BEGINNER NEEDS ADVICES !

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erwin_ve
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Re: BEGINNER NEEDS ADVICES !

Post by erwin_ve » Wed Sep 13, 2017 4:06 pm

Hi Jok,

I would start with: A multimeter. A Fluke is Nice, but expensive.
A Dynatek multimeter is a cheaper choice. Widely available in the EU and often used by electronic students.
All other things you mentioned are not a must, a tone generator can be done with a app a scope might be handy when troubleshooting to pinpoint a certain problem in a stage. Regarding the power you get out of your amp: that does not sound right and might be the overall problem affecting all other things you mentioned.
So measuring voltages at the plates, cathodes and dropping string(the nodes at the filtering).
Once done we could chime in!
Cheers, Erwin

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Re: BEGINNER NEEDS ADVICES !

Post by j0k3335 » Wed Sep 13, 2017 4:39 pm

erwin_ve wrote:
Wed Sep 13, 2017 4:06 pm
Hi Jok,

I would start with: A multimeter. A Fluke is Nice, but expensive.
A Dynatek multimeter is a cheaper choice. Widely available in the EU and often used by electronic students.
All other things you mentioned are not a must, a tone generator can be done with a app a scope might be handy when troubleshooting to pinpoint a certain problem in a stage. Regarding the power you get out of your amp: that does not sound right and might be the overall problem affecting all other things you mentioned.
So measuring voltages at the plates, cathodes and dropping string(the nodes at the filtering).
Once done we could chime in!
Cheers, Erwin
Hi Erwin,

great start !

I will look for these Fluke or Dynatek multimers.

Then I will be able to make serious measuring of the different voltages you have mentioned.
This is really the start ( to solve this possible trouble !? ) : THANKS for the advices :wink:

Cheers,

José

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Re: BEGINNER NEEDS ADVICES !

Post by pompeiisneaks » Wed Sep 13, 2017 5:17 pm

I agree, the signal gen is nice, I finally got one that's an old tube one, but I used my phone and an app that did it for a while, it was 'okay' but not amazing, but now I've got a more precise signal generator (it's actually an oscillator only so only sine wave but that's all I need)

~Phil
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Re: BEGINNER NEEDS ADVICES !

Post by j0k3335 » Wed Sep 13, 2017 5:41 pm

pompeiisneaks wrote:
Wed Sep 13, 2017 5:17 pm
I agree, the signal gen is nice, I finally got one that's an old tube one, but I used my phone and an app that did it for a while, it was 'okay' but not amazing, but now I've got a more precise signal generator (it's actually an oscillator only so only sine wave but that's all I need)

~Phil
Thanks Phil for these complements !

Right now, I'm looking for a "serious" multimeter.

I will see ( and ask "again" advices ) for "what next" : but I think that after this multimeter, I probably have to concentrate to have some spare on caps, resistors ?
( I already have a lot of NOS tubes ... no problem for this. Concerning caps and resistors, I've Nothing in the "Dumble" style :( )

Thanks,

José

Nota : I try to play this head to note everything which is pleasant and not, which seems normal and not. So i'll have to re-open it.
As soon as possible, even with my old multimeter, I will take all measures concerning power stages and will communicate them : we will see if somebody find something wrong, strange !
Last edited by j0k3335 on Wed Sep 13, 2017 6:21 pm, edited 1 time in total.

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Re: BEGINNER NEEDS ADVICES !

Post by pompeiisneaks » Wed Sep 13, 2017 6:16 pm

IMO the NOS thing is pretty dangerous. Nowadays there are so many people pulling con jobs on their NOS stuff that there's an extremly likely chance you're getting "OS" not "NOS" It's been pulled from some device, used heavily and may fail at any moment. The only place I've seen high quality stuff recently has been on here.

I just focus on high quality new components myself, but to each their own, just be careful of ebay, they seem to be full of horrible people selling crap and telling you it's gold

~Phil
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Re: BEGINNER NEEDS ADVICES !

