Dumble Serial number 006X OD50WX

[Charlie Wilson]

Wow, thanks Gabe for sharing that. Now the question I have is, did Piher and Draloric manufacture resistors to a spec for Sprague? I have never have seen I resistor that looks exactly like a Q-Line Draloric that did not come out of a Q-Line package. The ones in Ampeg amps look close. The same with the Pihers. The endbells are not as pronounced on the ones that you shared pictures or like the ones Dumble used. Also I really think Dumble enjoyed going down to the electronic store and shopping for stuff. He told a mutual friend of mine that he always wants to put a least one Radio Shack part in his amps. Good for Gabe for having the foresight to stock up on the good stuff when you could still get it.
CW

[GPD]

Charlie Wrote: Did Piher and Draloric manufacture resistors to a spec for Sprague? I have never have seen I resistor that looks exactly like a Q-Line Draloric that did not come out of a Q-Line package. The ones in Ampeg amps look close. The same with the Pihers. The endbells are not as pronounced on the ones that you shared pictures or like the ones Dumble used.

Charlie,

I do not believe that Draloric or Piher made specialty specification resistors for Sprague. The Pihers in the Sprague Q-Line packaging look to be the same parts Piher produced in the 1970's and sold in bulk. The Draloric made Q-Line Flameproof parts fit into various LCA types (sizes) Draloric was making from the 1970's until the very early 1980's until when CGW acquired Draloric. You can find (though not easily) that matte flame proof coating with the yellow band (denoting the flame proof coating) in regular Draloric packaging from that era. They were available in 2%, 5% and even 10% tolerances. Your best bet is to find them in Europe, UK, South Africa or Australia though...they don't appear to have been well distributed in the USA. Sprague obviously sold them in 1/4, 1/2, 1 and 2 Watt ratings. The Draloric LCA's were available in many more types (sizes) than what Sprague required so Sprague just pick the type that fit their needs.

These are, of course, German made resistors. You have to keep in mind that the brand name "Draloric" didn't even exist until the mid 1970's. Prior to that, the company was Dralowid and prior to that it was Rosenthal. The Rosenthal brand persisted so you can find the same basic Draloric parts sometimes branded as "Rosenthal". The golden era of German CF's from these three brands is the 1960's through the very early 1980's. The LCA's evolved a little bit during these two decades but are all made in the same plants (Or Werks I should say ). The early 1980's parts are pretty good too...during the CGW ownership but by the time Vishay gets involved (late 1980's) you get big changes in construction and thus very different sounding parts. They also opened up production in Israel...I never cared for anything Draloric made after the early 1980's. They aren't bad parts but they do not sound/perform like the 60's and 70's parts.

Regarding the CF's found in vintage Ampeg amps...

What you see in the 1960's are Dralowid's which are easy to identify by the large amount of solder on the end caps/leads...these are excellent resistors. I really like them and they can also find them in old German amps (Like Dynacord) and I have seen them in other old European audio gear as well. These are what they call LCA's and this is where the whole 0309, 0411, 0411, 0617, etc. type designations first appear. They are made in Germany and in the same plants where the 1970's versions were made. BTW, the big change between the 1960's and the 1970's LCA's is the end caps and how they were soldered. They figured out how to get a better crimp and how to reduce the amount of solder used by the 1970's. Otherwise, the construction is nearly identical between the two decades. If you carefully remove the coatings and compare the two (I use a Dremel with a fine wire brush attachment) you'll see how similar they are...no surprise though...same company over a couple of decades making carbon film resistors.

Here is an example of a 1960's Ampeg using the Dralowid LCA's from that period:

Ampeg_60's_Dralowid_LCA.jpg

Here you can clearly see what I'm talking about...lots of solder holding the end cap to the lead.

Here is an example of a 1970's Ampeg using the Draloric LCA's from the 1970's:

Ampeg_70's_Draloric_LCA.jpg

As you noted, these look very similar to the Draloric resistors found in the Sprague packaging (construction-wise)...no surprise...because they are being made in the same factory using the same components and equipment.

