Mid boost circuit in place with its own resistor and cap to ground.
I assume this function is basically just bypassing the original stack - even though they still seem do a little bit - but most of the control is coming from the stacked 500 pot
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martin manning
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Re: Traynor YGM-3 (early) - Selmer cab

Post by martin manning »

To eliminate the mid boost circuit you'd have to disconnect it from the volume pot's wiper and at the junction of the top 47k's, and disconnect any long leads associated with the two 10k's and ground lift switch. Tone stacks are sensitive areas since they are usually feeding into a grid. The unmarked cap looks like it was penciled in by hand, someone's experiment perhaps. Are you mostly using the mid-boost circuit or the original tone controls?
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Barks
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Re: Traynor YGM-3 (early) - Selmer cab

Post by Barks »

Yes I do use it.
Mostly it is just adding a little when in combined mode with the treble and bass - though engaging the switch really lifts the sound during solos.
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Barks
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Re: Traynor YGM-3 (early) - Selmer cab

Post by Barks »

Ugh.
image.jpeg
First lug on the 1 meg vol pot was very loose in it's rivet - which may have been causing some continuity issues when I disconnected the mid boost circuit, after poking around desoldering and soldering.
It didn't take too kindly to my attempt to clamp it with a pair of pliers. Idiot!

New one on order along with some new wire and 10K 1/2 watt resistors to put the tone stack back to stock properly and see what happens.
I do like what this mid boost does though.
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Barks
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Re: Traynor YGM-3 (early) - Selmer cab

Post by Barks »

Still waiting for new pot and parts - note to self: don't break it and order prior to a major public holiday!

Decided to work on how the amp sits in the cab, and made a grill back as opposed to the old piece of flaking plywood.
New wing nuts to make removal easier of the chassis.
Tidying up nicely!
Traynor-Selmer back.jpg
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Barks
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Re: Traynor YGM-3 (early) - Selmer cab

Post by Barks »

Ok. new 1meg pot installed and wired up as it was. Mid circuit still in place.

New discovery that may be a "doh" moment. As I mentioned before - I'm an idiot!

When I was removing the valves I noticed I had an old Mullard in V2 position for the PI.

If you recall, way back I'd bought two TAD 84's and a Tungstol 12AX7 and TADAX7 for V1 and V2 respectivley - but broke the base of the Tungstol.
I put the Mullard in V1 as a replacement but it was too microphonic so swapped it for the TAD in V2 - and thought no more of it.

:roll: :oops:

It seems the Mullard was the reason for the excess fizz. It was too sensitive for the V2 position too.
With the Tungstol in V1 and TAD in V2 the fizz is now inbedded with the crunch and not so obvious now.

I cannot run it too loud at the moment but will report back.
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martin manning
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Re: Traynor YGM-3 (early) - Selmer cab

Post by martin manning »

Hmm. Could be a different kind of microphony, and therefore moving it later where S/N is higher is tamping it down.
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Barks
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Re: Traynor YGM-3 (early) - Selmer cab

Post by Barks »

Ok

Have cranked it and the fizz is still there but not as obvious as it was - so a more robust PI valve seems to have made some improvement.
I may be at the point of leaving it be for now - as my latest bout of tinkering actually damaged what is in essence a near 50 year old amp.
The main thing is the PT has made a vast improvement overall on the headroom and made the amp more dynamic and tighter - and now has variable bias - so I have to accept that regardless of the fizz (which is acceptable) this journey may have run it's course.
Let sleeping dogs lie.
I have also learned a lot in the process for which I am really grateful to you all!
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martin manning
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Re: Traynor YGM-3 (early) - Selmer cab

Post by martin manning »

Yes, good progress and for a guy with limited prior experience you've done very well. Cheers, Barks!
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Barks
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Re: Traynor YGM-3 (early) - Selmer cab

Post by Barks »

Thanks Martin!
I've indeed learned a lot.
To summaries for all:

Replaced transformer to correct spec and installed with guidance on sensible wiring.
Learned about Heater,Plate, Screen and Grid. And how voltages can change depending on the outlet it's plugged into nearly 250v here
Added bias pot and learned how to bias.
Added current sensing resistors
Changed PI values to smooth out and add headroom.
Swapped the brite cap in the PI.
Changed the value of C1 to remove a lot of unnecessary bass at V1
Made the Presence cap bypassable which took some hard aggressiveness off.

Learned to trouble shoot - and at the 11th hour to check the correct tubes in correct preamp stages - doh.

It's been a blast - thankyou!

I'll be looking at how to slow the Tremolo down a little now.

Bx
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martin manning
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Re: Traynor YGM-3 (early) - Selmer cab

Post by martin manning »

Should be easy to slow your trem down a bit. The LFO is a typical phase-shift type (see: http://www.valvewizard.co.uk/trem1.html). C18, C19, and C20 control the speed. I would try increasing C19 (0.015u now) to 0.022 or 0.033. You can just tack an 0.01u 500V cap of any type across it to gauge the effect.
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Barks
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Re: Traynor YGM-3 (early) - Selmer cab

Post by Barks »

Hi All,

just a quick update.

The Amp Rocks! The Tokai LS160 Goldtop P90 and amp are a perfect combo.

It is still going strong - just a temperamental hum on the reverb for me to resolve but this was an old issue from years ago as well.

A couple of clips of it at a reunion:

Au naturel with just a bit of delay - this is the only bit of moving footage I synced.:

https://youtu.be/DaK91yN5F9Q

Clean as above but with a tube screamer thrown in for the solo at the end with no drive; just level whacked up to boost into the amp. Static pics from the event.

https://youtu.be/DGZvg4LZ9Qk


Again, SOOO much thanks to Miles, Martin et all for the help.

Barks out. xzzz
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