Post by j0k3335 » Wed Sep 13, 2017 6:31 pm

pompeiisneaks wrote:
Wed Sep 13, 2017 6:16 pm
IMO the NOS thing is pretty dangerous. Nowadays there are so many people pulling con jobs on their NOS stuff that there's an extremly likely chance you're getting "OS" not "NOS" It's been pulled from some device, used heavily and may fail at any moment. The only place I've seen high quality stuff recently has been on here.

I just focus on high quality new components myself, but to each their own, just be careful of ebay, they seem to be full of horrible people selling crap and telling you it's gold

~Phil
Oh, I think you are right on this point !!! But some of my NOS are tubes , I have buy MYSELF news ( some 6L6 STR415 and GE 12AX7 directly from Randall Smith hands back in the 80' :D ), some from a serious guy in France,
... and some which are "gamble" as you explained :mrgreen:

But anyway I wish to follow your advice : to make sure, when you have identify good brand and model for each position, you get the SAME result at every replacement ! ... which is very difficult with NOS ( or buying large stocks ... but that too expensive )

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Re: BEGINNER NEEDS ADVICES !

Post by pompeiisneaks » Wed Sep 13, 2017 7:41 pm

If you're talking tube rolling, I'm not very savvy there. I've always just bought new tubes from JJ or EH, due to not being rich enough to buy the fancier ones :)

If you mean components, I've also generally just stuck with Metal Film resistors, occasionally trying out the nicer dale RN65 types but mostly the basic ones, and I've tried a few different types of caps, but mostly seem to like the poly 715P type. I'm by no means a veteran in these though, and others can give you a lot better recommendations I'm sure. :)

~Phil
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Re: BEGINNER NEEDS ADVICES !

Post by j0k3335 » Wed Sep 13, 2017 9:21 pm

pompeiisneaks wrote:
Wed Sep 13, 2017 7:41 pm
If you're talking tube rolling, I'm not very savvy there. I've always just bought new tubes from JJ or EH, due to not being rich enough to buy the fancier ones :)

If you mean components, I've also generally just stuck with Metal Film resistors, occasionally trying out the nicer dale RN65 types but mostly the basic ones, and I've tried a few different types of caps, but mostly seem to like the poly 715P type. I'm by no means a veteran in these though, and others can give you a lot better recommendations I'm sure. :)

~Phil
! Thanks Phil : that's already a lot of information for a "dummy" like me :mrgreen:

Cheers,

José
Nota : I've ordered a "serious" multimeter ! Will receive it next Monday . As soon as possible I will communicate all these measurements .
... now, back to studying in the "Dumble Discussion" section ... I'm only at page N° 50 ... :mrgreen:

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Re: BEGINNER NEEDS ADVICES !

Post by norburybrook » Thu Sep 14, 2017 10:08 am

I agree about NOS stuff.

Joey Landreth borrowed my 100w BM that I'd made from regular new parts with JJ valves. He'd just come from the states where he'd been playing a real Dumble ODS. He said 'this amp sounds better' .

I'd always had a sneaky suspicion that if I ever did get to play the real thing it wouldn't sound that different and Joey just confirmed that.

I'll point out he didn't say it directly to me, he was talking to someone else at the time who relayed the info to me afterwards so he wasn't just being kind.


M

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Re: BEGINNER NEEDS ADVICES !

Post by martin manning » Thu Sep 14, 2017 10:55 am

Clearly he doesn't have the ears to appreciate the difference! ;^)

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Re: BEGINNER NEEDS ADVICES !

Post by j0k3335 » Thu Sep 14, 2017 2:15 pm

norburybrook wrote:
Thu Sep 14, 2017 10:08 am
I agree about NOS stuff.

Joey Landreth borrowed my 100w BM that I'd made from regular new parts with JJ valves. He'd just come from the states where he'd been playing a real Dumble ODS. He said 'this amp sounds better' .

I'd always had a sneaky suspicion that if I ever did get to play the real thing it wouldn't sound that different and Joey just confirmed that.

I'll point out he didn't say it directly to me, he was talking to someone else at the time who relayed the info to me afterwards so he wasn't just being kind.

