Storing Cookies (See : http://ec.europa.eu/ipg/basics/legal/cookies/index_en.htm ) help us to bring you our services at overunity.com . If you use this website and our services you declare yourself okay with using cookies .More Infos here:
https://overunity.com/5553/privacy-policy/
If you do not agree with storing cookies, please LEAVE this website now. From the 25th of May 2018, every existing user has to accept the GDPR agreement at first login. If a user is unwilling to accept the GDPR, he should email us and request to erase his account. Many thanks for your understanding

User Menu

Custom Search

Author Topic: MH's ideal coil and voltage question  (Read 475735 times)

poynt99

  • TPU-Elite
  • Hero Member
  • *******
  • Posts: 3582
Re: MH's ideal coil and voltage question
« Reply #1605 on: July 08, 2016, 08:13:22 PM »
Yes I can understand why. Higher operating voltage for all the class A preamps would improve the signal to noise ratio with the higher gains that could be achieved plus the wider dynamic range. The jfets used back when had a Vds of ~30v so the signal swings were puny compared to say a 12AX7A or 7025.
I will be designing around a +18V supply for the preamp stages, and +24v (to start) for the output amplifier.

Output amp will be a full bridge switching type, hence the need for only 24V. CFB will be implemented to achieve an Ro of about 5R.

picowatt

  • Hero Member
  • *****
  • Posts: 2039
Re: MH's ideal coil and voltage question
« Reply #1606 on: July 08, 2016, 08:17:56 PM »
For audio "Hi-Fi", yes of course. For the "clean" channel of a guitar or bass amp, yes to a degree.
The amp is certainly 50% of the guitarist's "tone".

Pre/Pwr tubes and OPT's are obsolete, as I hope to prove in the near future.

I hope you appreciated the somewhat sarcastic humor from the standpoint of a sound man.  Been there done that...

I am, however, curious.  How do you intend to "prove" the obsolescence of Pre/Pwr tubes and OPT's?

Subjective listening tests or the use of a more "measured" approach?

PW

picowatt

  • Hero Member
  • *****
  • Posts: 2039
Re: MH's ideal coil and voltage question
« Reply #1607 on: July 08, 2016, 08:27:25 PM »
I will be designing around a +18V supply for the preamp stages, and +24v (to start) for the output amplifier.

Output amp will be a full bridge switching type, hence the need for only 24V. CFB will be implemented to achieve an Ro of about 5R.

Switching amplifier?  All I can think of in response to that is "yuck".

But then, as I said, guitar "amplifiers" were never really meant to be "amplifiers".

Just giving you a hard time...

PW

partzman

  • Sr. Member
  • ****
  • Posts: 379
Re: MH's ideal coil and voltage question
« Reply #1608 on: July 08, 2016, 08:34:20 PM »

Dynamic range?  In a guitar amplifier?  Surely you jest...

PW

 ;D No not really! My goal was to manufacture the most "musical" instrument amplifiers I could in both solid state and tube. The brand name was Spectra and at one point Gibson wanted us to manufacture our amplifiers exclusively for them to market with their guitar line which was not financially feasible for us at the time.  Later sold the business to Dean Markley and it took him less than two years to run it into the ground.  End of story.

pm

picowatt

  • Hero Member
  • *****
  • Posts: 2039
Re: MH's ideal coil and voltage question
« Reply #1609 on: July 08, 2016, 09:29:24 PM »
;D No not really! My goal was to manufacture the most "musical" instrument amplifiers I could in both solid state and tube. The brand name was Spectra and at one point Gibson wanted us to manufacture our amplifiers exclusively for them to market with their guitar line which was not financially feasible for us at the time.  Later sold the business to Dean Markley and it took him less than two years to run it into the ground.  End of story.

pm

Interesting...

Were the Spectra series amps by DM your designs or did DM just use the name?

And "JMF" would be ...?

PW

poynt99

  • TPU-Elite
  • Hero Member
  • *******
  • Posts: 3582
Re: MH's ideal coil and voltage question
« Reply #1610 on: July 08, 2016, 10:54:14 PM »
I hope you appreciated the somewhat sarcastic humor from the standpoint of a sound man.  Been there done that...