Anyway, the bad news is that finding these parts today is really quite challenging. Sometimes, you'll find an old TV or Radio repairman who passed away in Antwerp or Melbourne and he's got a stash of them in his bins...and somehow they don't get tossed when the estate is being dealt with. The packaged Sprague Q-Line parts? I'm sure some of it is tucked away in various dark corners of the USA...but unearthing them isn't going to be easy. Odds are most of what is left will probably get tossed into a landfill by those that are not aware of their desirability long before you are I will find them.

Jelle might find them though...he's a better at, more focused and determined at NOS parts acquisition than the rest of us!

Best Regards,


Gabe

[FUCHSAUDIO]

I agree that some (or certain) parts and part types can offer sonic advantages without question.

I built some very cool amps in the late 90's for myself using the black Holco audio grade resistors. They are quiet and sound amazing. Sadly they weren't RoHs and are no longer being made anyway. The RN series resistors are very good sounding and low noise, but I never compared them directly with the Holco's. BUT, they are also NOT RoHs (despite many builders using them in amps they export freely overseas).

You hear stories of HAD sending a customer to Radio Shack to buy a specific part, which becomes a story about how "he even knew what Radio Shack parts were special", but that's a little tough to swallow, as much as the Ben Harper comment "he measured my chassis before he made the amp and found the right one. He showed me the meter "...seriously ? This tends to tick my BS meter a little...LOL. Non-technical people are easily impressed, that's for sure.

It's interesting to note that a cathode resistor (which is fully bypassed at AC frequencies) has any effect at all on the sound of the circuit. I found that the cathode caps are equally as big a factor, perhaps more. Nichicon used-to make a cap called the Black Gate. It was a capacitor specifically designed for audio use and they sounded amazing. For the home builders and non-commercial builders, sourcing these parts certainly matters as much as good glass does.

From what I've read and studied, the R/C networks he put on coax ends and into tube grids were basically compensation networks to make up for cable capacitance losses and Miller effects from the tubes.

I tend to agree with Gabe, Dumble did have quite the ability to pick and chose parts and combinations thereof to get the sounds he was seeking. As far as my part choices, I pick what I like from the current legally usable offerings from Mallory, Wima, Panasonic, CRL, etc. Remember, as a manufacturer you need compliance with RoHs as well as consistency and good tone. There are many excellent choices out there to find your voice.

[talbany]

I agree that some (or certain) parts and part types can offer sonic advantages without question.

I built some very cool amps in the late 90's for myself using the black Holco audio grade resistors. They are quiet and sound amazing. Sadly they weren't RoHs and are no longer being made anyway. The RN series resistors are very good sounding and low noise, but I never compared them directly with the Holco's. BUT, they are also NOT RoHs (despite many builders using them in amps they export freely overseas).

You hear stories of HAD sending a customer to Radio Shack to buy a specific part, which becomes a story about how "he even knew what Radio Shack parts were special", but that's a little tough to swallow, as much as the Ben Harper comment "he measured my chassis before he made the amp and found the right one. He showed me the meter "...seriously ? This tends to tick my BS meter a little...LOL. Non-technical people are easily impressed, that's for sure.

It's interesting to note that a cathode resistor (which is fully bypassed at AC frequencies) has any effect at all on the sound of the circuit. I found that the cathode caps are equally as big a factor, perhaps more. Nichicon used-to make a cap called the Black Gate. It was a capacitor specifically designed for audio use and they sounded amazing. For the home builders and non-commercial builders, sourcing these parts certainly matters as much as good glass does.

From what I've read and studied, the R/C networks he put on coax ends and into tube grids were basically compensation networks to make up for cable capacitance losses and Miller effects from the tubes.

I tend to agree with Gabe, Dumble did have quite the ability to pick and chose parts and combinations thereof to get the sounds he was seeking. As far as my part choices, I pick what I like from the current legally usable offerings from Mallory, Wima, Panasonic, CRL, etc. Remember, as a manufacturer you need compliance with RoHs as well as consistency and good tone. There are many excellent choices out there to find your voice.