M
concerning about NOS, I will retain this :

"pompeiisneaks wrote: ↑
IMO the NOS thing is pretty dangerous. Nowadays there are so many people pulling con jobs on their NOS stuff that there's an extremly likely chance you're getting "OS" not "NOS" It's been pulled from some device, used heavily and may fail at any moment. The only place I've seen high quality stuff recently has been on here.
"
and I think Phil is absolutely right ... when you are talking about "N"os ... meaning there are not really "NEW" ... since a long time ! :mrgreen:
BUT if you start for NOS for whom you are confident, I hear some difference between old tubes and news one's !

Strangely, but I already explain I don't have a lot of experience, some amps are more sensitive than some others ?

My Fender Concert II don't really care about what kind of tubes you put in it !
My Fuchs ODS30 is very sensitive. I need to explain : with good current tubes you get good results, no doubt BUT playing with NOS tubes ... now you get, this time, real AMAZING results !!!

Baldwin has been rebadged tubes of different manufacturers but with very strict specifications: result == the bandwidth of these tubes seem very wide and I could not put in all positions of my Fuchs at the risk of having too bass, too treble !
On the other hand, one installed in V1 and the result is remarkable!

I was also surprised, since I play in the home studio at a fairly low level, that power tubes can be so important!
For example, the 6L6 STR415 (Randall Smith says that these are the best 6L6 that have been built!) Are too extreme for my Fuchs who demand more roundness with good Sylvania 6L6GC.

For the modern lamps, my JJ, Sovtek, Tung Sol, EH, have never equalled my Sylvania, Brimar, Ge and others "Baldwin": But my sources are safe with a small French merchant who tests and classifies his tubes and who I trust.
Only small disappointment: I bought two famous "Mullard" so expensive and they are not really better than my Brimar or Sylvania.

So there may also be "Hype" ???

... there, again, attention, I am not a specialist and I just report my findings.

(a specialist told me that we can not obtain tubes of the same quality at the time:
. certain metals can no longer be obtained so pure,
. sanitary, safety and environmental standards have led to the fact that the original manufacturing methods are no longer practicable.
. on the other hand, the use of the lamps being more limited now (Hi-Fi, music ... and some Russian military devices :mrgreen: EMP ? :mrgreen: ) the market is restricted and does not encourage manufacturers or have a high level manufacturing , nor to do research to re-obtain the quality of the past.
these are HIS words ... )

BUT : I will follow Phil advice ( and your remark in fact :) ) for the reason I explain previously : use current production to make sure to get the same result at each time I put new tubes in the amp !
Last edited by j0k3335 on Thu Sep 14, 2017 2:28 pm, edited 1 time in total.

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M Fowler
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Re: BEGINNER NEEDS ADVICES !

Post by M Fowler » Thu Sep 14, 2017 2:27 pm

Component choice and tube rolling are very important one finds that out after building many amps.

If your building a high quality amp such as a Dumble clone I would go for NOS or as close as you can find for component choice and tube roll when done.

For Fenders and Marshalls for example I've used a variety of caps and resistors. What did I like best, new MF resistors and new Xicon film caps.

Amp snobs are always going to suggest high end parts but a realist like me says just build the freaking thing already and quite wasting time. :D

My 2 cents worth for the day.

Mark

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Re: BEGINNER NEEDS ADVICES !

Post by j0k3335 » Sat Sep 16, 2017 2:52 pm

Hi Guys,

me again :)

So monday, I will get a serious multimeter and will re-open this head.

as expected, I will take all the voltages. I have found, here :wink: , a Excel sheet with all the Bluesmaster voltages : I will compare BUT I wish to give you these voltages and get all your advices !!!

As this head will be opened, there are 3 things that I would like to "tune up" a little bit ( I give the layout in the attachement ) :

. the MIDBOOST is really too extreme to my taste : is it with the 390pf cap on the switch that I have to "play" ? Correct ?

