Board Logo
« SLO Too Bright? Fizzy? PROBLEM SOLVED!! »

Welcome Guest. Please Login or Register.
Jan 19th, 2018, 9:08pm



« Previous Topic | Next Topic »
Pages: 1 2 3  Notify Send Topic Print
 veryhotthread  Author  Topic: SLO Too Bright? Fizzy? PROBLEM SOLVED!!  (Read 10673 times)
Giga
Decatone
ImageImageImageImage


member is offline

Avatar




PM


Posts: 159
xx Re: SLO Too Bright? Fizzy? PROBLEM SOLVED!!
« Reply #30 on: May 23rd, 2013, 4:23pm »

Yeah, I was half wrong shocked ; but V3B definitely is a gain stage which does make sense as putting a lower gain tube in V3 also heavily affects the clean channel. (and not in a good way).

Giga
User IP Logged

Heavision
Lucky 13
ImageImageImage


member is offline

Avatar




PM


Posts: 112
xx Re: SLO Too Bright? Fizzy? PROBLEM SOLVED!!
« Reply #31 on: May 25th, 2013, 2:33pm »

I thought V1 and V2 were the normal and OD gain stages? And V3 and V4 were for the EQ and FX loop? Therefore wouldn't V3 effect tone, but not necessarily gain?

Also, I've heard mixed things about V5 (PI tube) effecting tone. Not that it adds or subtracts gain; but that it can effect sustain and color/character or whatever.
User IP Logged

SLO ("bone stock")
Bogner 412, Scumbacks & Emis
a few guitars, (Highorder pickups!)
T.C. Hall Of Fame, Strymon Timeline
LOTS of picks
MHProd
Hot Rod
Image


member is offline

Avatar




PM


Posts: 18
xx Re: SLO Too Bright? Fizzy? PROBLEM SOLVED!!
« Reply #32 on: May 25th, 2013, 9:17pm »

Like I said, if it is something related to crossover distortion, it has nothing to do with preamp tubes.
User IP Logged

JLB
Super Lead Overdrive
ImageImageImageImageImage


member is offline

Avatar




PM

Gender: Male
Posts: 868
xx Re: SLO Too Bright? Fizzy? PROBLEM SOLVED!!
« Reply #33 on: May 27th, 2013, 11:26pm »

True, V3 and V4 also manage the effects loop as well. V5 is nothing more than a Phase Inverter. ANY 12AX7, 12AT7, NOS 5751 etc. that is in good working order will work fine. Mike never understands why guys waste a fantastic preamp tube in that position. It just needs to work.

I run a NOS 5751 there basically as a place to store one if I need it. Chances of me dropping my spare tubes box is high, chances of dropping amp in an ATA road case, VERY SLIM.. ha.

LB
BCM
« Last Edit: May 27th, 2013, 11:27pm by JLB » User IP Logged

James L. Burke III
Blues City Music owner
SLO-100 x 3 (3 option, 5 option, BCM one off)
Hot Rod 25 (#002)
44 BCM Combos (#001 & #002)
Surf Box (#98) Last USA model
Soldano GTO (#49) Last model
Diamond Amplification 327 SD (#001)
JRW
Decatone
ImageImageImageImage


member is offline

Avatar




PM


Posts: 151
xx Re: SLO Too Bright? Fizzy? PROBLEM SOLVED!!
« Reply #34 on: Jun 2nd, 2013, 4:00pm »

When you really think about it -- I wonder why there isn't a commercially available external octal tube base version of this circuit similar to how a bias probe or Yellow Jacket works?

Probably an enterprising opportunity there for such a simple idea I would think -- just saying...
User IP Logged

MHProd
Hot Rod
Image


member is offline

Avatar




PM


Posts: 18
xx Re: SLO Too Bright? Fizzy? PROBLEM SOLVED!!
« Reply #35 on: Jun 2nd, 2013, 4:08pm »

on Jun 2nd, 2013, 4:00pm, JRW wrote:
When you really think about it -- I wonder why there isn't a commercially available external octal tube base version of this circuit similar to how a bias probe or Yellow Jacket works?

Probably an enterprising opportunity there for such a simple idea I would think -- just saying...


I may or may not be working on something like this... grin
User IP Logged

soulcraft
Hot Rod
Image


member is offline

Avatar




PM


Posts: 7
xx Re: SLO Too Bright? Fizzy? PROBLEM SOLVED!!
« Reply #36 on: Jun 3rd, 2013, 05:36am »

V2 is the only preamp tube that will have no (or perhaps more accurately incredibly little) impact on the clean channel. Every other preamp tube is shared by both channels.

V3 cathode follower decreases the signal level for the FX send, and the gain stage in V4 boosts the signal back up. The V4 cathode follower drives the tone stack. In a loopless SLO there is no Driver or Recovery stage, no signal reduction or amplifying. No loop has it's advantages and may tame some of this high end stuff that keeps getting brought up and also noise from extra gain stages.

