Expensive Commercial Amps - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 19th September 2005, 03:12 AM   #11
HFGuy is offline HFGuy  Canada
diyAudio Member
 
Join Date: Sep 2004
Location: Toronto, Ontario
For the last little while i have been trying to decide what direction i wanted my system to head in. I starting with thinking about a gm70 amp, i even went as far as to design one. I thus wanted to look for speakers i could match it with down the road as it wouldnt make any sense to build a 50w amp if i couldnt find any speakers in the low 90dB range to use it with. But i couldnt think of any speakers that excited me in the low to mid 90dB range. I have since given up the gm70 idea not because its not practical but because of time. Building a large tube amp takes alot of time which as of the new school year has dissapeared. Iam now looking for a used Conrad Johnson Premier 12 which gives me enough power to allow low effec spks. Iam an ASIC designer by day and a tube amp lover by night, i need a tube amp just as a change. Its a shame DIY has to take a backseat to real life.
  Reply With Quote
Old 19th September 2005, 03:17 AM   #12
diyAudio Member
 
Brett's Avatar
 
Join Date: Jan 2002
Quote:
Originally posted by HFGuy
I starting with thinking about a gm70 amp, i even went as far as to design one. I thus wanted to look for speakers i could match it with down the road as it wouldnt make any sense to build a 50w amp if i couldnt find any speakers in the low 90dB range to use it with.
I ran a PP GM70 with a full frontloaded horn system of about 104dB.
  Reply With Quote
Old 19th September 2005, 11:59 AM   #13
HFGuy is offline HFGuy  Canada
diyAudio Member
 
Join Date: Sep 2004
Location: Toronto, Ontario
At the time i was trying to avoid high effec speakers as i planned to use AC filaments so i was unsure of the hum.
  Reply With Quote
Old 19th September 2005, 12:25 PM   #14
diyAudio Member
 
Geek's Avatar
 
Join Date: Sep 2004
Quote:
Originally posted by Brett
I ran a PP GM70 with a full frontloaded horn system of about 104dB.
And you can still hear?

Quote:
Originally posted by HFGuy
At the time i was trying to avoid high effec speakers as i planned to use AC filaments so i was unsure of the hum.
There's no logic in that.

Hum = bad supply or bad layout. Both preventable
  Reply With Quote
Old 19th September 2005, 12:32 PM   #15
HFGuy is offline HFGuy  Canada
diyAudio Member
 
Join Date: Sep 2004
Location: Toronto, Ontario
Your going to get hum with any AC heated DHT regardless of great layout and proper filtering. I had planned to go with AC filaments and try some of Steve Bench's tricks to minimize the hum. As a last resort i could have used DC heaters but i was really trying to avoid that.
  Reply With Quote
Old 19th September 2005, 08:31 PM   #16
beamnet is offline beamnet  Netherlands
diyAudio Member
 
beamnet's Avatar
 
Join Date: Jun 2004
Location: enschede
Send a message via MSN to beamnet
Odd Q, but... can you wire Opt's in parrallel?

then output power will be virtually unlimmited..
  Reply With Quote
Old 19th September 2005, 09:53 PM   #17
diyAudio Member
 
Join Date: Dec 2002
Location: dry ol Melbourne Australia
Default Extra resouces to go big league

HFGuy

ďI have since given up the gm70 idea not because its not practical but because of time. Building a large tube amp takes a lot of timeĒ

I havenít built a tube amp yet, though will reasonably soon do a preamp and a 2A3.

Iím considering a 300 SE/ PP, or 211/ GM70. The amp choice will affect what speakers I do.

I donít have much spare time either. I thought eg trannies would be dearer, but that and volts aside, how much more time would a large tube amp take?

And would a GM70 cost much more than a 300 SE/ PP?

Thanks
  Reply With Quote
Old 19th September 2005, 10:18 PM   #18
diyAudio Member
 
Brett's Avatar
 
Join Date: Jan 2002
Default Re: Extra resouces to go big league

Quote:
Originally posted by rick57
HI havenít built a tube amp yet, though will reasonably soon do a preamp and a 2A3.
What you could do, is build your pre and a nice little PP 2A3. Then later, once you're confident with what you're doing, especially with regards to high voltage, add a 3rd stage to the poweramp being PP 845/211/813T/GM70. An extra PS would be needed for the output stage, but it's actually easier to build it this way rather than trying to find a single PT that will provide your (say) 300V for the drivers and 1000V for the outputs.

You could even have both built into the one chassis with the 2A3's OPT being used as anode loads for the 2A3's, then cap coupled to the output stages. When you don't need all the extra juice, don't power up the big tubes and connect your speakers to the 2A3 ouputs. It does then mean you have to connect your speaker cables via a plug and socket arrangement for convenience, and we all know how anal retentive 'philes can get about them......

I'd go for the Ralph Power / Stigla 2A3 design (maybe with a CCS in the 2A3 tail) or the Lynn Olson Petit Amity. Or whatever else you like in the 2-10W range. Heck trioded EL84's are excellent and will make great drivers for the bigger tubes.

This approach is larger, and will ultimately cost more, but you can have an amp running sooner, learn more (especially HV safety - can't reinforce that enough) and best of all will give you time to hunt around for surplus iron/caps/sundry parts for the HV output stage at a cost saving which can be put into the second set of OPT's.

Mind you ANY amp, properly built with transmitter type tubes will be big, heavy and expensive. And probably have low WAF.

The other alternative is to get sensibly efficient speakers and just settle for a smaller amp.
  Reply With Quote
Old 19th September 2005, 10:41 PM   #19
beamnet is offline beamnet  Netherlands
diyAudio Member
 
beamnet's Avatar
 
Join Date: Jun 2004
Location: enschede
Send a message via MSN to beamnet
Why is more watts more work? It takes the same amount of parts doesn't it? They are only bigger.

Well, they might involve another gain stage, but that isn't that much extra work once you've begun soldering...

The chassis is often the biggest job...

Once you have all the parts and your soldering iron is hot...
  Reply With Quote
Old 20th September 2005, 02:09 AM   #20
diyAudio Member
 
tubelab.com's Avatar
 
Join Date: Jul 2005
Location: West Virginia panhandle
More watts may not be a lot more work, but it is more money. More watts means bigger parts which costs bigger bucks. Since the parts are bigger, and heavier, the chassis will be bigger, and take more work to fabricate. More watts usually means more volts, which requires MUCH more care do deal with. This often requires more capacitors in the power supply, which is more work. The "work" factor begins to go up exponentially when the power level goes outside the expected norm. There is considerable "work" just finding parts to build a SE amp above the 50 to 75 watt level.

Brett proposed building an amp in "stages" starting with a 2A3 SE and adding a power stage using a transmitting tube. I think this is a good idea, and I have done this. I designed the Tubelab SE amp to be a 2 to 10 watt amp, which is also used as the driver board in my 845SE and my 833A SE amp. In fact I will build the board as a 45 SE amp and listen to it first, even if it is giong to be used as a driver board in a larger amp.
__________________
Too much power is almost enough! Turn it up till it explodes - then back up just a little.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Commercial or DIY amps Dr_EM Solid State 48 20th May 2008 06:12 AM
Any new commercial Class-D amps available? iwamusr Class D 0 18th December 2007 07:37 PM
Industrial vs Commercial amps and OPT's homemade Tubes / Valves 10 28th September 2007 04:18 AM
Which commercial amps still ..... Madmike2 Solid State 29 1st August 2005 01:52 AM


New To Site? Need Help?

All times are GMT. The time now is 10:16 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2