. same thing with the PAB : way too violent for me. In a post I read, there is a 68K concerned by this PAB, and probably this is the one to adjust ? But I can't find it in this layout ( probably another value OR I don't look at the correct place ? )

. less important, but, when the iron solder will be hot ... : is there a way to increase a little bit the OD ? ( without playing with the clean volume or the OD trimmer, I mean ) . In this one, I have a switch to shunt the Hrm Trimmer and get a more traditional OD. I didn't wish to play with the clean volume or the OD trimmer BECAUSE I get the tone I wish, it's just to have a little bit more overdrive .

If some of you have some ideas or could send me to the correct post ? ( I already have read 53 of these 118 pages, re-read the first 20, ... but didn't found something really helpful ( found some ideas, of course, ...but )

Thanks and have a good weekend,

José
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Re: BEGINNER NEEDS ADVICES !

Post by martin manning » Sat Sep 16, 2017 5:16 pm

j0k3335 wrote:
Sat Sep 16, 2017 2:52 pm
. the MIDBOOST is really too extreme to my taste : is it with the 390pf cap on the switch that I have to "play" ? Correct ?
No. Reduce the 0.002 on the preamp board, 3rd cap from the input end. Try 0.001.
j0k3335 wrote:
Sat Sep 16, 2017 2:52 pm
. same thing with the PAB : way too violent for me. In a post I read, there is a 68K concerned by this PAB, and probably this is the one to adjust ? But I can't find it in this layout ( probably another value OR I don't look at the correct place ? )
It's on the Mid pot.
j0k3335 wrote:
Sat Sep 16, 2017 2:52 pm
. less important, but, when the iron solder will be hot ... : is there a way to increase a little bit the OD ? ( without playing with the clean volume or the OD trimmer, I mean ) . In this one, I have a switch to shunt the Hrm Trimmer and get a more traditional OD. I didn't wish to play with the clean volume or the OD trimmer BECAUSE I get the tone I wish, it's just to have a little bit more overdrive .
Did you try turning up the Drive a bit and then reducing the Level to bring the OD volume back in line?

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Re: BEGINNER NEEDS ADVICES !

Post by j0k3335 » Sat Sep 16, 2017 5:41 pm

martin manning wrote:
Sat Sep 16, 2017 5:16 pm
j0k3335 wrote:
Sat Sep 16, 2017 2:52 pm
. the MIDBOOST is really too extreme to my taste : is it with the 390pf cap on the switch that I have to "play" ? Correct ?
No. Reduce the 0.002 on the preamp board, 3rd cap from the input end. Try 0.001.
j0k3335 wrote:
Sat Sep 16, 2017 2:52 pm
. same thing with the PAB : way too violent for me. In a post I read, there is a 68K concerned by this PAB, and probably this is the one to adjust ? But I can't find it in this layout ( probably another value OR I don't look at the correct place ? )
It's on the Mid pot.
j0k3335 wrote:
Sat Sep 16, 2017 2:52 pm
. less important, but, when the iron solder will be hot ... : is there a way to increase a little bit the OD ? ( without playing with the clean volume or the OD trimmer, I mean ) . In this one, I have a switch to shunt the Hrm Trimmer and get a more traditional OD. I didn't wish to play with the clean volume or the OD trimmer BECAUSE I get the tone I wish, it's just to have a little bit more overdrive .
Did you try turning up the Drive a bit and then reducing the Level to bring the OD volume back in line?
Thanks martin,

first for a so fast answer !

second for all this clarifications and advices ! ( the 68k resistor position that I didn't think it was THE one of the PAB demonstrates that without a schematic : I lost ! ... may be it's coz I am a
"Dumble beginner" ... with some experiences, seeing a layout (and knowing the relays actions ) , it will become "a reflex" :)

... so I have to continue to make my home work :oops:

Thanks again and good weekend :wink:

( I forgot the last point , the OD : Yes I have done this . That I try to mean is that, at maximum, both OD (with or without HRM) have less overdrive than my Fuchs ODS30 for example ? ( and this one is NOT adjust really high with the internal trimmers ) If I put the OD trimmer at max, Drive at max, clean volume around 7, (playing with or without PAB/Midboost ... ) I can come close BUT
in this case the TONE become unpleasant.

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