Why did I like 4 ohms???

[Dr.Mavashi]

Really working on dialing my tone on my Laney AOR now that its home, I am using MassLite,
the pre-amp is all the way UP
MV is barely above 2
MassLite's LowMids are on 0.5 and MidsHighs are on 9.
Bass and Trebble are PULLED and are all the way up
Mids 4.5(12 o'clock).
Presence 0
Spina TS9 Drive 4 Leve 8 tone 9
main pup Invader in the bridge

I couldn't find the sweet spots around these settings while in 16 ohms mode, then I switched to 4 ohm. And so many things went right, its not overkill in over all output, the bottom end is SO MUCH more articulate and tighter I don't think I will plug in into 16 ohms anytime soon. I am not sure about the leads, but rythm tone was about 80% there. Basically the 16 ohms has all the balls in the world and more, but its uncontrollable. But with 4 ohms I can adjust the level of bass and trebble trade off easily with a tone knob. With 16 ohms the tone knob was not very useful.

 

[Red_Label]

Re: Why did I like 4 ohms???

I've been using the 8 ohm inputs for years. But last weekend I switched over to 4 ohms (and went from one 4X12 to two 4X12 cabs) and I am totally IN-LOVE with my sound. It's so big and full now.

 

[Rich_S]

Re: Why did I like 4 ohms???

Dr. M, let make sure we understand what you did. Are you saying the changed the impedance on the head AND on the cabinet, so they are still matched, but at 4 ohms instead of 16?

If that's the case, then the difference is that you've reduced the reactance in the circuit. Reactance is the componenet of electrical impedance that "fights back" against changes in signal level. The faster the change, the harder reactance fights back. This has a couple of results. First, it likely increases the treble overall. Second, it probably tightens the low end. THe higher reactance at 16 ohms would tend to push back on loud chunky rhythm parts, making them mushy. The 4-ohm setting doesn't fight you as hard, making the the chunky parts more immediate, and "chunkier".

I'll say it again: Gerald Weber has a excellent chapter on this in his latest book.

 

[Red_Label]

Re: Why did I like 4 ohms???

Rich,

Right now, I'm running out of my Traynor YCS100 head into my Marshall 1960A cab set at a mono 4 ohms, and an old G12-30 Sunn cab that's now wired mono at 4 ohms. I just set it up this way last weekend and love it! But my question is, does it hurt the head at all just to run the one Marshall cab mono at 4 ohms? Because usually when I've just run one cab I've gone out of both outputs and then ran the cab in stereo mode at 2X8 ohms. I suspect that there's no problem with running only one out and leaving the other empty, I just wanted to make sure. Thanks.

 

[Rich_S]

Re: Why did I like 4 ohms???

Are you running the YCS100 at 100 watts or 30 watts, and what impedance switch setting do you use?

Your speaker jacks are in parallel, so if you use both cabs, you should be using a 2-ohm setting which is only available at 30 watts. That said, tube amps are generally pretty tolerant of small (2:1 or less) impedance mis-matches. Also, if you do mis-match, tube amps prefer the speakers to be lower that the amp setting. Higher-than-expected impedance is what tube amps don't like, a little isn't terrible, but a lot (especially an open circuit) is what blows up screen grids resistors and output transformers.

 

[jeremy]

Re: Why did I like 4 ohms???

there are a few things happening when you use the different outputs. i tend to like running at the highest impedance since it uses the whole transformer

 

[Red_Label]

Re: Why did I like 4 ohms???

Are you running the YCS100 at 100 watts or 30 watts, and what impedance switch setting do you use?

Your speaker jacks are in parallel, so if you use both cabs, you should be using a 2-ohm setting which is only available at 30 watts. That said, tube amps are generally pretty tolerant of small (2:1 or less) impedance mis-matches. Also, if you do mis-match, tube amps prefer the speakers to be lower that the amp setting. Higher-than-expected impedance is what tube amps don't like, a little isn't terrible, but a lot (especially an open circuit) is what blows up screen grids resistors and output transformers.

I'm using 100 watts. The back of the head has a switch for impedence and I have the switch set on 4 ohms per output at 100 watts. Each cab is wired/switched to 4 ohms in mono mode. So I should be fine, right?

When I just run the one Marshall cab (due to stage space limitations), should I switch back to using both outputs at 8 phms into the one cab "stereo", or just run one output at 4 ohms in mono mode?

 

[Red_Label]

Re: Why did I like 4 ohms???

there are a few things happening when you use the different outputs. i tend to like running at the highest impedance since it uses the whole transformer

Hmmm... so you're saying I'd be better off switching over to 2X8 ohm mode when running one cab instead of 1X4 ohms?

 

[wixedmords]

Re: Why did I like 4 ohms???

