Bringing Up My First Amp

[erwin_ve]

giant Yawn!!

You got my attention:-) I wonder what his fixed resistors are, I Always thought the bass with 1M pot on the hrm was a bit weird, just on/off and basically a minumum setting.

[norburybrook]

giant Yawn!!

You got my attention:-) I wonder what his fixed resistors are, I Always thought the bass with 1M pot on the hrm was a bit weird, just on/off and basically a minumum setting.

yes, after using the 1M on my first HRM build I've never used one since!!

we all like gut shots...…


M

[donvan]

Since everything is working, my next step is to make/add the pedal. Where is everyone getting their pedals from these days?

[norburybrook]

I just use Hammond pedal enclosures a couple of footswitches/LEDS's and make my own.




M

[donvan]

I just use Hammond pedal enclosures a couple of footswitches/LEDS's and make my own.

Yeah, I guess that would work. What length of cable works for you?

[norburybrook]

I just use Hammond pedal enclosures a couple of footswitches/LEDS's and make my own.

Yeah, I guess that would work. What length of cable works for you?

How long is a piece of string?


I usually do 6 meters. I use van Damme Star quad cable, so that's 2 pairs plus a shield/ground works perfectly for the boost and OD. You can choose to hard wire at the pedal end or put another 5 pin DIN socket on the pedal as well. Doing it that way if you use standard 'midi' 5 pin connectors you can always pick up a replacement midi cable at any music store if ever breaks.Oviously that won't work if you use the old 'Dumble Switchraft' 5 pin XLR socket on the amp.

Be warned about bright LED's they're REALLY BRIGHT...… too bright for most with the 1k CLR.



M

[donvan]

Thanks Marcus.

[donvan]

I'm in the "break-in" phase with my 100 watt, 183 amp and thought I'd write some notes (random ramblings) on what I've experienced so far.

I have a tele, a strat, and an ES335. I was really liking the sound of the 335 and tele but having a hard time finding tone settings that I liked for the strat. Lot's of notes were ice picky. If I rolled that off with amp tone controls or guitar tone controls the result was too muddy. I found a post here about a strat switch which is merely a matter of changing the value of the capacitor that is in series with the Mid pot. Most here seem to make their "strat switch" by switching between .01uF and .047uF caps. My current value is .01 so as a test I jumpered in a .047 in parallel. I feel like I have a pretty good ear but I really didn't hear a whole lot of difference. It made me wonder if my jumpers were not making a good connection (or maybe my ears are not as good as I thought). I found one post by a member here who said he didn't hear much difference with his strat switch but at the time he was playing at very low levels. Does anyone have any experience with a strat switch? Does yours result in a pretty big difference or is it incredibly subtle?

I recently heard an interview with a guitar player who made mention of turning down the *volume* on their guitar to change the tone. That seemed really counter intuitive to me. I have always played with my guitar volume control all the way up and used a volume pedal but low and behold, that was it! I was able to find the tone I'd been looking for by backing off the guitar volume. Maybe everyone but me already knew that but it was a big breakthrough for me. I've played strats since the 80s so it is a little embarrassing to admit that I just discovered this but I am now enjoying the tone that I get with my strat - no strat switch required!

Last week my amp developed an issue. After being on for a couple of minutes it would start making scratches and pops - sort of like what you hear when adjust an old, dirty pot. Since the volume of this noise was not affected by any volume control changes I figured it must be in the power amp. Sure enough, it turned out to be a bad power tube. I'm guessing the amp and the tubes probably only have about 20 hours on them. Is it normal for a power tube to go that fast? At this time, I don't have expensive tubes. I've got JJ KT77s. I wanted to get familiar with the amp before I go and start "tube rolling".

Speaking of "tube rolling" when I went to order a replacement KT77 I read a review that said this: "The breakup is earlier than a 6L6 with more compression but not as compressed as the EL34."

As far as compression goes, does this apply to an amp like an ODS where the overdrive is mostly coming from the pre-amp?

Yeah, I know. That's a lot of rambling.

[norburybrook]

@Donovan,

greetings from New Zealand

I would expect output tubes on a Dumble to last for more than 20 hours!!!

I have El34's in mine well the EHX version of the old Mullard EL34.

My #183 100w is the last amp I built and it's certainly not harsh in anyway with any guitar, it's actually a very smooth amp to be honest compared to the 70's second gen for example.


Volume rolling can have massive tonal effects depending on guitar/wiring/pickups/amp combination. I had a TW Express that was incredibly picky about the type of pots on the guitar, some guitars worked great, some didn't, that was an extreme example though as it was a crazy amp.

