tablebeast
Well-known member
The Swollensak Project!
Hi, I have been stocking up on Wollensak reel to Reel Tube based tape recorders models T-1500 (All Mono) and T-1515 (Stereo Pre, Mono Power). Even in stock form once you unplug the noisy tape motor it makes a great little guitar amp with an early 60's type sound. You can get these on ebay for less than $50 including shipping any day of the week. The design is unusual (for a guitar amp at least) in that it has 12AB5 power tubes and a transformer set up as the power section driver. What I would like to do is remove everything from this circuit that is unnessary (like the internal switching, tape parts, tape related circuit compromises, etc) and make the circuit as optimised for electric guitar and bass amplification as possible. Here is a link to a schematic scan:
http://www.circuit-bent.com/forms/wollt1500.pdf
Here are some modification goals:
- Info freely available to the public. I will host on swollensak.com
- Remove unecessary parts but reuse as many original parts as possible.
- Retain the same tone layout with single volume and EQ knobs.
- Add independant power and standby switches.
- Replace combo input jack with single input and footswitch for hi/lo gain.
- Retain the ability to turn the power section off and use it as a pre only.
- Replace 2 prong Power jack with standard grounded IEC.
- Move fuse to better location.
- Add some FX circuits in all the now empty tape section space.
- Start w/ simple mods and add more complex circuits later.
- Maintain web page as a FREE DIY project site.
- http://www.swollensak.com
The unit has one 12AX7 configured as a preamp, one 12AT7 configured as an AF amp and two 12AB5's as the power amp with a transformer as driver. Let me know your ideas and I should have a site up some time in the next week. Thanks in advance.
Jesse
Hi, I have been stocking up on Wollensak reel to Reel Tube based tape recorders models T-1500 (All Mono) and T-1515 (Stereo Pre, Mono Power). Even in stock form once you unplug the noisy tape motor it makes a great little guitar amp with an early 60's type sound. You can get these on ebay for less than $50 including shipping any day of the week. The design is unusual (for a guitar amp at least) in that it has 12AB5 power tubes and a transformer set up as the power section driver. What I would like to do is remove everything from this circuit that is unnessary (like the internal switching, tape parts, tape related circuit compromises, etc) and make the circuit as optimised for electric guitar and bass amplification as possible. Here is a link to a schematic scan:
http://www.circuit-bent.com/forms/wollt1500.pdf
Here are some modification goals:
- Info freely available to the public. I will host on swollensak.com
- Remove unecessary parts but reuse as many original parts as possible.
- Retain the same tone layout with single volume and EQ knobs.
- Add independant power and standby switches.
- Replace combo input jack with single input and footswitch for hi/lo gain.
- Retain the ability to turn the power section off and use it as a pre only.
- Replace 2 prong Power jack with standard grounded IEC.
- Move fuse to better location.
- Add some FX circuits in all the now empty tape section space.
- Start w/ simple mods and add more complex circuits later.
- Maintain web page as a FREE DIY project site.
- http://www.swollensak.com
The unit has one 12AX7 configured as a preamp, one 12AT7 configured as an AF amp and two 12AB5's as the power amp with a transformer as driver. Let me know your ideas and I should have a site up some time in the next week. Thanks in advance.
Jesse