I tend to find the sound a little bit tighter, smoother, at lower impedance. the higher impedance has more grain, more character to my ears. This is only my a very marginal amount.

You can only swap the impedance selection around if you have a impedance measurement in between to standard settings, like say 5.3 ohms. In this case you could use either 8 ohm or 4 ohm settings. It is a bad idea to go swapping settings just for sake of changing your sound. There is a reason those settings are there.

 

[Rich_S]

Re: Why did I like 4 ohms???

Whoa. I just looked at the manual for the YCS100. Their description of the speakers outputs/power setting/impedance selector just plain sux. First, they tell you to make sure it's set correctly, then they baffle you with a counter-intuitive instructions , too much theory, and unlikely examples. (Who would ever run that amp on its 30-watt setting, driving eight 16-ohm cabinets?)

However, I'm fairly certain that the impedance switch settings correspond to the TOTAL impedance, not the impedance per output jack. So, with your (2) 4-ohm cabs plugged in, the switch should be set for 2 ohms, which it does not have at 100 watts. The Traynor manual dishes a lot of hooey about "minimum impedance" which looks to be copied from a solid-state amp manual. Normally, tube amps can forgive speaker with lower-than-the-setting impedance.

Does your Marshall cab have a switch for 4/16 ohm mono? If so, I'd use 16, and rewire the Sunn for 16 as well. Then set the amp to 8 ohms when you use both cabs. For just the Marshall, set amp and cab both to 4 ohms. If the 1960 doesn't have such a switch, I don't know what I'd do.

 

[Red_Label]

Re: Why did I like 4 ohms???

Whoa. I just looked at the manual for the YCS100. Their description of the speakers outputs/power setting/impedance selector just plain sux. First, they tell you to make sure it's set correctly, then they baffle you with a counter-intuitive instructions , too much theory, and unlikely examples. (Who would ever run that amp on its 30-watt setting, driving eight 16-ohm cabinets?)

However, I'm fairly certain that the impedance switch settings correspond to the TOTAL impedance, not the impedance per output jack. So, with your (2) 4-ohm cabs plugged in, the switch should be set for 2 ohms, which it does not have at 100 watts. The Traynor manual dishes a lot of hooey about "minimum impedance" which looks to be copied from a solid-state amp manual. Normally, tube amps can forgive speaker with lower-than-the-setting impedance.

Does your Marshall cab have a switch for 4/16 ohm mono? If so, I'd use 16, and rewire the Sunn for 16 as well. Then set the amp to 8 ohms when you use both cabs. For just the Marshall, set amp and cab both to 4 ohms. If the 1960 doesn't have such a switch, I don't know what I'd do.

The more questions that I get answered, the more that I come up with! lol So that ohm rating on the back of the amp is for TOTAL impedence? Weird. That just doesn't seem logical that any amp maker would do that considering the average intelligence of the average amp user (me included!). The average Joe doesn't have a clue about dividing or multiplying impedence and how to calculate it based on their load.

Anyways... I'm including two pics. One is of the back of the Traynor head. The other is the back of the 1960A cab. What you can see at the top of the 1960A is that their are ratings for 4 and 16 ohms in mono config listed there.

 

[Rich_S]

Re: Why did I like 4 ohms???

So, in mono mode, you can select 4 or 16 ohms on the cab based on which jack you plug into? Assuming I have that correct...

What you've shown in the photos is wrong. In stereo mode, the cab functions as a pair of 8-ohm cabinets. You've run a pair of cables to the head, and plugged them into a pair or paralleled output jacks, giving you a total speaker impedance of 4 ohms. So, the amp's switch should be on 4 ohms. You could acheive the same result using a single cable plugged into the 4-ohm cabinet input.

Side note: the 2-cable setup actually has one advantage; reliability. The way you have it now (but with the amp switched moved to 4 ohms), if a speaker cable fails, you'll be left with 2 speakers running at 8 ohms. This, the amp will survive. If you're only using a single speaker cable, and it fails open, any significant amouint of playing could smoke the OT or other parts of the outptu stage. A speaker cable suddenly failing open mid-gig is unlikely, but two cables both failing simultaneously is extremely unlikely.

Now that we have the Marshall cab figured out, let's look at the 2-cab setup. If it was me, I'd rewire the Sunn cab for 16 ohms, use the 1960 in mono mode with the 16-ohm input, and set the amp to 8 ohms.

 

[Red_Label]

Re: Why did I like 4 ohms???

So, in mono mode, you can select 4 or 16 ohms on the cab based on which jack you plug into? Assuming I have that correct...

What you've shown in the photos is wrong. In stereo mode, the cab functions as a pair of 8-ohm cabinets. You've run a pair of cables to the head, and plugged them into a pair or paralleled output jacks, giving you a total speaker impedance of 4 ohms. So, the amp's switch should be on 4 ohms. You could acheive the same result using a single cable plugged into the 4-ohm cabinet input.