As for a commercially available conjunctive filter that fits outside the chassis, that sounds interesting. The first issues that spring to mind for me would be that you'd need two external sockets bridging the OT primaries outside the chassis. Since not all amps have the same power tube spacing, the link would need to be flexible or adjustable. That to me means some risk of breakage from flexing or vibration. I'd worry about the possible fault conditions if that was the case, since shorting primaries is normally a bad plan.

Secondly, in my experience, you can't always fit power tubes into extra sockets and seat them in the amp while the amp is in it's shell. Take the JJ 6L6GC. It has a deep plastic base (compared to a sovtek 5881 button base) and adding to that depth with the usual external sockets I've seen actually increases the height of the tube a lot, and having clearance to get the tube, extra base, and lets not forget the pins of the socket in to the amp can be difficult. If you want to avoid having to take the amp out the shell to fit the item then it could be a challenge.

And lastly for me, I think the less stuff carrying high voltages outside any amplifiers chassis, the better.

That said, if you think of a good way to do it, more power to you!



User IP Logged

MHProd
Hot Rod
Image


member is offline

Avatar




PM


Posts: 18
xx Re: SLO Too Bright? Fizzy? PROBLEM SOLVED!!
« Reply #37 on: Jun 3rd, 2013, 7:52pm »

Very good points Soulcraft.

These issues are all being addressed in my design.

If I was to do something 'just' for the SLO, it would actually be very easy. But it would only work properly for the SLO (or other amps with an identical OT primary impedance), so I'm working on a 'variable design' for other amps (Soldano, Boogies, etc...).

More soon.
« Last Edit: Jun 4th, 2013, 12:49am by MHProd » User IP Logged

cstwo
Hot Rod
Image


member is offline

Avatar




PM


Posts: 2
xx Re: SLO Too Bright? Fizzy? PROBLEM SOLVED!!
« Reply #38 on: Jul 26th, 2013, 05:36am »

Hi MHProd ,

can you send me the schematics of this mod , I would like to try it , my amp tech is asking

tx a lot

christian.somers@telenet.be
User IP Logged

MHProd
Hot Rod
Image


member is offline

Avatar




PM


Posts: 18
xx Re: SLO Too Bright? Fizzy? PROBLEM SOLVED!!
« Reply #39 on: Jan 3rd, 2015, 10:59pm »

Happy New Year guys!

Just wanted to give a brief update on my SLO.

I just changed the tubes to a quad of TADs 6L6GC-STR biased around 42ma (just under 70% plate dissipation, tubes are rated for 30W) and swapped the JAN 5751 in V1 to a RCA 7025. Slightly different flavor than the Shuguang KT66s I had before. A bit more focused and more muscle.

Thanks to the conjunctive filter, the amp still sounds very smooth and I'm always impressed with the sound of this thing...

I also invested in a Torpedo Reload attenuator a few months back and now the amp's volume pretty much stays on 7. By far the best attenuator on the market (tried all the usual suspects including the Rivera. I couldn't get access to the Tone King Ironman though. The Reload's design is unique to anything else currently available.) Best thing I bought for the last 10 years!

User IP Logged

alerich
Avenger
ImageImage


member is offline

Avatar

This one goes to 11.


PM

Gender: Male
Posts: 25
xx Re: SLO Too Bright? Fizzy? PROBLEM SOLVED!!
« Reply #40 on: Jan 7th, 2015, 9:22pm »

on May 9th, 2013, 10:27pm, JLB wrote:
Sorry guys, I've been dealing with imbeciles all day long and I don't want to sound callous at all I promise, but I'm claiming BS on this.

A "design fault"? You have to be kidding me. The SLO is ICONIC in every way possible.


The conjunctive filter will do exactly what the OP and the linked article say it will. Whether the result is to your liking or even whether you feel you need it in the first place is in the ear of the beholder. I don't mean to sound callous but calling it BS is just simple ignorance.

User IP Logged

Heavision
Lucky 13
ImageImageImage


member is offline

Avatar




PM


Posts: 112
xx Re: SLO Too Bright? Fizzy? PROBLEM SOLVED!!
« Reply #41 on: Jan 19th, 2015, 5:27pm »

My fizzy, ice pick, kazoo-sounding tone problems are back, big time. I swear it comes and goes.
User IP Logged

SLO ("bone stock")
Bogner 412, Scumbacks & Emis
a few guitars, (Highorder pickups!)
T.C. Hall Of Fame, Strymon Timeline
LOTS of picks
Pages: 1 2 3  Notify Send Topic Print
« Previous Topic | Next Topic »

Donate $6.99 for 50,000 Ad-Free Pageviews!

| |

This forum powered for FREE by Conforums ©
Sign up for your own Free Message Board today!
Terms of Service | Privacy Policy | Conforums Support | Parental Controls