Here's a few shots of my personal build 70's style..I added the built in loop..Not my best work but not bad either...No fet yet.. 100 watter steel chassis and NOS Allen Bradley pots I had laying around..they act like 30% taper w/ seasoned iron..Judging by the post's here on how some believed the OD was a touch harsh I used NOS Allen Bradley carbon comps for the OD section...The topology is pretty much like #13 tone stack (axe the reverb)...How does it sound..
The clean channel is pretty amazing..Big clean open loads of headroom being 100 watts..Some nice low end bloom and scary loud..Definitely the loudest of my Dumble collection.. Having the earlier tone stack 1m treble/ 1m bass/ 250k mid doesn't offer much range on the stack especially in rock mode but enough to compensate for different guitars.... The OD network cuts a noticeable amount of bass, bumps the mids.. boost's the vol quite a bit.. The OD tone is focused and cuts... A Strat on the bridge is like whew... It's not a painful cut but a real attention grabber.... I am glad I used the CComps here as any more and for me would be a bit over the top in spots.... The comps do add a bit of hiss..The OD on these amps is much different than the later models IMHO definitely carries more of that 70's clean mid-rangey loud vibe to it...These amps really shine when sliding on them and when cranked nails the Lindley tone..The loop does help get a better tone feel at lower volumes and with a nice outboard unit sounds better than any Twin I’ve ever played through...The 100 watts in this style is over the top as a 50 would be more than enough to do any decent size club.. I prefer a closed back cabinet with this design FWIW..
This was a fun build and recommend it to anyone who is chasing the Lindley tone..Hope some of this sheds more light on the vibe tone of the the earlier 70's style..
Tony
70's Build
Moderators: pompeiisneaks, Colossal
70's Build
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Last edited by talbany on Sat Jan 15, 2011 9:11 am, edited 2 times in total.
" The psychics on my bench is the same as Dumble'"
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David Root
- Posts: 3540
- Joined: Fri Aug 04, 2006 3:00 pm
- Location: Chilliwack BC
Re: 70's Build
Looks really good Tony! I'm planning a 50W #13 w/out reverb so this is very helpful to me. Thank you.
Besides the odd carbon comp resistor, would you think a few NOS Black Cat coupling caps here and there would add more old time taste or not? I have some I could use.
My plan is a combo in a Princeton Reverb chassis/cabinet. Why do you prefer this circuit in a closed cabinet and would only 50W make any difference in that respect?
Besides the odd carbon comp resistor, would you think a few NOS Black Cat coupling caps here and there would add more old time taste or not? I have some I could use.
My plan is a combo in a Princeton Reverb chassis/cabinet. Why do you prefer this circuit in a closed cabinet and would only 50W make any difference in that respect?
Re: 70's Build
Looks great! Neat build. Thnx for sharing pics and knowledge about the CC resistors in this particular build. 
Re: 70's Build
Dave
Glad it helped.. I cannot really think of any place that I would use NOS paper caps in this design...
This tone stack set in rock mode has a real pronounced open midrange especially in OD.. The closed back helps to better balance the lows and mids IMO..The speakers I tested it with are the G12-65's so other slightly darker speakers like EV's may help. I was thinking of lowering or removing the 500pf bypass cap over the 220k OD entrance resistor..still giving my ears time to adjust.. This amp in a 50w combo would be very cool.. I do recommend adding the loop build it in if you can as it's a nice improvement.. Check your inbox...
Tony
Glad it helped.. I cannot really think of any place that I would use NOS paper caps in this design...
This tone stack set in rock mode has a real pronounced open midrange especially in OD.. The closed back helps to better balance the lows and mids IMO..The speakers I tested it with are the G12-65's so other slightly darker speakers like EV's may help. I was thinking of lowering or removing the 500pf bypass cap over the 220k OD entrance resistor..still giving my ears time to adjust.. This amp in a 50w combo would be very cool.. I do recommend adding the loop build it in if you can as it's a nice improvement.. Check your inbox...
Tony
" The psychics on my bench is the same as Dumble'"
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UltraHookedOnPhonix
- Posts: 414
- Joined: Thu Dec 15, 2005 9:32 pm
- Location: Dumbleland
Re: 70's Build
Great looking amp Tony!
What is that neat coax cable with the clear jacket? I've seen it in some TR amps.
What is that neat coax cable with the clear jacket? I've seen it in some TR amps.
