Carbon comp v carbon film, poly-which?

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greiswig
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Re: Carbon comp v carbon film, poly-which?

Post by greiswig »

phsyconoodler wrote:Yes,it's hard to really say for sure,all I know is in my amps the Vishay-Dale resistors did nothing at all.
...as compared to what? Carbon comp or a different brand of metal film?
-g
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phsyconoodler
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Re: Carbon comp v carbon film, poly-which?

Post by phsyconoodler »

Carbon film is what I use.
Crystal latice or vacuum,that is the question.
Trace
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Re: Carbon comp v carbon film, poly-which?

Post by Trace »

There's so many more factors here. Lead dress for one can change the entire charactor of an amp. It's really hard to say that the difference is a component selection, the wire type, or unobtainuim in the air.

Component differences alone are significant. Quality/type of components, how well things are/are not soldered, etc and then you have to factor the transformers into the equation. This all plays into the art of amplifier design.


Have a great day
Trace
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Structo
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Re: Carbon comp v carbon film, poly-which?

Post by Structo »

Don't forget the fairy dust liberally sprinkled over select components.
That's the key to the crystal lattice structure! :lol:
Tom

Don't let that smoke out!
Trace
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Re: Carbon comp v carbon film, poly-which?

Post by Trace »

Structo wrote:Don't forget the fairy dust liberally sprinkled over select components.
That's the key to the crystal lattice structure! :lol:
Forgive me if I'm over looking the obvious but I'm not sure I'm following you?


Happy New Year
Trace
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phsyconoodler
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Re: Carbon comp v carbon film, poly-which?

Post by phsyconoodler »

There is a 'mystique' surrounding Dumble amps and people seem to think they need to use special resistors and exactly the same part numbers as Dr.D did to get a good sounding amp.It amounts to a lot of 'fairy dust' and BS.A resistor is a resistor and if it resists it's done it's job.I don't care if it's carbon,metal or pork.
There is a certain amount of magic in the circuit and using good quality parts is always a good idea,but the 'fairy dust' content is best left at home.
Some guys perpetuate the BS and others build amps that sound great.
Crystal latice or vacuum,that is the question.
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Bob-I
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Re: Carbon comp v carbon film, poly-which?

Post by Bob-I »

phsyconoodler wrote:There is a 'mystique' surrounding Dumble amps and people seem to think they need to use special resistors and exactly the same part numbers as Dr.D did to get a good sounding amp.It amounts to a lot of 'fairy dust' and BS.A resistor is a resistor and if it resists it's done it's job.I don't care if it's carbon,metal or pork.
Not exactly. Resistor are not truly linear over all frequencies so the type does matter. I personally heard a fairly dramatic difference the first time I put Metal Film's in place of CC's. I've simply stuck with what I heard in other builds.
There is a certain amount of magic in the circuit and using good quality parts is always a good idea,but the 'fairy dust' content is best left at home.
Some guys perpetuate the BS and others build amps that sound great.
That's true. Ken Fisher tried to teach many folks to build his amps, including Dr. Z and the amps never sounded the same as his (I've read). Sometimes it's the builders ear and the connection with the amp that makes it sound great. I think builders like HAD and Fisher used what ever was available and made them sound great.
Trace
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Re: Carbon comp v carbon film, poly-which?

Post by Trace »

There is a 'mystique' surrounding Dumble amps and people seem to think they need to use special resistors and exactly the same part numbers as Dr.D did to get a good sounding amp.It amounts to a lot of 'fairy dust' and BS.

I have worked on a few Dumbles one was epoxied and the others were not. Generally speaking there were few variables in the standard values and that makes sense as he did not use the exact same transformers all the time. Given that transformer companies are allowed a 40% tolerance it stands to reason that you would have to finesse the circuitry in some key areas to get the same tone and feel you are looking for (hence the implementation of trim pots into the circuit). Along similar lines I've worked on a few Trainwrecks over the years and even though the models may have been the same Ken also finessed his circuits for the tone and feel. I've also worked on an amp that Ken designed for a player that he never put into production and that amp had a great deal of gain in it and over all was some what of a departure from his prior models.

A resistor is a resistor and if it resists it's done it's job.I don't care if it's carbon,metal or pork. There is a certain amount of magic in the circuit and using good quality parts is always a good idea,but the 'fairy dust' content is best left at home.

Agreed my friend - The biggest factor to take into account is the tolerances of all the components. In the end the tone/feel is the sum of the whole.

Some guys perpetuate the BS and others build amps that sound great.

