-40%

Altec 438C/436C Tube Compressor and Mic Preamp

$ 1531.2

Availability: 100 in stock
  • Type: Vintage Dynamics Processor
  • All returns accepted: ReturnsNotAccepted
  • Model: 438C
  • Brand: Altec Lansing
  • Country/Region of Manufacture: United States
  • Condition: This item is listed in multiple sites as well as locally at my shop . There is a slight chance that it may sell before I can remove the item form this site.I reserve the right to cancel the listing at any time. The item can be tested here at the shop when you pick it up. Operational but being sold as is no returns . I will supply a link to a video showing the unit working.After it leaves my shop it is as is no returns.Thanks

    Description

    I hate to sell this but over the past 40 years I have owned over 30 Altec 436/438A/B/C variants. If I feel the need to have another one I will just build it . I have all the original transformers to build  one.
    Classic mid-60's Altec 438A Tube Compressor with the most desirable feature set of all of the Altec models. The 438A has a microphone preamp which utilizes a 12AY7 tube.  This 438A has been upgraded to a  "C" version, it now has controls for both "Release Time" as well as "Threshold" on the front panel. It   had it electrolytic caps replaced and any other cap that was out of spec ( tested on my Z meter) I prefer to leave original caps in the circuit provided that they meet tolerance for their value and are not leaky .  The one major change is the Mic / Line switch . This sends the line input to the 4651A transformer directly  , bypassing the extra gain of the mic preamp . After the 4651A transformer is a 50K dual pot exactly as in the 436C.  When coming into the line input of the 438C , you have a 436C
    When the switch is set for mic input you have a mic preamp and compressor with the bonus of the 50K pot (volume)  as a inter-stage control. Using  the mic gain control you can drive the mic preamp into saturation but  not overload the gain reduction tube .
    I have photos of the schematic of the 438A showing very basically  what we did. You can also see from the 436C schematic that the line in on this 438C is identical to the 436C .
    The tube compliment is: (1) 12AY7 (1) 6BC8 (1) 6CG7 (1) 6AL5 The transformers are all Peerless: K308D, 4651A, 16402.
    This item is listed in multiple sites as well as locally at my shop .
    There is a slight chance that it may sell before I can remove the item form this site.
    I reserve the right to cancel the listing at any time.
    The item can be tested here at the shop when you pick it up.
    Operational but being sold as is no returns . I can supply a link to a video showing the unit working.
    After it leaves my shop it is as is no returns.
    Thanks