Side note: the 2-cable setup actually has one advantage; reliability. The way you have it now (but with the amp switched moved to 4 ohms), if a speaker cable fails, you'll be left with 2 speakers running at 8 ohms. This, the amp will survive. If you're only using a single speaker cable, and it fails open, any significant amouint of playing could smoke the OT or other parts of the outptu stage. A speaker cable suddenly failing open mid-gig is unlikely, but two cables both failing simultaneously is extremely unlikely.

Now that we have the Marshall cab figured out, let's look at the 2-cab setup. If it was me, I'd rewire the Sunn cab for 16 ohms, use the 1960 in mono mode with the 16-ohm input, and set the amp to 8 ohms.

Yeah, you just switch the switch to mono mode and then plug into the 16 ohm input.

Sounds good... I will switch the amp switch to 4 ohms when just using the one cab (regardless of whether one or two cables are connecting the cab).

How would I wire 4 - 16 ohm (actually, they're 15 ohms each) speakers to come-out at a total of 16 ohms? Actually, if I were to do that I think I might as well buy the same jackplate and switch setup that's on the 1960A cab. They have them for sale on Ebay for $40. I could buy one of those and wire it into that cab and have some versatility that way.

 

[Dr.Mavashi]

Re: Why did I like 4 ohms???

Oh-oh, I guess I walked very thin ice yesterday. I ran 16 ohms out of my AOR into a 4 ohms on my JCM900 1960A in mono. Still, the sound was so much articulated and responsive with 16/4 than 16/16 and I gues 4/4 would be even better right? Thanks for all the feed back.

 

[Rich_S]

Re: Why did I like 4 ohms???

Oh-oh, I guess I walked very thin ice yesterday. I ran 16 ohms out of my AOR into a 4 ohms on my JCM900 1960A in mono. Still, the sound was so much articulated and responsive with 16/4 than 16/16 and I gues 4/4 would be even better right? Thanks for all the feed back.

A 4 ohm cab on a 16 ohm amp isn't terrible; the other way around would be worse. 4/4 would be best.

 

[Red_Label]

Re: Why did I like 4 ohms???

Side note: the 2-cable setup actually has one advantage; reliability. The way you have it now (but with the amp switched moved to 4 ohms), if a speaker cable fails, you'll be left with 2 speakers running at 8 ohms. This, the amp will survive. If you're only using a single speaker cable, and it fails open, any significant amouint of playing could smoke the OT or other parts of the outptu stage. A speaker cable suddenly failing open mid-gig is unlikely, but two cables both failing simultaneously is extremely unlikely.

I was just looking at my own pic a little more closely and it looks like I'd better just go with one cable when using the one cab. Because it says on that backplate not to use both inputs into the cab when Mono is selected.

 

[Rich_S]

Re: Why did I like 4 ohms???

I was just looking at my own pic a little more closely and it looks like I'd better just go with one cable when using the one cab. Because it says on that backplate not to use both inputs into the cab when Mono is selected.

What I meant was , to keep it in stereo with 2 cables, but with the amp set to 4 ohms. By all means, do not plug in both cables in mono.


All this is making me appreciate my combo amp even more.

 

[Red_Label]

Re: Why did I like 4 ohms???

All this is making me appreciate my combo amp even more.

LOL!

Yeah. I hear ya. But there's something about that wall of sound behind me. My 1X12 even with extension cab just doesn't have the same effect.

 

[Dr.Mavashi]

Re: Why did I like 4 ohms???

Alright, after three hours of playing, the 4 ohms on amp/4 on speaker took me tonal heaven. Period. Now, what really has nailed it is a certain combo of JJ in the right Vs. But basically it is a night and day difference between the 16 ohms setting, a lot tighter bottom end with much sharper punch of the mids and much better EQ over all. You people are gonna roll your eyes and say "yeah right" but basically I have now a Bogner extacy type of crunch with Engle like tightness of bottom end and classic "sabbath dark" Laney mids. I love it, of course as always, a reminder: Spina's TS is included and is the fundamental part of set up.
P.S.
JJ's ECC83s
V1 ECC83s - Gold pin
V2 ECC83s - high gain
V3 ECC83s - balanced
V4 ECC83s - high gain
This combo of this paricular matchings of Vs and tubeys was what nailed it.
Now all I have to do is replace at least two of these horrible G12T-75s with V30s and might actually phisically wet myself from this tone.

 

[schecterplayer]

Re: Why did I like 4 ohms???

So if i replaced the 16 ohm speaker in my combo with an 8 ohm it wouldnt be a problem? or had someone wire me a second output jack so i could run another 16ohm in another cab?