Traynor YBA-200 Power Tube Pull

lobamon · #1 11-11-2010, 08:42 AM

I love the tone I get from my Traynor YBA-200 played through my 2X15 Ampeg V4B folded horn cab. The problem, for me, is that in order to hit the sweet spot on the amp I have to turn it up loud enough to drown out the rest of my band. If they turn up we out play our PA.
A buddy of mine says I might be able to pull 2 of the power tubes and achieve the sweet spot saturation at a lower volume. I have seen this done on 100 watt guitar amps with great results. He says that the ohm switch settings will be lowered by half.(ie. 8 ohm setting becomes 4ohms and the 4 ohm setting becomes 2 ohms)

Can anyone out there in TB land confirm/debunk his advice?

Thanks in advance.

T-Bird · #2 11-11-2010, 10:16 AM

Hi.

I've done that with success on a Marshall JMP 1959, but I don't know enough about the YBA-200 circuit to offer any advice about Your amp's capability of doing that.

Regards
Sam

Marton · #3 11-11-2010, 10:18 AM

You can't achieve your sound by cranking up the gain and lowering the master ?

Grooveman1961 · #4 11-11-2010, 10:21 AM

Confirmed, with some comments.

I don't have first hand experience with the traynor, but I do have experience with marshall and ampeg.

just pulling the tubes will work, but the remaining two will now be overbiased. Its ok if you like the sound, and safe for the tubes and amp. Best case would be to rebias.

BTW, My absolute favorite bass rig is my peavey vb2 through my v4b. Kudos for hauling that bad boy around. People call the 810 a fridge, well that would make the v4b a Deep freezer!

BassmanPaul · #5 11-11-2010, 10:49 AM

True to an extent. You do have to pull one tube from each side of the OPT primary. Usually if you pull the outside pair that will be fine but some amps are wired differently. You'll have to verify your particular case.

BbbyBld · #6 11-11-2010, 10:53 AM

If you pull half of the power tubes out, you have to go down one impedance setting, so if you have an 8 ohm cab, you would use the 4 ohm output on the amp.

lobamon · #7 11-11-2010, 11:50 AM

Thanks for the feedback. Here is a like to the schematic of the amp.

http://www.traynoramps.com/downloads...n/smyba200.pdf

I can't wait till I get into my circuits class next semester so I can begin to have a better understanding of this stuff.
To BbbyBld-
My cab is 4 ohms. It has been said that the yba200 is stable @ 2 ohm when you use the 4 ohm setting on the switch. Will it still be okay to run my cab set to 4 ohms?
That is if the schematic helps to determine whether I can even pull the 2 outside tube.

Thanks again.

lobamon · #8 11-11-2010, 12:02 PM

The sweet spot on my particular amp is achieved by setting the preamp at 1 o'clock(that is where the EQ becomes fully engaged and each knob truly controls tone best.) and the master to around 2 o'clock.
When I back the master down saturation of the power section goes down the amp looses "it". The notes don't pop out as nicely and the subtleties of playing are less apparent.

recreate.me · #9 11-11-2010, 12:05 PM

Thats a great inquiry, i have a YBA 3 CS head i was wondering if i could do the same. Is this the case with every tube amp?

What exactly does the overbiased tubes sound like?

MikeM · #10 11-11-2010, 12:05 PM

I tried pulling tubes on my SVT and the volume never really changed. I just got a little different high mid sound. The thing that works for me is using less speaker for lower volume.

The original version of that Traynor had that weird self bias thing, would that be effected with pulling tubes ?

okcrum · #11 11-11-2010, 12:20 PM

Quote:

Originally Posted by lobamon

Thanks for the feedback. Here is a like to the schematic of the amp.

http://www.traynoramps.com/downloads...n/smyba200.pdf

I can't wait till I get into my circuits class next semester so I can begin to have a better understanding of this stuff.
To BbbyBld-
My cab is 4 ohms. It has been said that the yba200 is stable @ 2 ohm when you use the 4 ohm setting on the switch. Will it still be okay to run my cab set to 4 ohms?
That is if the schematic helps to determine whether I can even pull the 2 outside tube.