Re: 70's Build
Ultra
Thanks.. I got it from Steve @ Apex.... Teflon,,I got it quite a few years ago and to be honest don't even remember the guage or type..Steve said he would send this stuff everyone else uses... It's excellent looking coax the only problem I have with it is the core wire is pretty small( stranded)..So small I don't use it on my production amps so saved it for these little personal builds and prototypes...Anyway If you get it from him make sure you specify your desired guage..
Tony
Thanks.. I got it from Steve @ Apex.... Teflon,,I got it quite a few years ago and to be honest don't even remember the guage or type..Steve said he would send this stuff everyone else uses... It's excellent looking coax the only problem I have with it is the core wire is pretty small( stranded)..So small I don't use it on my production amps so saved it for these little personal builds and prototypes...Anyway If you get it from him make sure you specify your desired guage..
Tony
" The psychics on my bench is the same as Dumble'"
Re: 70's Build
A very cool project Tony.
I really enjoyed your description of the amps performance.
Exactly the way I remember these early Dumbles.
If you remove the 500 pF cap in the OD entrance you might encounter
oscillation problems when using the FET input.
A tweak to improve the range of the eq in Rock mode is to change the
.02 cap wired to the bass pot to .01.I used this for a couple of years,
different tone of course.
What is the value of the series resistor following the V2b coupling cap?
I have seen values from 1 Meg to 4.7 Meg here, on some amps
the OD was too loud, on my amp it was´t loud enough.
You´ll be hearing from me soon, Marcos
I really enjoyed your description of the amps performance.
Exactly the way I remember these early Dumbles.
If you remove the 500 pF cap in the OD entrance you might encounter
oscillation problems when using the FET input.
A tweak to improve the range of the eq in Rock mode is to change the
.02 cap wired to the bass pot to .01.I used this for a couple of years,
different tone of course.
What is the value of the series resistor following the V2b coupling cap?
I have seen values from 1 Meg to 4.7 Meg here, on some amps
the OD was too loud, on my amp it was´t loud enough.
You´ll be hearing from me soon, Marcos
Re: 70's Build
Nice Tony, I'll bet it sounds great!
Marcos, it looks like a 1 Meg on my monitor.
Marcos, it looks like a 1 Meg on my monitor.
Tom
Don't let that smoke out!
Don't let that smoke out!
Re: 70's Build
marcos wrote:A very cool project Tony.
I really enjoyed your description of the amps performance.
Exactly the way I remember these early Dumbles.
If you remove the 500 pF cap in the OD entrance you might encounter
oscillation problems when using the FET input.
A tweak to improve the range of the eq in Rock mode is to change the
.02 cap wired to the bass pot to .01.I used this for a couple of years,
different tone of course.
What is the value of the series resistor following the V2b coupling cap?
I have seen values from 1 Meg to 4.7 Meg here, on some amps
the OD was too loud, on my amp it was´t loud enough.
You´ll be hearing from me soon, Marcos
Marcos
Good to hear from you and thanks again for all your help and insight on these early beasts..
Yeah I went into this project accepting the fact that this was going to be a different animal all together and not get at all hung up on spending the next 2 months tweaking it into something it's not..These day's Iv'e been more apt to giving things time..Been there too often....Right now I have a 1 Meg on V2b w/180k to ground...The problem is if I set it so the transition from clean to OD is transparent or a a slight 3-5db boost the OD doesn't have quite the gain I like...At high volumes w/ hot set of humbuckers it's money but at lower club gig levels could use a bump in gain without the added volume..Is there a value there you found to work?..The range issue hasn't really bothered me that much yet so I am going to give it some time..Other than that it's a blast to build and play..Your other tweaks are noted.. Thanks again!!
Tony
" The psychics on my bench is the same as Dumble'"
Re: 70's Build
Hi Tony,
I see that it really makes sense to leave the amp as it is in your case,
since you have a collection of Dumble-style amps.Tweaking the 70s design will eventually lead to something like a 124 type I guess.
No, I never found a value that works for the series resistor in all cases,
I changed it a couple of times, and eventually went for a Ratio control.
You may find a value that works for a certain setting, but then you might
decide to use the FET input, and you will have to change it again.
I still wonder why HAD did not install a Ratio pot in the first series of amps, because everyone encountered the problems you mentioned.
As far as I know some players, like Rick Vito, never used the channel
switching option, leaving the amp in overdrive mode all the time.
I did the same thing in the first couple of years.
