The No.1 Website for Pro Audio
 Search This Thread  Search This Forum  Search Reviews  Search Gear Database  Search Gear for sale  Search Gearslutz Go Advanced
What's so bad about Ampex 354??? Equalisers (HW)
Old 1st November 2016
  #1
Lives for gear
 

What's so bad about Ampex 354???

In researching oldschool Ampex tube-based reel-to-reels, I've heard people knock the 354, mainly because it can't be converted to preamps and it apparently was prone to overheating. Also apparently it's tough to work on due to cramped/confined quarters.

I don't care about making preamps, I intend to use it as an actual R2R with two Ampex MX35's. But I'm a little worried about the overheating and difficulty servicing. Can anyone elaborate on this?

Is it possible to improve the cooling with some modern options (computer fans? silent water cooling?). Also, is it really that much of a dog to work on? Is it something many techs wouldn't want to touch, or more of an inconvenience, but not a deal killer? Thanks fellas!
Old 1st November 2016
  #2
Lives for gear
 

Ampex 354

Quote:
Originally Posted by jdurango View Post
In researching oldschool Ampex tube-based reel-to-reels, I've heard people knock the 354, mainly because it can't be converted to preamps and it apparently was prone to overheating. Also apparently it's tough to work on due to cramped/confined quarters.
1. a 354 or the related PR10 can be converted to a microphone preamplifier. It is a fair amount of work, butchers the original intent/design, and frankly not recommended. What is possible is installation of the 40 or 60 dB plug in mic preampliifers that go in the accessory sockets. Suitable preamps can be fabricated with readily available parts.
2. overheating: first time I've heard of that and I have many units. The 6DJ8/6BK7 output tube does get hot but no more so than the 12AU7 in a 351.
In case some one is nitpicking, a 6DJ8 is NOT a direct replacement for 6BK7 in most circuits but either tube can be used in the 354 output stage.
3. take a look at historical Columbia studio photos. 300 based 8 tracks were fabricated with four 354 electronics. Armin Steiner/Sound Labs in Hollywood had a machine with eight channels of PR10 electronics. The sonics are very good, honestly, not quite as spacious for lack of better words as the 351, but certainly has the tube "thing".
4. Compared to 351 or 350 electronics, yes, the 354 is harder to work on. Cramped quarters. Not an major issue.
5. Cooling: as long as the fan or whatever device does not interfere in a negative sense, yes, cooling will prolong the life of all the components.
In summary, a fine unit.

Last edited by cathode; 1st November 2016 at 07:00 AM.. Reason: grammar
Old 1st November 2016
  #3
Lives for gear
 

Quote:
Originally Posted by cathode View Post
1. a 354 or the related PR10 can be converted to a microphone preamplifier. It is a fair amount of work, butchers the original intent/design, and frankly not recommended. What is possible is installation of the 40 or 60 dB plug in mic preampliifers that go in the accessory sockets. Suitable preamps can be fabricated with readily available parts.
2. overheating: first time I've heard of that and I have many units. The 6DJ8/6BK7 output tube does get hot but no more so than the 12AU7 in a 351.
In case some one is nitpicking, a 6DJ8 is NOT a direct replacement for 6BK7 in most circuits but either tube can be used in the 354 output stage.
3. take a look at historical Columbia studio photos. 300 based 8 tracks were fabricated with four 354 electronics. Armin Steiner/Sound Labs in Hollywood had a machine with eight channels of PR10 electronics. The sonics are very good, honestly, not quite as spacious for lack of better words as the 351, but certainly has the tube "thing".
4. Compared to 351 or 350 electronics, yes, the 354 is harder to work on. Cramped quarters. Not an major issue.
5. Cooling: as long as the fan or whatever device does not interfere in a negative sense, yes, cooling will prolong the life of all the components.
In summary, a fine unit.
That's very helpful! Thank you! I'd love to build an 8-track version of such a machine, but can't imagine how much it would cost for a headstack and have to imagine such a thing would be unobtanium these days, not to mention beefier motors/spindles, pinch roller, guides, dancer arms and all the other transport hardware.

Anyway, I'll keep an eye out for a good deal on a 354 or 351-2. Thanks a ton!
Old 15th November 2016
  #4
Lives for gear
 

Quote:
Originally Posted by cathode View Post
1. a 354 or the related PR10 can be converted to a microphone preamplifier. It is a fair amount of work, butchers the original intent/design, and frankly not recommended. What is possible is installation of the 40 or 60 dB plug in mic preampliifers that go in the accessory sockets. Suitable preamps can be fabricated with readily available parts.
2. overheating: first time I've heard of that and I have many units. The 6DJ8/6BK7 output tube does get hot but no more so than the 12AU7 in a 351.
In case some one is nitpicking, a 6DJ8 is NOT a direct replacement for 6BK7 in most circuits but either tube can be used in the 354 output stage.
3. take a look at historical Columbia studio photos. 300 based 8 tracks were fabricated with four 354 electronics. Armin Steiner/Sound Labs in Hollywood had a machine with eight channels of PR10 electronics. The sonics are very good, honestly, not quite as spacious for lack of better words as the 351, but certainly has the tube "thing".
4. Compared to 351 or 350 electronics, yes, the 354 is harder to work on. Cramped quarters. Not an major issue.
5. Cooling: as long as the fan or whatever device does not interfere in a negative sense, yes, cooling will prolong the life of all the components.
In summary, a fine unit.
Quick follow up. Can you speak to the sound of the 354 vs the 351? I've heard that they sound very similar, another page (fixthatmix.com) described the 354 thusly:

"The 354 has no built in mic preamps. If a recordist wanted to use mikes directly with the 354, Ampex made octal plug-in mic preamp modules. These mic preamps are not very good. They use very simple transistor circuits with the Beyer mic transformers. This is not the sound you are after if you are here reading about tube mic preamps."
Old 15th November 2016
  #5
Gear Maniac
 
jordan s's Avatar
 

I converted one of these to a dual mic pre a while ago. From what I recall, I just placed a 1:20 Beyer mic transformer at the input.
Old 15th November 2016
  #6
Lives for gear
 

Quote:
Originally Posted by jordan s View Post
I converted one of these to a dual mic pre a while ago. From what I recall, I just placed a 1:20 Beyer mic transformer at the input.
How would you describe the sound? Ever compared it to a 350/351 based preamp? Thanks!
Top Mentioned Products
Topic:
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Forum Jump
Forum Jump