You can make a Dumble ODS work keeping it on the OD channel and using your guitar volume control, maybe not so conventional but if you like to control the 'crunch/hair' then I've found this is the best way.


The ODS is a complex amp in it's relation to the guitar used/playing style etc so I'd suggest experimenting and living with it for a while to find out what works best for YOU. You may find that the ODS actually isn't the amp for you at all, I know quite a few players that don't like the ODS. Just because they're 'expensive' elusive amps doesn't mean they're the right amp for you. Fortunately we can find this out without spending $100,0000



MC

[talbany]

I'm in the "break-in" phase with my 100 watt, 183 amp and thought I'd write some notes (random ramblings) on what I've experienced so far.

I have a tele, a strat, and an ES335. I was really liking the sound of the 335 and tele but having a hard time finding tone settings that I liked for the strat. Lot's of notes were ice picky. If I rolled that off with amp tone controls or guitar tone controls the result was too muddy. I found a post here about a strat switch which is merely a matter of changing the value of the capacitor that is in series with the Mid pot. Most here seem to make their "strat switch" by switching between .01uF and .047uF caps. My current value is .01 so as a test I jumpered in a .047 in parallel. I feel like I have a pretty good ear but I really didn't hear a whole lot of difference. It made me wonder if my jumpers were not making a good connection (or maybe my ears are not as good as I thought). I found one post by a member here who said he didn't hear much difference with his strat switch but at the time he was playing at very low levels. Does anyone have any experience with a strat switch? Does yours result in a pretty big difference or is it incredibly subtle?

I recently heard an interview with a guitar player who made mention of turning down the *volume* on their guitar to change the tone. That seemed really counter intuitive to me. I have always played with my guitar volume control all the way up and used a volume pedal but low and behold, that was it! I was able to find the tone I'd been looking for by backing off the guitar volume. Maybe everyone but me already knew that but it was a big breakthrough for me. I've played strats since the 80s so it is a little embarrassing to admit that I just discovered this but I am now enjoying the tone that I get with my strat - no strat switch required!

Last week my amp developed an issue. After being on for a couple of minutes it would start making scratches and pops - sort of like what you hear when adjust an old, dirty pot. Since the volume of this noise was not affected by any volume control changes I figured it must be in the power amp. Sure enough, it turned out to be a bad power tube. I'm guessing the amp and the tubes probably only have about 20 hours on them. Is it normal for a power tube to go that fast? At this time, I don't have expensive tubes. I've got JJ KT77s. I wanted to get familiar with the amp before I go and start "tube rolling".

Speaking of "tube rolling" when I went to order a replacement KT77 I read a review that said this: "The breakup is earlier than a 6L6 with more compression but not as compressed as the EL34."

As far as compression goes, does this apply to an amp like an ODS where the overdrive is mostly coming from the pre-amp?

Yeah, I know. That's a lot of rambling.

Generally speaking in my experience If a tube fails it will usually occur within the 1st 10-12 hours of lighting it off. After that if there are no issues your (for the most part) good to go for the life of the tube if the amp is well cared for and set up properly. Of course, you always want to keep an eye on it for the first several hours. Keep your probes on them and go back and check on them while it's cookin just to make sure they don't drift away on you. EL-34's (especially newer ones) are notorious for drifting. Even after several gigs I will go back and check them again just to make sure!!. I also keep a note of where each tube is biased. I do this with a marker on the chassis somewhere so when I go back to see how far they drifted (they always drift somewhere) 6l6 (triodes) are not as bad and generally more stable than the 34's and there close cousins.
Of course a tube can and will go at anytime and for any reason.

Tony

[Charlie Wilson]

I'm in the "break-in" phase with my 100 watt, 183 amp and thought I'd write some notes (random ramblings) on what I've experienced so far.

I have a tele, a strat, and an ES335. I was really liking the sound of the 335 and tele but having a hard time finding tone settings that I liked for the strat. Lot's of notes were ice picky. If I rolled that off with amp tone controls or guitar tone controls the result was too muddy. I found a post here about a strat switch which is merely a matter of changing the value of the capacitor that is in series with the Mid pot. Most here seem to make their "strat switch" by switching between .01uF and .047uF caps. My current value is .01 so as a test I jumpered in a .047 in parallel. I feel like I have a pretty good ear but I really didn't hear a whole lot of difference. It made me wonder if my jumpers were not making a good connection (or maybe my ears are not as good as I thought). I found one post by a member here who said he didn't hear much difference with his strat switch but at the time he was playing at very low levels. Does anyone have any experience with a strat switch? Does yours result in a pretty big difference or is it incredibly subtle?

