I would like to hear about people's experience with various components. I have a Jolida JD9 II which I changed op amps to OPA627 from OP37's, changed the coupling caps (I presume) and output tubes -- tried three brands and added dampening to the rather large chassis. I think it sounds quite good. The total was around $940.

Always striving for better sound I built the Retro putting it in its own small chassis (as my preamp/DAC chassis is full) with Neutrik single ended inputs and balanced output connectors. I used an 8-pin DIN connector for DC power -- compatible with an external +/-15VDC supply I ordered. As it hasn't arrived I put 16 alkaline batteries in a box and connected power. (The Retro box has a power switch.)

The Retro has more detail than the Jolida -- no doubt about it. Less slurring in S's and some other resonances are less objectionable as well which I assumed were due to my speakers and walls vibrating. The sound overall is more open and detailed -- more real.

If in doubt I think it is worth a try. I am glad I did.

Cost: $150 kit, $10 case, $20 for Neutrik connectors, and a power supply -- $100 or so or $8 for a case for batteries. Use a rechargeable sealed lead acid batteries (around $40 for two 1 amp-hr) and add a DPDT charge switch and connectors -- $35 for a charger to charge each battery separately (inconvenient). Total: $280 with purchased power supply; $263 battery option instead of external power supply. My battery/charger is considerably more -- a nice case $155 incl. shipping from China and I will build a charger with load sensing to disconnect charging when the preamp is on -- for a total of approximately $450 to $500 -- parts are on order.

Connections:

I have a Dynavector XX2 MK II on a Rega RP8 turntable and Lundahl LL1933Ag step up transformers. I used RCA connectors for the step up transformer case. These transformers with a step input appear to be optimally damped -- no RC needed on the secondary as another transformer I tried required.

I tried the differential input connection (from the Lundahl transformers using RCA connectors) but got hum -- center of RCA to IN/OUT.1 and outside RCA conductor on IN/OUT.6 as these are not grounded and are straight from the transformer. I tried various grounding including center tap on the Lundahl. I am currently using single ended input (center pin of RCA to Retro terminal IN/OUT.1 and IN/Out.6 grounded) and I am using Retro balanced outputs to the preamp. This sounds great but will wonder about differential input configuration.

Dec 30, 2014: Fixed my balanced connection hum problem. The Lundahl transformer pin 8 is to the core. Originally connected as what I thought was their recommendation. Changed so in 8 is connected to the primary (parallel windings). No connection of primary to secondary. Then connected the series secondary windings pin 6 and 9 to the Retro balanced inputs and it worked. I also soldered grounding banana leads up to connect the chassis of the transformer to the chassis of the Retro which connects to the power supply common.

The balanced connection sounds more refined and dynamic. Was worth the effort to get here!

Edited by user Friday, January 2, 2015 2:33:45 AM(UTC)  | Reason: Fixed my balanced connection/hum problem