Thanks again.

Your buddy has it backwards, but BbbyBld has it right.

The 4 ohm setting on the amp becomes 8 ohms, and the 8 ohm setting becomes 16 ohms with two output tubes removed.

So you'd rewire your 4 ohm cab to 16 ohms (put the speakers in series in the cab) and set the output on the amp to 8 ohms with two tubes pulled. Or add a series/parallel switch to the cab to make it easy.

lobamon · #12 11-11-2010, 12:21 PM

I had to send my YBA200 back to Traynor in Canada to have it repaired / 200-2 mod performed after it went out with a bang during a show. So it is not self biasing anymore.

lobamon · #13 11-11-2010, 12:24 PM

Here is the yba200-2 schematic link. I guess I should've posted it since Traynor updated the bias portion of the circuit.

http://www.traynoramps.com/downloads...smyba200-2.pdf

lobamon · #14 11-11-2010, 12:29 PM

Quote:

Originally Posted by okcrum

Your buddy has it backwards, but BbbyBld has it right.

The 4 ohm setting on the amp becomes 8 ohms, and the 8 ohm setting becomes 16 ohms with two output tubes removed.

So you'd rewire your 4 ohm cab to 16 ohms (put the speakers in series in the cab) and set the output on the amp to 8 ohms with two tubes pulled. Or add a series/parallel switch to the cab to make it easy.

I most likely misquoted him.

Would rewiring the speaker cab make it sound any different?

okcrum · #15 11-11-2010, 02:05 PM

Quote:

Originally Posted by lobamon

I most likely misquoted him.

Would rewiring the speaker cab make it sound any different?

It should not, other than the lower volume levels. Just watch the phasing; make sure you connect + on one speaker to - on the other, then the unconnected - to the sleeve connection and the unconnected + to the tip connection on the jack.

jastacey · #16 11-12-2010, 07:19 AM

I had one of those cabinets 30 years ago, and had the same issue, I solved it by using a small 2x10 cabinet, so I could hear my self, the folded horn cabinet is throwing the sound out 25-35 feet out, in front of you ... really no need topull your tubes ...IMHO

lobamon · #17 11-12-2010, 12:15 PM

Quote:

Originally Posted by jastacey

I had one of those cabinets 30 years ago, and had the same issue, I solved it by using a small 2x10 cabinet, so I could hear my self, the folded horn cabinet is throwing the sound out 25-35 feet out, in front of you ... really no need topull your tubes ...IMHO

I stand across the room from my amp during band practice, and hear what I am playing just fine. I have a home made Eminence loaded 4X10 that I have the same issue with through the same amp. I have toyed with the idea of pairing the cabs, but Im not playing venues large enough to tote the fridge and a 4X10. lol

It's just harmonic tube saturation that I'm after. Both pre and power.

fu22ba55 · #18 11-12-2010, 12:28 PM

I was under the impression (from previous threads like this, some of which I kind of started) that while it's possible to pull some tubes, long-term, it's a bad idea and could potentially damage your amp's output stage?

I've asked three different wooly-old tube-amp techs this same question (about SVTs) in the past couple of months, and they all say "yeah it will work for a while, but that's not what the amp was engineered to do, so it's not a good idea for the amp's longevity."

If 200 watts is too much, V4s and V4Bs are pretty abundant, and can be had for not too much money ($400-$600)

BassmanPaul · #19 11-12-2010, 01:33 PM

If you have four output tubes pulling a pair will in essence cut its output by 50%. If you compensate with the cabinet impedance as Bobby advised your amp will be fine. With an SVT having six outputs pulling a pair will drop its output by a third. The rub comes in when you cannot match the cabinet impedances to the load the output stage is expecting.

lobamon · #20 11-12-2010, 05:40 PM

Thanks for the input everyone. Im gonna rewire my cab and pull the 2 outside tubes. We have rehearsal tomorrow. I'll let you know the result of this little experiment.