I recently heard an interview with a guitar player who made mention of turning down the *volume* on their guitar to change the tone. That seemed really counter intuitive to me. I have always played with my guitar volume control all the way up and used a volume pedal but low and behold, that was it! I was able to find the tone I'd been looking for by backing off the guitar volume. Maybe everyone but me already knew that but it was a big breakthrough for me. I've played strats since the 80s so it is a little embarrassing to admit that I just discovered this but I am now enjoying the tone that I get with my strat - no strat switch required!

Last week my amp developed an issue. After being on for a couple of minutes it would start making scratches and pops - sort of like what you hear when adjust an old, dirty pot. Since the volume of this noise was not affected by any volume control changes I figured it must be in the power amp. Sure enough, it turned out to be a bad power tube. I'm guessing the amp and the tubes probably only have about 20 hours on them. Is it normal for a power tube to go that fast? At this time, I don't have expensive tubes. I've got JJ KT77s. I wanted to get familiar with the amp before I go and start "tube rolling".

Speaking of "tube rolling" when I went to order a replacement KT77 I read a review that said this: "The breakup is earlier than a 6L6 with more compression but not as compressed as the EL34."

As far as compression goes, does this apply to an amp like an ODS where the overdrive is mostly coming from the pre-amp?

Yeah, I know. That's a lot of rambling.

Donvan, as far as tone and volume knobs on the Strat, watch some youtube videos of Strat master Jeff Beck.
CW

[talbany]

I'm in the "break-in" phase with my 100 watt, 183 amp and thought I'd write some notes (random ramblings) on what I've experienced so far.

I have a tele, a strat, and an ES335. I was really liking the sound of the 335 and tele but having a hard time finding tone settings that I liked for the strat. Lot's of notes were ice picky. If I rolled that off with amp tone controls or guitar tone controls the result was too muddy. I found a post here about a strat switch which is merely a matter of changing the value of the capacitor that is in series with the Mid pot. Most here seem to make their "strat switch" by switching between .01uF and .047uF caps. My current value is .01 so as a test I jumpered in a .047 in parallel. I feel like I have a pretty good ear but I really didn't hear a whole lot of difference. It made me wonder if my jumpers were not making a good connection (or maybe my ears are not as good as I thought). I found one post by a member here who said he didn't hear much difference with his strat switch but at the time he was playing at very low levels. Does anyone have any experience with a strat switch? Does yours result in a pretty big difference or is it incredibly subtle?

I recently heard an interview with a guitar player who made mention of turning down the *volume* on their guitar to change the tone. That seemed really counter intuitive to me. I have always played with my guitar volume control all the way up and used a volume pedal but low and behold, that was it! I was able to find the tone I'd been looking for by backing off the guitar volume. Maybe everyone but me already knew that but it was a big breakthrough for me. I've played strats since the 80s so it is a little embarrassing to admit that I just discovered this but I am now enjoying the tone that I get with my strat - no strat switch required!

Last week my amp developed an issue. After being on for a couple of minutes it would start making scratches and pops - sort of like what you hear when adjust an old, dirty pot. Since the volume of this noise was not affected by any volume control changes I figured it must be in the power amp. Sure enough, it turned out to be a bad power tube. I'm guessing the amp and the tubes probably only have about 20 hours on them. Is it normal for a power tube to go that fast? At this time, I don't have expensive tubes. I've got JJ KT77s. I wanted to get familiar with the amp before I go and start "tube rolling".

Speaking of "tube rolling" when I went to order a replacement KT77 I read a review that said this: "The breakup is earlier than a 6L6 with more compression but not as compressed as the EL34."

As far as compression goes, does this apply to an amp like an ODS where the overdrive is mostly coming from the pre-amp?

Yeah, I know. That's a lot of rambling.

Donvan, as far as tone and volume knobs on the Strat, watch some youtube videos of Strat master Jeff Beck.
CW

Definitely!!.

https://www.youtube.com/watch?v=ZFx__GfJHWw

[ayan]

I'm in the "break-in" phase with my 100 watt, 183 amp and thought I'd write some notes (random ramblings) on what I've experienced so far.