Marcos
I see that it really makes sense to leave the amp as it is in your case,
since you have a collection of Dumble-style amps.Tweaking the 70s design will eventually lead to something like a 124 type I guess.
No, I never found a value that works for the series resistor in all cases,
I changed it a couple of times, and eventually went for a Ratio control.
You may find a value that works for a certain setting, but then you might
decide to use the FET input, and you will have to change it again.
I still wonder why HAD did not install a Ratio pot in the first series of amps, because everyone encountered the problems you mentioned.
As far as I know some players, like Rick Vito, never used the channel
switching option, leaving the amp in overdrive mode all the time.
I did the same thing in the first couple of years.
Marcos
-
tubedogsmith
- Posts: 597
- Joined: Mon Jan 17, 2005 11:52 pm
Re: 70's Build
Tony, looks very nice. What does having the deep switch and the mid switch going at the same time sound like?
Re: 70's Build
Way to go Tony!!
She's a beauty!
I'm really loving my 70's build.
A couple of things I've learned using mine:
1. I can't explain it, but you're right, this is the best amp for slide or lap steel that I've ever used.
2. Implement the FET input. Funk gave me this bit of advice early on and I am forever grateful. Wasn't really crazy about this amp until I plugged into the FET. You can use it to cure a variety of minor ills with this style amp. Don't know that it's very useful in the later amps but for some reason in this one it rocks.
3. The ratio of clean to OD volume changes depending on how hot of a signal the first stage sees (you probably already know this but....). With my Gretsch, the change from clean to OD was giving me a HUGE volume boost. But I noticed that the P90 in my Les Paul Jr. gave almost unity gain between the two channels. Dropped a Dynacomp set fairly hot inline between the Gretsch and the FET input and presto! Outboard ratio control. I'd wager you could use any flavor of clean boost (or maybe even the FET trim) you like and get this same effect.
4. The midrange control on mine does very little. You can see a shift on the scope, but it's almost inaudible.
5. Mine's only 50 watts and is WAY LOUD! I haven't been able to set mine over 2 yet without everybody getting pissed off. 'Course the JTM45 PT is giving me about 480v on the plates.
Anyway, Here's to the much maligned 70's style Dumble!
Cheers,
Carey
She's a beauty!
I'm really loving my 70's build.
A couple of things I've learned using mine:
1. I can't explain it, but you're right, this is the best amp for slide or lap steel that I've ever used.
2. Implement the FET input. Funk gave me this bit of advice early on and I am forever grateful. Wasn't really crazy about this amp until I plugged into the FET. You can use it to cure a variety of minor ills with this style amp. Don't know that it's very useful in the later amps but for some reason in this one it rocks.
3. The ratio of clean to OD volume changes depending on how hot of a signal the first stage sees (you probably already know this but....). With my Gretsch, the change from clean to OD was giving me a HUGE volume boost. But I noticed that the P90 in my Les Paul Jr. gave almost unity gain between the two channels. Dropped a Dynacomp set fairly hot inline between the Gretsch and the FET input and presto! Outboard ratio control. I'd wager you could use any flavor of clean boost (or maybe even the FET trim) you like and get this same effect.
4. The midrange control on mine does very little. You can see a shift on the scope, but it's almost inaudible.
5. Mine's only 50 watts and is WAY LOUD! I haven't been able to set mine over 2 yet without everybody getting pissed off. 'Course the JTM45 PT is giving me about 480v on the plates.
Anyway, Here's to the much maligned 70's style Dumble!
Cheers,
Carey
<i> "I've suffered for my music. Now it's your turn."</i>
Re: 70's Build
It looks like the Kitty Hawk used a 580K series resistor.marcos wrote:A very cool project Tony.
I really enjoyed your description of the amps performance.
Exactly the way I remember these early Dumbles.
If you remove the 500 pF cap in the OD entrance you might encounter
oscillation problems when using the FET input.
A tweak to improve the range of the eq in Rock mode is to change the
.02 cap wired to the bass pot to .01.I used this for a couple of years,
different tone of course.
What is the value of the series resistor following the V2b coupling cap?
I have seen values from 1 Meg to 4.7 Meg here, on some amps
the OD was too loud, on my amp it was´t loud enough.
You´ll be hearing from me soon, Marcos
http://ampgarage.com/forum/download/file.php?id=9526
<i> "I've suffered for my music. Now it's your turn."</i>
Re: 70's Build
Ooops! Yeah, what he said.two tone wrote:sorry,thats 560k
<i> "I've suffered for my music. Now it's your turn."</i>