It's all about hands on experience and when one has built a great deal of amplifiers (of all kinds), serviced, repaired, etc you then have the experience to draw from. From experience we learn that all things are explained and with this we can set aside the illogical for the logical. I'm not trying to sway anyone one but rather lending my own opinion to the tonal pallet.


Have a great Tuesday morning guys!
Trace
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Structo
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Re: Carbon comp v carbon film, poly-which?

Post by Structo »

Trace, I was just trying to inject a little humor into this thread with the fairy dust comment.

Alexander made a comment on a video about the crystal lattice structure of semiconductors compared to tubes concerning the flow of electrons.

Not being an amp tech and doing it for a living I just have to rely on others experience.
The reason manufacturers used carbon comp resistors is because that was what was available at the time.
Do they even make them nowadays? Or are the ones sold NOS?

I've always read that carbon comps were noisier, hissier and tend to drift more due to the heat developed in amps.

Most of the reading I have done says they are fine to use in some stages but to not put them in the signal path.

The drifting of values and breakdown of tolerances are probably the reason for example, that some older amps have "the tone" while others sound atrocious.

In my reading, mainly here, it seems to be the general consensus that precision metal film ( Vishay/ Dale) plate resistors sound the best to discerning ears, especially on the Dumble builds.

It's all I can go by since I don't have the experience of building a bunch of amps or service a lot of them on my bench.
Tom

Don't let that smoke out!
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Funkalicousgroove
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Re: Carbon comp v carbon film, poly-which?

Post by Funkalicousgroove »

There are general "Themes" in the different Dumble amps, ie, Metal Film plate and cathode resistors, Mylar for most of the coupling caps, with the occasional polyprop cap. I saw one that only had 2 Orange Drops, certainly no RN65's, and used Peavey Transformers. The tone of it is AMAZING!!!

With these I think Lead dress is very important, and general types of components should be used in certain places, but I don't think that there is just 1 and only 1 part/manufacturer that is an absolute.
Owner/Solder Jockey Bludotone Amp Works
Trace
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Re: Carbon comp v carbon film, poly-which?

Post by Trace »

Trace, I was just trying to inject a little humor into this thread with the fairy dust comment.

Fair enough, life can always use some humor :)

Alexander made a comment on a video about the crystal lattice structure of semiconductors compared to tubes concerning the flow of electrons. Not being an amp tech and doing it for a living I just have to rely on others experience. The reason manufacturers used carbon comp resistors is because that was what was available at the time.Do they even make them nowadays? Or are the ones sold NOS?

Metal film has been around for a while but over all it's all about what ever works best for you.

I've always read that carbon comps were noisier, hissier and tend to drift more due to the heat developed in amps.

They can be nosier, tolerances tend to wider and they can/do drift. I've seen lots of old amps, etc and for all these reasons we primarily use metal film resistors.

Most of the reading I have done says they are fine to use in some stages but to not put them in the signal path.

You can put them in the signal path and they work fine.

The drifting of values and breakdown of tolerances are probably the reason for example, that some older amps have "the tone" while others sound atrocious.

Generally speaking; Older transformers tended to made better than a lot of modern day transformers (there are of course exceptions).

In my reading, mainly here, it seems to be the general consensus that precision metal film ( Vishay/ Dale) plate resistors sound the best to discerning ears, especially on the Dumble builds.

I have done some Dumble builds and have always used polypropylene caps and metal film resistors (with great success).

It's all I can go by since I don't have the experience of building a bunch of amps or service a lot of them on my bench.

Fair enough my friend and that all comes with time, depending on your goals, etc. We've seen just about every amp there and it's amazing at all the different designs.


Have a great Wednesday evening
Trace
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greiswig
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Re: Carbon comp v carbon film, poly-which?

Post by greiswig »

Funkalicousgroove wrote:There are general "Themes" in the different Dumble amps, ie, Metal Film plate and cathode resistors, Mylar for most of the coupling caps, with the occasional polyprop cap. I saw one that only had 2 Orange Drops, certainly no RN65's, and used Peavey Transformers. The tone of it is AMAZING!!!

With these I think Lead dress is very important, and general types of components should be used in certain places, but I don't think that there is just 1 and only 1 part/manufacturer that is an absolute.
Brandon, this caught my eye. Your point is well taken that HAD could even make a Peavey sound good :wink: , but I didn't know that the cathode resistors were also typically MF types. The only pictures I've seen were gooped up over that section of the amp.
-g
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