Andy
Intresting to hear you say that!. I've been sort of preaching these findings here for years (along with seasoned iron) Much of it has been met with great skepticism
It's OK people can believe and hear things they want to believe.All I can say is In the early days when I first started building these clones I always wondered why these amps never sounded the same as when I actually heard a real ODS or watched clips on the net.It wasn't until I decided to finally build one with the same (or close) Type parts that these amps finally sounded like the real deal. Some of those old amps I still have and you can clearly hear it in a side by side comparison. I do agree however that there are still some new parts out there that sound wonderful in guitar amps. I've also heard old 60's amps that use these older parts that don't always sound that good so the parts thing is only a part of it. BUT if you are chasing a particular sound the parts are a critical ingredient needed to get you there. IMO
I am sure you already know this

Tony

[FUCHSAUDIO]

When I got into manufacturing of tube high end audio in the early 80's, I came from the music end of things. Guitar amps and the like. Brute force power...

I was basically "taught how to listen" by my mentor at the time Harvey Rosenberg. Electrostatic Quad speakers, high end cables, moving coil cartridges, reel-to-reel master tapes recorded and played back on tube gear, holy shit !!!

I never really thought cable and passive parts mattered worth a damn. I came to appreciate what "parts sounded like". Even today, I hear a crappy guitar cable or a part's sonic signature and realize not only does a part matter, but they matter as a the sum of the parts. Don't kid yourself, there are modern parts (some not even costly) that sound excellent. Heck even Dumble had "pedestrian parts" in some locations, but he liked them or liked the sum of those parts. Not to mention chassis resistance testing (cough). I also learned that audiophile things like bias pots per tube and DC preamp tube filaments and such really mattered !! This despite mentors like Dennis Kager telling me "why bother?"...okay.. I designed most of my production amps to use a foot or less (total) coax in the whole amp...because it matters and hey good coax costs money !!) lol

I actually employ vintage iron mostly in ODS mods (because that's what's there). I do sometimes sell-off vintage iron to a few builders who sell D-clones to customers who specifically want vintage iron while MY customer wants 4-8-16 ohm outputs. Win-win... The new Classic Tone iron is very good and does sound good after a break-in, but all these things support my contention that AGE can certainly be a factor. The old iron can sound great as well, it's just feature-limited (in the case of Fender) often.

An old D'Angelico archtop can be a thing of beauty. So can a 58 Les Paul. Yes, modern builders can be more precise with CAD woodworking and science and we've all learned lots of things since the days when these things were built. The glaring problem is we can never compare anything made today with anything made in yesteryear, because they really don't have the benefit of being the same age and never will. Remember, MOST of the Dumbles we hear (for the most part) are very old. The classic Carlton, and the Robben stuff (even the new stuff), is amps that are over 30+ years old. Most of Carlo's amps (except for the Bludo and Fuchs' )are old old Dumbles and Mesa's.

A few guitar makers I know do things to age their instruments and I also do some things to try to accelerate the process. One builder I know is using speakers to vibrate his guitar bodies with low frequencies to "fee up the wood"...Since I'm burning things in anyway, I'm trying some things to speed the process too. My main ODS is 15 years old and is like an old friend. Warm, organic, round and sings. New ODS's are terrific and offer more features, but (as a guy who hears and plays new amps all day), I can tell you they do need to break in. Sad thing is how many people buy and sell amps (not only from us) and sell them in weeks or months, and never own them long enough to learn how to dial them in or let them BREAK IN !!!

[martin manning]

Cable capacitance is a real thing, different cables have different capacitance per unit length, and the effect is easily calculated. No magic in that. Individual bias pots, dc filaments are also real things that can be measured. That can’t be said of many of the things that people say have some special quality.

[norburybrook]

Andy, good to see you on this thread and thank you for your contributions to the amp world. I think the analogy with anything wood is a bad one though because wood is not a consistent material, far from it, as anyone who has played a batch of the same guitar form the same manufacturer will tell you. I'm also interested in your comments about break in on amps and them getting better with age. I agree about people not spending enough time with an amp to learn how it really works and sticking with it , i think that's a problem with a lot of things though not just amps due to the new generations attention span, or lack of

I 'feel' that amps definitely have some sort of settling in phase but i couldn't tell you what that was, and it's maybe 'me' who is settling into the amp rather than the other way round Also the ageing thing is tricky because at some point is it going to start getting worse tonally? if so then it will have a sweet spot in the middle. how long is that, and at what age? Also in my experience the same amp can sound magic one day and ordinary the next, I've had this in the studio where the amps/mics haven't moved and I've come back in the next day and it's just not happening, again is that me though? this begs the question then; can you convince yourself some NOS unabtanium part sounds better?, I suppose technically that's called 'confirmation bias' and it's a real thing. Placebo is also a real thing, Red pills work better than white pills, scientific fact . I've done it myself turning a mixing console knob on the wrong channel and convinced myself it had made a subtle difference to the channel I was listening to


Just thinking out loud here and putting down my thoughts.

