concert lead D1079

[sunnfanpsyche]

on Sunn drawing D1079 B a power amp section schematic, the power supply is changed.Does that mean That I should apply the design on the 1079 bridge rectifier CR1 to the bridge of the concert lead that I have on a design similar to D 1004 G and add the new componets?And does that mean a new power supply transformer for the middle tap of T1 in D1079 because the secondary to drawing  D1079 B has a connection in the middle of the tap to feeder to ground near the capacitors that are just after the bridge rectifier and are not far from where a raw B+ would be if it were present at least I think.The D1079 makes the supply voltages from one bridge not three and just loweres the voltages to make a supply to the pre-amp instead of three bridges making three supplys.How do I ground and how do I feed supply?I think I can get the rest of the changes about or around the transistors of the power amp stage.

[loudthud]

The D1004G schematic is a bridge output stage. Note the ground at the collector of Q2. The power supply must float, it can't be connected to ground. The advantage of this configuration is that two power transistors are always in series with the load so they never go into the second breakdown region. This was important when 2N3055s were first being made.

The D1079B schematic is a more conventional totem pole output. It requires a split supply that must have a center tap ground. By the time this came out, the current production 2N3055s were much more rugged than those available when the Concert series were first being build. The 2N3055 had become a throw-away number, the manufacturers just stuck any die in the package that was made to be a more powerfull transistor but didn't meet all the specs. The 2N3055 has pretty loose specs.

Unless you have an early Concert with a blown transformer, there is really no reason to try to update your amp because you'll have to replace the transformer.