I am, however, curious.  How do you intend to "prove" the obsolescence of Pre/Pwr tubes and OPT's?

Subjective listening tests or the use of a more "measured" approach?

PW
I did appreciate the humor. I especially liked the comment from the sound man "Could you turn it down a little?" Lol.

Proof will be in the pudding; the tone and "feel". But it will just as easily be proved via the scope. I can already duplicate the wave shaping and Ro from just about any class A triode stage using a 12AX7 etc. Most designers have missed the boat when trying to duplicate the breakup of tube circuits. Also, I can operate the MOSFETs in either pentode or triode mode. So I'm at the point I can take any existing tube guitar amp and replicate it using MOSFETs etc.

FETs (all types) already make better tubes than tubes do. Get your mind around that one. ;)

poynt99

  • TPU-Elite
  • Hero Member
  • *******
  • Posts: 3582
Re: MH's ideal coil and voltage question
« Reply #1611 on: July 08, 2016, 10:57:04 PM »
Switching amplifier?  All I can think of in response to that is "yuck".

But then, as I said, guitar "amplifiers" were never really meant to be "amplifiers".

Just giving you a hard time...

PW

Yes, "digital" amp. I know it sounds revolting, but have you heard any hi-fi "digital" amps yet? I have a couple and they are pretty damn good.

poynt99

  • TPU-Elite
  • Hero Member
  • *******
  • Posts: 3582
Re: MH's ideal coil and voltage question
« Reply #1612 on: July 08, 2016, 11:01:03 PM »
Sorry to hear about the amp line PM.

SS Marshalls are not so good. Perhaps yours was better.

Dean Markley still sells amps. I've never heard one live, nor on YT. Must check them out.

btw, they have many or all of the Spectra guitar amp schematics online here.

poynt99

  • TPU-Elite
  • Hero Member
  • *******
  • Posts: 3582
Re: MH's ideal coil and voltage question
« Reply #1613 on: July 08, 2016, 11:35:59 PM »

And "JMF" would be ...?

PW
Those would be Jon's initials.

poynt99

  • TPU-Elite
  • Hero Member
  • *******
  • Posts: 3582
Re: MH's ideal coil and voltage question
« Reply #1614 on: July 08, 2016, 11:40:06 PM »
The DM CD-60 sounds pretty damn sweet.  8)

https://www.youtube.com/watch?v=hsgMYbr1zVw

partzman

  • Sr. Member
  • ****
  • Posts: 379
Re: MH's ideal coil and voltage question
« Reply #1615 on: July 09, 2016, 02:03:29 AM »
The DM CD-60 sounds pretty damn sweet.  8)

https://www.youtube.com/watch?v=hsgMYbr1zVw

Thanks Poynt!

Our tube series was 30T, 60T, and 120T and ended up relabeled and repackaged as the DM CD series with a few minor changes. The solid state models were treated in a similar fashion plus many models were dropped. JMF was vertically integrated in that we had our own tool and die shop to make tooling for the metal fabrication shop, complete pcb fabrication including cnc drilling with PTH and gold plating lines, transformer winding, wood working, and of course assembly lines plus wave soldering, etc. We did everything in-house except injection molding in an effort to control quality.

As time went on, DM's people lost control of some of the processes which was the beginning of the end. I have lost track of where his amps are built today.

Sorry to take this thread so far off course!

pm

poynt99

  • TPU-Elite
  • Hero Member
  • *******
  • Posts: 3582
Re: MH's ideal coil and voltage question
« Reply #1616 on: July 09, 2016, 04:19:08 AM »
The amplifiers are now made in China of course.

In this interview Markley says he designed the CD60 around 1985.

minnie

  • Hero Member
  • *****
  • Posts: 1244
Re: MH's ideal coil and voltage question
« Reply #1617 on: July 13, 2016, 03:37:58 PM »



   Looks as if tinman has given up!!!
        John.