THD Type O 212 Combo

This is a mid-1990s model. 50 watt combo. Cabinet (2X12) is theile ported from rear and houses two THD Longhorn 12" speakers. Inputs & controls are on top ala bluesbreaker.

Amp is not an effect laiden model or a channel switcher. It is however, a very flexible single channel design reminent of vintage plexi / bassman. Additionally, There is a foot-switchable / bypassible all tube effects loop.

You can adjust input voltage for a variac effect. Selectable solid-state or reactive rectifier. Uses almost any common type of tubes in both pre-amp and power amp sections. Thus - Type "O"? No master volume but does have a post phase inverter output knob that attenuates volume.

Two inputs include high and low. When plugged in, you adjust both a "normal" and a "bright" volume control; like a jumpered plexi. Great tonal & overdrive variation from two volume knobs alone. Regular tone knobs control trebble, bass, mid and presence.

More versatile for top volume control then any amp I've ever seen, but still no channel switcheroo on the fly! On the bottom of the amp there is a switch labeled "mode". I think this is an impediance selector that you use for tone preference.

I play high-end stratocasters and love SRV, Hendrix and etc... This is a classic-rock amp. It gets you noticed!

I configured to use with SS rectifier, NOS EL 34s & 12AX7s. This yields an awesome vintage plexi type sound. The speakers / cab are notably sweeter then celestion w/extra thickness from the port.

I have played this amp onstage beside both 70's & 80's Marshalls and Boogies. The gear groopies always preferred the THD. 50 watts + Longhorns + theile-port = vintage 1/2 stack from heaven. I'm glad someone(THD)never gave up on ftting that sound into a smaller more convenient box. I don't see / hear this anywhere else today.

High input sound is hot (not high gain) and loves the Fulltone pedals. ('69, '70, FD2) The low input is actually useable too! It knida puts you into more of a Fendery sound w/o big volume drop...More of an alturnative cleaner input then a true "low" input.

Still Blasting! Replaced a 12AX7 one time (input). It started to get a little farty. Fulltone undoubtably contributed to this - a good thing! Much less "hiss" then a real plexi when volumes are set high. Tube amps can't score a "10" for reliability anyway. The day will come when tubes fail big.

I have talked to Andy Marshall several times. I own other THD products too. I consulted with him via-phone to test various tubes in this amp until I found the ones I liked. 6L6/5881s in the power amp sounded very good as well. I used these for about one year with the reactive rectifier before going to the EL34s. Also, I breifely used KT66s.

I have played guitar for 25 years. I generally favor classic Marshall amplifiers. My search to find a "more convenient" classic marshall stack sound ended with this purchase. I may have in fact exceeded the goal. If my THD Type "O" were stolen I would cry because I have never seen another one for sale since.