I have a tele, a strat, and an ES335. I was really liking the sound of the 335 and tele but having a hard time finding tone settings that I liked for the strat. Lot's of notes were ice picky. If I rolled that off with amp tone controls or guitar tone controls the result was too muddy. I found a post here about a strat switch which is merely a matter of changing the value of the capacitor that is in series with the Mid pot. Most here seem to make their "strat switch" by switching between .01uF and .047uF caps. My current value is .01 so as a test I jumpered in a .047 in parallel. I feel like I have a pretty good ear but I really didn't hear a whole lot of difference. It made me wonder if my jumpers were not making a good connection (or maybe my ears are not as good as I thought). I found one post by a member here who said he didn't hear much difference with his strat switch but at the time he was playing at very low levels. Does anyone have any experience with a strat switch? Does yours result in a pretty big difference or is it incredibly subtle?

I recently heard an interview with a guitar player who made mention of turning down the *volume* on their guitar to change the tone. That seemed really counter intuitive to me. I have always played with my guitar volume control all the way up and used a volume pedal but low and behold, that was it! I was able to find the tone I'd been looking for by backing off the guitar volume. Maybe everyone but me already knew that but it was a big breakthrough for me. I've played strats since the 80s so it is a little embarrassing to admit that I just discovered this but I am now enjoying the tone that I get with my strat - no strat switch required!

Last week my amp developed an issue. After being on for a couple of minutes it would start making scratches and pops - sort of like what you hear when adjust an old, dirty pot. Since the volume of this noise was not affected by any volume control changes I figured it must be in the power amp. Sure enough, it turned out to be a bad power tube. I'm guessing the amp and the tubes probably only have about 20 hours on them. Is it normal for a power tube to go that fast? At this time, I don't have expensive tubes. I've got JJ KT77s. I wanted to get familiar with the amp before I go and start "tube rolling".

Speaking of "tube rolling" when I went to order a replacement KT77 I read a review that said this: "The breakup is earlier than a 6L6 with more compression but not as compressed as the EL34."

As far as compression goes, does this apply to an amp like an ODS where the overdrive is mostly coming from the pre-amp?

Yeah, I know. That's a lot of rambling.

A couple of thoughts on your post(s). First, going back to a while ago when you asked why tie the cathodes of the in-phase power tubes together, the reason is you want to balance the overall signal with the PI trimmer. If you do it to one half of the power section at a time, when you add the two halves (which is what actually happens, as the power tube pairs run in parallel) your signal may not be symmetrical anymore.

As far as the .01 VS .047uF mid cap, the difference is rather significant and you should be able to hear it well. If you turn the mids up, the difference will decrease, though. It took me a long time to be comfortable dialing in Skyliner amps with a Strat, and maybe in the end I just accepted things for what they were. I believe that if you dial an amp to play on the bridge pickup, it will not necessarily work all that well with say middle and bridge pickups combined. That quacky position kills a lot of high end and adds more midrange, while the bridge pickup always has a tendency to be on the bright side. Anyway, as far as setting the amp, if I recall correctly what worked well for me was to turn the preamp volume up and dial the overdrive gain ("Level" in the old amps) only as high as it will go before sounding harsh. Keep the bass somewhat low, especially on a Skyliner amp, and you will need to have some treble otherwise the sound will not "chirp." The midrange control will add gain and sustain, but will also make the sound harsher. It's a bit of a balancing act, and one other thing you may notice is that the clean channel -- when the preamp volume control is turned up -- will have a tendency to get loud and possibly louder than the lead channel (unless we're talking about an HRM amp, in which case the volume controls are not cascaded and this phenomenon is not a concern). A long time ago I had posted a little clip of how I dialed a Strat (middle + bridge combo) on a 102 amp, I found it here on the board and am attaching it again. It was recorded far form the speaker cab an not pointing at it, so it sounds darker than it actually was in the room. At the end of the day, for a Strat, my favorite voicing was the "classic" and I had added some tweaks at the OD entrance to smooth out the sound even more.

These days, I continue to do all my playing with a pedalboard, where I get all my sounds from. That has freed me to be able to use any amp available to me, but at the end of the day, I still prefer the Dumble type of amps with Skyliner EQ as a "clean" platform.

Best,

Gil

[donvan]

Marcus, Tony, Charlie, Gil,
Thanks for taking the time to read the posts and offer your comments. There is a lot of good information there. I can't wait to dig into this more and try it all out.

Gil, I really like the sound you are getting with your strat. Well done!

[donvan]

Since I had to replace a power tube and will need to re-set the the PI trim it's probably a good time to revisit biasing. When I first brought up the amp someone mentioned that Dumble tended to bias on the colder side so I went fairly cold at 55% of max power dissipation.

What is the general consensus on where to set the bias on a 183 ODS circuit? I am more concerned with tone than volume since this is a 100 watt amp and 50 watts would have more than enough volume for me.

Thanks,
Don