A lot of amp component parts scientifically are very low in tolerance, resistors @ - or +10% caps 20% that could add up to a huge difference in values over an amp like an ODS using exactly the same parts, that could be a reason things sound different. I've built about 8 or 9 ODS amps with NOS iron, NOS Piher , NOS Dale resistors, NOS valves, and ones with new iron and new modern resistors/caps. I couldn't tell you which was which in a blind test. Fortunately they ALL sound great, so for me personally the short journey compared to you guys has led me to not get too worried about this now. I'm not making amps for a living though so I don't have to worry about this like you guys do, and I applaud you for doing it

I'll conclude by saying I agree with Andy Bauer who I saw talking recently, and he would sit with Bogner and swap resistor all night on amps comparing tone. He's a real tone hound,whereas his good friend Steve Lukather thought he was mad and didn't really care at all about that stuff as long as he could plug in to a decent amp he was happy. The point Andy made was;

If it matters to 'YOU' then that's what you should do.

So if you can hear a difference using XY or Z and it makes you play better then do it, that's what's important

MC

[talbany]

The whole thing about parts can certainly be subjective and within the ears of the player!. Some people simply cannot hear the difference between a Mullard XF-2 or a Blackplate RCA to the newer Russian/Chinese tubes made today.So spotting the difference between Iron that has some age on it and a fresh iron off the winder chances are he will not notice it as well!. On the flip side as documented here! some people can absolutely hear a difference.
Also you cannot just change 1 or 2 resistors in an amp and expect to hear a drastic change.It's everything working with everything else. I never understood the description people place on these parts when they say that this part sounds "better" or this part has some special quality or the one that bugs me the most is "Magic Dust". Why can it simply be that certain parts carry with them a certain sonic character!. A silver mica cap can sound different than a ceramic cap. A carbon composition resistor can sound different than a metal film resistor and a 30 year old transformer can sound different than a fresh one!. SO which is a" Better" system one with all Phier resistors and Phillips mustard caps along with a ceramic treble cap that is 30 years old or system B? a brand new amp loaded with a silver mica treble caps,Mallory 150 coupling caps, and Xicon carbon film resistors. This is a question only the player can answer and if you can't buy the cheaper amp
As far as us amp manufactures go some use the sonic character of these parts to their advantage to help shape the overall sound we want to achieve (Dumble/Fuchs/We obviously did this) other amp manufacturers don't care and use whatever is cheap or available. if our goal is to try and replicate a particular sound of an amp that is 30+ years old we would naturally want to use the same type parts that were used in the originals we are trying to copy.This is not to say you still can't build a good sounding amp with different parts. So the whole "good/bad sounding thing depends on the player's opinion. As a guitar player, I could really care less what is loaded in my favorite amp. I just know I love the sound and play it because it is the sound that inspires me to play. Us old amp manufactures come across some strange un-explainable phenomena when designing and building hundreds of amps and working with all kinds of different parts we can either choose to accept them or ignore them or use them to our advantage!. Many of these are trade secrets discovered over many hours of R&D and never discussed publicly here and certainly don't want to get into an argument over them.

As far as us player not wanting to stick with a certain amp for a while this could be many things. The most obvious to me is. These players generally don't know what sound they are after. One week they want to sound like SRV the next they want to sound like Robben Ford. The problem being "THEY" don't sound like these players.Others tend to think there is always something out there that to them sounds"better" there are greener pastures on the other side. Many of these players will never be completely happy because they don't know what it is they are searching for.They don't have that sound in there head and simply don't have the patience to develop one!.

Breaking in a tube amp has been around the Hi-Fi community of amp manufacturers for years now. Many of these boutique companies do not let their amps leave the factory without a set burn in time. There can be many reasons for this.

BTW. I've often wondered why Dumble covered his amps preamp in silicone? When anyone with a meter and knows anything about guitar amp design can simply meter the amp out and know what value was under the goo. Could it be the part "type" he was trying to protect?? ...Humm

Tony

[Charlie Wilson]

Ok, here I go. I don’t know if the question is, does it matter if components sound different or do they actually sound different? As the point of building an amplifier is to amplify the sound of an instrument (safety and reliability are givens) then what it sounds like should be the most important criteria. To ignore what the components sound like is really odd to me. Frankly I take offense to the notion that “some people” are imagining they hear differences in various components. It is not subtle. If that doesn’t matter to someone who builds amplifiers then maybe building computers is a more suitable activity. Sorry for the rant but this keeps coming up and has gotten a little old.
CW

[martin manning]

BTW. I've often wondered why Dumble covered his amps preamp in silicone? When anyone with a meter and knows anything about guitar amp design can simply meter the amp out and know what value was under the goo. Could it be the part "type" he was trying to protect?? ...Humm

That's an interesting thought. At the time, use of precision MF resistors in production guitar amps wasn't common, so that may be part of it. I believe in the main he was protecting the circuit from those who would copy it. All products assembled from off-the-shelf parts are subject to this threat- the ingredients are available to everyone, so anyone with reasonable skill can duplicate it and become a competitor.

[talbany]

BTW. I've often wondered why Dumble covered his amps preamp in silicone? When anyone with a meter and knows anything about guitar amp design can simply meter the amp out and know what value was under the goo. Could it be the part "type" he was trying to protect?? ...Humm

That's an interesting thought. At the time, use of precision MF resistors in production guitar amps wasn't common, so that may be part of it. I believe in the main he was protecting the circuit from those who would copy it. All products assembled from off-the-shelf parts are subject to this threat- the ingredients are available to everyone, so anyone with reasonable skill can duplicate it and become a competitor.

Yes and he only covered the stack and OD section. If he really wanted it protected why not just goop everything??
Just to cover main ones the plates? cathodes types. Maybe
Tony

[norburybrook]

if it's covered with silicone then there'l be no vibration of components ....subtle tone choices......


how do you fix stuff if it's gooped?



M

[martin manning]

Some fun with audio illusions: http://mentalfloss.com/article/545157/b ... -they-work

There are lots more articles and videos out there on this subject.

[martin manning]

if it's covered with silicone then there'l be no vibration of components ....subtle tone choices......

how do you fix stuff if it's gooped?

Those parts under the goop rarely fail, so maintenance probably isn’t an issue. Some people will put a dab of silicone between closely spaced caps on the main board to stabilize them. HAD did that with ceramics, which are known to be microphonic, and used two in parallel where one would do. There may be some thought behind that, or maybe he just didn’t have the right value on hand.

[pompeiisneaks]

Ok, here I go. I don’t know if the question is, does it matter if components sound different or do they actually sound different? As the point of building an amplifier is to amplify the sound of an instrument (safety and reliability are givens) then what it sounds like should be the most important criteria. To ignore what the components sound like is really odd to me. Frankly I take offense to the notion that “some people” are imagining they hear differences in various components. It is not subtle. If that doesn’t matter to someone who builds amplifiers then maybe building computers is a more suitable activity. Sorry for the rant but this keeps coming up and has gotten a little old.
CW

I think most agree with this sentiment 100. The bigger problem becomes proving which things DO or DON'T impact tone. I've heard people go on and on in audiophile discussions about how solid state rectification kills HIFI amps tonality and tube rectified is the only way to go... I can't remotely see how a tube rectifier can do anything more than introduce sag. Which is preferred in guitar amps for SOME people. HIFI Sag is considered a horrible thing.

Some of these tonal notes may be very clear, and obvious and even measurable. The biggest debate point I often see is people saying X does not change tone, prove it to me, with some kind of double blind test etc.

I think anyone's heard what a non X5F style ceramic cap sounds like in audio signal paths, it's horrible. It's obvious, but they're not designed for audio path and very microphonic and add other bad sounds to the signal.

Does that make sense?

Due to everyone's personal audio measurement device (ears) being different, it's super impossible to prove some things without scientific measurement. Opinions are like assholes... as the saying goes

Basically this debate will go on ad infinitum since nobody has taken enough time to setup true, detailed, documented proof tests with scientific methods and measuring devices to prove there is a difference.

There's no profit in it, so nobody does.

~Phil